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Li W, Tao Z, Zhou M, Jiang H, Wang L, Ji B, Zhao Y. Antibiotic adjuvants against multidrug-resistant Gram-negative bacteria: important component of future antimicrobial therapy. Microbiol Res 2024; 287:127842. [PMID: 39032266 DOI: 10.1016/j.micres.2024.127842] [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: 04/24/2024] [Revised: 07/13/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024]
Abstract
The swift emergence and propagation of multidrug-resistant (MDR) bacterial pathogens constitute a tremendous global health crisis. Among these pathogens, the challenge of antibiotic resistance in Gram-negative bacteria is particularly pressing due to their distinctive structure, such as highly impermeable outer membrane, overexpressed efflux pumps, and mutations. Several strategies have been documented to combat MDR Gram-negative bacteria, including the structural modification of existing antibiotics, the development of antimicrobial adjuvants, and research on novel targets that MDR bacteria are sensitive to. Drugs functioning as adjuvants to mitigate resistance to existing antibiotics may play a pivotal role in future antibacterial therapy strategies. In this review, we provide a brief overview of potential antibacterial adjuvants against Gram-negative bacteria and their mechanisms of action, and discuss the application prospects and potential for bacterial resistance to these adjuvants, along with strategies to reduce this risk.
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Affiliation(s)
- Wenwen Li
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Zhen Tao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Motan Zhou
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Huilin Jiang
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Liudi Wang
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Bingjie Ji
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Yongshan Zhao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China.
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Pan Z, Dai C, Li W. Material-based treatment strategies against intraosseous implant biofilm infection. Biochem Biophys Rep 2024; 39:101764. [PMID: 39040541 PMCID: PMC11261528 DOI: 10.1016/j.bbrep.2024.101764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/22/2024] [Accepted: 06/25/2024] [Indexed: 07/24/2024] Open
Abstract
Implant-associated infections present a significant clinical obstacle for orthopedic practitioners, with bacterial biofilm formation serving as a pivotal factor in the initiation, progression, and management of such infections. Conventional approaches have proven inadequate in fully eradicating biofilm-related infections. Consequently, novel material-based therapeutic strategies have been developed, encompassing the utilization of antimicrobial agents, delivery vehicles, and synergistic antibacterial systems. In this review, we provide a succinct overview of recent advancements in anti-biofilm strategies, with the aim of offering insights that may aid in the treatment of intraosseous implant infections.
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Affiliation(s)
- Zhuoer Pan
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China
- Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China
| | - Chengxin Dai
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China
- Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China
| | - Weixu Li
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China
- Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China
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Scribano D, Cheri E, Pompilio A, Di Bonaventura G, Belli M, Cristina M, Sansone L, Zagaglia C, Sarshar M, Palamara AT, Ambrosi C. Acinetobacter baumannii OmpA-like porins: functional characterization of bacterial physiology, antibiotic-resistance, and virulence. Commun Biol 2024; 7:948. [PMID: 39107399 PMCID: PMC11303520 DOI: 10.1038/s42003-024-06645-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 07/29/2024] [Indexed: 08/10/2024] Open
Abstract
Acinetobacter baumannii is a critical opportunistic pathogen associated with nosocomial infections. The high rates of antibiotic-resistance acquisition make most antibiotics ineffective. Thus, new medical countermeasures are urgently needed. Outer membrane proteins (OMPs) are prime candidates for developing novel drug targets and antibacterial strategies. However, there are substantial gaps in our knowledge of A. baumannii OMPs. This study reports the impact of OmpA-like protein on bacterial physiology and virulence in A. baumannii strain AB5075. We found that PsaB (ABUW_0505) negatively correlates to stress tolerance, while ArfA (ABUW_2730) significantly affects bacterial stiffness, cell shape, and cell envelope thickness. Furthermore, we expand our knowledge on YiaD (ABUW_3045), demonstrating structural and virulence roles of this porin, in addition to meropenem resistance. This study provides solid foundations for understanding how uncharacterized OMPs contribute to A. baumannii's physiological and pathological processes, aiding the development of innovative therapeutic strategies against A. baumannii infections.
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Affiliation(s)
- Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Elena Cheri
- Research Laboratories, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Arianna Pompilio
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
- Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Giovanni Di Bonaventura
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
- Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Manuel Belli
- Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Rome, Italy
- Laboratory of Molecular and Cellular Pathology, IRCCS San Raffaele Roma, Rome, Italy
| | - Mario Cristina
- Laboratory of Molecular and Cellular Pathology, IRCCS San Raffaele Roma, Rome, Italy
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Luigi Sansone
- Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Rome, Italy
- Laboratory of Molecular and Cellular Pathology, IRCCS San Raffaele Roma, Rome, Italy
| | - Carlo Zagaglia
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Meysam Sarshar
- Research Laboratories, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anna Teresa Palamara
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory Affiliated to Institute Pasteur Italia-Cenci Bolognetti Foundation, Rome, Italy
| | - Cecilia Ambrosi
- Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Rome, Italy.
- Laboratory of Microbiology of Chronic-Neurodegenerative Diseases, IRCCS San Raffaele Roma, Rome, Italy.
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Chen J, Wang Y, Zhang N, Li J, Liu X. Genotypic and phenotypic characteristics of Acinetobacter baumannii isolates from the people's hospital of Qingyang City, Gansu province. BMC Genomics 2024; 25:727. [PMID: 39060939 PMCID: PMC11282657 DOI: 10.1186/s12864-024-10601-x] [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: 08/04/2023] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
BACKGROUND Acinetobacter baumannii (A. baumannii) is a common opportunistic pathogen in hospitals that causes nosocomial infection. In order to understand the phenotypic and genotypic characteristics of A. baumannii isolates, we sequenced and analyzed 62 A. baumannii isolates from a hospital in Gansu province. RESULTS Non-repeated 62 A. baumannii isolates were collected from August 2015 to November 2021. Most isolates (56/62) were resistant to multiple drugs. All the 62 A. baumannii isolates were resistant to aztreonam and contained blaADC-25 gene which exists only on chromosome contigs. The 62 isolates in this study were not clustered in a single clade, but were dispersed among multiple clades in the common genome. Seven sequence types were identified by Multilocus sequence type (MLST) analysis and most isolates (52/62) belonged to ST2. The plasmids were grouped into 11 clusters by MOB-suite. CONCLUSIONS This study furthers the understanding of A. baumannii antimicrobial-resistant genotypes, and may aid in prevention and control nosocomial infection caused by drug-resistant A. baumannii.
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Affiliation(s)
- Jiali Chen
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China
- School of Medicine, Nankai University, Tianjin, 300071, China
| | - Yang Wang
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China
| | - Na Zhang
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Juan Li
- Department of Clinical Laboratory Medicine, Qingyang People's Hospital, Qingyang, Gansu, 745000, China.
| | - Xiong Liu
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
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Qiu Z, Yuan K, Cao H, Chen S, Chen F, Mo F, Guo G, Peng J. Cross-talk of MLST and transcriptome unveiling antibiotic resistance mechanism of carbapenem resistance Acinetobacter baumannii clinical strains isolated in Guiyang, China. Front Microbiol 2024; 15:1394775. [PMID: 38946905 PMCID: PMC11211267 DOI: 10.3389/fmicb.2024.1394775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 05/23/2024] [Indexed: 07/02/2024] Open
Abstract
Introduction Acinetobacter baumannii (A. baumannii) is an important opportunistic pathogen causing nosocomial infection in the clinic. The occurrence rate of antibiotic resistance is increasing year by year, resulting in a highly serious situation of bacterial resistance. Methods To better understand the local epidemiology of multidrug-resistant A. baumannii, an investigation was conducted on the antibiotic resistance of different types of A. baumannii and its relationship with the genes of A. baumannii. Furthermore, the molecular mechanism underlying antibiotic resistance in A. baumannii was investigated through transcriptome analysis. Results These results showed that a total of 9 STs were detected. It was found that 99% of the strains isolated in the hospital belonged to the same STs, and the clone complex CC208 was widely distributed in various departments and all kinds of samples. Furthermore, these A. baumannii strains showed high resistance to ertapenem, biapenem, meropenem, and imipenem, among which the resistance to ertapenem was the strongest. The detection rate of bla OXA-51 gene in these carbapenem resistance A. baumannii (CRAB) reached 100%; Additionally, the transcriptome results showed that the resistance genes were up-regulated in resistance strains, and these genes involved in biofilm formation, efflux pumps, peptidoglycan biosynthesis, and chaperonin synthesis. Discussion These results suggest that the CC208 STs were the main clonal complex, and showed high carbapenem antibiotic resistance. All these resistant strains were distributed in various departments, but most of them were distributed in intensive care units (ICU). The bla OXA-23 was the main antibiotic resistance genotype; In summary, the epidemic trend of clinical A. baumannii in Guiyang, China was analyzed from the molecular level, and the resistance mechanism of A. baumannii to carbapenem antibiotics was analyzed with transcriptome, which provided a theoretical basis for better control of A. baumannii.
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Affiliation(s)
- Zhilang Qiu
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Cellular Immunotherapy Engineering Research Center of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- The Key and Characteristic Laboratory of Modern Pathogen Biology, Basic Medical College, Guizhou Medical University, Guiyang, China
| | - Kexin Yuan
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
- The Key and Characteristic Laboratory of Modern Pathogen Biology, Basic Medical College, Guizhou Medical University, Guiyang, China
| | - Huijun Cao
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Sufang Chen
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Cellular Immunotherapy Engineering Research Center of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- The Key and Characteristic Laboratory of Modern Pathogen Biology, Basic Medical College, Guizhou Medical University, Guiyang, China
| | - Feifei Chen
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Cellular Immunotherapy Engineering Research Center of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
| | - Fei Mo
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Guo Guo
- The Key and Characteristic Laboratory of Modern Pathogen Biology, Basic Medical College, Guizhou Medical University, Guiyang, China
- Translational Medicine Research Center, Guizhou Medical University, Guiyang, China
| | - Jian Peng
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Cellular Immunotherapy Engineering Research Center of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- The Key and Characteristic Laboratory of Modern Pathogen Biology, Basic Medical College, Guizhou Medical University, Guiyang, China
- Translational Medicine Research Center, Guizhou Medical University, Guiyang, China
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Nayak S, Akshay SD, Deekshit VK, Raj JM, Maiti B. Exposure to imipenem at sub-minimum inhibitory concentration leads to altered expression of major outer membrane proteins in Acinetobacter baumannii. J Appl Microbiol 2024; 135:lxae105. [PMID: 38653725 DOI: 10.1093/jambio/lxae105] [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: 02/06/2024] [Revised: 04/15/2024] [Accepted: 04/22/2024] [Indexed: 04/25/2024]
Abstract
AIMS Acinetobacter baumannii is a nosocomial pathogen known to be multidrug-resistant (MDR), especially to drugs of the carbapenem class. Several factors contribute to resistance, including efflux pumps, β-lactamases, alteration of target sites, and permeability defects. In addition, outer membrane proteins (OMPs), like porins are involved in the passage of antibiotics, and their alteration could lead to resistance development. This study aimed to explore the possible involvement of porins and OMPs in developing carbapenem resistance due to differential expression. METHODS AND RESULTS The antibiotic-susceptible and MDR isolates of A. baumannii were first studied for differences in their transcriptional levels of OMP expression and OMP profiles. The antibiotic-susceptible isolates were further treated with imipenem, and it was found that the omp genes were differentially expressed. Six of the nine genes studied were upregulated at 1 h of exposure to imipenem. Their expression gradually decreased with time, further confirmed by their OMP profile and two-dimensional gel electrophoresis. CONCLUSIONS This study could identify OMPs that were differentially expressed on exposure to imipenem. Hence, this study provides insights into the role of specific OMPs in antibiotic resistance in A. baumannii.
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Affiliation(s)
- Srajana Nayak
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Bio & Nano Technology, Deralakatte, Mangaluru 575018, India
| | - Sadanand Dangari Akshay
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Bio & Nano Technology, Deralakatte, Mangaluru 575018, India
| | - Vijaya Kumar Deekshit
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Infectious Diseases & Microbial Genomics, Deralakatte, Mangaluru 575018, India
| | - Juliet Mohan Raj
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Infectious Diseases & Microbial Genomics, Deralakatte, Mangaluru 575018, India
| | - Biswajit Maiti
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Bio & Nano Technology, Deralakatte, Mangaluru 575018, India
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Li P, Zhang S, Wang J, Al-Shamiri MM, Luo K, Liu S, Mi P, Wu X, Liu H, Tian H, Han B, Lei J, Han S, Han L. The role of type VI secretion system genes in antibiotic resistance and virulence in Acinetobacter baumannii clinical isolates. Front Cell Infect Microbiol 2024; 14:1297818. [PMID: 38384301 PMCID: PMC10879597 DOI: 10.3389/fcimb.2024.1297818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
Introduction The type VI secretion system (T6SS) is a crucial virulence factor in the nosocomial pathogen Acinetobacter baumannii. However, its association with drug resistance is less well known. Notably, the roles that different T6SS components play in the process of antimicrobial resistance, as well as in virulence, have not been systematically revealed. Methods The importance of three representative T6SS core genes involved in the drug resistance and virulence of A. baumannii, namely, tssB, tssD (hcp), and tssM was elucidated. Results A higher ratio of the three core genes was detected in drug-resistant strains than in susceptible strains among our 114 A. baumannii clinical isolates. Upon deletion of tssB in AB795639, increased antimicrobial resistance to cefuroxime and ceftriaxone was observed, alongside reduced resistance to gentamicin. The ΔtssD mutant showed decreased resistance to ciprofloxacin, norfloxacin, ofloxacin, tetracycline, and doxycycline, but increased resistance to tobramycin and streptomycin. The tssM-lacking mutant showed an increased sensitivity to ofloxacin, polymyxin B, and furazolidone. In addition, a significant reduction in biofilm formation was observed only with the ΔtssM mutant. Moreover, the ΔtssM strain, followed by the ΔtssD mutant, showed decreased survival in human serum, with attenuated competition with Escherichia coli and impaired lethality in Galleria mellonella. Discussion The above results suggest that T6SS plays an important role, participating in the antibiotic resistance of A. baumannii, especially in terms of intrinsic resistance. Meanwhile, tssM and tssD contribute to bacterial virulence to a greater degree, with tssM being associated with greater importance.
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Affiliation(s)
- Pu Li
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Sirui Zhang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Jingdan Wang
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Mona Mohamed Al-Shamiri
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Kai Luo
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Shuyan Liu
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Peng Mi
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
- Department of Laboratory Medicine, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Xiaokang Wu
- Department of Laboratory Medicine, the Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Haiping Liu
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
- Department of Laboratory Medicine, Xi’an Daxing Hospital, Xi’an, China
| | - Huohuan Tian
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Bei Han
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
| | - Jin’e Lei
- Department of Laboratory Medicine, the First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Shaoshan Han
- Department of Hepatobiliary Surgery, the First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Lei Han
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy in Acinetobacter baumannii undecaprenyl biosynthesis and maintenance of lipid asymmetry impacts outer membrane and antimicrobial resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.556980. [PMID: 37790371 PMCID: PMC10542541 DOI: 10.1101/2023.09.22.556980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Acinetobacter baumannii is a Gram-negative healthcare-associated pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The outer membrane has an asymmetric composition that is important for structural integrity and barrier to the environment. Therefore, Gram-negative bacteria have mechanisms to uphold this asymmetry such as the maintenance of lipid asymmetry system (Mla), which removes glycerophospholipids from the outer leaflet of the outer membrane and transports them to the inner membrane. Loss of this system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978, 17978VU and 17978UN. We show here that ΔmlaF mutants in the two strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. We used comparative genetics to identify interactions between ATCC 17978 strain alleles and mlaF to uncover the cause behind the phenotypic differences. Although allele differences in obgE were previously reported to synergize with ΔmlaF to affect growth and stringent response, we show that obgE alleles do not affect membrane stress resistance. Instead, a single nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, synergizes with ΔmlaF to increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier known to be required for biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. Our data suggest that in the absence of the Mla system, the cellular level of Und-P is critical for envelope integrity, antibiotic resistance, and lipooligosaccharide abundance. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii outer membrane and stress resistance.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
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Al-Shamiri MM, Wang J, Zhang S, Li P, Odhiambo WO, Chen Y, Han B, Yang E, Xun M, Han L, Han S. Probiotic Lactobacillus Species and Their Biosurfactants Eliminate Acinetobacter baumannii Biofilm in Various Manners. Microbiol Spectr 2023; 11:e0461422. [PMID: 36920192 PMCID: PMC10100725 DOI: 10.1128/spectrum.04614-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
Acinetobacter baumannii is a critical biofilm-forming pathogen that has presented great challenges in the clinic due to multidrug resistance. Thus, new methods of intervention are needed to control biofilm-associated infections. In this study, among three tested Lactobacillus species, Lactobacillus rhamnosus showed significant antimaturation and antiadherence effects against A. baumannii biofilm. Lactic acid (LA) and acetic acid (AA) were the most effective antibiofilm biosurfactants (BSs) produced by L. rhamnosus. This antibiofilm phenomenon produced by LA and AA was due to the strong bactericidal effect, which worked from very early time points, as determined by colony enumeration and confocal laser scanning microscope. The cell destruction of A. baumannii appeared in both the cell envelope and cytoplasm. A discontinuous cell envelope, the leakage of cell contents, and the increased extracellular activity of ATPase demonstrated the disruption of the cell membrane by LA and AA. These effects also demonstrated the occurrence of protein lysis. In addition, bacterial DNA interacted with and was damaged by LA and AA, resulting in significantly reduced expression of biofilm and DNA repair genes. The results highlight the possibility and importance of using probiotics in clinical prevention. Probiotics can be utilized as novel biocides to block and decrease biofilm formation and microbial contamination in medical equipment and during the treatment of infections. IMPORTANCE A. baumannii biofilm is a significant virulence factor that causes the biofilm colonization of invasive illnesses. Rising bacterial resistance to synthetic antimicrobials has prompted researchers to look at natural alternatives, such as probiotics and their derivatives. In this study, L. rhamnosus and its BSs (LA and AA) demonstrated remarkable antibiofilm and antimicrobial characteristics, with a significant inhibitory effect on A. baumannii. These effects were achieved by several mechanisms, including the disruption of the cell envelope membrane, protein lysis, reduced expression of biofilm-related genes, and destruction of bacterial DNA. The results provide support for the possibility of using probiotics and their derivatives in the clinical prevention and therapy of A. baumannii infections.
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Affiliation(s)
- Mona Mohamed Al-Shamiri
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Jingdan Wang
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Sirui Zhang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Pu Li
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Woodvine Otieno Odhiambo
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Yanjiong Chen
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Bei Han
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - E. Yang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Meng Xun
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Lei Han
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Shaoshan Han
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
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A bioinformatics approach to introduce novel multi-epitope vaccines against Acinetobacter baumannii retrieved from immunogenic extracellular loops of outer membrane proteins. INFORMATICS IN MEDICINE UNLOCKED 2022. [DOI: 10.1016/j.imu.2022.100989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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