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Diani E, Bianco G, Gatti M, Gibellini D, Gaibani P. Colistin: Lights and Shadows of an Older Antibiotic. Molecules 2024; 29:2969. [PMID: 38998921 PMCID: PMC11243602 DOI: 10.3390/molecules29132969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/17/2024] [Accepted: 06/20/2024] [Indexed: 07/14/2024] Open
Abstract
The emergence of antimicrobial resistance represents a serious threat to public health and for infections due to multidrug-resistant (MDR) microorganisms, representing one of the most important causes of death worldwide. The renewal of old antimicrobials, such as colistin, has been proposed as a valuable therapeutic alternative to the emergence of the MDR microorganisms. Although colistin is well known to present several adverse toxic effects, its usage in clinical practice has been reconsidered due to its broad spectrum of activity against Gram-negative (GN) bacteria and its important role of "last resort" agent against MDR-GN. Despite the revolutionary perspective of treatment with this old antimicrobial molecule, many questions remain open regarding the emergence of novel phenotypic traits of resistance and the optimal usage of the colistin in clinical practice. In last years, several forward steps have been made in the understanding of the resistance determinants, clinical usage, and pharmacological dosage of this molecule; however, different points regarding the role of colistin in clinical practice and the optimal pharmacokinetic/pharmacodynamic targets are not yet well defined. In this review, we summarize the mode of action, the emerging resistance determinants, and its optimal administration in the treatment of infections that are difficult to treat due to MDR Gram-negative bacteria.
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Affiliation(s)
- Erica Diani
- Department of Diagnostic and Public Health, Microbiology Section, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Gabriele Bianco
- Department of Experimental Medicine, University of Salento, 73100 Lecce, Italy
| | - Milo Gatti
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy
| | - Davide Gibellini
- Department of Diagnostic and Public Health, Microbiology Section, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Paolo Gaibani
- Department of Diagnostic and Public Health, Microbiology Section, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
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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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Erdmann MB, Gardner PP, Lamont IL. The PitA protein contributes to colistin susceptibility in Pseudomonas aeruginosa. PLoS One 2023; 18:e0292818. [PMID: 37824582 PMCID: PMC10569645 DOI: 10.1371/journal.pone.0292818] [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: 08/03/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of problematic infections in individuals with predisposing conditions. Infections can be treated with colistin but some isolates are resistant to this antibiotic. To better understand the genetic basis of resistance, we experimentally evolved 19 independent resistant mutants from the susceptible laboratory strain PAO1. Whole genome sequencing identified mutations in multiple genes including phoQ and pmrB that have previously been associated with resistance, pitA that encodes a phosphate transporter, and carB and eno that encode enzymes of metabolism. Individual mutations were engineered into the genome of strain PAO1. Mutations in pitA, pmrB and phoQ increased the minimum inhibitory concentration (MIC) for colistin 8-fold, making the bacteria resistant. Engineered pitA/phoQ and pitA/pmrB double mutants had higher MICs than single mutants, demonstrating additive effects on colistin susceptibility. Single carB and eno mutations did not increase the MIC suggesting that their effect is dependent on the presence of other mutations. Many of the resistant mutants had increased susceptibility to β-lactams and lower growth rates than the parental strain demonstrating that colistin resistance can impose a fitness cost. Two hundred and fourteen P. aeruginosa isolates from a range of sources were tested and 18 (7.8%) were colistin resistant. Sequence variants in genes identified by experimental evolution were present in the 18 resistant isolates and may contribute to resistance. Overall our results identify pitA mutations as novel contributors to colistin resistance and demonstrate that resistance can reduce fitness of the bacteria.
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Affiliation(s)
| | - Paul P. Gardner
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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4
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Huang YT, Mao YC, Tseng CH, Liu CW, Liu PY. Identification of combinatorial mutations associated with colistin resistance in Shewanella algae. Microbes Infect 2023; 25:105143. [PMID: 37085044 DOI: 10.1016/j.micinf.2023.105143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/11/2023] [Accepted: 04/16/2023] [Indexed: 04/23/2023]
Abstract
Colistin is a last-resort antibiotic used to treat infections caused by drug-resistant gram-negative bacteria. However, the genetic mechanisms underlying colistin resistance in Shewanella algae are not well understood. In this study, we sequenced and compared the genomes of 23 mcr-negative colistin-resistant and sensitive S. algae samples from various sources. We applied a computational approach to identify combinatorial mutations associated with colistin resistance. Our analysis revealed a combination of three mutations (PmrB 451, PmrE168, PmrH292) that were strongly associated with colistin resistance in S. algae. This study provides insights into the genetic mechanisms of colistin resistance in S. algae and demonstrates the utility of a computational approach for identifying epistatic interactions among mutations. Identifying the genetic mutations responsible for colistin resistance in S. algae can inform the development of new treatments or strategies to combat infections caused by this emerging pathogen.
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Affiliation(s)
- Yao-Ting Huang
- Department of Computer Science and Information Engineering, National Chung Cheng University, Daxue Road Section 1, Minxiong Township, Chiayi County 62102, Taiwan
| | - Yan-Chiao Mao
- Division of Clinical Toxicology, Department of Emergency Medicine, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Section 4, Xitun District, Taichung 40705, Taiwan
| | - Chien-Hao Tseng
- Division of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Section 4, Xitun District, Taichung 40705, Taiwan
| | - Chia-Wei Liu
- Division of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Section 4, Xitun District, Taichung 40705, Taiwan
| | - Po-Yu Liu
- Division of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Section 4, Xitun District, Taichung 40705, Taiwan; Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, 145 Xingda Rd, South District, Taichung 40227, Taiwan; Ph.D. Program in Translational Medicine, National Chung Hsing University, 145 Xingda Rd, South District, Taichung 40227, Taiwan; Department of Post-Baccalaureate Medicine, National Chung Hsing University, 145 Xingda Rd, South District, Taichung 40227, Taiwan; Genomic Center for Infectious Diseases, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Section 4. Xitun District, Taichung 40705, Taiwan.
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5
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Yang F, Zhou Y, Bai Y, Pan X, Ha UH, Cheng Z, Wu W, Jin Y, Bai F. MvfR Controls Tolerance to Polymyxin B by Regulating rfaD in Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0042623. [PMID: 37039709 PMCID: PMC10269820 DOI: 10.1128/spectrum.00426-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/18/2023] [Indexed: 04/12/2023] Open
Abstract
Polymyxins are currently the last-resort antibiotics for the treatment of multidrug-resistant Gram-negative bacterial infections. To expand the understanding of the intrinsic resistance mechanism against polymyxins, a laboratory strain of Pseudomonas aeruginosa PAO1 was subjected to serial passage in the presence of sublethal doses of polymyxin B over a period of 30 days. By whole-genome sequencing of successively isolated polymyxin B-resistant isolates, we identified a frameshift mutation (L183fs) in the mvfR gene that further increased polymyxin resistance in the pmrB mutant background. A ΔmvfR mutation alone showed higher tolerance to polymyxin B due to altered lipopolysaccharide (LPS) on the surface of bacterial cells, which decreases its outer membrane permeability. In the ΔmvfR mutant, polymyxin B treatment caused the upregulation of rfaD, the gene involved in LPS core oligosaccharide synthesis, which is responsible for polymyxin tolerance. To the best of our knowledge, this is the first report of mvfR mutation conferring polymyxin resistance in P. aeruginosa via increased integrity of bacterial outer membrane. IMPORTANCE Antibiotic resistance imposes a considerable challenge for the treatment of P. aeruginosa infections. Polymyxins are the last-resort antibiotics for the treatment of multidrug-resistant P. aeruginosa infections. Understanding the development and mechanisms of bacterial resistance to polymyxins may provide clues for the development of new or improved therapeutic strategies effective against P. aeruginosa. In this study, using an in vitro evolution assay in combination with whole-genome sequencing, we demonstrated that MvfR controls tolerance to polymyxin B by regulating the rfaD gene in P. aeruginosa. Our results reveal a novel mechanism employed by P. aeruginosa in the defense against polymyxin antibiotics.
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Affiliation(s)
- Fan Yang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yuchen Zhou
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yuxi Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Un-Hwan Ha
- Department of Biotechnology and Bioinformatics, Korea University, Sejong, Republic of Korea
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
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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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7
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Prevalence of polymyxin resistance through the food chain, the global crisis. J Antibiot (Tokyo) 2022; 75:185-198. [PMID: 35079146 DOI: 10.1038/s41429-022-00502-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 09/30/2021] [Accepted: 10/10/2021] [Indexed: 12/24/2022]
Abstract
Antimicrobial resistance is one of the vital challenges facing global health today. Multi-drug resistant (MDR) infections are often treated with the narrow-spectrum drugs, colistin (polymyxin E) or polymyxin B, which are last-resort antibiotics for human therapeutics that are effective against Gram-negative bacteria. Unfortunately, resistance to these polymyxins has occurred because of selective pressure caused by the inappropriate use of those antibiotics, especially in farming. The mechanisms of resistance to polymyxins are mediated through intrinsic, mutational, or genetic alteration in chromosomal genes. The mechanism includes the regulatory network controlling chemical modifications of lipid A moiety of lipopolysaccharide, reducing the negative charge of lipid A and its affinity for polymyxins. Additionally, the unique mobile colistin/polymyxin B resistance (mcr) gene reported in Enterobacteriales is responsible for the horizontal dissemination of resistance to polymyxins via the food chain. There is now an urgent need to increase surveillance for detecting resistance to polymyxins. Therefore, this review presents an overview of presently available scientific literature on the mechanism of resistance to polymyxins, with their associated gene variants, evaluation methods, resistance transmission through the food chain via food bacteria, and related risk factors. We further focus on the significant implications of polymyxins usage in India and future views for food safety to preserve polymyxin activity.
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8
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Ayoub Moubareck C. Polymyxins and Bacterial Membranes: A Review of Antibacterial Activity and Mechanisms of Resistance. MEMBRANES 2020; 10:membranes10080181. [PMID: 32784516 PMCID: PMC7463838 DOI: 10.3390/membranes10080181] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 12/19/2022]
Abstract
Following their initial discovery in the 1940s, polymyxin antibiotics fell into disfavor due to their potential clinical toxicity, especially nephrotoxicity. However, the dry antibiotic development pipeline, together with the rising global prevalence of infections caused by multidrug-resistant (MDR) Gram-negative bacteria have both rejuvenated clinical interest in these polypeptide antibiotics. Parallel to the revival of their use, investigations into the mechanisms of action and resistance to polymyxins have intensified. With an initial known effect on biological membranes, research has uncovered the detailed molecular and chemical interactions that polymyxins have with Gram-negative outer membranes and lipopolysaccharide structure. In addition, genetic and epidemiological studies have revealed the basis of resistance to these agents. Nowadays, resistance to polymyxins in MDR Gram-negative pathogens is well elucidated, with chromosomal as well as plasmid-encoded, transferrable pathways. The aims of the current review are to highlight the important chemical, microbiological, and pharmacological properties of polymyxins, to discuss their mechanistic effects on bacterial membranes, and to revise the current knowledge about Gram-negative acquired resistance to these agents. Finally, recent research, directed towards new perspectives for improving these old agents utilized in the 21st century, to combat drug-resistant pathogens, is summarized.
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9
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Antibiotic Resistance by Enzymatic Modification of Antibiotic Targets. Trends Mol Med 2020; 26:768-782. [PMID: 32493628 DOI: 10.1016/j.molmed.2020.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 11/21/2022]
Abstract
Antibiotic resistance remains a significant threat to modern medicine. Modification of the antibiotic target is a resistance strategy that is increasingly prevalent among pathogens. Examples include resistance to glycopeptide and polymyxin antibiotics that occurs via chemical modification of their molecular targets in the cell envelope. Similarly, many ribosome-targeting antibiotics are impaired by methylation of the rRNA. In these cases, the antibiotic target is subjected to enzymatic modification rather than genetic mutation, and in many instances the resistance enzymes are readily mobilized among pathogens. Understanding the enzymes responsible for these modifications is crucial to combat resistance. Here, we review our current understanding of enzymatic modification of antibiotic targets as well as discuss efforts to combat these resistance mechanisms.
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10
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Adaptive and Mutational Responses to Peptide Dendrimer Antimicrobials in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2020; 64:AAC.02040-19. [PMID: 32015046 PMCID: PMC7179292 DOI: 10.1128/aac.02040-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/24/2020] [Indexed: 01/15/2023] Open
Abstract
Colistin (polymyxin E) is a last-resort antibiotic against multidrug-resistant isolates of Pseudomonas aeruginosa. However, the nephro-toxicity of colistin limits its use, spurring the interest in novel antimicrobial peptides (AMP). Here, we show that the synthetic AMP-dendrimer G3KL (MW 4,531.38 Da, 15 positive charges, MIC = 8 mg/liter) showed faster killing than polymyxin B (Pmx-B) with no detectable resistance selection in P. aeruginosa strain PA14. Colistin (polymyxin E) is a last-resort antibiotic against multidrug-resistant isolates of Pseudomonas aeruginosa. However, the nephro-toxicity of colistin limits its use, spurring the interest in novel antimicrobial peptides (AMP). Here, we show that the synthetic AMP-dendrimer G3KL (MW 4,531.38 Da, 15 positive charges, MIC = 8 mg/liter) showed faster killing than polymyxin B (Pmx-B) with no detectable resistance selection in P. aeruginosa strain PA14. Spontaneous mutants selected on Pmx-B, harboring loss of function mutations in the PhoQ sensor kinase gene, showed increased Pmx-B MICs and arnB operon expression (4-amino-l-arabinose addition to lipid A), but remained susceptible to dendrimers. Two mutants carrying a missense mutation in the periplasmic loop of the PmrB sensor kinase showed increased MICs for Pmx-B (8-fold) and G3KL (4-fold) but not for the dendrimer T7 (MW 4,885.64 Da, 16 positive charges, MIC = 8 mg/liter). The pmrB mutants showed increased expression of the arnB operon as well as of the speD2-speE2-PA4775 operon, located upstream of pmrAB, and involved in polyamine biosynthesis. Exogenous supplementation with the polyamines spermine and norspermine increased G3KL and T7 MICs in a phoQ mutant background but not in the PA14 wild type. This suggests that both addition of 4-amino-l-arabinose and secretion of polyamines are required to reduce susceptibility to dendrimers, probably neutralizing the negative charges present on the lipid A and the 2-keto-3-deoxyoctulosonic acid (KDO) sugars of the lipopolysaccharide (LPS), respectively. We further show by transcriptome analysis that the dendrimers G3KL and T7 induce adaptive responses through the CprRS two-component system in PA14.
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Liu X, Sun X, Deng X, Lv X, Wang J. Calycosin enhances the bactericidal efficacy of polymyxin B by inhibiting MCR-1 in vitro. J Appl Microbiol 2020; 129:532-540. [PMID: 32160376 DOI: 10.1111/jam.14635] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/23/2020] [Accepted: 03/06/2020] [Indexed: 01/09/2023]
Abstract
AIM To examine the synergistic effect of calycosin combined with polymyxin B against various mcr-1-positive bacterial strains. METHODS AND RESULTS In this study, we found a potential inhibitor of MCR-1, calycosin, that could significantly restore the antibacterial activity of polymyxin B. The synergistic effect of calycosin combined with polymyxin B against various mcr-1-positive bacterial strains was confirmed by checkerboard minimum inhibitory concentration assays, time-kill curve assays and disk diffusion assays. The fractional inhibitory concentration indexes ranged from 0·15 ± 0·03 to 0·28 ± 0·05, and the zones of inhibition increased from 13·33 ± 0·47 to 17·67 ± 0·47 mm with the combined therapy of calycosin and polymyxin B. In addition, the combined therapy significantly reduced the number of bacteria in the medium. However, at the concentrations required for the synergistic effect with polymyxin B, calycosin alone showed no effect on bacterial growth or MCR-1 production. Calycosin treatment exhibited no cytotoxicity to HeLa cells or A549 cells at calycosin concentrations below 32 µg ml-1 . CONCLUSIONS Therefore, our results suggested that calycosin could be used as a potential MCR-1 inhibitor to restore the bactericidal effect of polymyxin B without affecting bacterial viability or existing cytotoxicity. SIGNIFICANCE AND IMPACT OF THE STUDY The synergistic effect of calycosin combined with polymyxin B against various mcr-1-positive bacterial strains paves the way for future pharmaceutical applications of calycosin in fighting mcr-1-positive bacterial infections.
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Affiliation(s)
- X Liu
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, China.,Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - X Sun
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, China.,Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - X Deng
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, China.,Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - X Lv
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, China
| | - J Wang
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, China.,Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
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12
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Resistance and Heteroresistance to Colistin in Pseudomonas aeruginosa Isolates from Wenzhou, China. Antimicrob Agents Chemother 2019; 63:AAC.00556-19. [PMID: 31383654 DOI: 10.1128/aac.00556-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/28/2019] [Indexed: 01/26/2023] Open
Abstract
The goal was to investigate the mechanisms of colistin resistance and heteroresistance in Pseudomonas aeruginosa clinical isolates. Colistin resistance was determined by the broth microdilution method. Colistin heteroresistance was evaluated by population analysis profiling. Time-kill assays were also conducted. PCR sequencing was performed to detect the resistance genes among (hetero)resistant isolates, and quantitative real-time PCR assays were performed to determine their expression levels. Pulsed-field gel electrophoresis and multilocus sequence typing were performed. Lipid A characteristics were determined via matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS). Two resistant isolates and 9 heteroresistant isolates were selected in this study. Substitutions in PmrB were detected in 2 resistant isolates. Among heteroresistant isolates, 8 of 9 heteroresistant isolates had nonsynonymous PmrB substitutions, and 2 isolates, including 1 with a PmrB substitution, had PhoQ alterations. Correspondingly, the expression levels of pmrA or phoP were upregulated in PmrB- or PhoQ-substituted isolates. One isolate also found alterations in ParRS and CprRS. The transcript levels of the pmrH gene were observed to increase across all investigated isolates. MALDI-TOF MS showed additional 4-amino-4-deoxy-l-arabinose (l-Ara4N) moieties in lipid A profiles in (hetero)resistant isolates. In conclusion, both colistin resistance and heteroresistance in P. aeruginosa in this study mainly involved alterations of the PmrAB regulatory system. There were strong associations between mutations in specific genetic loci for lipid A synthesis and regulation of modifications to lipid A. The transition of colistin heteroresistance to resistance should be addressed in future clinical surveillance.
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Zhu Y, Czauderna T, Zhao J, Klapperstueck M, Maifiah MHM, Han ML, Lu J, Sommer B, Velkov T, Lithgow T, Song J, Schreiber F, Li J. Genome-scale metabolic modeling of responses to polymyxins in Pseudomonas aeruginosa. Gigascience 2018; 7:4931736. [PMID: 29688451 PMCID: PMC6333913 DOI: 10.1093/gigascience/giy021] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/22/2018] [Indexed: 01/06/2023] Open
Abstract
Background Pseudomonas aeruginosa often causes multidrug-resistant infections in immunocompromised patients, and polymyxins are often used as the last-line therapy. Alarmingly, resistance to polymyxins has been increasingly reported worldwide recently. To rescue this last-resort class of antibiotics, it is necessary to systematically understand how P. aeruginosa alters its metabolism in response to polymyxin treatment, thereby facilitating the development of effective therapies. To this end, a genome-scale metabolic model (GSMM) was used to analyze bacterial metabolic changes at the systems level. Findings A high-quality GSMM iPAO1 was constructed for P. aeruginosa PAO1 for antimicrobial pharmacological research. Model iPAO1 encompasses an additional periplasmic compartment and contains 3022 metabolites, 4265 reactions, and 1458 genes in total. Growth prediction on 190 carbon and 95 nitrogen sources achieved an accuracy of 89.1%, outperforming all reported P. aeruginosa models. Notably, prediction of the essential genes for growth achieved a high accuracy of 87.9%. Metabolic simulation showed that lipid A modifications associated with polymyxin resistance exert a limited impact on bacterial growth and metabolism but remarkably change the physiochemical properties of the outer membrane. Modeling with transcriptomics constraints revealed a broad range of metabolic responses to polymyxin treatment, including reduced biomass synthesis, upregulated amino acid catabolism, induced flux through the tricarboxylic acid cycle, and increased redox turnover. Conclusions Overall, iPAO1 represents the most comprehensive GSMM constructed to date for Pseudomonas. It provides a powerful systems pharmacology platform for the elucidation of complex killing mechanisms of antibiotics.
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Affiliation(s)
- Yan Zhu
- Monash Biomedicine Discovery Institute, Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia
| | - Tobias Czauderna
- Faculty of Information Technology, Monash University, Melbourne 3800, Australia
| | - Jinxin Zhao
- Monash Biomedicine Discovery Institute, Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia
| | | | | | - Mei-Ling Han
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Melbourne 3052, Australia
| | - Jing Lu
- Monash Institute of Cognitive and Clinical Neurosciences, Department of Anatomy and development biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia
| | - Björn Sommer
- Department of Computer and Information Science, University of Konstanz, Konstanz 78457, Germany
| | - Tony Velkov
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne 3010, Australia
| | - Trevor Lithgow
- Monash Biomedicine Discovery Institute, Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia
| | - Jiangning Song
- Monash Biomedicine Discovery Institute, Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia
| | - Falk Schreiber
- Faculty of Information Technology, Monash University, Melbourne 3800, Australia.,Department of Computer and Information Science, University of Konstanz, Konstanz 78457, Germany
| | - Jian Li
- Monash Biomedicine Discovery Institute, Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia
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Pang Z, Raudonis R, Glick BR, Lin TJ, Cheng Z. Antibiotic resistance in Pseudomonas aeruginosa: mechanisms and alternative therapeutic strategies. Biotechnol Adv 2018; 37:177-192. [PMID: 30500353 DOI: 10.1016/j.biotechadv.2018.11.013] [Citation(s) in RCA: 957] [Impact Index Per Article: 159.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 01/09/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is a leading cause of morbidity and mortality in cystic fibrosis patients and immunocompromised individuals. Eradication of P. aeruginosa has become increasingly difficult due to its remarkable capacity to resist antibiotics. Strains of Pseudomonas aeruginosa are known to utilize their high levels of intrinsic and acquired resistance mechanisms to counter most antibiotics. In addition, adaptive antibiotic resistance of P. aeruginosa is a recently characterized mechanism, which includes biofilm-mediated resistance and formation of multidrug-tolerant persister cells, and is responsible for recalcitrance and relapse of infections. The discovery and development of alternative therapeutic strategies that present novel avenues against P. aeruginosa infections are increasingly demanded and gaining more and more attention. Although mostly at the preclinical stages, many recent studies have reported several innovative therapeutic technologies that have demonstrated pronounced effectiveness in fighting against drug-resistant P. aeruginosa strains. This review highlights the mechanisms of antibiotic resistance in P. aeruginosa and discusses the current state of some novel therapeutic approaches for treatment of P. aeruginosa infections that can be further explored in clinical practice.
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Affiliation(s)
- Zheng Pang
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Renee Raudonis
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Tong-Jun Lin
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Zhenyu Cheng
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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Jochumsen N, Marvig RL, Damkiær S, Jensen RL, Paulander W, Molin S, Jelsbak L, Folkesson A. The evolution of antimicrobial peptide resistance in Pseudomonas aeruginosa is shaped by strong epistatic interactions. Nat Commun 2016; 7:13002. [PMID: 27694971 PMCID: PMC5494192 DOI: 10.1038/ncomms13002] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/24/2016] [Indexed: 11/25/2022] Open
Abstract
Colistin is an antimicrobial peptide that has become the only remaining alternative for the treatment of multidrug-resistant Gram-negative bacterial infections, but little is known of how clinical levels of colistin resistance evolve. We use in vitro experimental evolution and whole-genome sequencing of colistin-resistant Pseudomonas aeruginosa isolates from cystic fibrosis patients to reconstruct the molecular evolutionary pathways open for high-level colistin resistance. We show that the evolution of resistance is a complex, multistep process that requires mutation in at least five independent loci that synergistically create the phenotype. Strong intergenic epistasis limits the number of possible evolutionary pathways to resistance. Mutations in transcriptional regulators are essential for resistance evolution and function as nodes that potentiate further evolution towards higher resistance by functionalizing and increasing the effect of the other mutations. These results add to our understanding of clinical antimicrobial peptide resistance and the prediction of resistance evolution. Colistin is an antibiotic used in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis patients. Here, Jochumsen et al. reconstruct the pathways for the molecular evolution of colistin resistance in P. aeruginosa and show that the number of pathways is highly constrained by interactions among genes.
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Affiliation(s)
- Nicholas Jochumsen
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Rasmus L Marvig
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.,Center for Genomic Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Søren Damkiær
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Rune Lyngklip Jensen
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Wilhelm Paulander
- Department of Veterinary Disease Biology, University of Copenhagen, 1870 Frederiksberg C, Denmark
| | - Søren Molin
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lars Jelsbak
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Anders Folkesson
- National Veterinary Institute, Technical University of Denmark, Frederiksberg, Denmark
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Baron S, Hadjadj L, Rolain JM, Olaitan AO. Molecular mechanisms of polymyxin resistance: knowns and unknowns. Int J Antimicrob Agents 2016; 48:583-591. [PMID: 27524102 DOI: 10.1016/j.ijantimicag.2016.06.023] [Citation(s) in RCA: 283] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/14/2016] [Accepted: 06/23/2016] [Indexed: 12/19/2022]
Abstract
Colistin, also referred to as polymyxin E, is an effective antibiotic against most multidrug-resistant Gram-negative bacteria and is currently used as a last-line drug for treating severe bacterial infections. Colistin resistance has increased gradually for the last few years, and knowledge of its multifaceted mechanisms is expanding. This includes the newly discovered plasmid-mediated colistin resistance gene mcr-1, which has been detected in over 20 countries within 3 months of its first report. We previously reported all of the known mechanisms of polymyxin resistance in our first review in 2014, but an update seems necessary in 2016, considering the significant recent discoveries that have been made in this domain. This review provides an update about what is already known, what is new, and some unresolved questions with respect to colistin resistance.
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Affiliation(s)
- Sophie Baron
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France
| | - Linda Hadjadj
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France
| | - Jean-Marc Rolain
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France.
| | - Abiola Olumuyiwa Olaitan
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France.
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Olaitan AO, Morand S, Rolain JM. Mechanisms of polymyxin resistance: acquired and intrinsic resistance in bacteria. Front Microbiol 2014; 5:643. [PMID: 25505462 PMCID: PMC4244539 DOI: 10.3389/fmicb.2014.00643] [Citation(s) in RCA: 897] [Impact Index Per Article: 89.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/07/2014] [Indexed: 01/06/2023] Open
Abstract
Polymyxins are polycationic antimicrobial peptides that are currently the last-resort antibiotics for the treatment of multidrug-resistant, Gram-negative bacterial infections. The reintroduction of polymyxins for antimicrobial therapy has been followed by an increase in reports of resistance among Gram-negative bacteria. Some bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii, develop resistance to polymyxins in a process referred to as acquired resistance, whereas other bacteria, such as Proteus spp., Serratia spp., and Burkholderia spp., are naturally resistant to these drugs. Reports of polymyxin resistance in clinical isolates have recently increased, including acquired and intrinsically resistant pathogens. This increase is considered a serious issue, prompting concern due to the low number of currently available effective antibiotics. This review summarizes current knowledge concerning the different strategies bacteria employ to resist the activities of polymyxins. Gram-negative bacteria employ several strategies to protect themselves from polymyxin antibiotics (polymyxin B and colistin), including a variety of lipopolysaccharide (LPS) modifications, such as modifications of lipid A with phosphoethanolamine and 4-amino-4-deoxy-L-arabinose, in addition to the use of efflux pumps, the formation of capsules and overexpression of the outer membrane protein OprH, which are all effectively regulated at the molecular level. The increased understanding of these mechanisms is extremely vital and timely to facilitate studies of antimicrobial peptides and find new potential drugs targeting clinically relevant Gram-negative bacteria.
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Affiliation(s)
- Abiola O Olaitan
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université Marseille, France
| | - Serge Morand
- Institut des Sciences de l'Evolution, CNRS-IRD-UM2, CC065, Université Montpellier 2 Montpellier, France
| | - Jean-Marc Rolain
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université Marseille, France
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Kim SY, Choi HJ, Ko KS. Differential Expression of Two-Component Systems, pmrAB and phoPQ, with Different Growth phases of Klebsiella pneumoniae in the Presence or Absence of Colistin. Curr Microbiol 2014; 69:37-41. [DOI: 10.1007/s00284-014-0549-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 01/03/2014] [Indexed: 11/29/2022]
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