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Romero-González LE, Montelongo-Martínez LF, González-Valdez A, Quiroz-Morales SE, Cocotl-Yañez M, Franco-Cendejas R, Soberón-Chávez G, Pardo-López L, Bustamante VH. Pseudomonas aeruginosa Isolates from Water Samples of the Gulf of Mexico Show Similar Virulence Properties but Different Antibiotic Susceptibility Profiles than Clinical Isolates. Int J Microbiol 2024; 2024:6959403. [PMID: 38784405 PMCID: PMC11115996 DOI: 10.1155/2024/6959403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/14/2024] [Accepted: 04/27/2024] [Indexed: 05/25/2024] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen found in a wide variety of environments, including soil, water, and habitats associated with animals, humans, and plants. From a One Health perspective, which recognizes the interconnectedness of human, animal, and environmental health, it is important to study the virulence characteristics and antibiotic susceptibility of environmental bacteria. In this study, we compared the virulence properties and the antibiotic resistance profiles of seven isolates collected from the Gulf of Mexico with those of seven clinical strains of P. aeruginosa. Our results indicate that the marine and clinical isolates tested exhibit similar virulence properties; they expressed different virulence factors and were able to kill Galleria mellonella larvae, an animal model commonly used to analyze the pathogenicity of many bacteria, including P. aeruginosa. In contrast, the clinical strains showed higher antibiotic resistance than the marine isolates. Consistently, the clinical strains exhibited a higher prevalence of class 1 integron, an indicator of anthropogenic impact, compared with the marine isolates. Thus, our results indicate that the P. aeruginosa marine strains analyzed in this study, isolated from the Gulf of Mexico, have similar virulence properties, but lower antibiotic resistance, than those from hospitals.
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Affiliation(s)
- Luis E. Romero-González
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Luis F. Montelongo-Martínez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán, Mexico
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán, Mexico
| | - Sara E. Quiroz-Morales
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán, Mexico
| | - Miguel Cocotl-Yañez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán, Mexico
| | - Rafael Franco-Cendejas
- Instituto Nacional de Rehabilitación “Luis Guillermo Ibarra Ibarra,” Ciudad de México, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán, Mexico
| | - Liliana Pardo-López
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Víctor H. Bustamante
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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Gómez-Martínez J, Rocha-Gracia RDC, Bello-López E, Cevallos MA, Castañeda-Lucio M, Sáenz Y, Jiménez-Flores G, Cortés-Cortés G, López-García A, Lozano-Zarain P. Comparative Genomics of Pseudomonas aeruginosa Strains Isolated from Different Ecological Niches. Antibiotics (Basel) 2023; 12:antibiotics12050866. [PMID: 37237769 DOI: 10.3390/antibiotics12050866] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/27/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
The Pseudomonas aeruginosa genome can change to adapt to different ecological niches. We compared four genomes from a Mexican hospital and 59 genomes from GenBank from different niches, such as urine, sputum, and environmental. The ST analysis showed that high-risk STs (ST235, ST773, and ST27) were present in the genomes of the three niches from GenBank, and the STs of Mexican genomes (ST167, ST2731, and ST549) differed from the GenBank genomes. Phylogenetic analysis showed that the genomes were clustering according to their ST and not their niche. When analyzing the genomic content, we observed that environmental genomes had genes involved in adapting to the environment not found in the clinics and that their mechanisms of resistance were mutations in antibiotic resistance-related genes. In contrast, clinical genomes from GenBank had resistance genes, in mobile/mobilizable genetic elements in the chromosome, except for the Mexican genomes that carried them mostly in plasmids. This was related to the presence of CRISPR-Cas and anti-CRISPR; however, Mexican strains only had plasmids and CRISPR-Cas. blaOXA-488 (a variant of blaOXA50) with higher activity against carbapenems was more prevalent in sputum genomes. The virulome analysis showed that exoS was most prevalent in the genomes of urinary samples and exoU and pldA in sputum samples. This study provides evidence regarding the genetic variability among P. aeruginosa isolated from different niches.
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Affiliation(s)
- Jessica Gómez-Martínez
- Posgrado en Microbiología, Centro de Investigaciones de Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
| | - Rosa Del Carmen Rocha-Gracia
- Posgrado en Microbiología, Centro de Investigaciones de Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
| | - Elena Bello-López
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Miguel Angel Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Miguel Castañeda-Lucio
- Posgrado en Microbiología, Centro de Investigaciones de Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
| | - Yolanda Sáenz
- Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), 26006 Logroño, Spain
| | - Guadalupe Jiménez-Flores
- Laboratorio Clínico, Área de Microbiología, Hospital Regional Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado, Puebla 72570, Mexico
| | - Gerardo Cortés-Cortés
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | - Alma López-García
- Posgrado en Microbiología, Centro de Investigaciones de Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
| | - Patricia Lozano-Zarain
- Posgrado en Microbiología, Centro de Investigaciones de Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
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Gene-Gene Interactions Reduce Aminoglycoside Susceptibility of Pseudomonas aeruginosa through Efflux Pump-Dependent and -Independent Mechanisms. Antibiotics (Basel) 2023; 12:antibiotics12010152. [PMID: 36671353 PMCID: PMC9854422 DOI: 10.3390/antibiotics12010152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Pseudomonas aeruginosa causes a wide range of acute and chronic infections. Aminoglycosides are a cornerstone of treatment, but isolates are often resistant. The purpose of this research was to better understand the genetic basis of aminoglycoside resistance in P. aeruginosa. Bioinformatic approaches identified mutations in resistance-associated genes in the clinical isolates of P. aeruginosa. The common mutations were then engineered into the genome of P. aeruginosa reference strain PAO1. Mutations in the elongation factor gene fusA1 caused the biggest reduction in aminoglycoside susceptibility, with mutations in the two-component regulator gene amgS and the efflux pump regulator gene mexZ having less impact. This susceptibility was further reduced by combinations of mutations. Mutations in fusA1, amgS and mexZ all increased the expression of the mexXY efflux pump that is strongly associated with aminoglycoside resistance. Furthermore, the fusA1 amgS mexZ triple mutant had the highest efflux pump gene expression. Engineering fusA1 and amgS mutants lacking this efflux pump showed that fusA1 and amgS also reduce aminoglycoside susceptibility through additional mechanisms. The fusA1 and amgS mutations reduced bacterial growth, showing that these mutations have a fitness cost. Our findings demonstrate the complex interplay between mutations, efflux pump expression and other mechanisms for reducing the susceptibility of P. aeruginosa to aminoglycosides.
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Elmes K, Heywood A, Huang Z, Gavryushkin A. A fast lasso-based method for inferring higher-order interactions. PLoS Comput Biol 2022; 18:e1010730. [PMID: 36580499 PMCID: PMC9833600 DOI: 10.1371/journal.pcbi.1010730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 01/11/2023] [Accepted: 11/11/2022] [Indexed: 12/30/2022] Open
Abstract
Large-scale genotype-phenotype screens provide a wealth of data for identifying molecular alterations associated with a phenotype. Epistatic effects play an important role in such association studies. For example, siRNA perturbation screens can be used to identify combinatorial gene-silencing effects. In bacteria, epistasis has practical consequences in determining antimicrobial resistance as the genetic background of a strain plays an important role in determining resistance. Recently developed tools scale to human exome-wide screens for pairwise interactions, but none to date have included the possibility of three-way interactions. Expanding upon recent state-of-the-art methods, we make a number of improvements to the performance on large-scale data, making consideration of three-way interactions possible. We demonstrate our proposed method, Pint, on both simulated and real data sets, including antibiotic resistance testing and siRNA perturbation screens. Pint outperforms known methods in simulated data, and identifies a number of biologically plausible gene effects in both the antibiotic and siRNA models. For example, we have identified a combination of known tumour suppressor genes that is predicted (using Pint) to cause a significant increase in cell proliferation.
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Affiliation(s)
- Kieran Elmes
- Department of Computer Science, University of Otago, Dunedin, New Zealand
- School of Mathematics and Statistics, University of Canterbury, Christchurch, New Zealand
| | - Astra Heywood
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Zhiyi Huang
- Department of Computer Science, University of Otago, Dunedin, New Zealand
| | - Alex Gavryushkin
- School of Mathematics and Statistics, University of Canterbury, Christchurch, New Zealand
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Thacharodi A, Lamont IL. Aminoglycoside resistance in Pseudomonas aeruginosa: the contribution of the MexXY-OprM efflux pump varies between isolates. J Med Microbiol 2022; 71. [PMID: 35708991 DOI: 10.1099/jmm.0.001551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Introduction. Aminoglycoside antibiotics are widely used to treat infections of Pseudomonas aeruginosa. The MexXY-OprM efflux pump is an important contributor to aminoglycoside tolerance in P. aeruginosa reference strains and expression of the mexXY genes is repressed by the MexZ repressor protein. Direct investigation of the role of this efflux pump in clinical isolates is relatively limited.Hypothesis. The contribution of MexXY-OprM to P. aeruginosa aminoglycoside resistance is isolate-specific.Aim. To quantify the role of MexXY-OprM and its repressor, MexZ, in clinical isolates of P. aeruginosa. Methodology. The mexXY genes were deleted from ten clinical isolates of P. aeruginosa, and the mexZ gene from nine isolates. Antimicrobial susceptibility testing was carried out for commonly used antipseudomonal drugs on the engineered mutants and the isogenic wild-type isolates. RT-qPCR was used to measure expression of the mexX gene.Results. All but one of the mexXY mutants were more susceptible to the clinically used aminoglycosides tobramycin, gentamicin and amikacin but the degree to which susceptibility increased varied greatly between isolates. The mexXY mutants were also more susceptible to a fluoroquinolone, ciprofloxacin. In three isolates with functional MexZ, deletion of mexZ increased expression of mexXY and aminoglycoside tolerance. Conversely, deleting mexZ from six clinical isolates with mexZ sequence variants had little or no effect on expression of mexXY or on aminoglycoside susceptibility, consistent with the variants abolishing MexZ function. Genome analysis showed that over 50 % of 619 clinical isolates had sequence variants predicted to reduce the affinity of MexZ for DNA, likely increasing mexXY expression and hence efflux of aminoglycosides.Conclusion. Our findings show that the interplay between MexXY, MexZ and the level of mexXY expression plays an important role in aminoglycoside resistance in clinical isolates of P. aeruginosa but the magnitude of the contribution of this efflux pump to resistance is isolate-specific.
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Affiliation(s)
- Aswin Thacharodi
- 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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Prevalence of antibiotic resistance of Pseudomonas aeruginosa in cystic fibrosis infection: A systematic review and meta-analysis. Microb Pathog 2022; 165:105461. [DOI: 10.1016/j.micpath.2022.105461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 12/16/2022]
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β-lactam Resistance in Pseudomonas aeruginosa: Current Status, Future Prospects. Pathogens 2021; 10:pathogens10121638. [PMID: 34959593 PMCID: PMC8706265 DOI: 10.3390/pathogens10121638] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/06/2021] [Accepted: 12/16/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is a major opportunistic pathogen, causing a wide range of acute and chronic infections. β-lactam antibiotics including penicillins, carbapenems, monobactams, and cephalosporins play a key role in the treatment of P. aeruginosa infections. However, a significant number of isolates of these bacteria are resistant to β-lactams, complicating treatment of infections and leading to worse outcomes for patients. In this review, we summarize studies demonstrating the health and economic impacts associated with β-lactam-resistant P. aeruginosa. We then describe how β-lactams bind to and inhibit P. aeruginosa penicillin-binding proteins that are required for synthesis and remodelling of peptidoglycan. Resistance to β-lactams is multifactorial and can involve changes to a key target protein, penicillin-binding protein 3, that is essential for cell division; reduced uptake or increased efflux of β-lactams; degradation of β-lactam antibiotics by increased expression or altered substrate specificity of an AmpC β-lactamase, or by the acquisition of β-lactamases through horizontal gene transfer; and changes to biofilm formation and metabolism. The current understanding of these mechanisms is discussed. Lastly, important knowledge gaps are identified, and possible strategies for enhancing the effectiveness of β-lactam antibiotics in treating P. aeruginosa infections are considered.
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Cristina ML, Sartini M, Schinca E, Ottria G, Casini B, Spagnolo AM. Evaluation of Multidrug-Resistant P. aeruginosa in Healthcare Facility Water Systems. Antibiotics (Basel) 2021; 10:1500. [PMID: 34943711 PMCID: PMC8698422 DOI: 10.3390/antibiotics10121500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/29/2021] [Accepted: 12/02/2021] [Indexed: 11/29/2022] Open
Abstract
According to the WHO, P. aeruginosa is one of the antibiotic-resistant bacteria that represent the biggest threat to public health. The aim of the study was to establish the prevalence of antibiotic-resistant P. aeruginosa in the water systems of various healthcare facilities over the course of nine years. A total of 4500 tap water system samples were taken from seventeen healthcare facilities. The culture method was used to detect P. aeruginosa, and the isolates were then tested for antibiotic resistance using the standardised disc diffusion method. Eleven antibiotics from five different classes were tested. P. aeruginosa was found to have contaminated 2.07% (no. 93) of the water samples. The majority of positive samples came from the dental units (30.11%) and the ward kitchens (23.66%). Considering the total isolates, 56.99% (no. 3) were resistant to at least one of the antibiotics tested. A total of 71.43% of P. aeruginosa isolated from water emerging from dental unit handpieces was antibiotic-resistant, with 45% of it resistant to ≥3 classes of antibiotics. Out of the total isolates, 19.35% showed resistance to carbapenems. It would be advisable to systematically screen tap water for opportunistic micro-organisms such as P. aeruginosa, as many countries already do, including this in the Water Safety Plan.
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Affiliation(s)
- Maria Luisa Cristina
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genoa, Italy; (M.L.C.); (E.S.); (G.O.); (A.M.S.)
- S.S.D. U.O. Hospital Hygiene, E.O. Ospedali Galliera, 16128 Genova, Italy
| | - Marina Sartini
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genoa, Italy; (M.L.C.); (E.S.); (G.O.); (A.M.S.)
- S.S.D. U.O. Hospital Hygiene, E.O. Ospedali Galliera, 16128 Genova, Italy
| | - Elisa Schinca
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genoa, Italy; (M.L.C.); (E.S.); (G.O.); (A.M.S.)
- S.S.D. U.O. Hospital Hygiene, E.O. Ospedali Galliera, 16128 Genova, Italy
| | - Gianluca Ottria
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genoa, Italy; (M.L.C.); (E.S.); (G.O.); (A.M.S.)
- S.S.D. U.O. Hospital Hygiene, E.O. Ospedali Galliera, 16128 Genova, Italy
| | - Beatrice Casini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy;
| | - Anna Maria Spagnolo
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genoa, Italy; (M.L.C.); (E.S.); (G.O.); (A.M.S.)
- S.S.D. U.O. Hospital Hygiene, E.O. Ospedali Galliera, 16128 Genova, Italy
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Wardell SJT, Gauthier J, Martin LW, Potvin M, Brockway B, Levesque RC, Lamont IL. Genome evolution drives transcriptomic and phenotypic adaptation in Pseudomonas aeruginosa during 20 years of infection. Microb Genom 2021; 7. [PMID: 34826267 PMCID: PMC8743555 DOI: 10.1099/mgen.0.000681] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa chronically infects the lungs of patients with cystic fibrosis (CF). During infection the bacteria evolve and adapt to the lung environment. Here we use genomic, transcriptomic and phenotypic approaches to compare multiple isolates of P. aeruginosa collected more than 20 years apart during a chronic infection in a CF patient. Complete genome sequencing of the isolates, using short- and long-read technologies, showed that a genetic bottleneck occurred during infection and was followed by diversification of the bacteria. A 125 kb deletion, an 0.9 Mb inversion and hundreds of smaller mutations occurred during evolution of the bacteria in the lung, with an average rate of 17 mutations per year. Many of the mutated genes are associated with infection or antibiotic resistance. RNA sequencing was used to compare the transcriptomes of an earlier and a later isolate. Substantial reprogramming of the transcriptional network had occurred, affecting multiple genes that contribute to continuing infection. Changes included greatly reduced expression of flagellar machinery and increased expression of genes for nutrient acquisition and biofilm formation, as well as altered expression of a large number of genes of unknown function. Phenotypic studies showed that most later isolates had increased cell adherence and antibiotic resistance, reduced motility, and reduced production of pyoverdine (an iron-scavenging siderophore), consistent with genomic and transcriptomic data. The approach of integrating genomic, transcriptomic and phenotypic analyses reveals, and helps to explain, the plethora of changes that P. aeruginosa undergoes to enable it to adapt to the environment of the CF lung during a chronic infection.
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Affiliation(s)
| | - Jeff Gauthier
- Institut de biologie intégrative et des Systèmes, Université Laval, Québec, Canada
| | - Lois W Martin
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Marianne Potvin
- Institut de biologie intégrative et des Systèmes, Université Laval, Québec, Canada
| | - Ben Brockway
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Roger C Levesque
- Institut de biologie intégrative et des Systèmes, Université Laval, Québec, Canada
| | - Iain L Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Prevalence of the Genes Associated with Biofilm and Toxins Synthesis amongst the Pseudomonas aeruginosa Clinical Strains. Antibiotics (Basel) 2021; 10:antibiotics10030241. [PMID: 33670887 PMCID: PMC7997207 DOI: 10.3390/antibiotics10030241] [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: 01/26/2021] [Revised: 02/21/2021] [Accepted: 02/24/2021] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with an increasing isolation frequency in nosocomial outbreaks. The hypothesis tested was whether carbapenem-resistant P. aeruginosa strains display an altered carriage of the virulence factor genes, depending on the type of carbapenem resistance. The aim of the study was to investigate, by PCR, the frequency of 10 chosen virulence factors genes (phzM, phzS, exoT, exoY, exoU, toxA, exoS, algD, pilA and pilB) and the genotype distribution in 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. P. aeruginosa genes involved in phenazine dyes and exoenzyme T synthesis were noted with the highest frequency (100%). Fimbriae-encoding genes were detected with the lowest incidence: 15.9% and 4.7% for pilin A and B, respectively. The differences observed between the exoS gene prevalence amongst the carbapenemase-positive and the carbapenemase-negative strains and the pilA gene prevalence amongst the strains of different origins were statistically significant. Virulence genes’ prevalence and the genotype distribution vary amongst P. aeruginosa strains resistant to carbapenems, especially in terms of their carbapenemase synthesis ability and the strain origin.
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Carbapenem-Resistant Pseudomonas aeruginosa Strains-Distribution of the Essential Enzymatic Virulence Factors Genes. Antibiotics (Basel) 2020; 10:antibiotics10010008. [PMID: 33374121 PMCID: PMC7823804 DOI: 10.3390/antibiotics10010008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 11/23/2022] Open
Abstract
Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with increasing isolation frequency in nosocomial infections. Herein, we investigated whether antimicrobial-resistant P. aeruginosa strains, e.g., metallo-beta-lactamase (MBL)-producing isolates, may possess a reduced number of virulence genes, resulting from appropriate genome management to adapt to a changing hospital environment. Hospital conditions, such as selective pressure, may lead to the replacement of virulence genes by antimicrobial resistance genes that are crucial to survive under current conditions. The study aimed to compare, using PCR, the frequency of the chosen enzymatic virulence factor genes (alkaline protease-aprA, elastase B-lasB, neuraminidases-nan1 and nan2, and both variants of phospholipase C-plcH and plcN) to MBL distribution among 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. The gene encoding alkaline protease was noted with the highest frequency (100%), while the neuraminidase-1 gene was observed in 37.4% of the examined strains. The difference in lasB and nan1 prevalence amongst the MBL-positive and MBL-negative strains, was statistically significant. Although P. aeruginosa virulence is generally more likely determined by the complex regulation of the virulence gene expression, herein, we found differences in the prevalence of various virulence genes in MBL-producers.
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Wardell SJT, Rehman A, Martin LW, Winstanley C, Patrick WM, Lamont IL. A large-scale whole-genome comparison shows that experimental evolution in response to antibiotics predicts changes in naturally evolved clinical Pseudomonas aeruginosa. Antimicrob Agents Chemother 2019; 63:AAC.01619-19. [PMID: 31570397 PMCID: PMC6879238 DOI: 10.1128/aac.01619-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 09/23/2019] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of acute and chronic infections. An increasing number of isolates have mutations that make them antibiotic resistant, making treatment difficult. To identify resistance-associated mutations we experimentally evolved the antibiotic sensitive strain P. aeruginosa PAO1 to become resistant to three widely used anti-pseudomonal antibiotics, ciprofloxacin, meropenem and tobramycin. Mutants could tolerate up to 2048-fold higher concentrations of antibiotic than strain PAO1. Genome sequences were determined for thirteen mutants for each antibiotic. Each mutant had between 2 and 8 mutations. For each antibiotic at least 8 genes were mutated in multiple mutants, demonstrating the genetic complexity of resistance. For all three antibiotics mutations arose in genes known to be associated with resistance, but also in genes not previously associated with resistance. To determine the clinical relevance of mutations uncovered in this study we analysed the corresponding genes in 558 isolates of P. aeruginosa from patients with chronic lung disease and in 172 isolates from the general environment. Many genes identified through experimental evolution had predicted function-altering changes in clinical isolates but not in environmental isolates, showing that mutated genes in experimentally evolved bacteria can predict those that undergo mutation during infection. Additionally, large deletions of up to 479kb arose in experimentally evolved meropenem resistant mutants and large deletions were present in 87 of the clinical isolates. These findings significantly advance understanding of antibiotic resistance in P. aeruginosa and demonstrate the validity of experimental evolution in identifying clinically-relevant resistance-associated mutations.
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Affiliation(s)
| | - Attika Rehman
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Lois W Martin
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Craig Winstanley
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Wayne M Patrick
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Iain L Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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