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Madden DE, Baird T, Bell SC, McCarthy KL, Price EP, Sarovich DS. Keeping up with the pathogens: improved antimicrobial resistance detection and prediction from Pseudomonas aeruginosa genomes. Genome Med 2024; 16:78. [PMID: 38849863 PMCID: PMC11157771 DOI: 10.1186/s13073-024-01346-z] [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: 10/29/2023] [Accepted: 05/20/2024] [Indexed: 06/09/2024] Open
Abstract
BACKGROUND Antimicrobial resistance (AMR) is an intensifying threat that requires urgent mitigation to avoid a post-antibiotic era. Pseudomonas aeruginosa represents one of the greatest AMR concerns due to increasing multi- and pan-drug resistance rates. Shotgun sequencing is gaining traction for in silico AMR profiling due to its unambiguity and transferability; however, accurate and comprehensive AMR prediction from P. aeruginosa genomes remains an unsolved problem. METHODS We first curated the most comprehensive database yet of known P. aeruginosa AMR variants. Next, we performed comparative genomics and microbial genome-wide association study analysis across a Global isolate Dataset (n = 1877) with paired antimicrobial phenotype and genomic data to identify novel AMR variants. Finally, the performance of our P. aeruginosa AMR database, implemented in our AMR detection and prediction tool, ARDaP, was compared with three previously published in silico AMR gene detection or phenotype prediction tools-abritAMR, AMRFinderPlus, ResFinder-across both the Global Dataset and an analysis-naïve Validation Dataset (n = 102). RESULTS Our AMR database comprises 3639 mobile AMR genes and 728 chromosomal variants, including 75 previously unreported chromosomal AMR variants, 10 variants associated with unusual antimicrobial susceptibility, and 281 chromosomal variants that we show are unlikely to confer AMR. Our pipeline achieved a genotype-phenotype balanced accuracy (bACC) of 85% and 81% across 10 clinically relevant antibiotics when tested against the Global and Validation Datasets, respectively, vs. just 56% and 54% with abritAMR, 58% and 54% with AMRFinderPlus, and 60% and 53% with ResFinder. ARDaP's superior performance was predominantly due to the inclusion of chromosomal AMR variants, which are generally not identified with most AMR identification tools. CONCLUSIONS Our ARDaP software and associated AMR variant database provides an accurate tool for predicting AMR phenotypes in P. aeruginosa, far surpassing the performance of current tools. Implementation of ARDaP for routine AMR prediction from P. aeruginosa genomes and metagenomes will improve AMR identification, addressing a critical facet in combatting this treatment-refractory pathogen. However, knowledge gaps remain in our understanding of the P. aeruginosa resistome, particularly the basis of colistin AMR.
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Affiliation(s)
- Danielle E Madden
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Timothy Baird
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
- Respiratory Department, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Scott C Bell
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Queensland, Australia
- Children's Health Research Centre, Faculty of Medicine, The University of Queensland, South Brisbane, Queensland, Australia
| | - Kate L McCarthy
- University of Queensland Medical School, Herston, QLD, Australia
- Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Erin P Price
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Derek S Sarovich
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia.
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Simão FA, Almeida MM, Rosa HS, Marques EA, Leão RS. Genetic determinants of antimicrobial resistance in polymyxin B resistant Pseudomonas aeruginosa isolated from airways of patients with cystic fibrosis. Braz J Microbiol 2024; 55:1415-1425. [PMID: 38619733 PMCID: PMC11153443 DOI: 10.1007/s42770-024-01311-3] [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: 03/21/2024] [Indexed: 04/16/2024] Open
Abstract
Pseudomonas aeruginosa is the main pathogen associated with pulmonary exacerbation in patients with cystic fibrosis (CF). CF is a multisystemic genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene, which mainly affects pulmonary function. P. aeruginosa isolated from individuals with CF in Brazil is not commonly associated with multidrug resistance (MDR), especially when compared to global occurrence, where the presence of epidemic clones, capable of expressing resistance to several drugs, is often reported. Due to the recent observations of MDR isolates of P. aeruginosa in our centers, combined with these characteristics, whole-genome sequencing was employed for analyses related to antimicrobial resistance, plasmid identification, search for phages, and characterization of CF clones. All isolates in this study were polymyxin B resistant, exhibiting diverse mutations and reduced susceptibility to carbapenems. Alterations in mexZ can result in the overexpression of the MexXY efflux pump. Mutations in oprD, pmrB, parS, gyrA and parC may confer reduced susceptibility to antimicrobials by affecting permeability, as observed in phenotypic tests. The phage findings led to the assumption of horizontal genetic transfer, implicating dissemination between P. aeruginosa isolates. New sequence types were described, and none of the isolates showed an association with epidemic CF clones. Analysis of the genetic context of P. aeruginosa resistance to polymyxin B allowed us to understand the different mechanisms of resistance to antimicrobials, in addition to subsidizing the understanding of possible relationships with epidemic strains that circulate among individuals with CF observed in other countries.
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Affiliation(s)
- Felipe A Simão
- Laboratório de Microbiologia da Fibrose Cística, Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mila M Almeida
- Laboratório de Microbiologia da Fibrose Cística, Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Heloísa S Rosa
- Laboratório de Microbiologia da Fibrose Cística, Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elizabeth A Marques
- Laboratório de Microbiologia da Fibrose Cística, Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Robson S Leão
- Laboratório de Microbiologia da Fibrose Cística, Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
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3
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Chen S, Cao H, Xu Z, Huang J, Liu Z, Li T, Duan C, Wu W, Wen Y, Zhang LH, Xu Z. A type I-F CRISPRi system unveils the novel role of CzcR in modulating multidrug resistance of Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0112323. [PMID: 37646520 PMCID: PMC10581170 DOI: 10.1128/spectrum.01123-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/16/2023] [Indexed: 09/01/2023] Open
Abstract
Pseudomonas aeruginosa has abundant signaling systems that exquisitely control its antibiotic resistance in response to different environmental cues. Understanding the regulation of antibiotic resistance will provide important implications for precise antimicrobial interventions. However, efficient genetic tools for functional gene characterizations are sometimes not available, particularly, in clinically isolated strains. Here, we established a type I-F CRISPRi (CSYi) system for programmable gene silencing. By incorporating anti-CRISPR proteins, this system was even applicable to bacterial hosts encoding a native type I-F CRISPR-Cas system. With the newly developed gene-silencing system, we revealed that the response regulator CzcR from the zinc (Zn2+)-responsive two-component system CzcS/CzcR is a repressor of efflux pumps MexAB-OprM and MexGHI-OpmD, which inhibits the expression of both operons by directly interacting with their promoters. Repression of MexAB-OprM consequently increases the susceptibility of P. aeruginosa to multiple antibiotics such as levofloxacin and amikacin. Together, this study provided a simple approach to study gene functions, which enabled us to unveil the novel role of CzcR in modulating efflux pump genes and multidrug resistance in P. aeruginosa. IMPORTANCE P. aeruginosa is a ubiquitous opportunistic pathogen frequently causing chronic infections. In addition to being an important model organism for antibiotic-resistant research, this species is also important for understanding and exploiting CRISPR-Cas systems. In this study, we established a gene-silencing system based on the most abundant type I-F CRISPR-Cas system in this species, which can be readily employed to achieve targeted gene repression in multiple bacterial species. Using this gene-silencing system, the physiological role of Zn2+ and its responsive regulator CzcR in modulating multidrug resistance was unveiled with great convenience. This study not only displayed a new framework to expand the abundant CRISPR-Cas and anti-CRISPR systems for functional gene characterizations but also provided new insights into the regulation of multidrug resistance in P. aeruginosa and important clues for precise anti-pseudomonal therapies.
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Affiliation(s)
- Shuzhen Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Huiluo Cao
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Zirui Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Zhiqing Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Ting Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Cheng Duan
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Weiyan Wu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Yongqi Wen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
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Kauser A, Parisini E, Suarato G, Castagna R. Light-Based Anti-Biofilm and Antibacterial Strategies. Pharmaceutics 2023; 15:2106. [PMID: 37631320 PMCID: PMC10457815 DOI: 10.3390/pharmaceutics15082106] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/29/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Biofilm formation and antimicrobial resistance pose significant challenges not only in clinical settings (i.e., implant-associated infections, endocarditis, and urinary tract infections) but also in industrial settings and in the environment, where the spreading of antibiotic-resistant bacteria is on the rise. Indeed, developing effective strategies to prevent biofilm formation and treat infections will be one of the major global challenges in the next few years. As traditional pharmacological treatments are becoming inadequate to curb this problem, a constant commitment to the exploration of novel therapeutic strategies is necessary. Light-triggered therapies have emerged as promising alternatives to traditional approaches due to their non-invasive nature, precise spatial and temporal control, and potential multifunctional properties. Here, we provide a comprehensive overview of the different biofilm formation stages and the molecular mechanism of biofilm disruption, with a major focus on the quorum sensing machinery. Moreover, we highlight the principal guidelines for the development of light-responsive materials and photosensitive compounds. The synergistic effects of combining light-triggered therapies with conventional treatments are also discussed. Through elegant molecular and material design solutions, remarkable results have been achieved in the fight against biofilm formation and antibacterial resistance. However, further research and development in this field are essential to optimize therapeutic strategies and translate them into clinical and industrial applications, ultimately addressing the global challenges posed by biofilm and antimicrobial resistance.
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Affiliation(s)
- Ambreen Kauser
- Department of Biotechnology, Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia; (A.K.); (E.P.)
- Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena 3, LV-1048 Riga, Latvia
| | - Emilio Parisini
- Department of Biotechnology, Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia; (A.K.); (E.P.)
- Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Giulia Suarato
- Istituto di Elettronica e di Ingegneria dell’Informazione e delle Telecomunicazioni, Consiglio Nazionale delle Ricerche, CNR-IEIIT, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Rossella Castagna
- Department of Biotechnology, Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia; (A.K.); (E.P.)
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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5
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Avakh A, Grant GD, Cheesman MJ, Kalkundri T, Hall S. The Art of War with Pseudomonas aeruginosa: Targeting Mex Efflux Pumps Directly to Strategically Enhance Antipseudomonal Drug Efficacy. Antibiotics (Basel) 2023; 12:1304. [PMID: 37627724 PMCID: PMC10451789 DOI: 10.3390/antibiotics12081304] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/26/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) poses a grave clinical challenge due to its multidrug resistance (MDR) phenotype, leading to severe and life-threatening infections. This bacterium exhibits both intrinsic resistance to various antipseudomonal agents and acquired resistance against nearly all available antibiotics, contributing to its MDR phenotype. Multiple mechanisms, including enzyme production, loss of outer membrane proteins, target mutations, and multidrug efflux systems, contribute to its antimicrobial resistance. The clinical importance of addressing MDR in P. aeruginosa is paramount, and one pivotal determinant is the resistance-nodulation-division (RND) family of drug/proton antiporters, notably the Mex efflux pumps. These pumps function as crucial defenders, reinforcing the emergence of extensively drug-resistant (XDR) and pandrug-resistant (PDR) strains, which underscores the urgency of the situation. Overcoming this challenge necessitates the exploration and development of potent efflux pump inhibitors (EPIs) to restore the efficacy of existing antipseudomonal drugs. By effectively countering or bypassing efflux activities, EPIs hold tremendous potential for restoring the antibacterial activity against P. aeruginosa and other Gram-negative pathogens. This review focuses on concurrent MDR, highlighting the clinical significance of efflux pumps, particularly the Mex efflux pumps, in driving MDR. It explores promising EPIs and delves into the structural characteristics of the MexB subunit and its substrate binding sites.
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Affiliation(s)
| | | | | | | | - Susan Hall
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia; (A.A.); (G.D.G.); (M.J.C.); (T.K.)
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6
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Vaillancourt M, Galdino ACM, Limsuwannarot SP, Celedonio D, Dimitrova E, Broerman M, Bresee C, Doi Y, Lee JS, Parks WC, Jorth P. A compensatory RNase E variation increases Iron Piracy and Virulence in multidrug-resistant Pseudomonas aeruginosa during Macrophage infection. PLoS Pathog 2023; 19:e1010942. [PMID: 37027441 PMCID: PMC10115287 DOI: 10.1371/journal.ppat.1010942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 04/19/2023] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
During chronic cystic fibrosis (CF) infections, evolved Pseudomonas aeruginosa antibiotic resistance is linked to increased pulmonary exacerbations, decreased lung function, and hospitalizations. However, the virulence mechanisms underlying worse outcomes caused by antibiotic resistant infections are poorly understood. Here, we investigated evolved aztreonam resistant P. aeruginosa virulence mechanisms. Using a macrophage infection model combined with genomic and transcriptomic analyses, we show that a compensatory mutation in the rne gene, encoding RNase E, increased pyoverdine and pyochelin siderophore gene expression, causing macrophage ferroptosis and lysis. We show that iron-bound pyochelin was sufficient to cause macrophage ferroptosis and lysis, however, apo-pyochelin, iron-bound pyoverdine, or apo-pyoverdine were insufficient to kill macrophages. Macrophage killing could be eliminated by treatment with the iron mimetic gallium. RNase E variants were abundant in clinical isolates, and CF sputum gene expression data show that clinical isolates phenocopied RNase E variant functions during macrophage infection. Together these data show how P. aeruginosa RNase E variants can cause host damage via increased siderophore production and host cell ferroptosis but may also be targets for gallium precision therapy.
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Affiliation(s)
- Mylene Vaillancourt
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Anna Clara Milesi Galdino
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Sam P. Limsuwannarot
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Diana Celedonio
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Elizabeth Dimitrova
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Matthew Broerman
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Catherine Bresee
- Biostatistics Core, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Yohei Doi
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Janet S. Lee
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - William C. Parks
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Peter Jorth
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
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7
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Dou Q, Zhu Y, Li C, Bian Z, Song H, Zhang R, Wang Y, Zhang X, Wang Y. 4F-Indole Enhances the Susceptibility of Pseudomonas aeruginosa to Aminoglycoside Antibiotics. Microbiol Spectr 2023; 11:e0451922. [PMID: 36975825 PMCID: PMC10100892 DOI: 10.1128/spectrum.04519-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023] Open
Abstract
Infections caused by multidrug-resistant bacteria are becoming increasingly serious. The aminoglycoside antibiotics have been widely used to treat severe Gram-negative bacterial infections. Here, we reported that a class of small molecules, namely, halogenated indoles, can resensitize Pseudomonas aeruginosa PAO1 to aminoglycoside antibiotics such as gentamicin, kanamycin, tobramycin, amikacin, neomycin, ribosomalin sulfate, and cisomicin. We selected 4F-indole as a representative of halogenated indoles to investigate its mechanism and found that the two-component system (TCS) PmrA/PmrB inhibited the expression of multidrug efflux pump MexXY-OprM, allowing kanamycin to act intracellularly. Moreover, 4F-indole inhibited the biosynthesis of several virulence factors, such as pyocyanin, type III secretion system (T3SS), and type VI secretion system (T6SS) exported effectors, and reduced the swimming and twitching motility by suppressing the expression of flagella and type IV pili. This study suggests that the combination of 4F-indole and kanamycin can be more effective against P. aeruginosa PAO1 and affect its multiple physiological activities, providing a novel insight into the reactivation of aminoglycoside antibiotics. IMPORTANCE Infections caused by Pseudomonas aeruginosa have become a major public health crisis. Its resistance to existing antibiotics causes clinical infections that are hard to cure. In this study, we found that halogenated indoles in combination with aminoglycoside antibiotics could be more effective than antibiotics alone against P. aeruginosa PAO1 and preliminarily revealed the mechanism of the 4F-indole-induced regulatory effect. Moreover, the regulatory effect of 4F-indole on different physiological behaviors of P. aeruginosa PAO1 was analyzed by combined transcriptomics and metabolomics. We explain that 4F-indole has potential as a novel antibiotic adjuvant, thus slowing down the further development of bacterial resistance.
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Affiliation(s)
- Qin Dou
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yuxiang Zhu
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Chunhui Li
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Zeran Bian
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Huihui Song
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Ruizhen Zhang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yingsong Wang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xile Zhang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yan Wang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
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Genome Analysis of Pseudomonas aeruginosa Strains from Chronically Infected Patients with High Levels of Persister Formation. Pathogens 2023; 12:pathogens12030426. [PMID: 36986348 PMCID: PMC10051920 DOI: 10.3390/pathogens12030426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 03/11/2023] Open
Abstract
The appearance of persister cells with low metabolic rates are key factors leading to antibiotic treatment failure. Such persisters are multidrug tolerant and play a key role in the recalcitrance of biofilm-based chronic infections. Here, we present the genomic analyses of three distinct Pseudomonas aeruginosa Egyptian persister-isolates recovered from chronic human infections. To calculate the persister frequencies, viable counts were determined before and after treatment with levofloxacin. The susceptibilities of isolates to different antibiotics were determined using the agar-dilution method. To determine their recalcitrance, the levofloxacin persisters were further challenged with lethal concentrations of meropenem, tobramycin, or colistin. Furthermore, the biofilm formation of the persister strains was estimated phenotypically, and they were reported to be strong biofilm-forming strains. The genotypic characterization of the persisters was performed using whole genome sequencing (WGS) followed by phylogenetic analysis and resistome profiling. Interestingly, out of the thirty-eight clinical isolates, three isolates (8%) demonstrated a persister phenotype. The three levofloxacin-persister isolates were tested for their susceptibility to selected antibiotics; all of the tested isolates were multidrug resistant (MDR). Additionally, the P. aeruginosa persisters were capable of surviving over 24 h and were not eradicated after exposure to 100X-MIC of levofloxacin. WGS for the three persisters revealed a smaller genome size compared to PAO1-genome. Resistome profiling indicated the presence of a broad collection of antibiotic-resistance genes, including genes encoding for antibiotic-modifying enzymes and efflux pump. Phylogenetic analysis indicated that the persister isolates belong to a distinct clade rather than the deposited P. aeruginosa strains in the GenBank. Conclusively, the persister isolates in our study are MDR and form a highly strong biofilm. WGS revealed a smaller genome that belongs to a distinct clade.
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Role of Efflux Pumps on Antimicrobial Resistance in Pseudomonas aeruginosa. Int J Mol Sci 2022; 23:ijms232415779. [PMID: 36555423 PMCID: PMC9779380 DOI: 10.3390/ijms232415779] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial resistance is an old and silent pandemic. Resistant organisms emerge in parallel with new antibiotics, leading to a major global public health crisis over time. Antibiotic resistance may be due to different mechanisms and against different classes of drugs. These mechanisms are usually found in the same organism, giving rise to multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. One resistance mechanism that is closely associated with the emergence of MDR and XDR bacteria is the efflux of drugs since the same pump can transport different classes of drugs. In Gram-negative bacteria, efflux pumps are present in two configurations: a transmembrane protein anchored in the inner membrane and a complex formed by three proteins. The tripartite complex has a transmembrane protein present in the inner membrane, a periplasmic protein, and a porin associated with the outer membrane. In Pseudomonas aeruginosa, one of the main pathogens associated with respiratory tract infections, four main sets of efflux pumps have been associated with antibiotic resistance: MexAB-OprM, MexXY, MexCD-OprJ, and MexEF-OprN. In this review, the function, structure, and regulation of these efflux pumps in P. aeruginosa and their actions as resistance mechanisms are discussed. Finally, a brief discussion on the potential of efflux pumps in P. aeruginosa as a target for new drugs is presented.
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López M, Rojo-Bezares B, Chichón G, Sáenz Y. Resistance to Fluoroquinolones in Pseudomonas aeruginosa from Human, Animal, Food and Environmental Origin: The Role of CrpP and Mobilizable ICEs. Antibiotics (Basel) 2022; 11:antibiotics11091271. [PMID: 36140050 PMCID: PMC9495688 DOI: 10.3390/antibiotics11091271] [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] [Received: 08/08/2022] [Revised: 09/09/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Fluoroquinolone resistance and the associated genetic mechanisms were assessed by antimicrobial susceptibility and whole genome sequencing in 56 Pseudomonas aeruginosa strains from human, animal, food and environmental origins. P. aeruginosa PAO1, PA7 and PA14 reference strains were also included in the study. Twenty-two strains (37%) were resistant to, at least, one fluoroquinolone agent. Correlation between the number of changes in GyrA and ParC proteins and the level of fluoroquinolone resistance was observed. Mutations or absence of genes, such as mexZ, mvaT and nalD encoding efflux pumps regulators, were also found in resistant strains. The crpP gene was detected in 43 strains (72.9%; 17 of them non-clinical strains), and coded seven different CrpP variants, including a novel one (CrpP-7). The crpP gene was located in 23 different chromosomal mobile integrative and conjugative elements (ICEs), inserted in two tRNAs integration sites. A great variety of structures was detected in the crpP-ICEs elements, e.g., the fimbriae related cup clusters, the mercury resistance mer operon, the pyocin S5 or S8 bacteriocin encoding genes, and mobilization genes. The location of crpP-like genes in mobilizable ICEs and linked to heavy metal resistance and virulence factors is of significant concern in P. aeruginosa. This work provides a genetic explanation of the fluoroquinolone resistance and crpP-associated pathogenesis of P. aeruginosa from a One-Health approach.
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Affiliation(s)
- María López
- Correspondence: (M.L.); (B.R.-B.); (Y.S.); Tel./Fax: +34-941-27-88-68
| | | | | | - Yolanda Sáenz
- Correspondence: (M.L.); (B.R.-B.); (Y.S.); Tel./Fax: +34-941-27-88-68
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New Variants of Pseudomonas aeruginosa High-Risk Clone ST233 Associated with an Outbreak in a Mexican Paediatric Hospital. Microorganisms 2022; 10:microorganisms10081533. [PMID: 36013951 PMCID: PMC9414371 DOI: 10.3390/microorganisms10081533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/23/2022] [Accepted: 07/23/2022] [Indexed: 02/01/2023] Open
Abstract
Recent multidrug resistance in Pseudomonas aeruginosa has favoured the adaptation and dissemination of worldwide high-risk strains. In June 2018, 15 P. aeruginosa strains isolated from patients and a contaminated multi-dose meropenem vial were characterized to assess their association to an outbreak in a Mexican paediatric hospital. The strains were characterized by antibiotic susceptibility profiling, virulence factors’ production, and biofilm formation. The clonal relationship among isolates was determined with pulse-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) sequencing. Repressor genes for the MexAB-OprM efflux pump were sequenced for haplotype identification. Of the strains, 60% were profiled as extensively drug-resistant (XDR), 33% as multidrug-resistant (MDR), and 6.6% were classified as sensitive (S). All strains presented intermediate resistance to colistin, and 80% were sensitive to aztreonam. Pyoverdine was the most produced virulence factor. The PFGE technique was performed for the identification of the outbreak, revealing eight strains with the same electrophoretic pattern. ST235 and ten new sequence types (STs) were identified, all closely related to ST233. ST3241 predominated in 26.66% of the strains. Twenty-five synonymous and seventeen nonsynonymous substitutions were identified in the regulatory genes of the MexAB-OprM efflux pump, and nalC was the most variable gene. Six different haplotypes were identified. Strains from the outbreak were metallo-β-lactamases and phylogenetically related to the high-risk clone ST233.
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Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:microorganisms10061239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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Evaluation of a Conformationally Constrained Indole Carboxamide as a Potential Efflux Pump Inhibitor in Pseudomonas aeruginosa. Antibiotics (Basel) 2022; 11:antibiotics11060716. [PMID: 35740123 PMCID: PMC9220351 DOI: 10.3390/antibiotics11060716] [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] [Received: 04/21/2022] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
Efflux pumps in Gram-negative bacteria such as Pseudomonas aeruginosa provide intrinsic antimicrobial resistance by facilitating the extrusion of a wide range of antimicrobials. Approaches for combating efflux-mediated multidrug resistance involve, in part, developing indirect antimicrobial agents capable of inhibiting efflux, thus rescuing the activity of antimicrobials previously rendered inactive by efflux. Herein, TXA09155 is presented as a novel efflux pump inhibitor (EPI) formed by conformationally constraining our previously reported EPI TXA01182. TXA09155 demonstrates strong potentiation in combination with multiple antibiotics with efflux liabilities against wild-type and multidrug-resistant (MDR) P. aeruginosa. At 6.25 µg/mL, TXA09155, showed ≥8-fold potentiation of levofloxacin, moxifloxacin, doxycycline, minocycline, cefpirome, chloramphenicol, and cotrimoxazole. Several biophysical and genetic studies rule out membrane disruption and support efflux inhibition as the mechanism of action (MOA) of TXA09155. TXA09155 was determined to lower the frequency of resistance (FoR) to levofloxacin and enhance the killing kinetics of moxifloxacin. Most importantly, TXA09155 outperformed the levofloxacin-potentiation activity of EPIs TXA01182 and MC-04,124 against a CDC/FDA panel of MDR clinical isolates of P. aeruginosa. TXA09155 possesses favorable physiochemical and ADME properties that warrant its optimization and further development.
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14
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Aguilar-Rodea P, Zúñiga G, Cerritos R, Rodríguez-Espino BA, Gomez-Ramirez U, Nolasco-Romero CG, López-Marceliano B, Rodea GE, Mendoza-Elizalde S, Reyes-López A, Olivares Clavijo H, Vigueras Galindo JC, Velázquez-Guadarrama N, Rosas-Pérez I. Nucleotide substitutions in the mexR, nalC and nalD regulator genes of the MexAB-OprM efflux pump are maintained in Pseudomonas aeruginosa genetic lineages. PLoS One 2022; 17:e0266742. [PMID: 35536836 PMCID: PMC9089866 DOI: 10.1371/journal.pone.0266742] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 03/25/2022] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa has different resistant mechanisms including the constitutive MexAB-OprM efflux pump. Single nucleotide polymorphisms (SNPs) in the mexR, nalC, and nalD repressors of this efflux pump can contribute to antimicrobial resistance; however, it is unknown whether these changes are mainly related to genetic lineages or environmental pressure. This study identifies SNPs in the mexR, nalC, and nalD genes in clinical and environmental isolates of P. aeruginosa (including high-risk clones). Ninety-one P. aeruginosa strains were classified according to their resistance to antibiotics, typified by multilocus sequencing, and mexR, nalC, and nalD genes sequenced for SNPs identification. The mexAB-oprM transcript expression was determined. The 96.7% of the strains were classified as multidrug resistant. Eight strains produced serine carbapenemases, and 11 strains metallo-β-lactamases. Twenty-three new STs and high-risk clones ST111 and ST233 were identified. SNPs in the mexR, nalC, and nalD genes revealed 27 different haplotypes (patterns). Sixty-two mutational changes were identified, 13 non-synonymous. Haplotype 1 was the most frequent (n = 40), and mainly identified in strains ST1725 (33/40), with 57.5% pan drug resistant strains, 36.5% extensive drug resistant and two strains exhibiting serin-carbapenemases. Haplotype 12 (n = 9) was identified in ST233 and phylogenetically related STs, with 100% of the strains exhibiting XDR and 90% producing metallo-β-lactamases. Haplotype 5 was highly associated with XDR and related to dead when compared to ST1725 and ST233 (RRR 23.34; p = 0.009 and RRR 32.01; p = 0.025). A significant relationship between the mexR-nalC-nalD haplotypes and phylogenetically related STs was observed, suggesting mutational changes in these repressors are highly maintained within genetic lineages. In addition, phylogenetically related STs showed similar resistant profiles; however, the resistance was (likely or partly) attributed to the MexAB-OprM efflux pump in 56% of the strains (only 45.05% showed mexA overtranscription), in the remaining strains the resistance could be attributed to carbapenemases or mechanisms including other pumps, since same SNPs in the repressor genes gave rise to different resistance profiles.
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Affiliation(s)
- Pamela Aguilar-Rodea
- Posgrado en Ciencias de la Tierra, Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad de México, México
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
- Laboratorio de Aerobiología, Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Gerardo Zúñiga
- Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - René Cerritos
- Centro de Investigación en Políticas Población y Salud, Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Benjamín Antonio Rodríguez-Espino
- Laboratorio de Investigación y Diagnóstico en Nefrología y Metabolismo Mineral Óseo, Hospital Infantil de México Federico Gómez, Ciudad de México, México
| | - Uriel Gomez-Ramirez
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
- Programa de Posgrado en Ciencias Químicobiologicas, Escuela Nacional de Ciencias Biológicas. Instituto Politécnico Nacional, Ciudad de México, México
| | - Carolina G. Nolasco-Romero
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
- Programa de Posgrado en Ciencias Químicobiologicas, Escuela Nacional de Ciencias Biológicas. Instituto Politécnico Nacional, Ciudad de México, México
| | - Beatriz López-Marceliano
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
| | - Gerardo E. Rodea
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
| | - Sandra Mendoza-Elizalde
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
| | - Alfonso Reyes-López
- Centro de Estudios Económicos y Sociales en Salud, Dirección de Investigación, Hospital Infantil de México Federico Gómez, Ciudad de México, México
| | | | - Juan Carlos Vigueras Galindo
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
| | - Norma Velázquez-Guadarrama
- Unidad de Investigación en Enfermedades Infecciosas Área de Genética Bacteriana, Hospital Infantil de México Federico Gómez, Ciudad de México, México
- * E-mail: ,
| | - Irma Rosas-Pérez
- Laboratorio de Aerobiología, Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad de México, México
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Pseudomonas aeruginosa mexR and mexEF Antibiotic Efflux Pump Variants Exhibit Increased Virulence. Antibiotics (Basel) 2021; 10:antibiotics10101164. [PMID: 34680745 PMCID: PMC8532662 DOI: 10.3390/antibiotics10101164] [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: 08/31/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022] Open
Abstract
Antibiotic-resistant Pseudomonas aeruginosa infections are the primary cause of mortality in people with cystic fibrosis (CF). Yet, it has only recently become appreciated that resistance mutations can also increase P. aeruginosa virulence, even in the absence of antibiotics. Moreover, the mechanisms by which resistance mutations increase virulence are poorly understood. In this study we tested the hypothesis that mutations affecting efflux pumps can directly increase P. aeruginosa virulence. Using genetics, physiological assays, and model infections, we show that efflux pump mutations can increase virulence. Mutations of the mexEF efflux pump system increased swarming, rhamnolipid production, and lethality in a mouse infection model, while mutations in mexR that increased expression of the mexAB-oprM efflux system increased virulence during an acute murine lung infection without affecting swarming or rhamnolipid gene expression. Finally, we show that an efflux pump inhibitor, which represents a proposed novel treatment approach for P. aeruginosa, increased rhamnolipid gene expression in a dose-dependent manner. This finding is important because rhamnolipids are key virulence factors involved in dissemination through epithelial barriers and cause neutrophil necrosis. Together, these data show how current and proposed future anti-Pseudomonal treatments may unintentionally make infections worse by increasing virulence. Therefore, treatments that target efflux should be pursued with caution.
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16
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Camus L, Vandenesch F, Moreau K. From genotype to phenotype: adaptations of Pseudomonas aeruginosa to the cystic fibrosis environment. Microb Genom 2021; 7:mgen000513. [PMID: 33529147 PMCID: PMC8190622 DOI: 10.1099/mgen.0.000513] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is one of the main microbial species colonizing the lungs of cystic fibrosis patients and is responsible for the decline in respiratory function. Despite the hostile pulmonary environment, P. aeruginosa is able to establish chronic infections thanks to its strong adaptive capacity. Various longitudinal studies have attempted to compare the strains of early infection with the adapted strains of chronic infection. Thanks to new '-omics' techniques, convergent genetic mutations, as well as transcriptomic and proteomic dysregulations have been identified. As a consequence of this evolution, the adapted strains of P. aeruginosa have particular phenotypes that promote persistent infection.
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Affiliation(s)
- Laura Camus
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
| | - François Vandenesch
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Lyon, France
- Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Karen Moreau
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
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Hedayati Ch M, Abolhassani Targhi A, Shamsi F, Heidari F, Salehi Moghadam Z, Mirzaie A, Behdad R, Moghtaderi M, Akbarzadeh I. Niosome-encapsulated tobramycin reduced antibiotic resistance and enhanced antibacterial activity against multidrug-resistant clinical strains of Pseudomonas aeruginosa. J Biomed Mater Res A 2020; 109:966-980. [PMID: 32865883 DOI: 10.1002/jbm.a.37086] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/02/2020] [Accepted: 08/08/2020] [Indexed: 12/18/2022]
Abstract
In the current study, niosome-encapsulated tobramycin based on Span 60 and Tween 60 was synthesized and its biological efficacies including anti-bacterial, anti-efflux, and anti-biofilm activities were investigated against multidrug resistant (MDR) clinical strains of Pseudomonas aeruginosa. The niosomal formulations were characterized using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering measurement. The encapsulation efficiency was found to be 69.54% ±; 0.67. The prepared niosomal formulations had a high storage stability to 60 days with small changes in size and drug entrapment, which indicates that it is a suitable candidate for pharmaceutical applications. The results of biological study showed the anti-bacterial activity via reduction of antibiotic resistance, enhanced anti-efflux and anti-biofilm activities by more folds in comparison to free tobramycin. In addition, niosome encapsulated tobramycin down-regulated the MexAB-OprM efflux genes, pslA and pelA biofilm related genes in MDR P. aeruginosa strains. The anti-proliferative activity of formulation was evaluated against HEK293 cell lines, which exhibited negligible cytotoxicity against HEK293 cells. The finding of our study shows that encapsulation of tobramycin in niosome enhanced the antibacterial activity and reduced antibiotic resistance in MDR strains of P. aeruginosa comparing to free tobramycin and it can be considered as a favorable drug delivery system.
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Affiliation(s)
- Mojtaba Hedayati Ch
- Department of Microbiology, Guilan University of Medical Sciences, Rasht, Iran
| | | | - Farzaneh Shamsi
- Department of Biology, Roudehen Branch, Islamic Azad University, Roudehen, Iran
| | - Fatemeh Heidari
- Department of Cellular and Molecular Biology, Islamic Azad University, Tehran Medical Branch, Tehran, Iran
| | | | - Amir Mirzaie
- Department of Biology, Roudehen Branch, Islamic Azad University, Roudehen, Iran
| | - Reyhaneh Behdad
- Department of Biology, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran
| | - Maryam Moghtaderi
- Department of Chemical Engineering, University of Tehran, Tehran, Iran
| | - Iman Akbarzadeh
- Department of Chemical and Petrochemical Engineering, Sharif University of Technology, Tehran, Iran
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18
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Suresh M, Skariyachan S, Narayanan N, Pullampara Rajamma J, Panickassery Ramakrishnan MK. Mutational Variation Analysis of oprD Porin Gene in Multidrug-Resistant Clinical Isolates of Pseudomonas aeruginosa. Microb Drug Resist 2020; 26:869-879. [PMID: 32083512 DOI: 10.1089/mdr.2019.0147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The present study deals with the outer membrane OprD porin protein in 29 clinical bacterial isolates of multidrug-resistant Pseudomonas aeruginosa. oprD porin gene expression was investigated using real-time reverse transcription-PCR. Amplicons from oprD and its transcriptional regulator mexT gene were sequenced and analyzed for mutations. Hypothetical models of selected mutant OprD-porin proteins were predicted and refined by homology modeling approach. oprD ampliconic sequences were also screened for restriction fragment length polymorphism (RFLP). The oprD gene was found to be downregulated in 89.7% (n = 26) of the isolates in comparison to the transcript levels in the reference strain P. aeruginosa-PAO (MTCC-3541). Interestingly, all these isolates displayed the presence of a conspicuous 8-bp deletion (GGCCAGCC) at nucleotide position 235 of mexT regulatory gene. Based on the mutational patterns observed in oprD gene, the isolates were classified into categories designated as A, B1-2, C1-4, D1-6, E1-2, and F. Our hypothetical models revealed that mutations were predominantly confined to the extracellular loops emanating from the β-barrel porin protein. These protein models also enabled clear visualization of loss of substantial portions of the truncated polypeptide. Incidentally, since most of the oprD amplicons of the clinical isolates were found to display distinct RFLP banding patterns, our results also provide a useful diagnostic tool for detection of P. aeruginosa porin mutants.
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Affiliation(s)
- Manju Suresh
- Department of Biotechnology, University of Calicut, Malappuram, India
| | | | - Nithya Narayanan
- Department of Biotechnology, University of Calicut, Malappuram, India
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Efficacy of Antibiotic Combinations against Multidrug-Resistant Pseudomonas aeruginosa in Automated Time-Lapse Microscopy and Static Time-Kill Experiments. Antimicrob Agents Chemother 2020; 64:AAC.02111-19. [PMID: 32179531 PMCID: PMC7269485 DOI: 10.1128/aac.02111-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/08/2020] [Indexed: 11/22/2022] Open
Abstract
Antibiotic combination therapy is used for severe infections caused by multidrug-resistant (MDR) Gram-negative bacteria, yet data regarding which combinations are most effective are lacking. This study aimed to evaluate the in vitro efficacy of polymyxin B in combination with 13 other antibiotics against four clinical strains of MDR Pseudomonas aeruginosa. We evaluated the interactions of polymyxin B in combination with amikacin, aztreonam, cefepime, chloramphenicol, ciprofloxacin, fosfomycin, linezolid, meropenem, minocycline, rifampin, temocillin, thiamphenicol, or trimethoprim by automated time-lapse microscopy using predefined cutoff values indicating inhibition of growth (≤106 CFU/ml) at 24 h. Antibiotic combination therapy is used for severe infections caused by multidrug-resistant (MDR) Gram-negative bacteria, yet data regarding which combinations are most effective are lacking. This study aimed to evaluate the in vitro efficacy of polymyxin B in combination with 13 other antibiotics against four clinical strains of MDR Pseudomonas aeruginosa. We evaluated the interactions of polymyxin B in combination with amikacin, aztreonam, cefepime, chloramphenicol, ciprofloxacin, fosfomycin, linezolid, meropenem, minocycline, rifampin, temocillin, thiamphenicol, or trimethoprim by automated time-lapse microscopy using predefined cutoff values indicating inhibition of growth (≤106 CFU/ml) at 24 h. Promising combinations were subsequently evaluated in static time-kill experiments. All strains were intermediate or resistant to polymyxin B, antipseudomonal β-lactams, ciprofloxacin, and amikacin. Genes encoding β-lactamases (e.g., blaPAO and blaOXA-50) and mutations associated with permeability and efflux were detected in all strains. In the time-lapse microscopy experiments, positive interactions were found with 39 of 52 antibiotic combination/bacterial strain setups. Enhanced activity was found against all four strains with polymyxin B used in combination with aztreonam, cefepime, fosfomycin, minocycline, thiamphenicol, and trimethoprim. Time-kill experiments showed additive or synergistic activity with 27 of the 39 tested polymyxin B combinations, most frequently with aztreonam, cefepime, and meropenem. Positive interactions were frequently found with the tested combinations, against strains that harbored several resistance mechanisms to the single drugs, and with antibiotics that are normally not active against P. aeruginosa. Further study is needed to explore the clinical utility of these combinations.
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Shriram V, Khare T, Bhagwat R, Shukla R, Kumar V. Inhibiting Bacterial Drug Efflux Pumps via Phyto-Therapeutics to Combat Threatening Antimicrobial Resistance. Front Microbiol 2018; 9:2990. [PMID: 30619113 PMCID: PMC6295477 DOI: 10.3389/fmicb.2018.02990] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 11/19/2018] [Indexed: 12/04/2022] Open
Abstract
Antibiotics, once considered the lifeline for treating bacterial infections, are under threat due to the emergence of threatening antimicrobial resistance (AMR). These drug-resistant microbes (or superbugs) are non-responsive to most of the commonly used antibiotics leaving us with few treatment options and escalating mortality-rates and treatment costs. The problem is further aggravated by the drying-pipeline of new and potent antibiotics effective particularly against the drug-resistant strains. Multidrug efflux pumps (EPs) are established as principal determinants of AMR, extruding multiple antibiotics out of the cell, mostly in non-specific manner and have therefore emerged as potent drug-targets for combating AMR. Plants being the reservoir of bioactive compounds can serve as a source of potent EP inhibitors (EPIs). The phyto-therapeutics with noteworthy drug-resistance-reversal or re-sensitizing activities may prove significant for reviving the otherwise fading antibiotics arsenal and making this combination-therapy effective. Contemporary attempts to potentiate the antibiotics with plant extracts and pure phytomolecules have gained momentum though with relatively less success against Gram-negative bacteria. Plant-based EPIs hold promise as potent drug-leads to combat the EPI-mediated AMR. This review presents an account of major bacterial multidrug EPs, their roles in imparting AMR, effective strategies for inhibiting drug EPs with phytomolecules, and current account of research on developing novel and potent plant-based EPIs for reversing their AMR characteristics. Recent developments including emergence of in silico tools, major success stories, challenges and future prospects are also discussed.
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Affiliation(s)
- Varsha Shriram
- Department of Botany, Prof. Ramkrishna More College, Savitribai Phule Pune University, Pune, India
| | - Tushar Khare
- Department of Biotechnology, Modern College of Arts, Science and Commerce (Savitribai Phule Pune University), Pune, India
| | - Rohit Bhagwat
- Department of Environmental Science, Savitribai Phule Pune University, Pune, India
| | - Ravi Shukla
- Centre for Advanced Materials and Industrial Chemistry, School of Science, RMIT University, Melbourne, VIC, Australia
| | - Vinay Kumar
- Department of Biotechnology, Modern College of Arts, Science and Commerce (Savitribai Phule Pune University), Pune, India.,Department of Environmental Science, Savitribai Phule Pune University, Pune, India
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