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Zhao Z, Yang T, Xiang G, Zhang S, Cai Y, Zhong G, Pu J, Shen C, Zeng J, Chen C, Huang B. A novel small RNA PhaS contributes to polymyxin B-heteroresistance in carbapenem-resistant Klebsiella pneumoniae. Emerg Microbes Infect 2024; 13:2366354. [PMID: 38979571 PMCID: PMC11238654 DOI: 10.1080/22221751.2024.2366354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 06/05/2024] [Indexed: 07/10/2024]
Abstract
In recent years, polymyxin has been used as a last-resort therapy for carbapenem-resistant bacterial infections. The emergence of heteroresistance (HR) to polymyxin hampers the efficacy of polymyxin treatment by amplifying resistant subpopulation. However, the mechanisms behind polymyxin HR remain unclear. Small noncoding RNAs (sRNAs) play an important role in regulating drug resistance. The purpose of this study was to investigate the effects and mechanisms of sRNA on polymyxin B (PB)-HR in carbapenem-resistant Klebsiella pneumoniae. In this study, a novel sRNA PhaS was identified by transcriptome sequencing. PhaS expression was elevated in the PB heteroresistant subpopulation. Overexpression and deletion of PhaS were constructed in three carbapenem-resistant K. pneumoniae strains. Population analysis profiling, growth curve, and time-killing curve analysis showed that PhaS enhanced PB-HR. In addition, we verified that PhaS directly targeted phoP through the green fluorescent protein reporter system. PhaS promoted the expression of phoP, thereby encouraging the expression of downstream genes pmrD and arnT. This upregulation of arnT promoted the 4-amino-4-deoxyL-arabinosaccharide (L-Ara4N) modification of lipid A in PhaS overexpressing strains, thus enhancing PB-HR. Further, within the promoter region of PhaS, specific PhoP recognition sites were identified. ONPG assays and RT-qPCR analysis confirmed that PhaS expression was positively modulated by PhoP and thus up-regulated by PB stimulation. To sum up, a novel sRNA enhancing PB-HR was identified and a positive feedback regulatory pathway of sRNA-PhoP/Q was demonstrated in the study. This helps to provide a more comprehensive and clear understanding of the underlying mechanisms behind polymyxin HR in carbapenem-resistant K. pneumoniae.
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Affiliation(s)
- Zhiwei Zhao
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Tingting Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Guoxiu Xiang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Shebin Zhang
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Yimei Cai
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Guosheng Zhong
- Department of Clinical Laboratory, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Jieying Pu
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Cong Shen
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Jianming Zeng
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Cha Chen
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
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Yamada N, Kamoshida G, Shiraishi T, Yamaguchi D, Matsuoka M, Yamauchi R, Kanda N, Kamioka R, Takemoto N, Morita Y, Fujimuro M, Yokota SI, Yahiro K. PmrAB, the two-component system of Acinetobacter baumannii, controls the phosphoethanolamine modification of lipooligosaccharide in response to metal ions. J Bacteriol 2024; 206:e0043523. [PMID: 38661375 PMCID: PMC11112996 DOI: 10.1128/jb.00435-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 04/03/2024] [Indexed: 04/26/2024] Open
Abstract
Acinetobacter baumannii is highly resistant to antimicrobial agents, and XDR strains have become widespread. A. baumannii has developed resistance to colistin, which is considered the last resort against XDR Gram-negative bacteria, mainly caused by lipooligosaccharide (LOS) phosphoethanolamine (pEtN) and/or galactosamine (GalN) modifications induced by mutations that activate the two-component system (TCS) pmrAB. Although PmrAB of A. baumannii has been recognized as a drug resistance factor, its function as TCS, including its regulatory genes and response factors, has not been fully elucidated. In this study, to clarify the function of PmrAB as TCS, we elucidated the regulatory genes (regulon) of PmrAB via transcriptome analysis using pmrAB-activated mutant strains. We discovered that PmrAB responds to low pH, Fe2+, Zn2+, and Al3+. A. baumannii selectively recognizes Fe2+ rather than Fe3+, and a novel region ExxxE, in addition to the ExxE motif sequence, is involved in the environmental response. Furthermore, PmrAB participates in the phosphoethanolamine modification of LOS on the bacterial surface in response to metal ions such as Al3+, contributing to the attenuation of Al3+ toxicity and development of resistance to colistin and polymyxin B in A. baumannii. This study demonstrates that PmrAB in A. baumannii not only regulates genes that play an important role in drug resistance but is also involved in responses to environmental stimuli such as metal ions and pH, and this stimulation induces LOS modification. This study reveals the importance of PmrAB in the environmental adaptation and antibacterial resistance emergence mechanisms of A. baumannii. IMPORTANCE Antimicrobial resistance (AMR) is a pressing global issue in human health. Acinetobacter baumannii is notably high on the World Health Organization's list of bacteria for which new antimicrobial agents are urgently needed. Colistin is one of the last-resort drugs used against extensively drug-resistant (XDR) Gram-negative bacteria. However, A. baumannii has become increasingly resistant to colistin, primarily by modifying its lipooligosaccharide (LOS) via activating mutations in the two-component system (TCS) PmrAB. This study comprehensively elucidates the detailed mechanism of drug resistance of PmrAB in A. baumannii as well as its biological functions. Understanding the molecular biology of these molecules, which serve as drug resistance factors and are involved in environmental recognition mechanisms in bacteria, is crucial for developing fundamental solutions to the AMR problem.
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Affiliation(s)
- Noriteru Yamada
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
- Laboratory of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Go Kamoshida
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
- Department of Infection Control Science, Meiji Pharmaceutical University, Tokyo, Japan
| | - Tsukasa Shiraishi
- Department of Microbiology, Sapporo Medical University School of Medicine, Hokkaido, Japan
| | - Daiki Yamaguchi
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Momoko Matsuoka
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Reika Yamauchi
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Nana Kanda
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Roku Kamioka
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Norihiko Takemoto
- Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yuji Morita
- Department of Infection Control Science, Meiji Pharmaceutical University, Tokyo, Japan
| | - Masahiro Fujimuro
- Laboratory of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Shin-ichi Yokota
- Department of Microbiology, Sapporo Medical University School of Medicine, Hokkaido, Japan
| | - Kinnosuke Yahiro
- Laboratory of Microbiology and Infection Control, Kyoto Pharmaceutical University, Kyoto, Japan
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Levin BR, Berryhill BA, Gil-Gil T, Manuel JA, Smith AP, Choby JE, Andersson DI, Weiss DS, Baquero F. Theoretical considerations and empirical predictions of the pharmaco- and population dynamics of heteroresistance. Proc Natl Acad Sci U S A 2024; 121:e2318600121. [PMID: 38588431 PMCID: PMC11032463 DOI: 10.1073/pnas.2318600121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 02/28/2024] [Indexed: 04/10/2024] Open
Abstract
Antibiotics are considered one of the most important contributions to clinical medicine in the last century. Due to the use and overuse of these drugs, there have been increasing frequencies of infections with resistant pathogens. One form of resistance, heteroresistance, is particularly problematic; pathogens appear sensitive to a drug by common susceptibility tests. However, upon exposure to the antibiotic, resistance rapidly ascends, and treatment fails. To quantitatively explore the processes contributing to the emergence and ascent of resistance during treatment and the waning of resistance following cessation of treatment, we develop two distinct mathematical and computer-simulation models of heteroresistance. In our analysis of the properties of these models, we consider the factors that determine the response to antibiotic-mediated selection. In one model, heteroresistance is progressive, with each resistant state sequentially generating a higher resistance level. In the other model, heteroresistance is non-progressive, with a susceptible population directly generating populations with different resistance levels. The conditions where resistance will ascend in the progressive model are narrower than those of the non-progressive model. The rates of reversion from the resistant to the sensitive states are critically dependent on the transition rates and the fitness cost of resistance. Our results demonstrate that the standard test used to identify heteroresistance is insufficient. The predictions of our models are consistent with empirical results. Our results demand a reevaluation of the definition and criteria employed to identify heteroresistance. We recommend that the definition of heteroresistance should include a consideration of the rate of return to susceptibility.
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Affiliation(s)
- Bruce R. Levin
- Department of Biology, Emory University, Atlanta, GA30322
- Emory Antibiotic Resistance Center, Atlanta, GA30322
| | - Brandon A. Berryhill
- Department of Biology, Emory University, Atlanta, GA30322
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA30322
| | - Teresa Gil-Gil
- Department of Biology, Emory University, Atlanta, GA30322
| | | | | | - Jacob E. Choby
- Emory Antibiotic Resistance Center, Atlanta, GA30322
- Emory Vaccine Center, Atlanta, GA30322
| | - Dan I. Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, UppsalaSE-75123, Sweden
| | - David S. Weiss
- Emory Antibiotic Resistance Center, Atlanta, GA30322
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA30322
- Georgia Emerging Infections Program, Georgia Department of Public Health, Atlanta, GA30322
| | - Fernando Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Biomédica en Red Epidemiología y Salud Pública, Madrid28034, Spain
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4
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Vijayakumar S, Swetha RG, Bakthavatchalam YD, Vasudevan K, Abirami Shankar B, Kirubananthan A, Walia K, Ramaiah S, Biswas I, Veeraraghavan B, Anbarasu A. Genomic investigation unveils colistin resistance mechanism in carbapenem-resistant Acinetobacter baumannii clinical isolates. Microbiol Spectr 2024; 12:e0251123. [PMID: 38214512 PMCID: PMC10846133 DOI: 10.1128/spectrum.02511-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
Colistin resistance in Acinetobacter baumannii is mediated by multiple mechanisms. Recently, mutations within pmrABC two-component system and overexpression of eptA gene due to upstream insertion of ISAba1 have been shown to play a major role. Thus, the aim of our study is to characterize colistin resistance mechanisms among the clinical isolates of A. baumannii in India. A total of 207 clinical isolates of A. baumannii collected from 2016 to 2019 were included in this study. Mutations within lipid A biosynthesis and pmrABC genes were characterized by whole-genome shotgun sequencing. Twenty-eight complete genomes were further characterized by hybrid assembly approach to study insertional inactivation of lpx genes and the association of ISAba1-eptA. Several single point mutations (SNPs), like M12I in pmrA, A138T and A444V in pmrB, and E117K in lpxD, were identified. We are the first to report two novel SNPs (T7I and V383I) in the pmrC gene. Among the five colistin-resistant A. baumannii isolates where complete genome was available, the analysis showed that three of the five isolates had ISAba1 insertion upstream of eptA. No mcr genes were identified among the isolates. We mapped the SNPs on the respective protein structures to understand the effect on the protein activity. We found that majority of the SNPs had little effect on the putative protein function; however, some SNPs might destabilize the local structure. Our study highlights the diversity of colistin resistance mechanisms occurring in A. baumannii, and ISAba1-driven eptA overexpression is responsible for colistin resistance among the Indian isolates.IMPORTANCEAcinetobacter baumannii is a Gram-negative, emerging and opportunistic bacterial pathogen that is often associated with a wide range of nosocomial infections. The treatment of these infections is hindered by increase in the occurrence of A. baumannii strains that are resistant to most of the existing antibiotics. The current drug of choice to treat the infection caused by A. baumannii is colistin, but unfortunately, the bacteria started to show resistance to the last-resort antibiotic. The loss of lipopolysaccharides and mutations in lipid A biosynthesis genes are the main reasons for the colistin resistance. The present study characterized 207 A. baumannii clinical isolates and constructed complete genomes of 28 isolates to recognize the mechanisms of colistin resistance. We showed the mutations in the colistin-resistant variants within genes essential for lipid A biosynthesis and that cause these isolates to lose the ability to produce lipopolysaccharides.
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Affiliation(s)
- Saranya Vijayakumar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Rayapadi G. Swetha
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | | | - Karthick Vasudevan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
- Department of Biotechnology, School of Applied Sciences, REVA University, Bangalore, India
| | - Baby Abirami Shankar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Kamini Walia
- Division of Epidemiology and Communicable Diseases, Indian Council for Medical Research, New Delhi, India
| | - Sudha Ramaiah
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Indranil Biswas
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas, USA
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Anand Anbarasu
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
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5
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Sánchez-León I, Pérez-Nadales E, Marín-Sanz JA, García-Martínez T, Martínez-Martínez L. Heteroresistance to colistin in wild-type Klebsiella pneumoniae isolates from clinical origin. Microbiol Spectr 2023; 11:e0223823. [PMID: 37962370 PMCID: PMC10714954 DOI: 10.1128/spectrum.02238-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/13/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE Colistin is one of the last remaining therapeutic options for dealing with Enterobacteriaceae. Unfortunately, heteroresistance to colistin is also rapidly increasing. We described the prevalence of colistin heteroresistance in a variety of wild-type strains of Klebsiella pneumoniae and the evolution of these strains with colistin heteroresistance to a resistant phenotype after colistin exposure and withdrawal. Resistant mutants were characterized at the molecular level, and numerous mutations in genes related to lipopolysaccharide formation were observed. In colistin-treated patients, the evolution of K. pneumoniae heteroresistance to resistance phenotype could lead to higher rates of therapeutic failure.
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Affiliation(s)
- Irene Sánchez-León
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
| | - Elena Pérez-Nadales
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Antonio Marín-Sanz
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Computer Sciences, University of Cordoba, Cordoba, Spain
| | - Teresa García-Martínez
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
| | - Luis Martínez-Martínez
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- Clinical Unit of Microbiology, Reina Sofía University Hospital, Cordoba, Spain
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6
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Levin BR, Berryhill BA, Gil-Gil T, Manuel JA, Smith AP, Choby JE, Andersson DI, Weiss DS, Baquero F. Theoretical Considerations and Empirical Predictions of the Pharmaco- and Population Dynamics of Heteroresistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.558832. [PMID: 37790545 PMCID: PMC10542493 DOI: 10.1101/2023.09.21.558832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Antibiotics are considered one of the most important contributions to clinical medicine in the last 100 years. Due to the use and overuse of these drugs, there have been increasing frequencies of infections with resistant pathogens. One form of resistance, heteroresistance, is particularly problematic; pathogens appear sensitive to a drug by common susceptibility tests. However, upon exposure to the antibiotic, resistance rapidly ascends, and treatment fails. To quantitatively explore the processes contributing to the emergence and ascent of resistance during treatment and the waning of resistance following cessation of treatment, we develop two distinct mathematical and computer-simulations models of heteroresistance. In our analysis of the properties of these models, we consider the factors that determine the response to antibiotic-mediated selection. In one model, heteroresistance is progressive, with each resistant state sequentially generating a higher resistance level. In the other model, heteroresistance is non-progressive, with a susceptible population directly generating populations with different resistance levels. The conditions where resistance will ascend in the progressive model are narrower than those of the non-progressive model. The rates of reversion from the resistant to the sensitive states are critically dependent on the transition rates and the fitness cost of resistance. Our results demonstrate that the standard test used to identify heteroresistance is insufficient. The predictions of our models are consistent with empirical results. Our results demand a reevaluation of the definition and criteria employed to identify heteroresistance. We recommend the definition of heteroresistance should include a consideration of the rate of return to susceptibility.
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Affiliation(s)
- Bruce R. Levin
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
- Emory Antibiotic Resistance Center; Atlanta, Georgia, 30322, USA
| | - Brandon A. Berryhill
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University; Atlanta, GA, 30322, USA
| | - Teresa Gil-Gil
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Joshua A. Manuel
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Andrew P. Smith
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Jacob E. Choby
- Emory Antibiotic Resistance Center; Atlanta, Georgia, 30322, USA
- Emory Vaccine Center; Atlanta, Georgia, 30322, USA
| | - Dan I. Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, SE-75123, Sweden
| | - David S. Weiss
- Emory Antibiotic Resistance Center; Atlanta, Georgia, 30322, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine; Atlanta, GA, 30322, USA
- Georgia Emerging Infections Program, Georgia Department of Public Health; Atlanta, GA, 30322, USA
| | - Fernando Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Médica en Red, Epidemiología y Salud Pública (CIBERESP) Madrid, Spain
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7
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Rogga V, Kosalec I. Untying the anchor for the lipopolysaccharide: lipid A structural modification systems offer diagnostic and therapeutic options to tackle polymyxin resistance. Arh Hig Rada Toksikol 2023; 74:145-166. [PMID: 37791675 PMCID: PMC10549895 DOI: 10.2478/aiht-2023-74-3717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/01/2023] [Accepted: 07/01/2023] [Indexed: 10/05/2023] Open
Abstract
Polymyxin antibiotics are the last resort for treating patients in intensive care units infected with multiple-resistant Gram-negative bacteria. Due to their polycationic structure, their mode of action is based on an ionic interaction with the negatively charged lipid A portion of the lipopolysaccharide (LPS). The most prevalent polymyxin resistance mechanisms involve covalent modifications of lipid A: addition of the cationic sugar 4-amino-L-arabinose (L-Ara4N) and/or phosphoethanolamine (pEtN). The modified structure of lipid A has a lower net negative charge, leading to the repulsion of polymyxins and bacterial resistance to membrane disruption. Genes encoding the enzymatic systems involved in these modifications can be transferred either through chromosomes or mobile genetic elements. Therefore, new approaches to resistance diagnostics have been developed. On another note, interfering with these enzymatic systems might offer new therapeutic targets for drug discovery. This literature review focuses on diagnostic approaches based on structural changes in lipid A and on the therapeutic potential of molecules interfering with these changes.
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Affiliation(s)
- Vanessa Rogga
- University of Zagreb Faculty of Pharmacy and Biochemistry, Department of Microbiology, Zagreb, Croatia
| | - Ivan Kosalec
- University of Zagreb Faculty of Pharmacy and Biochemistry, Department of Microbiology, Zagreb, Croatia
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Cain AK, Hamidian M. Portrait of a killer: Uncovering resistance mechanisms and global spread of Acinetobacter baumannii. PLoS Pathog 2023; 19:e1011520. [PMID: 37561719 PMCID: PMC10414682 DOI: 10.1371/journal.ppat.1011520] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023] Open
Abstract
Antibiotic resistance is a growing global concern in the field of medicine as it renders bacterial infections difficult to treat and often more severe. Acinetobacter baumannii is a gram-negative bacterial pathogen causing a wide range of infections, including pneumonia, sepsis, urinary tract infections, and wound infections. A. baumannii has emerged as a significant healthcare-associated pathogen due to its high level of antibiotic resistance. The global spread of antibiotic-resistant strains of A. baumannii has resulted in limited treatment options, leading to increased morbidity and mortality rates, especially in vulnerable populations such as the elderly and immunocompromised individuals, as well as longer hospital stays and higher healthcare costs. Further complicating the situation, multi- and pan-drug-resistant strains of A. baumannii are becoming increasingly common, and these deadly strains are resistant to all or almost all available antibiotics. A. baumannii employs various clever strategies to develop antibiotic resistance, including horizontal transfer of resistance genes, overexpression of inherent efflux pumps that remove drugs from the cell, intrinsic mutations, combined with natural selection under antibiotic selective pressure leading to emergence of successful resistance clones. The typical multidrug resistance phenotype of A. baumannii is, therefore, an orchestrated collimation of all these mechanisms combined with the worldwide spread of "global clones," rendering infections caused by this pathogen challenging to control and treat. To address the escalating problem of antibiotic resistance in A. baumannii, there is a need for increased surveillance, strict infection control measures, and the development of new treatment strategies, requiring a concerted effort by healthcare professionals, researchers, and policymakers.
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Affiliation(s)
- Amy K. Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mehrad Hamidian
- Australian Institute of Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
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9
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Sánchez-León I, García-Martínez T, Diene SM, Pérez-Nadales E, Martínez-Martínez L, Rolain JM. Heteroresistance to Colistin in Clinical Isolates of Klebsiella pneumoniae Producing OXA-48. Antibiotics (Basel) 2023; 12:1111. [PMID: 37508209 PMCID: PMC10375995 DOI: 10.3390/antibiotics12071111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Heteroresistance to colistin can be defined as the presence of resistant subpopulations in an isolate that is susceptible to this antibiotic. Colistin resistance in Gram-negative bacteria is more frequently related to chromosomal mutations and insertions. This work aimed to study heteroresistance in nine clinical isolates of Klebsiella pneumoniae producing OXA-48 and to describe genomic changes in mutants with acquired resistance in vitro. Antimicrobial susceptibility was determined by broth microdilution (BMD) and heteroresistance by population analysis profiling (PAP). The proteins related to colistin resistance were analyzed for the presence of mutations. Additionally, PCR of the mgrB gene was performed to identify the presence of insertions. In the nine parental isolates, the PAP method showed colistin heteroresistance of colonies growing on plates with concentrations of up to 64 mg/L, corresponding to stable mutant subpopulations. The MICs of some mutants from the PAP plate containing 4×MIC of colistin had absolute values of ≤2 mg/L that were higher than the parental MICs and were defined as persistent variants. PCR of the mgrB gene identified an insertion sequence that inactivated the gene in 21 mutants. Other substitutions in the investigated mutants were found in PhoP, PhoQ, PmrB, PmrC, CrrA and CrrB proteins. Colistin heteroresistance in K. pneumoniae isolates was attributed mainly to insertions in the mgrB gene and point mutations in colistin resistance proteins. The results of this study will improve understanding regarding the mechanisms of colistin resistance in mutants of K. pneumoniae producing OXA-48.
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Affiliation(s)
- Irene Sánchez-León
- Maimonides Biomedical Research Institute of Cordoba, 14004 Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
| | - Teresa García-Martínez
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
| | - Seydina M Diene
- Microbes Evolution Phylogeny and Infections (MEPHI), IRD, APHM, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-University, 13005 Marseille, France
| | - Elena Pérez-Nadales
- Maimonides Biomedical Research Institute of Cordoba, 14004 Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Luis Martínez-Martínez
- Maimonides Biomedical Research Institute of Cordoba, 14004 Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Clinical Unit of Microbiology, Reina Sofía University Hospital, 14004 Cordoba, Spain
| | - Jean-Marc Rolain
- Microbes Evolution Phylogeny and Infections (MEPHI), IRD, APHM, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-University, 13005 Marseille, France
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10
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Zhong ZX, Zhou S, Liang YJ, Wei YY, Li Y, Long TF, He Q, Li MY, Zhou YF, Yu Y, Fang LX, Liao XP, Kreiswirth BN, Chen L, Ren H, Liu YH, Sun J. Natural flavonoids disrupt bacterial iron homeostasis to potentiate colistin efficacy. SCIENCE ADVANCES 2023; 9:eadg4205. [PMID: 37294761 PMCID: PMC10256158 DOI: 10.1126/sciadv.adg4205] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/04/2023] [Indexed: 06/11/2023]
Abstract
In the face of the alarming rise in global antimicrobial resistance, only a handful of novel antibiotics have been developed in recent decades, necessitating innovations in therapeutic strategies to fill the void of antibiotic discovery. Here, we established a screening platform mimicking the host milieu to select antibiotic adjuvants and found three catechol-type flavonoids-7,8-dihydroxyflavone, myricetin, and luteolin-prominently potentiating the efficacy of colistin. Further mechanistic analysis demonstrated that these flavonoids are able to disrupt bacterial iron homeostasis through converting ferric iron to ferrous form. The excessive intracellular ferrous iron modulated the membrane charge of bacteria via interfering the two-component system pmrA/pmrB, thereby promoting the colistin binding and subsequent membrane damage. The potentiation of these flavonoids was further confirmed in an in vivo infection model. Collectively, the current study provided three flavonoids as colistin adjuvant to replenish our arsenals for combating bacterial infections and shed the light on the bacterial iron signaling as a promising target for antibacterial therapies.
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Affiliation(s)
- Zi-xing Zhong
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Shuang Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yu-jiao Liang
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yi-yang Wei
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yan Li
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Teng-fei Long
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Qian He
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Meng-yuan Li
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yu-feng Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yang Yu
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Liang-xing Fang
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Xiao-ping Liao
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Barry N. Kreiswirth
- Hackensack-Meridian Health Center for Discovery and Innovation, Nutley, NJ, USA
| | - Liang Chen
- Hackensack-Meridian Health Center for Discovery and Innovation, Nutley, NJ, USA
| | - Hao Ren
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Ya-hong Liu
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, PR China
| | - Jian Sun
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
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11
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Colistin Resistance in Acinetobacter baumannii: Molecular Mechanisms and Epidemiology. Antibiotics (Basel) 2023; 12:antibiotics12030516. [PMID: 36978383 PMCID: PMC10044110 DOI: 10.3390/antibiotics12030516] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/17/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Acinetobacter baumannii is recognized as a clinically significant pathogen causing a wide spectrum of nosocomial infections. Colistin was considered a last-resort antibiotic for the treatment of infections caused by multidrug-resistant A. baumannii. Since the reintroduction of colistin, a number of mechanisms of colistin resistance in A. baumannii have been reported, including complete loss of LPS by inactivation of the biosynthetic pathway, modifications of target LPS driven by the addition of phosphoethanolamine (PEtN) moieties to lipid A mediated by the chromosomal pmrCAB operon and eptA gene-encoded enzymes or plasmid-encoded mcr genes and efflux of colistin from the cell. In addition to resistance to colistin, widespread heteroresistance is another feature of A. baumannii that leads to colistin treatment failure. This review aims to present a critical assessment of relevant published (>50 experimental papers) up-to-date knowledge on the molecular mechanisms of colistin resistance in A. baumannii with a detailed review of implicated mutations and the global distribution of colistin-resistant strains.
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12
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Genomic Characterization of Colistin-Resistant Isolates from the King Fahad Medical City, Kingdom of Saudi Arabia. Antibiotics (Basel) 2022; 11:antibiotics11111597. [DOI: 10.3390/antibiotics11111597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Whole-genome sequencing is one of the best ways to investigate resistance mechanisms of clinical isolates as well as to detect and identify circulating multi-drug-resistant (MDR) clones or sub-clones in a given hospital setting. Methods: Here, we sequenced 37 isolates of Acinetobacter baumannii, 10 Klebsiella pneumoniae, and 5 Pseudomonas aeruginosa collected from the biobank of the hospital setting of the King Fahad Medical City. Complete phenotypic analyses were performed, including MALDI-TOF identification and antibiotic susceptibility testing. After the genome assembly of raw data, exhaustive genomic analysis was conducted including full resistome determination, genomic SNP (gSNP) analysis, and comparative genomics. Results: Almost all isolates were highly resistant to all tested antibiotics, including carbapenems and colistin. Resistome analysis revealed many antibiotic resistance genes, including those with resistance to β-lactams, aminoglycosides, macrolides, tetracyclines, sulfamids, quinolones, and phenicols. In A. baumannii isolates, the endemic carbapenemase blaOXA-23 gene was detected in 36 of the 37 isolates. Non-synonymous mutations in pmrB were detected in almost all of the isolates and likely mediated colistin resistance. Interestingly, while classical analyses, such as MLST, revealed the predominance of an ST2 clone in A. baumannii isolates, the genomic analysis revealed the presence of five circulating sub-clones and identified several isolate transmissions between patients. In the 10 K. pneumoniae isolates, several resistance genes were identified, and the observed carbapenem resistance was likely mediated by overexpression of the detected extended-spectrum-β-lactamase (ESBL) genes associated with low membrane permeability as few carbapenemase genes were detected with just blaOXA-48 in three isolates. Colistin resistance was mediated either by non-synonymous mutations in the MgrB regulator, PmrA, PmrB, and PhoQ proteins or the presence of the MCR-1 protein. Here, gSNP analysis also revealed the existence of bacterial clones and cases of isolate transmissions between patients. The five analyzed P. aeruginosa isolates were highly resistant to all tested antibiotics, including carbapenems mediated by loss or truncated OprD porin, and colistin resistance was associated with mutations in the genes encoding the PmrA, PmrB, or PhoQ proteins. Conclusion: We demonstrate here the usefulness of whole-genome sequencing to exhaustively investigate the dissemination of MDR isolates at the sub-clone level. Thus, we suggest implementing such an approach to monitor the emergence and spread of new clones or sub-clones, which classical molecular analyses cannot detect. Moreover, we recommend increasing the surveillance of the endemic and problematic colistin resistance mcr-1 gene to avoid extensive dissemination.
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13
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Lu Y, Liu Y, Zhou C, Liu Y, Long Y, Lin D, Xiong R, Xiao Q, Huang B, Chen C. Quorum sensing regulates heteroresistance in Pseudomonas aeruginosa. Front Microbiol 2022; 13:1017707. [PMID: 36386621 PMCID: PMC9650436 DOI: 10.3389/fmicb.2022.1017707] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/07/2022] [Indexed: 10/29/2023] Open
Abstract
The prevalence and genetic mechanism of antibiotic heteroresistance (HR) have attracted significant research attention recently. However, non-genetic mechanism of HR has not been adequately explored. The present study aimed to evaluate the role of quorum sensing (QS), an important mechanism of behavioral coordination in different subpopulations and consequent heteroresistance. First, the prevalence of HR to 7 antibiotics was investigated in 170 clinical isolates of P. aeruginosa using population analysis profiles. The results showed that P. aeruginosa was significantly heteroresistant to meropenem (MEM), amikacin (AMK), ciprofloxacin (CIP), and ceftazidime (CAZ). The observed HR was correlated with down-regulation of QS associated genes lasI and rhlI. Further, loss-of-function analysis results showed that reduced expression of lasI and rhlI enhanced HR of P. aeruginosa to MEM, AMK, CIP, and CAZ. Conversely, overexpression of these genes or treatment with 3-oxo-C12-HSL/C4-HSL lowered HR of P. aeruginosa to the four antibiotics. Additionally, although downregulation of oprD and upregulation of efflux-associated genes was evident in heteroresistant subpopulations, their expression was not regulated by LasI and RhlI. Moreover, fitness cost measurements disclosed higher growth rates of PAO1ΔlasI and PAO1ΔrhlI in the presence of sub-MIC antibiotic as compared with that of wild-type PAO1. Our data suggest that under temporary antibiotic pressure, downregulation of QS might result in less fitness cost and promote HR of P. aeruginosa.
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Affiliation(s)
- Yang Lu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, China
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yuyang Liu
- Department of Laboratory Medicine, Chengdu First People's Hospital, Chengdu, China
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Chenxu Zhou
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
- The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yaqin Liu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, China
| | - Yifei Long
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Dongling Lin
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Rui Xiong
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Qian Xiao
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Cha Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
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14
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Quantitative Pharmacodynamic Characterization of Resistance versus Heteroresistance of Colistin in E. coli Using a Semimechanistic Modeling of Killing Curves. Antimicrob Agents Chemother 2022; 66:e0079322. [PMID: 36040146 PMCID: PMC9487539 DOI: 10.1128/aac.00793-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heteroresistance corresponds to the presence, in a bacterial isolate, of an initial small subpopulation of bacteria characterized by a significant reduction in their sensitivity to a given antibiotic. Mechanisms of heteroresistance versus resistance are poorly understood. The aim of this study was to explore heteroresistance in mcr-positive and mcr-negative Escherichia coli strains exposed to colistin by use of modeling killing curves with a semimechanistic model. We quantify, for a range of phenotypically (susceptibility based on MIC) and genotypically (carriage of mcr-1 or mcr-3 or mcr-negative) different bacteria, a maximum killing rate (Emax) of colistin and the corresponding potency (EC50), i.e., the colistin concentrations corresponding to Emax/2. Heteroresistant subpopulations were identified in both mcr-negative and mcr-positive E. coli as around 0.06% of the starting population. Minority heteroresistant bacteria, both for mcr-negative and mcr-positive strains, differed from the corresponding dominant populations only by the maximum killing rate of colistin (differences for Emax by a factor of 12.66 and 3.76 for mcr-negative and mcr-positive strains, respectively) and without alteration of their EC50s. On the other hand, the resistant mcr-positive strains are distinguished from the mcr-negative strains by differences in their EC50, which can reach a factor of 44 for their dominant population and 22 for their heteroresistant subpopulations. It is suggested that the underlying physiological mechanisms differ between resistance and heteroresistance, with resistance being linked to a decrease in the affinity of colistin for its site of action, whereas heteroresistance would, rather, be linked to an alteration of the target, which will be more difficult to be further changed or destroyed.
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15
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Denissen J, Reyneke B, Waso-Reyneke M, Havenga B, Barnard T, Khan S, Khan W. Prevalence of ESKAPE pathogens in the environment: Antibiotic resistance status, community-acquired infection and risk to human health. Int J Hyg Environ Health 2022; 244:114006. [PMID: 35841823 DOI: 10.1016/j.ijheh.2022.114006] [Citation(s) in RCA: 76] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/30/2022] [Accepted: 06/30/2022] [Indexed: 01/10/2023]
Abstract
The ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens are characterised by increased levels of resistance towards multiple classes of first line and last-resort antibiotics. Although these pathogens are frequently isolated from clinical environments and are implicated in a variety of life-threatening, hospital-associated infections; antibiotic resistant ESKAPE strains have been isolated from environmental reservoirs such as surface water, wastewater, food, and soil. Literature on the persistence and subsequent health risks posed by the ESKAPE isolates in extra-hospital settings is however, limited and the current review aims to elucidate the primary reservoirs of these pathogens in the environment, their antibiotic resistance profiles, and the link to community-acquired infections. Additionally, information on the current state of research regarding health-risk assessments linked to exposure of the ESKAPE pathogens in the natural environment, is outlined.
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Affiliation(s)
- Julia Denissen
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Monique Waso-Reyneke
- Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein, 2028, South Africa
| | - Benjamin Havenga
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Tobias Barnard
- Water and Health Research Centre, University of Johannesburg, PO Box 17011, Doornfontein, 7305, South Africa
| | - Sehaam Khan
- Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein, 2028, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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16
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Kapel N, Caballero JD, MacLean RC. Localized pmrB hypermutation drives the evolution of colistin heteroresistance. Cell Rep 2022; 39:110929. [PMID: 35675785 PMCID: PMC9189680 DOI: 10.1016/j.celrep.2022.110929] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/02/2021] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
Colistin has emerged as an important last line of defense for the treatment of infections caused by antibiotic-resistant gram-negative pathogens, but colistin resistance remains poorly understood. Here, we investigate the responses of ≈1,000 populations of a multi-drug-resistant (MDR) strain of P. aeruginosa to a high dose of colistin. Colistin exposure causes rapid cell death, but some populations eventually recover due to the growth of sub-populations of heteroresistant cells. Heteroresistance is unstable, and resistance is rapidly lost under culture in colistin-free medium. The evolution of heteroresistance is primarily driven by selection for heteroresistance at two hotspot sites in the PmrAB regulatory system. Localized hypermutation of pmrB generates colistin resistance at 103–104 times the background resistance mutation rate (≈2 × 10-5 per cell division). PmrAB provides resistance to antimicrobial peptides that are involved in host immunity, suggesting that this pathogen may have evolved a highly mutable pmrB as an adaptation to host immunity. Pseudomonas populations recover from colistin due to the growth of heteroresistant cells Heteroresistance is driven by pre-existing mutations in the PmrAB regulatory system pmrB mutations arise at 103–104 times the background mutation rate Heteroresistance is unstable and is rapidly lost in the absence of colistin
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Affiliation(s)
- Natalia Kapel
- University of Oxford, Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Julio Diaz Caballero
- University of Oxford, Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - R Craig MacLean
- University of Oxford, Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK.
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17
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Kang M, Kim W, Lee J, Jung HS, Jeon CO, Park W. 6-Bromo-2-naphthol from Silene armeria extract sensitizes Acinetobacter baumannii strains to polymyxin. Sci Rep 2022; 12:8546. [PMID: 35595766 PMCID: PMC9123208 DOI: 10.1038/s41598-022-11995-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/04/2022] [Indexed: 12/02/2022] Open
Abstract
The overuse of antibiotics has led to the emergence of multidrug-resistant bacteria, which are resistant to various antibiotics. Combination therapies using natural compounds with antibiotics have been found to have synergistic effects against several pathogens. Synergistic natural compounds can potentiate the effects of polymyxins for the treatment of Acinetobacter baumannii infection. Out of 120 types of plant extracts, only Silene armeria extract (SAE) showed a synergistic effect with polymyxin B (PMB) in our fractional inhibitory concentration and time-kill analyses. The survival rate of G. mellonella infected with A. baumannii ATCC 17978 increased following the synergistic treatment. Interestingly, the addition of osmolytes, such as trehalose, canceled the synergistic effect of SAE with PMB; however, the underlying mechanism remains unclear. Quadrupole time-of-flight liquid chromatography-mass spectrometry revealed 6-bromo-2-naphthol (6B2N) to be a major active compound that exhibited synergistic effects with PMB. Pretreatment with 6B2N made A. baumannii cells more susceptible to PMB exposure in a time- and concentration-dependent manner, indicating that 6B2N exhibits consequential synergistic action with PMB. Moreover, the exposure of 6B2N-treated cells to PMB led to higher membrane leakage and permeability. The present findings provide a promising approach for utilizing plant extracts as adjuvants to reduce the toxicity of PMB in A. baumannii infection.
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Affiliation(s)
- Mingyeong Kang
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Wonjae Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Jaebok Lee
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Hye Su Jung
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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18
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Főldes A, Székely E, Voidăzan ST, Dobreanu M. Comparison of Six Phenotypic Assays with Reference Methods for Assessing Colistin Resistance in Clinical Isolates of Carbapenemase-Producing Enterobacterales: Challenges and Opportunities. Antibiotics (Basel) 2022; 11:antibiotics11030377. [PMID: 35326840 PMCID: PMC8944616 DOI: 10.3390/antibiotics11030377] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 02/27/2022] [Accepted: 03/09/2022] [Indexed: 02/01/2023] Open
Abstract
The global escalation of severe infections due to carbapenemase-producing Enterobacterales (CPE) isolates has prompted increased usage of parenteral colistin. Considering the reported difficulties in assessing their susceptibility to colistin, the purpose of the study was to perform a comparative evaluation of six phenotypic assays—the colistin broth disc elution (CBDE), Vitek 2 Compact (bioMérieux SA, Marcy l’Etoile, France), the Micronaut MIC-Strip Colistin (Merlin Diagnostika GMBH, Bornheim-Hensel, Germany), the gradient diffusion strip Etest (bioMérieux SA, Marcy l’Etoile, France), ChromID Colistin R Agar (COLR) (bioMérieux SA, Marcy l’Etoile, France), and the Rapid Polymyxin NP Test (ELITechGroup, Signes, France)—versus the reference method of broth microdilution (BMD). All false resistance results were further assessed using population analysis profiling (PAP). Ninety-two nonrepetitive clinical CPE strains collected from two hospitals were evaluated. The BMD confirmed 36 (39.13%) isolates susceptible to colistin. According to the BMD, the Micronaut MIC-Strip Colistin, the CBDE, and the COLR medium exhibited category agreement (CA) of 100%. In comparison with the BMD, the highest very major discrepancy (VMD) was noted for Etest (n = 15), and the only false resistance results were recorded for the Rapid Polymyxin NP Test (n = 3). Only the PAP method and the Rapid Polymyxin NP Test were able to detect heteroresistant isolates (n = 2). Thus, there is an urgent need to further optimize the diagnosis strategies for colistin resistance.
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Affiliation(s)
- Annamária Főldes
- Department of Microbiology, Laboratory of Medical Analysis, “Dr. Constantin Opriş” County Emergency Hospital, 430031 Baia Mare, Romania
- Doctoral School of Medicine and Pharmacy, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania
- Correspondence:
| | - Edit Székely
- Department of Microbiology, Central Clinical Laboratory, County Emergency Clinical Hospital, 540136 Targu Mures, Romania;
- Department of Microbiology, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania
| | - Septimiu Toader Voidăzan
- Department of Epidemiology, “George Emil Palade’’ University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania;
| | - Minodora Dobreanu
- Department of Clinical Biochemistry, Central Clinical Laboratory, County Emergency Clinical Hospital, 540136 Targu Mures, Romania;
- Department of Laboratory Medicine, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania
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Qu X, Bian X, Chen Y, Hu J, Huang X, Wang Y, Fan Y, Wu H, Li X, Li Y, Guo B, Liu X, Zhang J. Polymyxin B Combined with Minocycline: A Potentially Effective Combination against blaOXA-23-harboring CRAB in In Vitro PK/PD Model. Molecules 2022; 27:molecules27031085. [PMID: 35164349 PMCID: PMC8840471 DOI: 10.3390/molecules27031085] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/25/2022] [Accepted: 02/01/2022] [Indexed: 12/15/2022] Open
Abstract
Polymyxin-based combination therapy is commonly used to treat carbapenem-resistant Acinetobacter baumannii (CRAB) infections. In the present study, the bactericidal effect of polymyxin B and minocycline combination was tested in three CRAB strains containing blaOXA-23 by the checkerboard assay and in vitro dynamic pharmacokinetics/pharmacodynamics (PK/PD) model. The combination showed synergistic or partial synergistic effect (fractional inhibitory concentration index ≤0.56) on the tested strains in checkboard assays. The antibacterial activity was enhanced in the combination group compared with either monotherapy in in vitro PK/PD model. The combination regimen (simultaneous infusion of 0.75 mg/kg polymyxin B and 100 mg minocycline via 2 h infusion) reduced bacterial colony counts by 0.9–3.5 log10 colony forming units per milliliter (CFU/mL) compared with either drug alone at 24 h. In conclusion, 0.75 mg/kg polymyxin B combined with 100 mg minocycline via 2 h infusion could be a promising treatment option for CRAB bloodstream infections.
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Affiliation(s)
- Xingyi Qu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
- Phase I Unit, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Xingchen Bian
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
- Department of Biological Medicines & Shanghai Engineering Research Center of Immunotherapeutics, School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Yuancheng Chen
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
- Phase I Unit, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jiali Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Xiaolan Huang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Yu Wang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Yaxin Fan
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Hailan Wu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Xin Li
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Yi Li
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Beining Guo
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
| | - Xiaofen Liu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
- Correspondence: (X.L.); (J.Z.); Tel.: +86-21-52888190 (J.Z.)
| | - Jing Zhang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, China; (X.Q.); (X.B.); (J.H.); (X.H.); (Y.W.); (Y.F.); (H.W.); (X.L.); (Y.L.); (B.G.)
- Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai 200040, China
- National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China;
- Phase I Unit, Huashan Hospital, Fudan University, Shanghai 200040, China
- Correspondence: (X.L.); (J.Z.); Tel.: +86-21-52888190 (J.Z.)
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Abstract
Infection by multidrug-resistant (MDR) Acinetobacter baumannii is one of the major causes of hospital-acquired infections worldwide. The ability of A. baumannii to survive in adverse conditions as well as its extensive antimicrobial resistance make it one of the most difficult to treat pathogens associated with high mortality rates. The aim of this study was to investigate MDR A. baumannii that has spread among pediatric cancer patients in the Children’s Cancer Hospital Egypt 57357. Whole-genome sequencing was used to characterize 31 MDR A. baumannii clinical isolates. Phenotypically, the isolates were MDR, with four isolates showing resistance to the last-resort antibiotic colistin. Multilocus sequence typing showed the presence of eight clonal groups, two of which were previously reported to cause outbreaks in Egypt, and one novel sequence type (ST), Oxf-ST2246. Identification of the circulating plasmids showed the presence of two plasmid lineages in the isolates, strongly governed by sequence type. A large number of antimicrobial genes with a range of resistance mechanisms were detected in the isolates, including β-lactamases and antibiotic efflux pumps. Analysis of insertion sequences (ISs) revealed the presence of ISAba1 and ISAba125 in all the samples, which amplify β-lactamase expression, causing extensive carbapenem resistance. Mutation analysis was used to decipher underlying mutations responsible for colistin resistance and revealed novel mutations in several outer membrane proteins, in addition to previously reported mutations in pmrB. Altogether, understanding the transmissibility of A. baumannii as well as its resistance and virulence mechanisms will help develop novel treatment options for better management of hospital-acquired infections. IMPORTANCEAcinetobacter baumannii represents a major health threat, in particular among immunocompromised cancer patients. The rise in carbapenem-resistant A. baumannii, and the development of resistance to the last-resort antimicrobial agent colistin, complicates the management of A. baumannii outbreaks and increases mortality rates. Here, we investigate 31 multidrug resistant A. baumannii isolates from pediatric cancer patients in Children’s Cancer Hospital Egypt (CCHE) 57357 via whole-genome sequencing. Multilocus sequence typing (MLST) showed the presence of eight clonal groups including a novel sequence type. In silico detection of antimicrobial-resistant genes and virulence factors revealed a strong correlation between certain virulence genes and mortality as well as several point mutations in outer membrane proteins contributing to colistin resistance. Detection of CRISPR/Cas sequences in the majority of the samples was strongly correlated with the presence of prophage sequences and associated with failure of bacteriophage therapy. Altogether, understanding the genetic makeup of circulating A. baumannii is essential for better management of outbreaks.
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Hematian A, Goudarzi H, Ghalavand Z, Goudarzi M, Shafieian M, Hashemi A, Ghafourian S. The relationship between phoH and colistin-heteroresistant in clinical isolates of Acinetobacter baumannii. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Drown them in their own garbage: a new strategy to reverse polymyxin resistance? J Bacteriol 2021; 204:e0057421. [PMID: 34843378 DOI: 10.1128/jb.00574-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purcell and colleagues offer new insights into a major mechanism of polymyxin resistance in Gram-negative bacteria. Inactivating a single lipid recycling enzyme causes accumulation of waste lipid by-products that inhibit a key factor responsible for polymyxin resistance.
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Colistin Resistance Onset Strategies and Genomic Mosaicism in Clinical Acinetobacter baumannii Lineages. Pathogens 2021; 10:pathogens10111516. [PMID: 34832671 PMCID: PMC8623500 DOI: 10.3390/pathogens10111516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 11/16/2022] Open
Abstract
The treatment of multidrug-resistant Gram-negative infections is based on colistin. As result, COL-resistance (COL-R) can develop and spread. In Acinetobacter baumannii, a crucial step is to understand COL-R onset and stability, still far to be elucidated. COL-R phenotypic stability, onset modalities, and phylogenomics were investigated in a clinical A. baumannii sample showing a COL resistant (COLR) phenotype at first isolation. COL-R was confirmed by Minimum-Inhibitory-Concentrations as well as investigated by Resistance-Induction assays and Population-Analysis-Profiles (PAPs) to determine: (i) stability; (ii) inducibility; (iii) heteroresistance. Genomics was performed by Mi-Seq Whole-Genome-Sequencing, Phylogenesis, and Genomic Epidemiology by bioinformatics. COLRA. baumannii were subdivided as follows: (i) 3 A. baumannii with stable and high COL MICs defining the “homogeneous-resistant” onset phenotype; (ii) 6 A. baumannii with variable and lower COL MICs displaying a “COL-inducible” onset phenotype responsible for adaptive-resistance or a “subpopulation” onset phenotype responsible for COL-heteroresistance. COL-R stability and onset strategies were not uniquely linked to the amount of LPS and cell envelope charge. Phylogenomics categorized 3 lineages clustering stable and/or unstable COL-R phenotypes with increasing genomic complexity. Likewise, different nsSNP profiling in genes already associated with COL-R marked the stable and/or unstable COL-R phenotypes. Our investigation finds out that A. baumannii can range through unstable or stable COLR phenotypes emerging via different “onset strategies” within phylogenetic lineages displaying increasing genomic mosaicism.
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Milani ES, Hasani A, Varschochi M, Sadeghi J, Memar MY, Hasani A. Biocide resistance in Acinetobacter baumannii: appraising the mechanisms. J Hosp Infect 2021; 117:135-146. [PMID: 34560167 DOI: 10.1016/j.jhin.2021.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022]
Abstract
A global upsurge in antibiotic-resistant Acinetobacter baumannii requires supervised selection of biocides and disinfectants to avert nosocomial infections by reducing its spread. Moreover, inadequate and improper biocides have been reported as a contributing factor in antimicrobial resistance. Regardless of the manner of administration, a biocidal concentration that does not kill the target bacteria creates a stress response, propagating the resistance mechanisms. This is an essential aspect of the disinfection programme and the overall bio-contamination management plan. Knowing the mechanisms of action of biocides and resistance modalities may open new avenues to discover novel agents. This review describes the mechanisms of action of some biocides, resistance mechanisms, and approaches to study susceptibility/resistance to these agents.
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Affiliation(s)
- E S Milani
- Infectious and Tropical Diseases Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - A Hasani
- Infectious and Tropical Diseases Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Clinical Research Development Unit, Sina Educational, Research and Treatment Centre, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - M Varschochi
- Infectious and Tropical Diseases Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
| | - J Sadeghi
- Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - M Y Memar
- Infectious and Tropical Diseases Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
| | - A Hasani
- Department of Clinical Biochemistry and Laboratory Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Zhang CZ, Zhang Y, Ding XM, Lin XL, Lian XL, Trampari E, Thomson NM, Ding HZ, Webber MA, Jiang HX. Emergence of ciprofloxacin heteroresistance in foodborne Salmonella enterica serovar Agona. J Antimicrob Chemother 2021; 75:2773-2779. [PMID: 32747937 DOI: 10.1093/jac/dkaa288] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/03/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Bacterial heteroresistance has been increasingly identified as an important phenomenon for many antibiotic/bacterium combinations. OBJECTIVES To investigate ciprofloxacin heteroresistance in Salmonella and characterize mechanisms contributing to ciprofloxacin heteroresistance. METHODS Ciprofloxacin-heteroresistant Salmonella were identified by population analysis profiling (PAP). Target mutations and the presence of PMQR genes were detected using PCR and sequencing. Expression of acrB, acrF and qnrS was conducted by quantitative RT-PCR. Competition ability and virulence were also compared using pyrosequencing, blue/white screening, adhesion and invasion assays and a Galleria model. Two subpopulations were whole-genome sequenced using Oxford Nanopore and Illumina platforms. RESULTS PAP identified one Salmonella from food that yielded a subpopulation demonstrating heteroresistance to ciprofloxacin at a low frequency (10-9 to 10-7). WGS and PFGE analyses confirmed that the two subpopulations were isogenic, with six SNPs and two small deletions distinguishing the resistant from the susceptible. Both subpopulations possessed a T57S substitution in ParC and carried qnrS. The resistant subpopulation was distinguished by overexpression of acrB and acrF, a deletion within rsxC and altered expression of soxS. The resistant population had a competitive advantage against the parental population when grown in the presence of bile salts but was attenuated in the adhesion and invasion of human intestinal cells. CONCLUSIONS We determined that heteroresistance resulted from a combination of mutations in fluoroquinolone target genes and overexpression of efflux pumps associated with a deletion in rsxC. This study warns that ciprofloxacin heteroresistance exists in Salmonella in the food chain and highlights the necessity for careful interpretation of antibiotic susceptibility.
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Affiliation(s)
- Chuan-Zhen Zhang
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.,Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK
| | - Yan Zhang
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Min Ding
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Ling Lin
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
| | - Xin-Lei Lian
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
| | - Eleftheria Trampari
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK
| | - Nicholas M Thomson
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK
| | - Huan-Zhong Ding
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Mark A Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7UH, UK
| | - Hong-Xia Jiang
- Guangdong Key Laboratory for Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
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Ngudsuntia A, Lunha K, Lulitanond A, Tippayawat P, Sukkasem C, Charoensri N, Chanawong A. Colistin Susceptibility Testing by Rapid Colistin Disk Elution Test Among Enterobacteriaceae in Low-Resource Setting. Microb Drug Resist 2021; 27:1685-1691. [PMID: 34129391 DOI: 10.1089/mdr.2020.0613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We modified rapid polymyxin Nordmann-Poirel (RPNP) test, called rapid colistin disk elution (RCDE) test, for detecting colistin resistance in Gram-negative bacilli and evaluated its performance compared with colistin broth disk elution (CBDE) test recommended by Clinical and Laboratory Standards Institute (CLSI). The RCDE test was performed by using a 10-μg colistin disk in 2.7 mL volume (final colistin concentration of 3.7 μg/mL) of either cation-adjusted Mueller-Hinton broth or phenol red broth base media with bacterial inoculum of 1-μL loop, and 1-4 and 16-20 hr incubation for Enterobacteriaceae and Acinetobacter baumannii isolates, respectively. Both tests were evaluated in 236 Enterobacteriaceae and 49 A. baumannii isolates using broth microdilution as reference method. Among the Enterobacteriaceae isolates, categorical agreement and very major error (VME or false intermediate susceptibility) rate were 98.3% and 5.4%, respectively, for the RCDE test, compared with 97.9% and 7.1%, respectively, for the CBDE test. Both tests had major error (ME or false resistance) rate of 0.6%. For the A. baumannii isolates, the RCDE and CBDE tests gave high VME rates of 8.3% and 16.7%, respectively. The RCDE test showed good performance comparable with the CBDE test but is cheaper and more rapid (3 hr) and convenient, thus suggesting as an alternative for detecting colistin resistance among Enterobacteriaceae in low-income countries.
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Affiliation(s)
- Arisa Ngudsuntia
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Kamonwan Lunha
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Aroonlug Lulitanond
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Patcharaporn Tippayawat
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Chutipapa Sukkasem
- Clinical Microbiology Laboratory, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Nicha Charoensri
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Aroonwadee Chanawong
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
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Ilsan NA, Lee YJ, Kuo SC, Lee IH, Huang TW. Antimicrobial Resistance Mechanisms and Virulence of Colistin- and Carbapenem-Resistant Acinetobacter baumannii Isolated from a Teaching Hospital in Taiwan. Microorganisms 2021; 9:microorganisms9061295. [PMID: 34198665 PMCID: PMC8232278 DOI: 10.3390/microorganisms9061295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 01/01/2023] Open
Abstract
Acinetobacter baumannii, a Gram-negative bacterium, is an important nosocomial pathogen. Colistin-resistant A. baumannii is becoming a new concern, since colistin is one of the last-line antibiotics for infections by carbapenem-resistant A. baumannii. From 452 carbapenem-resistant isolates collected in a teaching hospital in Taipei, Taiwan, we identified seven that were resistant to colistin. Carbapenem resistance in these isolates is attributed to the presence of carbapenemase gene blaOXA-23 in their genomes. Colistin resistance is presumably conferred by mutations in the sensor kinase domain of PmrB found in these isolates, which are known to result in modification of colistin target lipid A via the PmrB-PmrA-PmrC signal transduction pathway. Overexpression of pmrC, eptA, and naxD was observed in all seven isolates. Colistin resistance mediated by pmrB mutations has never been reported in Taiwan. One of the seven isolates contained three mutations in lpxD and exhibited an altered lipopolysaccharide profile, which may contribute to its colistin resistance. No significant difference in growth rates was observed between the isolates and the reference strain, suggesting no fitness cost of colistin resistance. Biofilm formation abilities of the isolates were lower than that of the reference. Interestingly, one of the isolates was heteroresistant to colistin. Four of the isolates were significantly more virulent to wax moth larvae than the reference.
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Affiliation(s)
- Noor Andryan Ilsan
- International Master/Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
| | - Yuarn-Jang Lee
- Department of Internal Medicine, Division of Infectious Diseases, Taipei Medical University Hospital, Taipei 11031, Taiwan;
- Department of Internal Medicine, Division of Infectious Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Shu-Chen Kuo
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan 35053, Taiwan;
| | - I-Hui Lee
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Tzu-Wen Huang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Correspondence: ; Tel./Fax: +886-2-2736-1661 (ext. 3925); (ext. 3921)
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Abstract
In this study, we investigated the colistin heteroresistance patterns in Acinetobacter baumannii isolates. To identify colistin heteroresistance, population analysis profiling was performed for six in vitro colistin-susceptible A. baumannii isolates. Survival rates with and without prior exposure to colistin (at concentrations between 0 and 32 mg/L) were measured in media with and without colistin. Amino acid substitutions were also detected in colonies that survived in media with 4 mg/L colistin without further antibiotic treatment in six A. baumannii isolates. A stability test was also performed to investigate whether colistin resistance is maintained without antibiotic treatment. Although only three isolates showed typical colistin heteroresistance pattern, colistin-resistant populations were identified even without prior exposure to colistin in all A. baumannii isolates. Nearly all colonies of typical colistin-heteroresistant isolates (Type I heteroresistance) that survived after exposure to high colistin concentrations were found to be colistin-resistant, whereas no resistant colonies were identified in the other isolates (Type II heteroresistance). Stability tests showed that most of the surviving populations in media with 4 mg/L colistin without further antibiotic exposure failed to preserve resistance to colistin. Colistin-resistant populations also showed either no change in amino acid sequences, or diverse amino acid substitutions. We identified two types of colistin heteroresistance in A. baumannii isolates. Because Type I colistin-heteroresistant A. baumannii isolates could not be eradicated in vitro by high concentrations of colistin, differentiating two colistin heteroresistance types would be important for the treatment of A. baumannii infections using colistin.
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Affiliation(s)
- Yoon-Kyoung Hong
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Hyunkeun Kim
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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29
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Abstract
Antibiotic resistance is a major global health challenge and, worryingly, several key Gram negative pathogens can become resistant to most currently available antibiotics. Polymyxins have been revived as a last-line therapeutic option for the treatment of infections caused by multidrug-resistant Gram negative bacteria, in particular Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacterales. Polymyxins were first discovered in the late 1940s but were abandoned soon after their approval in the late 1950s as a result of toxicities (e.g., nephrotoxicity) and the availability of "safer" antibiotics approved at that time. Therefore, knowledge on polymyxins had been scarce until recently, when enormous efforts have been made by several research teams around the world to elucidate the chemical, microbiological, pharmacokinetic/pharmacodynamic, and toxicological properties of polymyxins. One of the major achievements is the development of the first scientifically based dosage regimens for colistin that are crucial to ensure its safe and effective use in patients. Although the guideline has not been developed for polymyxin B, a large clinical trial is currently being conducted to optimize its clinical use. Importantly, several novel, safer polymyxin-like lipopeptides are developed to overcome the nephrotoxicity, poor efficacy against pulmonary infections, and narrow therapeutic windows of the currently used polymyxin B and colistin. This review discusses the latest achievements on polymyxins and highlights the major challenges ahead in optimizing their clinical use and discovering new-generation polymyxins. To save lives from the deadly infections caused by Gram negative "superbugs," every effort must be made to improve the clinical utility of the last-line polymyxins. SIGNIFICANCE STATEMENT: Antimicrobial resistance poses a significant threat to global health. The increasing prevalence of multidrug-resistant (MDR) bacterial infections has been highlighted by leading global health organizations and authorities. Polymyxins are a last-line defense against difficult-to-treat MDR Gram negative pathogens. Unfortunately, the pharmacological information on polymyxins was very limited until recently. This review provides a comprehensive overview on the major achievements and challenges in polymyxin pharmacology and clinical use and how the recent findings have been employed to improve clinical practice worldwide.
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Affiliation(s)
- Sue C Nang
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Mohammad A K Azad
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Tony Velkov
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Qi Tony Zhou
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Jian Li
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
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30
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Li L, Li R, Qi C, Gao H, Wei Q, Tan L, Sun F. Mechanisms of polymyxin resistance induced by Salmonella typhimurium in vitro. Vet Microbiol 2021; 257:109063. [PMID: 33932721 DOI: 10.1016/j.vetmic.2021.109063] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/29/2021] [Indexed: 11/26/2022]
Abstract
The increase incidence of multi-drug resistant (MDR) Salmonella has become a major global health concern. Polymyxin, an ancient polypeptide antibiotic, has been given renewed attention over recent years, resulting in resistance of Gram-negative bacteria to polymyxin, but its resistance mechanism is not completely clear. Thus, it is important to study its resistance mechanisms. In this study, an in vitro induced polymyxin-resistant strain of Salmonella typhimurium in the laboratory were constructed to investigate the mechanism of resistance of Salmonella to polymyxin. Gradual induction of Salmonella typhimurium ATCC13311 (AT) by concentration increment was used to screen for a highly polymyxin-resistant strain AT-P128. The broth dilution technique was used to compare the sensitivity of the two strains to different antimicrobial drugs. Single nucleotide polymorphisms (SNPs) were then identified by whole genome sequencing, and differences in gene expression between the two strains were compared by transcriptome sequencing and reverse transcription-quantitative PCR (RT-qPCR). Finally, for the first time, the CRISPR/Cas9 gene-editing system was used to construct gene deletion mutants in Salmonella to knock out the phoP gene of AT-P128. The results showed that strain AT-P128 was significantly more resistant to amoxicillin, ceftiofur, ampicillin, fluphenazine, and chloramphenicol and significantly less resistant to sulfamethoxazole than the parental strain AT. The growth curve results showed no significant change in the growth rate between AT-P128 and AT. Motility and biofilm formation assays showed a significant decrease in AT-P128. Additionally, the WGS results showed that AT-P128 had mutations in 9 genes involving 14 SNPs. RNA-seq and RT-qPCR results showed increased expression of phoPQ. The loss of the phoP gene decreased AT-P128ΔphoP resistance to polymyxin by 32-fold. These results suggested that polymyxin resistance affected the biology, genome components, and gene expression levels of Salmonella and that the PhoPQ two-component system played a key role in polymyxin resistance in Salmonella, providing insights into the diversity and complexity of polymyxin resistance in Salmonella.
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Affiliation(s)
- Lin Li
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China; Anhui Province Key Lab of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei, Anhui 230036, PR China
| | - Rui Li
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China
| | - Caili Qi
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China
| | - Haixia Gao
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China
| | - Qiling Wei
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China
| | - Lei Tan
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China
| | - Feifei Sun
- Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230026, PR China; Anhui Province Key Lab of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei, Anhui 230036, PR China.
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31
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Lopes SP, Jorge P, Sousa AM, Pereira MO. Discerning the role of polymicrobial biofilms in the ascent, prevalence, and extent of heteroresistance in clinical practice. Crit Rev Microbiol 2021; 47:162-191. [PMID: 33527850 DOI: 10.1080/1040841x.2020.1863329] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antimicrobial therapy is facing a worrisome and underappreciated challenge, the phenomenon of heteroresistance (HR). HR has been gradually documented in clinically relevant pathogens (e.g. Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia spp., Acinetobacter baumannii, Klebsiella pneumoniae, Candida spp.) towards several drugs and is believed to complicate the clinical picture of chronic infections. This type of infections are typically mediated by polymicrobial biofilms, wherein microorganisms inherently display a wide range of physiological states, distinct metabolic pathways, diverging refractory levels of stress responses, and a complex network of chemical signals exchange. This review aims to provide an overview on the relevance, prevalence, and implications of HR in clinical settings. Firstly, related terminologies (e.g. resistance, tolerance, persistence), sometimes misunderstood and overlapped, were clarified. Factors generating misleading HR definitions were also uncovered. Secondly, the recent HR incidences reported in clinically relevant pathogens towards different antimicrobials were annotated. The potential mechanisms underlying such occurrences were further elucidated. Finally, the link between HR and biofilms was discussed. The focus was to recognize the presence of heterogeneous levels of resistance within most biofilms, as well as the relevance of polymicrobial biofilms in chronic infectious diseases and their role in resistance spreading. These topics were subject of a critical appraisal, gaining insights into the ascending clinical implications of HR in antimicrobial resistance spreading, which could ultimately help designing effective therapeutic options.
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Affiliation(s)
- Susana Patrícia Lopes
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Paula Jorge
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
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McCarthy RR, Larrouy-Maumus GJ, Meiqi Tan MGC, Wareham DW. Antibiotic Resistance Mechanisms and Their Transmission in Acinetobacter baumannii. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1313:135-153. [PMID: 34661894 DOI: 10.1007/978-3-030-67452-6_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The discovery of penicillin over 90 years ago and its subsequent uptake by healthcare systems around the world revolutionised global health. It marked the beginning of a golden age in antibiotic discovery with new antibiotics readily discovered from natural sources and refined into therapies that saved millions of lives. Towards the end of the last century, the rate of discovery slowed to a near standstill. The lack of discovery is compounded by the rapid emergence and spread of bacterial pathogens that exhibit resistance to multiple antibiotic therapies and threaten the sustainability of global healthcare systems. Acinetobacter baumannii is an opportunistic pathogen whose prevalence and impact has grown significantly over the last 20 years. It is recognised as a barometer of the antibiotic resistance crisis due to the diverse array of mechanisms by which it can become resistant.
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Affiliation(s)
- Ronan R McCarthy
- Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UK.
| | - Gerald J Larrouy-Maumus
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Mei Gei C Meiqi Tan
- Antimicrobial Research Group, Blizard Institute, Queen Mary University London, London, UK
| | - David W Wareham
- Antimicrobial Research Group, Blizard Institute, Queen Mary University London, London, UK
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Sykes EME, Deo S, Kumar A. Recent Advances in Genetic Tools for Acinetobacter baumannii. Front Genet 2020; 11:601380. [PMID: 33414809 PMCID: PMC7783400 DOI: 10.3389/fgene.2020.601380] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022] Open
Abstract
Acinetobacter baumannii is classified as a top priority pathogen by the World Health Organization (WHO) because of its widespread resistance to all classes of antibiotics. This makes the need for understanding the mechanisms of resistance and virulence critical. Therefore, tools that allow genetic manipulations are vital to unravel the mechanisms of multidrug resistance (MDR) and virulence in A. baumannii. A host of current strategies are available for genetic manipulations of A. baumannii laboratory-strains, including ATCC® 17978TM and ATCC® 19606T, but depending on susceptibility profiles, these strategies may not be sufficient when targeting strains newly obtained from clinic, primarily due to the latter's high resistance to antibiotics that are commonly used for selection during genetic manipulations. This review highlights the most recent methods for genetic manipulation of A. baumannii including CRISPR based approaches, transposon mutagenesis, homologous recombination strategies, reporter systems and complementation techniques with the spotlight on those that can be applied to MDR clinical isolates.
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Affiliation(s)
| | | | - Ayush Kumar
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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34
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Marr CM, MacDonald U, Trivedi G, Chakravorty S, Russo TA. An Evaluation of BfmR-Regulated Antimicrobial Resistance in the Extensively Drug Resistant (XDR) Acinetobacter baumannii Strain HUMC1. Front Microbiol 2020; 11:595798. [PMID: 33193275 PMCID: PMC7658413 DOI: 10.3389/fmicb.2020.595798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/06/2020] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is a problematic pathogen due to its common expression of extensive drug resistance (XDR) and ability to survive in the healthcare environment. These characteristics are mediated, in part, by the signal transduction system BfmR/BfmS. We previously demonstrated, in antimicrobial sensitive clinical isolates, that BfmR conferred increased resistance to meropenem and polymyxin E. In this study, potential mechanisms were informed, in part, by a prior transcriptome analysis of the antimicrobial sensitive isolate AB307-0294, which identified the porins OprB and aquaporin (Omp33-36, MapA) as plausible mediators for resistance to hydrophilic antimicrobials such as meropenem. Studies were then performed in the XDR isolate HUMC1, since delineating resistance mechanisms in this genomic background would be more translationally relevant. In HUMC1 BfmR likewise increased meropenem and polymyxin E resistance and upregulated gene expression of OprB and aquaporin. However, the comparison of HUMC1 with isogenic mutant constructs demonstrated that neither OprB nor aquaporin affected meropenem resistance; polymyxin E susceptibility was also unaffected. Next, we determined whether BfmR-mediated biofilm production affected either meropenem or polymyxin E susceptibilities. Interestingly, biofilm formation increased resistance to polymyxin E, but had little, if any effect on meropenem activity. Additionally, BfmR mediated meropenem resistance, and perhaps polymyxin E resistance, was due to BfmR regulated factors that do not affect biofilm formation. These findings increase our understanding of the mechanisms by which BfmR mediates intrinsic antimicrobial resistance in a clinically relevant XDR isolate and suggest that the efficacy of different classes of antimicrobials may vary under biofilm inducing conditions.
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Affiliation(s)
- Candace M Marr
- Department of Medicine, University at Buffalo, Buffalo, NY, United States.,Erie County Medical Center, Buffalo, NY, United States
| | - Ulrike MacDonald
- Department of Medicine, University at Buffalo, Buffalo, NY, United States.,Veterans Affairs Western New York Healthcare System, Buffalo, NY, United States
| | - Grishma Trivedi
- Department of Medicine, University at Buffalo, Buffalo, NY, United States.,Veterans Affairs Western New York Healthcare System, Buffalo, NY, United States
| | | | - Thomas A Russo
- Department of Medicine, University at Buffalo, Buffalo, NY, United States.,Veterans Affairs Western New York Healthcare System, Buffalo, NY, United States.,Department of Microbiology and Immunology, University at Buffalo, Buffalo, NY, United States.,Witebsky Center for Microbial Pathogenesis, University at Buffalo, Buffalo, NY, United States
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35
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R 93P Substitution in the PmrB HAMP Domain Contributes to Colistin Heteroresistance in Escherichia coli Isolates from Swine. Antimicrob Agents Chemother 2020; 64:AAC.01509-20. [PMID: 32868331 DOI: 10.1128/aac.01509-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/19/2020] [Indexed: 02/04/2023] Open
Abstract
Here, the mechanisms of colistin heteroresistance (CHR) were assessed in 12 Escherichia coli isolates from swine in China. CHR was investigated by population analysis profile tests. CHR stability was studied by culturing isolates for five overnight incubation periods in colistin-free medium. Subsequently, the mcr-1 gene and mutations in PmrAB, PhoPQ, and MgrB were screened in parental isolates and resistant subpopulations. Additionally, the expression levels of phoPQ, its target gene pagP, and its negative regulator gene mgrB, as well as pmrAB and its target genes pmrHFIJKLM and pmrC, were determined by real-time relative quantitative PCR. Eleven of the 12 isolates were confirmed to show CHR, with 17 resistant subpopulations. Also, 11 of the 17 subpopulations (64.71%) harbored point mutations in PmrB and/or PhoQ, differing from their parental isolates. However, only one stable resistant subpopulation (EPF42-4) was identified; it harbored an arginine-to-proline substitution at position 93 (R93P) within the PmrB HAMP (histidine kinase, adenylyl cyclase, methyl-binding protein, and phosphatase) domain. Compared to the pmrB expression levels in the parental isolate EPF42 and E. coli K-12 MG1655, remarkable pmrB overexpression was observed in EPF42-4, which showed upregulated pmrA, pmrK, and pmrC expression. Structural analysis demonstrated that the R93P substitution promotes conformational changes in the HAMP domain, leading to an acceleration in its signal transduction ability and the activation of PmrB expression. In conclusion, point mutations in PmrB and/or PhoQ were primarily associated with CHR. The R93P substitution resulted in the establishment of stable resistant subpopulations in E. coli showing CHR.
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36
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Liao W, Lin J, Jia H, Zhou C, Zhang Y, Lin Y, Ye J, Cao J, Zhou T. Resistance and Heteroresistance to Colistin in Escherichia coli Isolates from Wenzhou, China. Infect Drug Resist 2020; 13:3551-3561. [PMID: 33116674 PMCID: PMC7553605 DOI: 10.2147/idr.s273784] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/15/2020] [Indexed: 12/20/2022] Open
Abstract
Background Colistin is being administered as last-line therapy for patients that have failed to respond to other available antibiotics that are active against Escherichia coli. The underlying mechanisms of colistin resistance and heteroresistance remain largely uncharacterized. The present study investigated the mechanisms of resistance and heteroresistance to colistin in Escherichia coli isolates from Wenzhou, China. Materials and Methods Colistin resistance was detected by the broth microdilution method (BMD). Colistin heteroresistance was determined by population analysis profiles (PAPs). The polymerase chain reaction (PCR) was conducted to detect mcr-1, mcr-2, mcr-3, pmrA, pmrB, phoP, phoQ and mgrB, and quantitative real-time PCR (qRT-PCR) was used to determine the expression levels of mcr-1, pmrC, pmrA and pmrB. Lipid A characterization was conducted by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Results 0.69% (2/291) of Escherichia coli strains were resistant to colistin, whereas the heteroresistance rate reached 1.37% (4/291). mcr-1, the mobile colistin-resistance gene, was present in the two resistant isolates. The substitutions in PmrB were detected in the two heteroresistant isolates. The transcripts levels of the pmrCAB operon were upregulated in two of the heteroresistant isolates. carbonylcyanide m-chlorophenylhydrazone (CCCP) was able to reverse colistin resistance of all isolates tested and exhibited a significantly higher effect on colistin-heteroresistant isolates. MALDI-TOF MS indicated that the additional phosphoethanolamine (PEtn) moieties in lipid A profiles were present both in colistin-resistant and heteroresistant isolates. Conclusion The present study was the first to investigate the differential mechanisms between colistin resistance and heteroresistance. The development of colistin heteroresistance should be addressed in future clinical surveillance.
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Affiliation(s)
- Wenli Liao
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jie Lin
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Huaiyu Jia
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Cui Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Ying Zhang
- Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Yishuai Lin
- Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jianzhong Ye
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jianming Cao
- Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
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Lunha K, Thet KT, Ngudsuntia A, Charoensri N, Lulitanond A, Tavichakorntrakool R, Wonglakorn L, Faksri K, Chanawong A. PmrB mutations including a novel 10-amino acid repeat sequence insertion associated with low-level colistin resistance in carbapenem-resistant Acinetobacter baumannii. INFECTION GENETICS AND EVOLUTION 2020; 85:104577. [PMID: 33007498 DOI: 10.1016/j.meegid.2020.104577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 09/22/2020] [Accepted: 09/27/2020] [Indexed: 10/23/2022]
Abstract
The global emergence of colistin resistance in carbapenem-resistant Acinetobacter baumannii (CRAB) clinical isolates is a serious public health concern. We therefore aimed to investigate colistin resistance mechanisms in 5 colistin-resistant (COL-R) CRAB isolates collected from Thai patients in 2016 by whole genome sequencing (WGS) compared with those of 5 colistin-intermediate (COL-I) CRAB isolates from the same period. All isolates were subjected to antimicrobial susceptibility testing, efflux pump inhibitor-based test and WGS. Mutations in known genes associated with colistin resistance were analyzed and deleterious mutations were then predicted by PROVEAN tool. The 10 CRAB isolates carried blaOXA-23 with the addition of blaOXA-58 in 1 isolate. All COL-R isolates exhibited colistin MICs of 4 μg/mL except for 1 isolate with that of 16 μg/mL. They belonged to ST2, ST16, ST23, ST164 and ST215, whereas the COL-I isolates with colistin MICs of ≤0.25-1 μg/mL were ST2, ST164 and ST215. Neither increased efflux pump activity nor mcr gene was found in any COL-R isolate. Three COL-R isolates contained different PmrB variants: a novel 10-amino acid (aa) repeat sequence insertion, VILGCILIFS between positions 27 and 28 (S27_A28insVILGCILIFS) in transmembrane domain (TM); a 1-aa insertion, alanine between positions 162 and 163 (A162_I163insA) in TM; and a 1-aa substitution, A226T in histidine kinase domain. One COL-R isolate possessed PmrA variant with A80V substitution. These alterations were predicted as deleterious. Mechanisms of colistin resistance in the remaining COL-R isolate were still unknown. In conclusion, the alterations in both PmrB and PmrA were predicted and suggested as initial mutations responsible for low-level colistin resistance in our CRAB isolates. Under selective pressure, these isolates may exhibit higher level colistin resistance by the additional mutations, leading to more therapeutic difficulties.
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Affiliation(s)
- Kamonwan Lunha
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Khin Thet Thet
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Arisa Ngudsuntia
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Nicha Charoensri
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Aroonlug Lulitanond
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Ratree Tavichakorntrakool
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Lumyai Wonglakorn
- Clinical Microbiology Laboratory, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Kiatichai Faksri
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Aroonwadee Chanawong
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
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Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing Klebsiella pneumoniae. Microorganisms 2020; 8:microorganisms8091279. [PMID: 32825799 PMCID: PMC7569871 DOI: 10.3390/microorganisms8091279] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/14/2020] [Accepted: 08/20/2020] [Indexed: 01/24/2023] Open
Abstract
Colistin-heteroresistant (CST-HR) Enterobacterales isolates have been identified recently, challenging the clinical laboratories since routine susceptibility tests fail to detect this phenotype. In this work we describe the first CST-HR phenotype in extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates in South America. Additionally, we determine the genomic mechanisms of colistin heteroresistance in these strains. The CST-HR phenotype was analyzed by the population analysis profile (PAP) method, and mutations associated with this phenotype were determined by whole-genome sequencing (WGS) and the local BLAST+ DB tool. As a result, 8/60 isolates were classified as CST-HR according to the PAP method. From WGS, we determined that the CST-HR isolates belong to three different Sequence Types (STs) and four K-loci: ST11 (KL15 and KL81), ST25 (KL2), and ST1161 (KL19). We identified diverse mutations in the two-component regulatory systems PmrAB and PhoPQ, as well as a disruption of the mgrB global regulator mediated by IS1-like and IS-5-like elements, which could confer resistance to CST in CST-HR and ESBL-producing isolates. These are the first descriptions in Chile of CST-HR in ESBL-producing K. pneumoniae isolates. The emergence of these isolates could have a major impact on the effectiveness of colistin as a “last resort” against these isolates, thus jeopardizing current antibiotic alternatives; therefore, it is important to consider the epidemiology of the CST-HR phenotype.
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Ayoub Moubareck C. Polymyxins and Bacterial Membranes: A Review of Antibacterial Activity and Mechanisms of Resistance. MEMBRANES 2020; 10:membranes10080181. [PMID: 32784516 PMCID: PMC7463838 DOI: 10.3390/membranes10080181] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 12/19/2022]
Abstract
Following their initial discovery in the 1940s, polymyxin antibiotics fell into disfavor due to their potential clinical toxicity, especially nephrotoxicity. However, the dry antibiotic development pipeline, together with the rising global prevalence of infections caused by multidrug-resistant (MDR) Gram-negative bacteria have both rejuvenated clinical interest in these polypeptide antibiotics. Parallel to the revival of their use, investigations into the mechanisms of action and resistance to polymyxins have intensified. With an initial known effect on biological membranes, research has uncovered the detailed molecular and chemical interactions that polymyxins have with Gram-negative outer membranes and lipopolysaccharide structure. In addition, genetic and epidemiological studies have revealed the basis of resistance to these agents. Nowadays, resistance to polymyxins in MDR Gram-negative pathogens is well elucidated, with chromosomal as well as plasmid-encoded, transferrable pathways. The aims of the current review are to highlight the important chemical, microbiological, and pharmacological properties of polymyxins, to discuss their mechanistic effects on bacterial membranes, and to revise the current knowledge about Gram-negative acquired resistance to these agents. Finally, recent research, directed towards new perspectives for improving these old agents utilized in the 21st century, to combat drug-resistant pathogens, is summarized.
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Thet KT, Lunha K, Srisrattakarn A, Lulitanond A, Tavichakorntrakool R, Kuwatjanakul W, Charoensri N, Chanawong A. Colistin heteroresistance in carbapenem-resistant Acinetobacter baumannii clinical isolates from a Thai university hospital. World J Microbiol Biotechnol 2020; 36:102. [PMID: 32613355 PMCID: PMC7327205 DOI: 10.1007/s11274-020-02873-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/21/2020] [Indexed: 01/22/2023]
Abstract
Colistin is the last resort for the treatment of infections with carbapenem-resistant (CR) Gram-negative bacteria particularly Acinetobacter baumannii (CRAB). Currently, both colistin-resistant and -heteroresistant A. baumannii isolates have been reported globally. We therefore investigated the colistin heteroresistance rate in 75 non-duplicate colistin-susceptible CRAB clinical isolates from a Thai university collected in 2016. Minimum inhibitory concentrations (MICs) of colistin for all isolates were determined by broth microdilution method and carbapenemase genes were detected by PCR methods. All isolates were genotyped by ERIC-PCR method and screened for colistin heteroresistance by modified population analysis profile (PAP) method. The colistin MIC range for the 75 isolates was 0.5-2 µg/mL, with MIC50 and MIC90 of 1 and 2 µg/mL, respectively. Thirty-three isolates (44%) were considered colistin-heteroresistant with subpopulations growing at 3-8 μg/mL of colistin. After three daily passages of the subpopulations on antibiotic-free medium, their colistin MICs ranged from 4 to > 32 µg/mL, with MIC50 and MIC90 of 32 and > 32 µg/mL, respectively. Eight different ERIC-PCR profiles were obtained among the 33 isolates and all carried blaOXA-23-like. The high rate of colistin heteroresistance in the CRAB isolates highlights the possibility of treatment failure of CRAB infections by colistin due to the selection of colistin-resistant subpopulations.
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Affiliation(s)
- Khin Thet Thet
- Medical Technology Programme, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Kamonwan Lunha
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Arpasiri Srisrattakarn
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Aroonlug Lulitanond
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Ratree Tavichakorntrakool
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Waewta Kuwatjanakul
- Clinical Microbiology Unit, Faculty of Medicine, Srinagarind Hospital, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Nicha Charoensri
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Aroonwadee Chanawong
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand.
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Fodor A, Abate BA, Deák P, Fodor L, Gyenge E, Klein MG, Koncz Z, Muvevi J, Ötvös L, Székely G, Vozik D, Makrai L. Multidrug Resistance (MDR) and Collateral Sensitivity in Bacteria, with Special Attention to Genetic and Evolutionary Aspects and to the Perspectives of Antimicrobial Peptides-A Review. Pathogens 2020; 9:pathogens9070522. [PMID: 32610480 PMCID: PMC7399985 DOI: 10.3390/pathogens9070522] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic poly-resistance (multidrug-, extreme-, and pan-drug resistance) is controlled by adaptive evolution. Darwinian and Lamarckian interpretations of resistance evolution are discussed. Arguments for, and against, pessimistic forecasts on a fatal “post-antibiotic era” are evaluated. In commensal niches, the appearance of a new antibiotic resistance often reduces fitness, but compensatory mutations may counteract this tendency. The appearance of new antibiotic resistance is frequently accompanied by a collateral sensitivity to other resistances. Organisms with an expanding open pan-genome, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, can withstand an increased number of resistances by exploiting their evolutionary plasticity and disseminating clonally or poly-clonally. Multidrug-resistant pathogen clones can become predominant under antibiotic stress conditions but, under the influence of negative frequency-dependent selection, are prevented from rising to dominance in a population in a commensal niche. Antimicrobial peptides have a great potential to combat multidrug resistance, since antibiotic-resistant bacteria have shown a high frequency of collateral sensitivity to antimicrobial peptides. In addition, the mobility patterns of antibiotic resistance, and antimicrobial peptide resistance, genes are completely different. The integron trade in commensal niches is fortunately limited by the species-specificity of resistance genes. Hence, we theorize that the suggested post-antibiotic era has not yet come, and indeed might never come.
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Affiliation(s)
- András Fodor
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
| | - Birhan Addisie Abate
- Ethiopian Biotechnology Institute, Agricultural Biotechnology Directorate, Addis Ababa 5954, Ethiopia;
| | - Péter Deák
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Institute of Biochemistry, Biological Research Centre, H-6726 Szeged, Hungary
| | - László Fodor
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
| | - Ervin Gyenge
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
| | - Michael G. Klein
- Department of Entomology, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, USA;
| | - Zsuzsanna Koncz
- Max-Planck Institut für Pflanzenzüchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany;
| | | | - László Ötvös
- OLPE, LLC, Audubon, PA 19403-1965, USA;
- Institute of Medical Microbiology, Semmelweis University, H-1085 Budapest, Hungary
- Arrevus, Inc., Raleigh, NC 27612, USA
| | - Gyöngyi Székely
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
- Centre for Systems Biology, Biodiversity and Bioresources, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania
| | - Dávid Vozik
- Research Institute on Bioengineering, Membrane Technology and Energetics, Faculty of Engineering, University of Veszprem, H-8200 Veszprém, Hungary; or or
| | - László Makrai
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
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Karakonstantis S, Saridakis I. Colistin heteroresistance in Acinetobacter spp.: systematic review and meta-analysis of the prevalence and discussion of the mechanisms and potential therapeutic implications. Int J Antimicrob Agents 2020; 56:106065. [PMID: 32599229 DOI: 10.1016/j.ijantimicag.2020.106065] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/30/2020] [Accepted: 06/20/2020] [Indexed: 01/29/2023]
Abstract
BACKGROUND Colistin is one of the few remaining options for carbapenem-resistant Acinetobacter baumannii (A. baumannii); however, emergence of resistance from heteroresistant populations is possible. This review aimed to systematically search and consolidate the literature on the prevalence, mechanisms and therapeutic implications of colistin heteroresistance in Acinetobacter spp. METHODS A systematic search was conducted in PubMed and Scopus. The pooled prevalence of colistin heteroresistance was calculated using meta-analysis of proportions with the Freeman-Tukey transformation and the random-effects (DerSimonian and Laird) method. RESULTS Based on 15 studies the prevalence of colistin heteroresistance was 33% (95% CI 16-53%) but considerable heterogeneity was observed (I2 = 96%, P < 0.001). Prior exposure to colistin was associated with a higher proportion of resistant subpopulations. Colistin heteroresistance may result from chromosomal mutations in resistant subpopulations (predominantly in PmrAB and lpx genes) resulting in lipopolysaccharide modification or loss, or overexpression of efflux pumps. No dosage scheme of colistin monotherapy can prevent the emergence of resistant subpopulations in vitro, but few studies have reported in vivo emergence of resistance from heteroresistant A. baumannii during treatment, and studies examining the correlation between heteroresistance and clinical/microbiological outcomes are lacking. Several colistin-based combinations have been shown in vitro to prevent the emergence of the resistant subpopulations but none have been translated so far into clinical benefit. Reasons for this discrepancy are discussed. CONCLUSIONS Colistin heteroresistance was common but highly variable between studies. The impact of colistin heteroresistance (frequency of emergent resistance during treatment and correlation with treatment outcomes) requires further study.
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Affiliation(s)
- Stamatis Karakonstantis
- School of Medicine, University of Crete, Heraklion, Crete, Greece; Internal Medicine Department, General Hospital of Heraklion Venizeleio, Heraklion, Crete, Greece.
| | - Ioannis Saridakis
- Internal Medicine Department, General Hospital of Heraklion Venizeleio, Heraklion, Crete, Greece
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Çağlan E, Nigiz Ş, Sancak B, Gür D. Resistance and heteroresistance to colistin among clinical isolates of Acinetobacter baumannii. Acta Microbiol Immunol Hung 2020; 67:107-111. [PMID: 31813259 DOI: 10.1556/030.66.2019.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 08/13/2019] [Indexed: 01/05/2023]
Abstract
Colistin is one of the most effective alternatives for treating Acinetobacter baumannii infections. The aim of this study was to determine colistin resistance and heteroresistance rates in A. baumannii from clinical samples in Hacettepe University clinical microbiology laboratory between June 2016 and January 2017. A total of 200 isolates were included in the study. In vitro susceptibility to amikacin, gentamicin, ceftazidime, piperacillin/tazobactam, meropenem, ciprofloxacin, and tigecycline were determined by disk diffusion test. Most isolates were multiresistant as they exhibited resistance to aminoglycosides, β-lactams, and fluoroquinolones. Colistin susceptibility was determined by broth microdilution (BMD) test (EUCAST standards) and was compared with E-test (bioMérieux, France) in 120 isolates. In 14 blood isolates that were susceptible to colistin (MIC ≤ 2 mg/L), heteroresistance was investigated with the population analysis profile (PAP) method. Overall resistance (n = 200) to colistin was 28% by BMD. Among the 120 isolates where the two tests were compared, resistance to colistin was 25.8% versus 4.2% with BMD and E-test, respectively. Three blood isolates (21.4%) were heteroresistant to colistin. With E-test, a majority of the resistant isolates are overlooked and in vitro susceptibility to colistin should be determined with broth dilution method. This is the first study in Turkey reporting heteroresistance in A. baumannii isolates by the PAP method and emphasizes the need to test for heteroresistance in relation to clinical outcome in serious infections due to A. baumannii.
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Affiliation(s)
- Ecem Çağlan
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Şeyma Nigiz
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Banu Sancak
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Deniz Gür
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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Palmieri M, D’Andrea MM, Pelegrin AC, Perrot N, Mirande C, Blanc B, Legakis N, Goossens H, Rossolini GM, van Belkum A. Abundance of Colistin-Resistant, OXA-23- and ArmA-Producing Acinetobacter baumannii Belonging to International Clone 2 in Greece. Front Microbiol 2020; 11:668. [PMID: 32425900 PMCID: PMC7212473 DOI: 10.3389/fmicb.2020.00668] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/24/2020] [Indexed: 12/14/2022] Open
Abstract
Carbapenem resistant Acinetobacter baumannii (CRAB) represents one of the most challenging pathogens in clinical settings. Colistin is routinely used for treatment of infections by this pathogen, but increasing colistin resistance has been reported. We obtained 122 CRAB isolates from nine Greek hospitals between 2015 and 2017, and those colistin resistant (ColR; N = 40, 32.8%) were whole genome sequenced, also by including two colistin susceptible (ColS) isolates for comparison. All ColR isolates were characterized by a previously described mutation, PmrBA226V, which was associated with low-level colistin resistance. Some isolates were characterized by additional mutations in PmrB (E140V or L178F) or PmrA (K172I or D10N), first described here, and higher colistin minimum inhibitory concentrations (MICs), up to 64 mg/L. Mass spectrometry analysis of lipid A showed the presence of a phosphoethanolamine (pEtN) moiety on lipid A, likely resulting from the PmrA/B-induced pmrC overexpression. Interestingly, also the two ColS isolates had the same lipid A modification, suggesting that not all lipid A modifications lead to colistin resistance or that other factors could contribute to the resistance phenotype. Most of the isolates (N = 37, 92.5%) belonged to the globally distributed international clone (IC) 2 and comprised four different sequence types (STs) as defined by using the Oxford scheme (ST 425, 208, 451, and 436). Three isolates belonged to IC1 and ST1567. All the genomes harbored an intrinsic bla OXA-51 group carbapenemase gene, where bla OXA-66 and bla OXA-69 were associated with IC2 and IC1, respectively. Carbapenem resistance was due to the most commonly reported acquired carbapenemase gene bla OXA-23, with ISAba1 located upstream of the gene and likely increasing its expression. The armA gene, associated with high-level resistance to aminoglycosides, was detected in 87.5% of isolates. Collectively, these results revealed a convergent evolution of different clonal lineages toward the same colistin resistance mechanism, thus limiting the effective therapeutic options for the treatment of CRAB infections.
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Affiliation(s)
- Mattia Palmieri
- bioMérieux, Data Analytics Unit, La Balme-les-Grottes, France
| | - Marco Maria D’Andrea
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | | | - Nadine Perrot
- bioMérieux, R&D Microbiology, La Balme-les-Grottes, France
| | | | | | | | - Herman Goossens
- Laboratory of Medical Microbiology, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
- Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy
| | - Alex van Belkum
- bioMérieux, Data Analytics Unit, La Balme-les-Grottes, France
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Acquisition of Colistin Resistance Links Cell Membrane Thickness Alteration with a Point Mutation in the lpxD Gene in Acinetobacter baumannii. Antibiotics (Basel) 2020; 9:antibiotics9040164. [PMID: 32268563 PMCID: PMC7235794 DOI: 10.3390/antibiotics9040164] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 02/04/2023] Open
Abstract
Acinetobacter baumannii is one of the most common causes of nosocomial infections in intensive care units. Its ability to acquire diverse mechanisms of resistance limits the therapeutic choices for its treatment. This especially concerns colistin, which has been reused recently as a last-resort drug against A. baumannii. Here, we explored the impact of gaining colistin resistance on the susceptibility of A. baumannii to other antibiotics and linked colistin resistance acquisition to a gene mutation in A. baumannii. The susceptibility of 95 A. baumannii isolates revealed that 89 isolates were multi-drug resistance (MDR), and nine isolates were resistant to colistin. Subsequently, three isolates, i.e., MS48, MS50, and MS64, exhibited different resistance patterns when colistin resistance was induced and gained resistance to almost all tested antibiotics. Upon TEM examination, morphological alterations were reported for all induced isolates and a colistin-resistant clinical isolate (MS34Col-R) compared to the parental sensitive strains. Finally, genetic alterations in PmrB and LpxACD were assessed, and a point mutation in LpxD was identified in the MS64Col-R and MS34Col-R mutants, corresponding to Lys117Glu substitution in the lipid-binding domain. Our findings shed light on the implications of using colistin in the treatment of A. baumannii, especially at sub-minimum inhibitory concentrations concentrations, since cross-resistance to other classes of antibiotics may emerge, beside the rapid acquisition of resistance against colistin itself due to distinct genetic events.
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Ma X, He Y, Yu X, Cai Y, Zeng J, Cai R, Lu Y, Chen L, Chen C, Huang B. Ceftazidime/avibactam Improves the Antibacterial Efficacy of Polymyxin B Against Polymyxin B Heteroresistant KPC-2-Producing Klebsiella pneumoniae and Hinders Emergence of Resistant Subpopulation in vitro. Front Microbiol 2019; 10:2029. [PMID: 31551966 PMCID: PMC6735287 DOI: 10.3389/fmicb.2019.02029] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 08/19/2019] [Indexed: 12/11/2022] Open
Abstract
Due to the increasing multidrug resistance and limited antibiotics, polymyxin B revived as the last resort for the treatment of carbapenemase-producing Klebsiella pneumoniae (CRKP). Unfortunately, the heteroresistance hampers polymyxin B monotherapy treatment via the amplification of resistant subpopulation. Reliable polymyxin B based combinations are demanded. Ceftazidime/avibactam has been regarded as a new salvage therapy against CRKP. The occurrence of heteroresistance was confirmed by population analysis profiling (PAP). Our study demonstrated that polymyxin B and ceftazidime/avibactam combinations improved the in vitro antimicrobial activity of polymyxin B and delayed or suppressed the regrowth of resistant subpopulation by time-kill studies. Ceftazidime/avibactam at around MIC values (0.5–1 × MIC) plus clinically achievable concentrations of polymyxin B (0.5–2 mg/L) resulted in sustained killing against polymyxin B-heteroresistant isolates. Active PmrAB and PhoPQ systems and a pmrA mutation (G53R) in resistant subpopulation might associate with heteroresistance, but further investigation was required. Our findings suggested that the heteroresistance represented barriers to polymyxin B efficacy, and the combination of polymyxin B with ceftazidime/avibactam could be potentially valuable for the treatment of heteroresistant CRKP. Further, in vivo studies need to be performed to evaluate the efficacy of this combination against heteroresistant strains.
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Affiliation(s)
- Xingyan Ma
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yuting He
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xuegao Yu
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yimei Cai
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jianming Zeng
- Department of Laboratory Medicine, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Renxin Cai
- Department of Laboratory Medicine, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Yang Lu
- Department of Laboratory Medicine, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Liang Chen
- Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Cha Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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Resistance and Heteroresistance to Colistin in Pseudomonas aeruginosa Isolates from Wenzhou, China. Antimicrob Agents Chemother 2019; 63:AAC.00556-19. [PMID: 31383654 DOI: 10.1128/aac.00556-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/28/2019] [Indexed: 01/26/2023] Open
Abstract
The goal was to investigate the mechanisms of colistin resistance and heteroresistance in Pseudomonas aeruginosa clinical isolates. Colistin resistance was determined by the broth microdilution method. Colistin heteroresistance was evaluated by population analysis profiling. Time-kill assays were also conducted. PCR sequencing was performed to detect the resistance genes among (hetero)resistant isolates, and quantitative real-time PCR assays were performed to determine their expression levels. Pulsed-field gel electrophoresis and multilocus sequence typing were performed. Lipid A characteristics were determined via matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS). Two resistant isolates and 9 heteroresistant isolates were selected in this study. Substitutions in PmrB were detected in 2 resistant isolates. Among heteroresistant isolates, 8 of 9 heteroresistant isolates had nonsynonymous PmrB substitutions, and 2 isolates, including 1 with a PmrB substitution, had PhoQ alterations. Correspondingly, the expression levels of pmrA or phoP were upregulated in PmrB- or PhoQ-substituted isolates. One isolate also found alterations in ParRS and CprRS. The transcript levels of the pmrH gene were observed to increase across all investigated isolates. MALDI-TOF MS showed additional 4-amino-4-deoxy-l-arabinose (l-Ara4N) moieties in lipid A profiles in (hetero)resistant isolates. In conclusion, both colistin resistance and heteroresistance in P. aeruginosa in this study mainly involved alterations of the PmrAB regulatory system. There were strong associations between mutations in specific genetic loci for lipid A synthesis and regulation of modifications to lipid A. The transition of colistin heteroresistance to resistance should be addressed in future clinical surveillance.
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Richter P, Krüger M, Prasad B, Gastiger S, Bodenschatz M, Wieder F, Burkovski A, Geißdörfer W, Lebert M, Strauch SM. Using Colistin as a Trojan Horse: Inactivation of Gram-Negative Bacteria with Chlorophyllin. Antibiotics (Basel) 2019; 8:E158. [PMID: 31547053 PMCID: PMC6963628 DOI: 10.3390/antibiotics8040158] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 12/11/2022] Open
Abstract
Colistin (polymyxin E) is a membrane-destabilizing antibiotic used against Gram-negative bacteria. We have recently reported that the outer membrane prevents the uptake of antibacterial chlorophyllin into Gram-negative cells. In this study, we used sub-toxic concentrations of colistin to weaken this barrier for a combination treatment of Escherichia coli and Salmonella enterica serovar Typhimurium with chlorophyllin. In the presence of 0.25 µg/mL colistin, chlorophyllin was able to inactivate both bacteria strains at concentrations of 5-10 mg/L for E. coli and 0.5-1 mg/L for S. Typhimurium, which showed a higher overall susceptibility to chlorophyllin treatment. In accordance with a previous study, chlorophyllin has proven antibacterial activity both as a photosensitizer, illuminated with 12 mW/cm2, and in darkness. Our data clearly confirmed the relevance of the outer membrane in protection against xenobiotics. Combination treatment with colistin broadens chlorophyllin's application spectrum against Gram-negatives and gives rise to the assumption that chlorophyllin together with cell membrane-destabilizing substances may become a promising approach in bacteria control. Furthermore, we demonstrated that colistin acts as a door opener even for the photodynamic inactivation of colistin-resistant (mcr-1-positive) E. coli cells by chlorophyllin, which could help us to overcome this antimicrobial resistance.
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Affiliation(s)
- Peter Richter
- Cell Biology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Marcus Krüger
- Clinic for Plastic, Aesthetic and Hand Surgery, Otto von Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
| | - Binod Prasad
- Cell Biology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Susanne Gastiger
- Microbiology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Mona Bodenschatz
- Microbiology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Florian Wieder
- Cell Biology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Andreas Burkovski
- Microbiology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Walter Geißdörfer
- Microbiological Diagnostics, Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Wasserturmstraße 3/5, 91054 Erlangen, Germany.
| | - Michael Lebert
- Cell Biology Division, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstraße 5, 91058 Erlangen, Germany.
| | - Sebastian M Strauch
- Postgraduate Program in Health and Environment, University of Joinville Region, Rua Paulo Malschitzki, 10, Joinville 89219-710, Brazil.
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Affiliation(s)
- Victor I. Band
- Emory Antibiotic Resistance Center, Emory University, Atlanta, Georgia, United States of America
- Emory Vaccine Center, Emory University, Atlanta, Georgia, United States of America
| | - David S. Weiss
- Emory Antibiotic Resistance Center, Emory University, Atlanta, Georgia, United States of America
- Emory Vaccine Center, Emory University, Atlanta, Georgia, United States of America
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
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Sequential emergence of colistin and rifampicin resistance in an OXA-72- producing outbreak strain of Acinetobacter baumannii. Int J Antimicrob Agents 2019; 53:669-673. [DOI: 10.1016/j.ijantimicag.2019.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/21/2018] [Accepted: 01/21/2019] [Indexed: 11/24/2022]
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