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Yano H, Hayashi W, Kawakami S, Aoki S, Anzai E, Zuo H, Kitamura N, Hirabayashi A, Kajihara T, Kayama S, Sugawara Y, Yahara K, Sugai M. Nationwide genome surveillance of carbapenem-resistant Pseudomonas aeruginosa in Japan. Antimicrob Agents Chemother 2024; 68:e0166923. [PMID: 38564665 PMCID: PMC11064530 DOI: 10.1128/aac.01669-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
Japan is a country with an approximate 10% prevalence rate of carbapenem-resistant Pseudomonas aeruginosa (CRPA). Currently, a comprehensive overview of the genotype and phenotype patterns of CRPA in Japan is lacking. Herein, we conducted genome sequencing and quantitative antimicrobial susceptibility testing for 382 meropenem-resistant CRPA isolates that were collected from 78 hospitals across Japan from 2019 to 2020. CRPA exhibited susceptibility rates of 52.9%, 26.4%, and 88.0% against piperacillin-tazobactam, ciprofloxacin, and amikacin, respectively, whereas 27.7% of CRPA isolates was classified as difficult-to-treat resistance P. aeruginosa. Of the 148 sequence types detected, ST274 (9.7%) was predominant, followed by ST235 (7.6%). The proportion of urine isolates in ST235 was higher than that in other STs (P = 0.0056, χ2 test). Only 4.1% of CRPA isolates carried the carbapenemase genes: blaGES (2) and blaIMP (13). One ST235 isolate carried the novel blaIMP variant blaIMP-98 in the chromosome. Regarding chromosomal mutations, 87.1% of CRPA isolates possessed inactivating or other resistance mutations in oprD, and 28.8% showed mutations in the regulatory genes (mexR, nalC, and nalD) for the MexAB-OprM efflux pump. Additionally, 4.7% of CRPA isolates carried a resistance mutation in the PBP3-encoding gene ftsI. The findings from this study and other surveillance studies collectively demonstrate that CRPA exhibits marked genetic diversity and that its multidrug resistance in Japan is less prevailed than in other regions. This study contributes a valuable data set that addresses a gap in genotype/phenotype information regarding CRPA in the Asia-Pacific region, where the epidemiological background markedly differs between regions.
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Affiliation(s)
- Hirokazu Yano
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Wataru Hayashi
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Sayoko Kawakami
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Sadao Aoki
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Eiko Anzai
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Hui Zuo
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Norikazu Kitamura
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Aki Hirabayashi
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Toshiki Kajihara
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Shizuo Kayama
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Yo Sugawara
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Koji Yahara
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
| | - Motoyuki Sugai
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
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Müller M, Wiencierz A, Gehringer C, Muigg V, Bassetti S, Siegemund M, Hinic V, Tschudin-Sutter S, Egli A. Factors associated with non-carbapenemase mediated carbapenem resistance of Gram-negative bacteria: a retrospective case-control study. Int Microbiol 2024; 27:597-606. [PMID: 37556067 PMCID: PMC10991015 DOI: 10.1007/s10123-023-00405-6] [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: 03/04/2023] [Revised: 07/10/2023] [Accepted: 07/15/2023] [Indexed: 08/10/2023]
Abstract
Infections with carbapenemase-producing Gram-negative bacteria are related to increased morbidity and mortality, yet little is known regarding infections caused by non-beta-lactamase mediated carbapenem-resistant bacteria. Our objective was to identify risk factors for, and the clinical impact of infections caused by carbapenem-resistant carbapenemase-negative Enterobacterales and Pseudomonas aeruginosa. This retrospective matched case-control study was performed at the University Hospital of Basel, Switzerland, in 2016. We focused on other resistance mechanisms by excluding laboratory-confirmed carbapenemase-positive cases. Carbapenem resistance was set as the primary endpoint, and important risk factors were investigated by conditional logistic regression. The clinical impact of carbapenem resistance was estimated using regression models containing the resistance indicator as explanatory factor and adjusting for potential confounders. Seventy-five cases of infections with carbapenem-resistant, carbapenemase-negative bacteria were identified and matched with 75 controls with carbapenem-susceptible infections. The matched data set was well-balanced regarding age, gender, and comorbidity. Duration of prior carbapenem treatment (OR 1.15, [1.01, 1.31]) correlated with resistance to carbapenems. Our study showed that patients with carbapenem-resistant bacteria stayed 1.59 times (CI [0.81, 3.14]) longer in an ICU. The analyzed dataset did not provide evidence for strong clinical implications of resistance to carbapenems or increased mortality. The duration of prior carbapenem treatment seems to be a strong risk factor for the development of carbapenem resistance. The higher risk for a longer ICU stay could be a consequence of a carbapenem resistance. In contrast to carbapenemase-producers, the clinical impact of carbapenamase-negative, carbapenem-resistant strains may be limited. Trial registration: The study design was prospectively approved by the local Ethics Commission on 10.08.2017 (EKNZ BASEC 2017-00222).
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Affiliation(s)
- Marius Müller
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Andrea Wiencierz
- Clinical Trial Unit, University Hospital Basel, Basel, Switzerland
| | - Christian Gehringer
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Internal Medicine, University Hospital Basel, Basel, Switzerland
| | - Veronika Muigg
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Stefano Bassetti
- Internal Medicine, University Hospital Basel, Basel, Switzerland
| | - Martin Siegemund
- Intensive Care Medicine, Department of Acute Medicine, University Hospital Basel, Basel, Switzerland
- Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Vladimira Hinic
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Sarah Tschudin-Sutter
- Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland
| | - Adrian Egli
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland.
- Institute of Medical Microbiology, University of Zurich, Gloriastrasse 28/30, 8006, Zurich, Switzerland.
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Sastre-Femenia MÀ, Fernández-Muñoz A, Gomis-Font MA, Taltavull B, López-Causapé C, Arca-Suárez J, Martínez-Martínez L, Cantón R, Larrosa N, Oteo-Iglesias J, Zamorano L, Oliver A. Pseudomonas aeruginosa antibiotic susceptibility profiles, genomic epidemiology and resistance mechanisms: a nation-wide five-year time lapse analysis. THE LANCET REGIONAL HEALTH. EUROPE 2023; 34:100736. [PMID: 37753216 PMCID: PMC10518487 DOI: 10.1016/j.lanepe.2023.100736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/28/2023] [Accepted: 08/31/2023] [Indexed: 09/28/2023]
Abstract
Background Pseudomonas aeruginosa healthcare-associated infections are one of the top antimicrobial resistance threats world-wide. In order to analyze the current trends, we performed a Spanish nation-wide high-resolution analysis of the susceptibility profiles, the genomic epidemiology and the resistome of P. aeruginosa over a five-year time lapse. Methods A total of 3.180 nonduplicated P. aeruginosa clinical isolates from two Spanish nation-wide surveys performed in October 2017 and 2022 were analyzed. MICs of 13 antipseudomonals were determined by ISO-EUCAST. Multidrug resistance (MDR)/extensively drug resistance (XDR)/difficult to treat resistance (DTR)/pandrug resistance (PDR) profiles were defined following established criteria. All XDR/DTR isolates were subjected to whole genome sequencing (WGS). Findings A decrease in resistance to all tested antibiotics, including older and newer antimicrobials, was observed in 2022 vs 2017. Likewise, a major reduction of XDR (15.2% vs 5.9%) and DTR (4.2 vs 2.1%) profiles was evidenced, and even more patent among ICU isolates [XDR (26.0% vs 6.0%) and DTR (8.9% vs 2.6%)] (p < 0.001). The prevalence of Extended-spectrum β-lactamase/carbapenemase production was slightly lower in 2022 (2.1%. vs 3.1%, p = 0.064). However, there was a significant increase in the proportion of carbapenemase production among carbapenem-resistant strains (29.4% vs 18.1%, p = 0.0246). While ST175 was still the most frequent clone among XDR, a slight reduction in its prevalence was noted (35.9% vs 45.5%, p = 0.106) as opposed to ST235 which increased significantly (24.3% vs 12.3%, p = 0.0062). Interpretation While the generalized decrease in P. aeruginosa resistance, linked to a major reduction in the prevalence of XDR strains, is encouraging, the negative counterpart is the increase in the proportion of XDR strains producing carbapenemases, associated to the significant advance of the concerning world-wide disseminated hypervirulent high-risk clone ST235. Continued high-resolution surveillance, integrating phenotypic and genomic data, is necessary for understanding resistance trends and analyzing the impact of national plans on antimicrobial resistance. Funding MSD and the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea-NextGenerationEU.
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Affiliation(s)
- Miquel Àngel Sastre-Femenia
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
| | - Almudena Fernández-Muñoz
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
| | - María Antonia Gomis-Font
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
| | - Biel Taltavull
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
| | - Carla López-Causapé
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
| | - Jorge Arca-Suárez
- Servicio de Microbiología, Complexo Hospitalario Universitario A Coruña, Instituto Investigación Biomédica A Coruña (INIBIC), CIBERINFEC, A Coruña, España
| | - Luis Martínez-Martínez
- Unidad de Gestión Clínica de Microbiología, Hospital Universitario Reina Sofía, Departamento de Química Agrícola, Edafología y Microbiología, Universidad de Córdoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), CIBERINFEC, Córdoba, España
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal- IRYCIS, CIBERINFEC, Madrid, España
| | - Nieves Larrosa
- Servicio de Microbiología, Hospital Universitario Vall d`Hebron, Vall d’Hebron Institut de Recerca (VHIR), Departamento de Genética y Microbiología, Universitat Autònoma de Barcelona, CIBERINFEC, Barcelona, España
| | - Jesús Oteo-Iglesias
- Centro Nacional de Microbiología, CIBERINFEC, Instituto de Salud Carlos III, Madrid, España
| | - Laura Zamorano
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), CIBERINFEC, Palma de Mallorca, España
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Yasuda N, Fujita T, Fujioka T, Tagawa M, Kohira N, Torimaru K, Shiota S, Kumagai T, Morita D, Ogawa W, Tsuchiya T, Kuroda T. Effects of the order of exposure to antimicrobials on the incidence of multidrug-resistant Pseudomonas aeruginosa. Sci Rep 2023; 13:8826. [PMID: 37258635 DOI: 10.1038/s41598-023-35256-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 05/15/2023] [Indexed: 06/02/2023] Open
Abstract
Multidrug-resistant Pseudomonas aeruginosa (MDRP) is one of the most important pathogens in clinical practice. To clarify the mechanisms contributing to its emergence, we isolated MDRPs using the P. aeruginosa PAO1, the whole genome sequence of which has already been elucidated. Mutant strains resistant to carbapenems, aminoglycosides, and new quinolones, which are used to treat P. aeruginosa infections, were isolated; however, none met the criteria for MDRPs. Then, PAO1 strains were exposed to these antimicrobial agents in various orders and the appearance rate of MDRP varied depending on the order of exposure; MDRPs more frequently appeared when gentamicin was applied before ciprofloxacin, but were rarely isolated when ciprofloxacin was applied first. Exposure to ciprofloxacin followed by gentamicin increased the expression of MexCD-OprJ, an RND-type multidrug efflux pump, due to the NfxB mutation. In contrast, exposure to gentamicin followed by ciprofloxacin resulted in more mutations in DNA gyrase. These results suggest that the type of quinolone resistance mechanism is related to the frequency of MDRP and that the risk of MDRP incidence is highly dependent on the order of exposure to gentamicin and ciprofloxacin.
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Affiliation(s)
- Nami Yasuda
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
| | - Tomoko Fujita
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
| | - Takahiro Fujioka
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
| | - Mei Tagawa
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
| | - Naoki Kohira
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
| | - Kensho Torimaru
- Department of Microbiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Sumiko Shiota
- Department of Molecular Biology, School of Pharmacy, Shujitsu University, 1-6-1 Nishigawara, Naka-ku, Okayama, 703-8516, Japan
| | - Takanori Kumagai
- Department of Microbiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Daichi Morita
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
- Department of Microbiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Wakano Ogawa
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
- Department of Microbiology and Biochemistry, Daiichi University of Pharmacy, 22-1, Tamagawa-Machi, Minami-ku, Fukuoka, 815-8511, Japan
| | - Tomofusa Tsuchiya
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
| | - Teruo Kuroda
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan.
- Department of Microbiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
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Biggel M, Johler S, Roloff T, Tschudin-Sutter S, Bassetti S, Siegemund M, Egli A, Stephan R, Seth-Smith HMB. PorinPredict: In Silico Identification of OprD Loss from WGS Data for Improved Genotype-Phenotype Predictions of P. aeruginosa Carbapenem Resistance. Microbiol Spectr 2023; 11:e0358822. [PMID: 36715510 PMCID: PMC10100854 DOI: 10.1128/spectrum.03588-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/29/2022] [Indexed: 01/31/2023] Open
Abstract
The increasing integration of genomics into routine clinical diagnostics requires reliable computational tools to identify determinants of antimicrobial resistance (AMR) from whole-genome sequencing data. Here, we developed PorinPredict, a bioinformatic tool that predicts defects of the Pseudomonas aeruginosa outer membrane porin OprD, which are strongly associated with reduced carbapenem susceptibility. PorinPredict relies on a database of intact OprD variants and reports inactivating mutations in the coding or promoter region. PorinPredict was validated against 987 carbapenemase-negative P. aeruginosa genomes, of which OprD loss was predicted for 454 out of 522 (87.0%) meropenem-nonsusceptible and 46 out of 465 (9.9%) meropenem-susceptible isolates. OprD loss was also found to be common among carbapenemase-producing isolates, resulting in even further increased MICs. Chromosomal mutations in quinolone resistance-determining regions and OprD loss commonly co-occurred, likely reflecting the restricted use of carbapenems for multidrug-resistant infections as recommended in antimicrobial stewardship programs. In combination with available AMR gene detection tools, PorinPredict provides a robust and standardized approach to link P. aeruginosa phenotypes to genotypes. IMPORTANCE Pseudomonas aeruginosa is a major cause of multidrug-resistant nosocomial infections. The emergence and spread of clones exhibiting resistance to carbapenems, a class of critical last-line antibiotics, is therefore closely monitored. Carbapenem resistance is frequently mediated by chromosomal mutations that lead to a defective outer membrane porin OprD. Here, we determined the genetic diversity of OprD variants across the P. aeruginosa population and developed PorinPredict, a bioinformatic tool that enables the prediction of OprD loss from whole-genome sequencing data. We show a high correlation between predicted OprD loss and meropenem nonsusceptibility irrespective of the presence of carbapenemases, which are a second widespread determinant of carbapenem resistance. Isolates with resistance determinants to other antibiotics were disproportionally affected by OprD loss, possibly due to an increased exposure to carbapenems. Integration of PorinPredict into genomic surveillance platforms will facilitate a better understanding of the clinical impact of OprD modifications and transmission dynamics of resistant clones.
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Affiliation(s)
- Michael Biggel
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Tim Roloff
- Division of Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Institute of Medical Microbiology, University of Zurich, Zurich
| | - Sarah Tschudin-Sutter
- Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland
| | - Stefano Bassetti
- Internal Medicine, University Hospital Basel, Basel, Switzerland
| | - Martin Siegemund
- Intensive Care Unit, University Hospital Basel, Basel, Switzerland
| | - Adrian Egli
- Division of Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Institute of Medical Microbiology, University of Zurich, Zurich
| | - Roger Stephan
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Helena M. B. Seth-Smith
- Division of Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Institute of Medical Microbiology, University of Zurich, Zurich
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Geng J, Liu H, Chen S, Long J, Jin Y, Yang H, Duan G. Comparative genomic analysis of Escherichia coli strains obtained from continuous imipenem stress evolution. FEMS Microbiol Lett 2022; 369:6526866. [PMID: 35147175 DOI: 10.1093/femsle/fnac015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/07/2022] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
The carbapenem-resistant Escherichia coli (E. coli) has aroused increasing attention worldwide, especially in terms of imipenem (IMP) resistance. The molecular mechanism of IMP resistance remains unclear. This study aimed to explore the resistance mechanisms of IMP in E. coli. Susceptible Sx181-0-1 strain was induced into resistance strains by adaptive laboratory evolution. The drug resistance spectrum was measured using the disk diffusion and microbroth dilution methods. Whole-genome sequencing and resequencing were used to analyze the non-synonymous single-nucleotide polymorphisms (nsSNPs) between the primary susceptible strain and resistant strains. The expression levels of these genes with nsSNPs were identified by real-time quantitative PCR (RT-qPCR). Resistance phenotype appeared in the induced 15th generation (induction time = 183 h). Sx181-32 and Sx181-256, which had minimum inhibitory concentrations of IMP of 8 and 64 µg mL-1, were isolated during continuous subculture exposed to increasing concentrations of IMP, respectively. Nineteen nsSNPs were observed both in Sx181-32 and Sx181-256, including rpsU, sdaC, zwf, ttuC, araJ, dacC, mrdA, secF, dacD, lpxD, mrcB, ftsI, envZ, and two unknown function genes (orf01892 and orf01933). Among these 15 genes, five genes (dacC, mrdA, lpxD, mrcB, and ftsI) were mainly involved in cell wall synthesis. The mrdA (V338A, L378P, and M574I) and mrcB (P784L, A736V, and T708A) had three amino acid substitutions, respectively. The expression levels of rpsU, ttuC and orf01933 were elevated in both Sx181-32 and Sx181-256 compared to Sx181-0-1. The expression levels of these genes were elevated in Sx181-256, except for araJ. Bacteria developed resistance to antimicrobials by regulating various biological processes, among which the most involved is the cell wall synthesis (dacC, mrdA, lpxD, mrcB, and ftsI). The combination mutations of mrdA, envZ, and ftsI genes may increase the resistance to IMP. Our study could improve the understanding of the molecular mechanism underlying the IMP resistance of E. coli.
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Affiliation(s)
- Juan Geng
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Huiying Liu
- People's Hospital of Henan University of Chinese Medicine, Zhengzhou, China.,People's Hospital of Zhengzhou, Zhengzhou, China
| | - Shuaiyin Chen
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Jinzhao Long
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Yuefei Jin
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Haiyan Yang
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Guangcai Duan
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
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7
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OUP accepted manuscript. J Antimicrob Chemother 2022; 77:1862-1872. [DOI: 10.1093/jac/dkac122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/21/2022] [Indexed: 11/14/2022] Open
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8
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Nockelmann L, Cremanns M, Gatermann SG, Pfennigwerth N. Evaluation of the rCIM for carbapenemase detection in Enterobacterales and Pseudomonas aeruginosa and description of the TSBrCIM, an optimized variant. J Microbiol Methods 2021; 190:106345. [PMID: 34662678 DOI: 10.1016/j.mimet.2021.106345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/24/2021] [Accepted: 09/24/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES The rapid Carbapenem Inactivation Method (rCIM) was evaluated with a strain collection of 164 and 69 carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa, respectively, that produced various carbapenemases. For an improved carbapenemase detection in Enterobacterales, an optimized variant of the rCIM named TSBrCIM was developed. METHODS Bacterial isolates were incubated with two meropenem disks in distilled water (rCIM) or tryptic soy broth (TSBrCIM). After centrifugation, the supernatant was incubated with a susceptible E. coli indicator strain in tryptic soy broth. Growth of the indicator strain implied carbapenemase activity in the test strain. RESULTS The rCIM detected 100/113 carbapenemase-producing Enterobacterales, resulting in a sensitivity of 88.5% and a specificity of 94.1%. For P. aeruginosa, sensitivity and specificity were 96.0% and 100%, respectively. The TSBrCIM was able to detect 105/113 carbapenemase-producing Enterobacterales, resulting in a sensitivity of 92.9% and a specificity of 96.1%. CONCLUSION This study shows that the TSBrCIM can be valuable tool for detection of carbapenemases in Enterobacterales in the clinical laboratory, while the rCIM showed the best results for carbapenemase detection in P. aeruginosa.
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Affiliation(s)
- Laura Nockelmann
- German National Reference Centre for Multidrug-resistant Gram-negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Martina Cremanns
- German National Reference Centre for Multidrug-resistant Gram-negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Sören G Gatermann
- German National Reference Centre for Multidrug-resistant Gram-negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Niels Pfennigwerth
- German National Reference Centre for Multidrug-resistant Gram-negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany.
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Upstream region of OprD mutations in imipenem-resistant and imipenem-sensitive Pseudomonas isolates. AMB Express 2021; 11:82. [PMID: 34089411 PMCID: PMC8179858 DOI: 10.1186/s13568-021-01243-3] [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: 04/20/2021] [Accepted: 05/31/2021] [Indexed: 01/07/2023] Open
Abstract
The current study was aimed at investigating the prevalence of the mutations upstream of the oprD coding region and its promoters among imipenem-resistant and sensitive Pseudomonas aeruginosa isolated from educational hospitals in Yazd City, Iran. All isolates were identified by the conventional biochemical tests. Then, the antibiotic resistance of these isolates was determined using the disk diffusion method according to the CLSI guidelines. Also, the E.test was performed to determine the minimum inhibitory concentrations (MIC) of imipenem. The mutations of this gene were recognized by the amplification of this region and subsequently sequenced. Sequencing of the genomic region upstream of oprD these regions were done in the 29 clinical strains. Statistical analysis was done by the statistical software SPSS-18. Seventy (77.7%) of isolates had MIC ≥ 16 and were resistant to imipenem. Mutations of the upstream of the oprD gene and its promoters were seen in 25 (86.2%) isolates and 4 isolates had no mutation. One isolate had a base substitution A→Cat nt 25 in the coding region and this isolate had a point mutation leading to an amino acid change at positions 9 (I→L). Our study results indicated that none of the strains had mutation in Shine-Dalgarno and the point mutations were the most common mutations upstream of the oprD coding region among P. aeruginosa isolates. Mutations were observed in imipenem-resistant isolates and it seems this mechanism is effective in resistance of isolates to imipenem and this confirmed that the indiscriminate use of antibiotic should be controlled.
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10
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Predicting Pseudomonas aeruginosa susceptibility phenotypes from whole genome sequence resistome analysis. Clin Microbiol Infect 2021; 27:1631-1637. [PMID: 34015532 DOI: 10.1016/j.cmi.2021.05.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 04/28/2021] [Accepted: 05/05/2021] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The aim was to develop and validate a Pseudomonas aeruginosa genotypic resistance score, based on analysis of the whole genome sequence resistome, to predict antimicrobial susceptibility phenotypes. METHODS A scoring system based on the analysis of mutation-driven resistance in 40 chromosomal genes and horizontally acquired resistance (Resfinder) was developed for ceftazidime, ceftolozane/tazobactam, meropenem, ciprofloxacin and tobramycin. Resistance genes/mutations were scored from 0 (no effect) to 1 (EUCAST clinical resistance). One hundred wild-type strains obtained from 51 different hospitals during a 2017 multicentre study were fully sequenced and analysed in order to define a catalogue of natural polymorphisms in the 40 chromosomal resistance genes. The capacity of genotypic score to predict the susceptibility phenotype was tested in 204 isolates randomly selected from the 51 hospitals (four from each hospital). RESULTS The analysis of the 100 wild-type isolates yielded a catalogue of 455 natural polymorphisms in the 40 genes involved in mutational resistance. However, resistance mutations and high-risk clones (such as ST235) were also documented among a few wild-type isolates. Overall, the capacity of the genotypic score (<0.5) for predicting phenotypic susceptibility (S + I in the case of meropenem) was very high (95-100%). In contrast, the capacity of the genotypic score to predict resistance (≥1) was far more variable depending on the agent. Prediction of meropenem clinical resistance was particularly low (18/39, 46.1%), whereas it classified clinical ceftolozane/tazobactam resistance in 100% (7/7) of cases. DISCUSSION Although a margin for improvement was evidenced in this proof of concept study, an overall good correlation between the genotypic resistance score and the susceptibility profile was documented. Further refining of the scoring system, automatization and testing of large international cohorts should follow.
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11
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Phenotypic Detection and Differentiation of Carbapenemase Classes Including OXA-48-Like Enzymes in Enterobacterales and Pseudomonas aeruginosa by a Highly Specialized Micronaut-S Microdilution Assay. J Clin Microbiol 2020; 58:JCM.00171-20. [PMID: 32878951 DOI: 10.1128/jcm.00171-20] [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: 01/29/2020] [Accepted: 08/27/2020] [Indexed: 12/21/2022] Open
Abstract
The objective of this study was to evaluate the Micronaut-S carbapenemase detection microtiter plate assay for the detection of carbapenemases and Ambler class determination. The Micronaut-S carbapenemase detection microtiter plate was tested using a challenging collection of 154 carbapenemase-producing and 150 carbapenemase-negative clinical strains of Enterobacterales and Pseudomonas aeruginosa The Micronaut-S carbapenemase detection assay was able to detect 148/154 carbapenemase producers correctly, whereas 5/150 non-carbapenemase-producing isolates tested as false positive. This resulted in an overall sensitivity of 96% and a specificity of 97%. Regarding the detection of the carbapenemase class, the sensitivities and specificities were 93%/100%, 96%/100%, and 97%/99% for class A (n = 27), class B (n = 54), and class D (n = 73) carbapenemases, respectively. The Micronaut-S carbapenemase detection microtiter plate represents an easy-to-use and valuable tool for accurate and reliable detection of carbapenemases. In addition, it provides identification of the class of carbapenemase in most cases which can provide significant therapy guidance.
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12
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Li F, Chen D, Li L, Liang D, Wang F, Zhang B. Analysis of Metallo-β-lactamases, oprD Mutation, and Multidrug Resistance of β-lactam Antibiotic-Resistant Strains of Pseudomonas aeruginosa Isolated from Southern China. Curr Microbiol 2020; 77:3264-3269. [PMID: 32785753 PMCID: PMC7536146 DOI: 10.1007/s00284-020-02148-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 07/25/2020] [Indexed: 12/20/2022]
Abstract
The purpose of this study was to analyze the metallo-β-lactamases (MBLs) genotype and oprD mutations of the β-lactam antibiotic-resistant Pseudomonas aeruginosa (PA) strains isolated from southern China. We collected 110 strains of β-lactam antibiotic-resistant PA from 2 hospitals during January 2016–December 2017 from Dongguan, South China. MBLs were detected, amplified, and typed using EDTA disc synergy test, PCR, and Sanger gene sequencing. The mutations and expression levels of oprD were detected using Sanger gene sequencing and qPCR. A total of 16.36% (18/110) β-lactam antibiotic-resistant PA strains produced MBLs, and the main genotypes of MBLs were IMP-25, VIM-2, and SIM-2. Sanger gene sequencing results showed that 107 of the 110 strains harbored mutations in oprD sequence, while 3 strains were negative for oprD amplification (2.73%). Among the 107 strains with positive amplification (97.27%), the rate of intentional mutations (including deletions, insertions, and premature stop codons) was 93.46% (100/107) and that of no disrupted mutation was 6.54% (7/107). qPCR analysis confirmed that the expression level of the OprD protein in the 7 strains of no disrupted mutation was significantly reduced. Among the β-lactam antibiotic-resistant PA strains in southern China, 16.36% were positive for MBLs. The loss rate of oprD was 2.73%, and almost all PA strains showed oprD amplification variation or transcription downregulation. Thus, impaired oprD expression and MBLs production may be some of the mechanisms of β-lactam antibiotic-resistance of PA strains in southern China.
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Affiliation(s)
- Fei Li
- Clinical Laboratory' Affiliated Dongguan People's Hospital, Southern Medical University, No.3 Xinguchong Wandao South Road, Wangjiang District, Dongguan, 523059, Guangdong, China
| | - Danna Chen
- Clinical Laboratory' Affiliated Dongguan People's Hospital, Southern Medical University, No.3 Xinguchong Wandao South Road, Wangjiang District, Dongguan, 523059, Guangdong, China
| | - Lijuan Li
- Clinical Laboratory' Affiliated Dongguan People's Hospital, Southern Medical University, No.3 Xinguchong Wandao South Road, Wangjiang District, Dongguan, 523059, Guangdong, China
| | - Dezhi Liang
- Clinical Laboratory' Affiliated Dongguan People's Hospital, Southern Medical University, No.3 Xinguchong Wandao South Road, Wangjiang District, Dongguan, 523059, Guangdong, China
| | - Fengping Wang
- Clinical Laboratory' Affiliated Dongguan People's Hospital, Southern Medical University, No.3 Xinguchong Wandao South Road, Wangjiang District, Dongguan, 523059, Guangdong, China
| | - Bashan Zhang
- Clinical Laboratory' Affiliated Dongguan People's Hospital, Southern Medical University, No.3 Xinguchong Wandao South Road, Wangjiang District, Dongguan, 523059, Guangdong, China.
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13
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Wee BA, Tai AS, Sherrard LJ, Ben Zakour NL, Hanks KR, Kidd TJ, Ramsay KA, Lamont I, Whiley DM, Bell SC, Beatson SA. Whole genome sequencing reveals the emergence of a Pseudomonas aeruginosa shared strain sub-lineage among patients treated within a single cystic fibrosis centre. BMC Genomics 2018; 19:644. [PMID: 30165811 PMCID: PMC6117919 DOI: 10.1186/s12864-018-5018-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/14/2018] [Indexed: 11/18/2022] Open
Abstract
Background Chronic lung infections caused by Pseudomonas aeruginosa are a significant cause of morbidity and mortality in people with cystic fibrosis (CF). Shared P. aeruginosa strains, that can be transmitted between patients, are of concern and in Australia the AUST-02 shared strain is predominant in individuals attending CF centres in Queensland and Western Australia. M3L7 is a multidrug resistant sub-type of AUST-02 that was recently identified in a Queensland CF centre and was shown to be associated with poorer clinical outcomes. The main aim of this study was to resolve the relationship of the emergent M3L7 sub-type within the AUST-02 group of strains using whole genome sequencing. Results A whole genome core phylogeny of 63 isolates indicated that M3L7 is a monophyletic sub-lineage within the context of the broader AUST-02 group. Relatively short branch lengths connected all of the M3L7 isolates. A phylogeny based on nucleotide polymorphisms present across the genome showed that the chronological estimation of the most recent common ancestor was around 2001 (± 3 years). SNP differences between sequential non-hypermutator M3L7 isolates collected 3–4 years apart from five patients suggested both continuous infection of the same strain and cross-infection of some M3L7 variants between patients. The majority of polymorphisms that were characteristic of M3L7 (i.e. acquired after divergence from all other AUST-02 isolates sequenced) were found to produce non-synonymous mutations in virulence and antibiotic resistance genes. Conclusions M3L7 has recently diverged from a common ancestor, indicating descent from a single carrier at a CF treatment centre in Australia. Both adaptation to the lung and transmission of M3L7 between adults attending this centre may have contributed to its rapid dissemination. Further genomic investigations are required on multiple intra-sample isolates of this sub-type to decipher potential mechanisms which facilitates its epidemiological success. Electronic supplementary material The online version of this article (10.1186/s12864-018-5018-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bryan A Wee
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Present Address: Usher Institute of Population Health Sciences & Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna S Tai
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia.,Department of Respiratory Medicine, Western Australia Adult Cystic Fibrosis Centre, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - Laura J Sherrard
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Present Address: School of Pharmacy, Queen's University Belfast, Belfast, United Kingdom
| | - Nouri L Ben Zakour
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Kirt R Hanks
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK.,Child Health Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Kay A Ramsay
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Present Address: Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Iain Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - David M Whiley
- Faculty of Medicine, UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia.,Microbiology Department, Pathology Queensland Central Laboratory, Brisbane, QLD, Australia
| | - Scott C Bell
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia.,Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia. .,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia. .,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia.
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14
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Shu JC, Kuo AJ, Su LH, Liu TP, Lee MH, Su IN, Wu TL. Development of carbapenem resistance in Pseudomonas aeruginosa is associated with OprD polymorphisms, particularly the amino acid substitution at codon 170. J Antimicrob Chemother 2018; 72:2489-2495. [PMID: 28535274 DOI: 10.1093/jac/dkx158] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/28/2017] [Indexed: 12/13/2022] Open
Abstract
Objectives Pan-susceptible Pseudomonas aeruginosa (PSPA) clinical isolates carrying an OprD with loop 7 shortening (the group-1A allele) were found to rapidly develop carbapenem resistance under continuous selection pressure. We further studied whether OprD polymorphisms are associated with the potential to develop carbapenem resistance. Methods OprD amino acid sequences of 126 PSPA clinical isolates were analysed to determine their STs using P. aeruginosa strain PAO1 as the control strain. Site-directed mutagenesis was performed in PAO1 to generate polymorphisms of interest. A disc diffusion method was used to select carbapenem-resistant variants from the mutant strains. Expression levels of oprD were determined by quantitative RT-PCR. MICs of carbapenems were determined by Etest. Results Forty-eight (38.1%) of the tested isolates carried the group-1A allele. Another two major STs, C1 and C2, both of which harboured an F170L polymorphism, were found in 21 (16.7%) and 39 (31.0%) isolates, respectively. The PAO1 type was also found in 14 (11.1%) isolates. Under continuous selective pressure, isolates of most STs developed carbapenem resistance at different numbers of passaging events; only those belonging to the PAO1 type remained susceptible. However, PAO1 mutants carrying either the oprD group-1A allele or the OprD-F170L polymorphism were able to develop carbapenem resistance. Reduced oprD expression triggered by continuous imipenem challenge was found in PAO1 mutants, but not in the PAO1 WT strain. Conclusions OprD polymorphisms, particularly the F170L substitution and the specific shortening in loop 7, appear to determine the potential for P. aeruginosa to develop carbapenem resistance.
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Affiliation(s)
- Jwu-Ching Shu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - An-Jing Kuo
- Department of Laboratory Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Lin-Hui Su
- Department of Laboratory Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsui-Ping Liu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan
| | - Ming-Hsun Lee
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - I-Ning Su
- Department of Laboratory Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan
| | - Tsu-Lan Wu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
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15
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Schiavano GF, Carloni E, Andreoni F, Magi S, Chironna M, Brandi G, Amagliani G. Prevalence and antibiotic resistance of Pseudomonas aeruginosa in water samples in central Italy and molecular characterization of oprD in imipenem resistant isolates. PLoS One 2017; 12:e0189172. [PMID: 29211780 PMCID: PMC5718518 DOI: 10.1371/journal.pone.0189172] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/20/2017] [Indexed: 12/18/2022] Open
Abstract
Scope This study aimed to analyse the prevalence, antibiotic resistance and genetic relatedness of P. aeruginosa isolates obtained from potable and recreational water samples (n. 8,351) collected from different settings (swimming pools, n. 207; healthcare facilities, n 1,684; accommodation facilities, n. 1,518; municipal waterworks, n. 4,500; residential buildings, n. 235). Possible mechanisms underlying resistance to imipenem, with particular focus on those involving oprD-based uptake, were also explored. Methods and results Isolation and identification of Pseudomonas aeruginosa was performed according to the standardized procedure UNI EN ISO 16266:2008 followed by PCR confirmation. Antibiotic Susceptibility testing was conducted according to EUCAST standardized disk diffusion method. Genetic relatedness of strains was carried out by RAPD. The sequence of the oprD gene was analyzed by standard method. Fifty-three samples (0.63%) were positive for P. aeruginosa, of which 10/207 (4.83%) were from swimming pools. Five isolates (9.43%) were resistant to imipenem, one to Ticarcillin + Clavulanate, one to both Piperacillin and Ticarcillin + Clavulanate. The highest isolation rate of imipenem resistant P. aeruginosa was observed in swimming pool water. Identical RAPD profiles were found in isolates from the same location in the same year or even in different years. Conclusions Imipenem resistant strains were identified as carbapenemase-negative and resistance has been associated with inactivating mutations within the oprD gene, with a concomitant loss of porin. RAPD results proved that a water system can remain colonized by one strain for long periods and the contamination may be difficult to eradicate. This study has revealed the presence of P. aeruginosa in different water samples, including resistant strains, especially in swimming pools, and confirmed the role of porins as a contributing factor in carbapenem resistance in Gram-negative bacteria.
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Affiliation(s)
- Giuditta Fiorella Schiavano
- Department of Biomolecular Sciences, Toxicological, Hygienistic and Environmental Sciences Unit, University of Urbino Carlo Bo, Urbino, PU, Italy
- * E-mail:
| | - Elisa Carloni
- Department of Biomolecular Sciences, Section of Biotechnology, University of Urbino Carlo Bo, Fano, PU, Italy
| | - Francesca Andreoni
- Department of Biomolecular Sciences, Section of Biotechnology, University of Urbino Carlo Bo, Fano, PU, Italy
| | - Silvia Magi
- Dipartimento provinciale ARPAM di Pesaro, Servizio Acque, Pesaro, Italy
| | - Maria Chironna
- Department of Biomedical Science and Human Oncology-Hygiene Section, Aldo Moro University of Bari, Bari, Italy
| | - Giorgio Brandi
- Department of Biomolecular Sciences, Toxicological, Hygienistic and Environmental Sciences Unit, University of Urbino Carlo Bo, Urbino, PU, Italy
| | - Giulia Amagliani
- Department of Biomolecular Sciences, Toxicological, Hygienistic and Environmental Sciences Unit, University of Urbino Carlo Bo, Urbino, PU, Italy
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16
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Insertional inactivation of oprD in carbapenem-resistant Pseudomonas aeruginosa strains isolated from burn patients in Tehran, Iran. New Microbes New Infect 2017; 21:75-80. [PMID: 29234497 PMCID: PMC5722278 DOI: 10.1016/j.nmni.2017.10.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/26/2017] [Accepted: 10/27/2017] [Indexed: 01/19/2023] Open
Abstract
In this study, we report the insertion sequence ISPpu21 in the oprD porin gene of carbapenem-resistant Pseudomonas aeruginosa isolates from burn patients in Tehran, Iran. Antibiotic susceptibility tests for P. aeruginosa isolates were determined. Production of metallo-β-lactamases (MBLs) and carbapenemase was evaluated and the β-lactamase-encoding and aminoglycoside-modifying enzyme genes were investigated by PCR and sequencing methods. The mRNA transcription level of oprD and mex efflux pump genes were evaluated by real-time PCR. The outer membrane protein profile was determined by SDS–PAGE. The genetic relationship between the P. aeruginosa isolates was assessed by random amplified polymorphic DNA PCR. In all, 10.52% (10/95) of clinical isolates of P. aeruginosa harboured the ISPpu21 insertion element in the oprD gene. The extended-spectrum β-lactamase-encoding gene in ISPpu21-carrying isolates was blaTEM. PCR assays targeting MBL and carbapenemase-encoding genes were also negative in all ten isolates. The rmtA, aadA, aadB and armA genes were positive in all ISPpu21 harbouring isolates. The relative expression levels of the mexX, mexB, mexT and mexD genes in ten isolates ranged from 0.1- to 1.4-fold, 1.1- to 3.68-fold, 0.3- to 8.22-fold and 1.7- to 35.17-fold, respectively. The relative expression levels of the oprD in ten isolates ranged from 0.57- to 35.01-fold, which was much higher than those in the control strain P. aeruginosa PAO1. Evaluation of the outer membrane protein by SDS–PAGE suggested that oprD was produced at very low levels by all isolates. Using random amplified polymorphic DNA PCR genotyping, eight of the ten isolates containing ISPpu21 were shown to be clonally related. The present study describes a novel molecular mechanism, ISPpu21 insertion of the oprD gene, associated with carbapenem resistance in clinical P. aeruginosa isolates.
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17
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Takata I, Yamagishi Y, Mikamo H. Association of the exoU genotype with a multidrug non-susceptible phenotype and mRNA expressions of resistance genes in Pseudomonas aeruginosa. J Infect Chemother 2017; 24:45-52. [PMID: 29107652 DOI: 10.1016/j.jiac.2017.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 08/10/2017] [Accepted: 08/31/2017] [Indexed: 12/28/2022]
Abstract
The increased prevalence of the virulence factor exoU + genotype among multidrug-resistant Pseudomonas aeruginosa has been previously reported. However, the genes that are related to the multidrug resistance of the exoU + genotype strain have not been analyzed and remain to be elucidated. The objective of this study was to analyze the correlations between virulence factors and resistance genes. The exoU + genotype was frequently found in carbapenem and fluoroquinolone non-susceptible strains. The imp carbapenemase genotype, the quinolone-resistance-determining region mutation in GyrA and ParC and the defective mutation in OprD were not frequently found in the exoU + genotype and carbapenem and fluoroquinolone non-susceptible strains. On the other hand, mexY and ampC mRNA overexpressing strains were more frequently found in the exoU + genotype and carbapenem and fluoroquinolone non-susceptible strains. Moreover, sequence type 235, a high risk clone of multidrug-resistant P. aeruginosa, was prevalent among the exoU + genotype and carbapenem and fluoroquinolone non-susceptible strains. ExoU is highly virulent protein, and the overexpression of efflux pumps and AmpC β-lactamase induce a multidrug-resistant phenotype. Therefore, the increased prevalence of P. aeruginosa strains with an exoU + genotype and the overexpression of efflux pumps and AmpC β-lactamase are likely to make P. aeruginosa infections difficult to treat. An understanding of the prevalence of both the exoU + genotype and the mRNA overexpression of resistance genes may help to select empirical therapy for the treatment of nosocomial infections caused by P. aeruginosa.
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Affiliation(s)
- Iichiro Takata
- Department of Clinical Infectious Diseases, Aichi Medical University Graduate School of Medicine, Aichi, Japan
| | - Yuka Yamagishi
- Department of Clinical Infectious Diseases, Aichi Medical University Graduate School of Medicine, Aichi, Japan
| | - Hiroshige Mikamo
- Department of Clinical Infectious Diseases, Aichi Medical University Graduate School of Medicine, Aichi, Japan.
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18
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Hirabayashi A, Kato D, Tomita Y, Iguchi M, Yamada K, Kouyama Y, Morioka H, Tetsuka N, Yagi T. Risk factors for and role of OprD protein in increasing minimal inhibitory concentrations of carbapenems in clinical isolates of Pseudomonas aeruginosa. J Med Microbiol 2017; 66:1562-1572. [PMID: 28984565 DOI: 10.1099/jmm.0.000601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE This study examined the risk factors for, and molecular mechanisms underlying, the increase in carbapenem minimum inhibitory concentrations (MICs) in clinical isolates of Pseudomonas aeruginosa. METHODOLOGY Consecutive clinical isolates of P. aeruginosa were collected. The MicroScan WalkAway system detected more than fourfold increases in the MICs of carbapenems in P. aeruginosa isolates serially recovered from some patients during their clinical course. The clinical risk factors associated with this increase were examined by multiple logistic regression analysis. Western blot analysis and nucleotide sequencing of the oprD gene of 19 clonally related and paired P. aeruginosa isolates from the same patients were undertaken to examine the mechanisms underlying the increase in MICs. RESULTS The results showed that prior use of carbapenems (OR, 2.799; 95 % CI, 1.088-7.200; P=0.033) and the use of ventilators or tracheostomies (OR, 2.648; 95 % CI, 1.051-6.671; P=0.039) were risk factors for increased carbapenem MICs. Analysis of the underlying mechanisms revealed that loss of functional OprD protein due to mutation of the oprD gene tended to occur in P. aeruginosa isolates with imipenem MICs of more than 8 µg ml-1; a reduction in OprD expression was observed in P. aeruginosa isolates with imipenem MICs of 4 or 8 µg ml-1. This difference in the resistance mechanism was not correlated with the MICs of meropenem. CONCLUSION This difference in the resistance mechanism of P. aeruginosa indicates a critical breakpoint at an imipenem MIC of 8 µg ml-1, in accordance with EUCAST criteria. Reducing carbapenem use will prevent P. aeruginosa clinical isolates from developing resistance to carbapenems.
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Affiliation(s)
- Aki Hirabayashi
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan.,Department of Infectious Diseases, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Daizo Kato
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan
| | - Yuka Tomita
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan
| | - Mitsutaka Iguchi
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan
| | - Keiko Yamada
- Department of Bacteriology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yuichi Kouyama
- Department of Hospital Pharmacy, Nagoya University Hospital, Nagoya, Aichi, Japan
| | - Hiroshi Morioka
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan.,Department of Infectious Diseases, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Nobuyuki Tetsuka
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan.,Department of Infectious Diseases, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Tetsuya Yagi
- Department of Infectious Diseases, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.,Department of Infectious Diseases, Nagoya University Hospital, Nagoya, Aichi, Japan
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19
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Haenni M, Bour M, Châtre P, Madec JY, Plésiat P, Jeannot K. Resistance of Animal Strains of Pseudomonas aeruginosa to Carbapenems. Front Microbiol 2017; 8:1847. [PMID: 29033910 PMCID: PMC5626926 DOI: 10.3389/fmicb.2017.01847] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/11/2017] [Indexed: 12/31/2022] Open
Abstract
Carbapenems are major antibiotics reserved to human medicine. This study aimed to investigate the mechanisms of carbapenem resistance of a selection of Pseudomonas aeruginosa veterinary strains from the French network Resapath. Thirty (5.7%) imipenem and/or meropenem non-susceptible P. aeruginosa of canine (n = 24), feline (n = 5), or bovine (n = 1) origin were identified in a large collection of 527 veterinary strains gathered by the Resapath. These resistant isolates belonged to 25 MultiLocus Sequence Types (MLST), of which 17 (68%) are shared with clinical (human) strains, such as high risk clones ST233 and ST395. Interestingly, none of the veterinary strains produced a carbapenemase, and only six of them (20%) harbored deletions or insertion sequence (IS) disrupting the porin OprD gene. The remaining 24 strains contained mutations or IS in various loci resulting in down-regulation of gene oprD coupled with upregulation of efflux system CzcCBA (n = 3; activation of sensor kinase CzcS ± CopS), MexEF-OprN (n = 4; alteration of oxido reductase MexS), MexXY (n = 8; activation of two-component system ParRS), or MexAB-OprM (n = 12; alteration of regulator MexR, NalC ± NalD). Two efflux pumps were co-produced simultaneously in three mutants. Finally, in 11 out of 12 strains displaying an intact porin OprD, derepression of MexAB-OprM accounted for a decreased susceptibility to meropenem relative to imipenem. Though not treated by carbapenems, animals thus represent a reservoir of multidrug resistant P. aeruginosa strains potentially able to contaminate fragile outpatients.
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Affiliation(s)
- Marisa Haenni
- Unité Antibiorésistance et Virulence Bactériennes, ANSES-Université de LyonLyon, France
| | - Maxime Bour
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de BesançonBesançon, France
| | - Pierre Châtre
- Unité Antibiorésistance et Virulence Bactériennes, ANSES-Université de LyonLyon, France
| | - Jean-Yves Madec
- Unité Antibiorésistance et Virulence Bactériennes, ANSES-Université de LyonLyon, France
| | - Patrick Plésiat
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de BesançonBesançon, France
| | - Katy Jeannot
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de BesançonBesançon, France
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Sherrard LJ, Tai AS, Wee BA, Ramsay KA, Kidd TJ, Ben Zakour NL, Whiley DM, Beatson SA, Bell SC. Within-host whole genome analysis of an antibiotic resistant Pseudomonas aeruginosa strain sub-type in cystic fibrosis. PLoS One 2017; 12:e0172179. [PMID: 28273168 PMCID: PMC5342179 DOI: 10.1371/journal.pone.0172179] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/31/2017] [Indexed: 02/07/2023] Open
Abstract
A Pseudomonas aeruginosa AUST-02 strain sub-type (M3L7) has been identified in Australia, infects the lungs of some people with cystic fibrosis and is associated with antibiotic resistance. Multiple clonal lineages may emerge during treatment with mutations in chromosomally encoded antibiotic resistance genes commonly observed. Here we describe the within-host diversity and antibiotic resistance of M3L7 during and after antibiotic treatment of an acute pulmonary exacerbation using whole genome sequencing and show both variation and shared mutations in important genes. Eleven isolates from an M3L7 population (n = 134) isolated over 3 months from an individual with cystic fibrosis underwent whole genome sequencing. A phylogeny based on core genome SNPs identified three distinct phylogenetic groups comprising two groups with higher rates of mutation (hypermutators) and one non-hypermutator group. Genomes were screened for acquired antibiotic resistance genes with the result suggesting that M3L7 resistance is principally driven by chromosomal mutations as no acquired mechanisms were detected. Small genetic variations, shared by all 11 isolates, were found in 49 genes associated with antibiotic resistance including frame-shift mutations (mexA, mexT), premature stop codons (oprD, mexB) and mutations in quinolone-resistance determining regions (gyrA, parE). However, whole genome sequencing also revealed mutations in 21 genes that were acquired following divergence of groups, which may also impact the activity of antibiotics and multi-drug efflux pumps. Comparison of mutations with minimum inhibitory concentrations of anti-pseudomonal antibiotics could not easily explain all resistance profiles observed. These data further demonstrate the complexity of chronic and antibiotic resistant P. aeruginosa infection where a multitude of co-existing genotypically diverse sub-lineages might co-exist during and after intravenous antibiotic treatment.
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Affiliation(s)
- Laura J. Sherrard
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Anna S. Tai
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
- School of Medicine, The University of Queensland, Brisbane, QLD, Australia
- Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia
- Western Australia Adult Cystic Fibrosis Centre, Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia
| | - Bryan A. Wee
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Kay A. Ramsay
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
- School of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy J. Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Centre for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
- Child Health Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Nouri L. Ben Zakour
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - David M. Whiley
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
- Pathology Queensland, Microbiology Department, Brisbane, QLD, Australia
| | - Scott A. Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Scott C. Bell
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
- Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia
- * E-mail:
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Pfennigwerth N, Lange F, Belmar Campos C, Hentschke M, Gatermann SG, Kaase M. Genetic and biochemical characterization of HMB-1, a novel subclass B1 metallo-β-lactamase found in aPseudomonas aeruginosaclinical isolate. J Antimicrob Chemother 2017; 72:1068-1073. [DOI: 10.1093/jac/dkw554] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/22/2016] [Indexed: 11/15/2022] Open
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Amoh T, Murakami K, Kariyama R, Hori K, Irie Y, Viducic D, Hirota K, Igarashi J, Suga H, Kumon H, Miyake Y. A <i>Pseudomonas aeruginosa</i> Quorum-Sensing autoinducer analog enhances the activity of antibiotics against resistant strains. THE JOURNAL OF MEDICAL INVESTIGATION 2017; 64:101-109. [DOI: 10.2152/jmi.64.101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Takashi Amoh
- Department of Oral Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Keiji Murakami
- Department of Oral Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Reiko Kariyama
- Department of Urology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
- Department of Food and Nutrition, Okayama Gakuin University
| | - Kenji Hori
- Innovation Center Okayama for Nanobio-targeted Therapy, Okayama University
| | | | - Darija Viducic
- Department of Oral Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Katsuhiko Hirota
- Department of Oral Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Jun Igarashi
- Discovery Research Lab., Otsuka Chemical Co. Ltd
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, the University of Tokyo
| | - Hiromi Kumon
- Department of Urology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
| | - Yoichiro Miyake
- Department of Oral Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School
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Mathlouthi N, Areig Z, Al Bayssari C, Bakour S, Ali El Salabi A, Ben Gwierif S, Zorgani AA, Ben Slama K, Chouchani C, Rolain JM. Emergence of Carbapenem-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Clinical Isolates Collected from Some Libyan Hospitals. Microb Drug Resist 2015; 21:335-41. [DOI: 10.1089/mdr.2014.0235] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
- Najla Mathlouthi
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
- Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Campus Universitaire, Université de Tunis El-Manar, El-Manar, Tunisie
| | - Zaynab Areig
- Infection Control Office, Benghazi Medical Centre, Benghazi, Libya
- Department of Microbiology, The Libyan Academy, Benghazi, Libya
| | - Charbel Al Bayssari
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
| | - Sofiane Bakour
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
| | - Allaaeddin Ali El Salabi
- Infection Control Office, Benghazi Medical Centre, Benghazi, Libya
- Department of Environmental Health, Faculty of Public Health, University of Benghazi, Benghazi, Libya
| | - Salha Ben Gwierif
- Department of Microbiology, The Libyan Academy, Benghazi, Libya
- Department of Botany, University of Benghazi, Benghazi, Libya
| | - Abdulaziz A. Zorgani
- Department of Medical Microbiology and Immunology, Faculty of Medicine, University of Tripoli, Libya
| | - Karim Ben Slama
- Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Campus Universitaire, Université de Tunis El-Manar, El-Manar, Tunisie
| | - Chedly Chouchani
- Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Campus Universitaire, Université de Tunis El-Manar, El-Manar, Tunisie
- Université de Carthage, Institut Supérieur des Sciences et Technologies de l'Environnement de Borj-Cedria, Hammam-Lif, Tunisie
| | - Jean-Marc Rolain
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
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24
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Richardot C, Plésiat P, Fournier D, Monlezun L, Broutin I, Llanes C. Carbapenem resistance in cystic fibrosis strains of Pseudomonas aeruginosa as a result of amino acid substitutions in porin OprD. Int J Antimicrob Agents 2015; 45:529-32. [DOI: 10.1016/j.ijantimicag.2014.12.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/24/2014] [Accepted: 12/30/2014] [Indexed: 11/16/2022]
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25
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Pfennigwerth N, Geis G, Gatermann SG, Kaase M. Description of IMP-31, a novel metallo-β-lactamase found in an ST235 Pseudomonas aeruginosa strain in Western Germany. J Antimicrob Chemother 2015; 70:1973-80. [PMID: 25835992 DOI: 10.1093/jac/dkv079] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/07/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The objective of this study was to characterize a novel IMP-type metallo-β-lactamase (MBL) found in an MDR clinical isolate of Pseudomonas aeruginosa. METHODS The P. aeruginosa isolate NRZ-00156 was recovered from an inguinal swab from a patient hospitalized in Western Germany and showed high MICs of carbapenems. MBL production was analysed by Etest for MBLs, an EDTA combined disc test and an EDTA bioassay. Typing of the isolate was performed by MLST. Genetic characterization of the new blaIMP gene was performed by sequencing the PCR products. A phylogenetic tree was constructed. The novel blaIMP gene was expressed in Escherichia coli TOP10 and the enzyme was subjected to biochemical characterization. RESULTS The P. aeruginosa isolate NRZ-00156 expressed the ST235 allelic profile and was resistant to all the β-lactams tested except aztreonam. The isolate was positive for MBL production and harboured a new IMP allele, blaIMP-31, located on a disrupted class I integron [also carrying the blaOXA-35, aac(6')-Ib, aac(3)-Ic and aphA15 genes]. Its closest relative was IMP-35, with 96.7% amino acid identity. Expression of blaIMP-31 demonstrated that E. coli TOP10 producing IMP-31 had elevated resistance to all the β-lactams tested except aztreonam. Kinetic data were obtained for both IMP-31 and IMP-1. In comparison with IMP-1, IMP-31 showed weaker hydrolytic activity against all the β-lactams tested, which resulted from lower kcat values. CONCLUSIONS The characterization of the new IMP-type gene blaIMP-31 from an ST235 P. aeruginosa isolate indicates an ongoing spread of highly divergent IMP-type carbapenemases in clinical P. aeruginosa strains and highlights the continuous need for the prevention of nosocomial infections caused by MDR Gram-negative bacteria.
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Affiliation(s)
- Niels Pfennigwerth
- Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Gabriele Geis
- Institute for Medical Laboratory Diagnostics Bochum GmbH, Castroper Straße 45, 44791 Bochum, Germany
| | - Sören G Gatermann
- Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Martin Kaase
- Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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26
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Musafer HK, Kuchma SL, Naimie AA, Schwartzman JD, Al-Mathkhury HJF, O'Toole GA. Investigating the link between imipenem resistance and biofilm formation by Pseudomonas aeruginosa. MICROBIAL ECOLOGY 2014; 68:111-120. [PMID: 24435545 PMCID: PMC8978818 DOI: 10.1007/s00248-013-0361-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 12/23/2013] [Indexed: 06/03/2023]
Abstract
Pseudomonas aeruginosa, a ubiquitous environmental organism, is a difficult-to-treat opportunistic pathogen due to its broad-spectrum antibiotic resistance and its ability to form biofilms. In this study, we investigate the link between resistance to a clinically important antibiotic, imipenem, and biofilm formation. First, we observed that the laboratory strain P. aeruginosa PAO1 carrying a mutation in the oprD gene, which confers resistance to imipenem, showed a modest reduction in biofilm formation. We also observed an inverse relationship between imipenem resistance and biofilm formation for imipenem-resistant strains selected in vitro, as well as for clinical isolates. We identified two clinical isolates of P. aeruginosa from the sputum of cystic fibrosis patients that formed robust biofilms, but were sensitive to imipenem (MIC ≤ 2 μg/ml). To test the hypothesis that there is a general link between imipenem resistance and biofilm formation, we performed transposon mutagenesis of these two clinical strains to identify mutants defective in biofilm formation, and then tested these mutants for imipenem resistance. Analysis of the transposon mutants revealed a role for previously described biofilm factors in these clinical isolates of P. aeruginosa, including mutations in the pilY1, pilX, pilW, algC, and pslI genes, but none of the biofilm-deficient mutants became imipenem resistant (MIC ≥ 8 μg/ml), arguing against a general link between biofilm formation and resistance to imipenem. Thus, assessing biofilm formation capabilities of environmental isolates is unlikely to serve as a good predictor of imipenem resistance. We also discuss our findings in light of the limited literature addressing planktonic antibiotic resistance factors that impact biofilm formation.
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Affiliation(s)
- Hadeel K Musafer
- Department of Biology, College of Science, University of Baghdad, Baghdad, Iraq
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Emergence of VIM-2 and IMP-15 carbapenemases and inactivation of oprD gene in carbapenem-resistant Pseudomonas aeruginosa clinical isolates from Lebanon. Antimicrob Agents Chemother 2014; 58:4966-70. [PMID: 24913164 DOI: 10.1128/aac.02523-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report here the emergence of VIM-2 and IMP-15 carbapenemases in a series of clinical isolates of carbapenem-resistant Pseudomonas aeruginosa in Lebanon. We also describe the disruption of the oprD gene by either mutations or insertion sequence (IS) elements ISPa1328 and ISPre2 isoform. Our study reemphasizes a rapid dissemination of the VIM-2 carbapenemase-encoding gene in clinical isolates of P. aeruginosa in the Mediterranean basin.
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28
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Sefraoui I, Berrazeg M, Drissi M, Rolain JM. Molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa clinical strains isolated from western Algeria between 2009 and 2012. Microb Drug Resist 2013; 20:156-61. [PMID: 24320688 DOI: 10.1089/mdr.2013.0161] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Infections caused by carbapenem-resistant Pseudomonas aeruginosa strains represent a major therapeutic and epidemiological problem. The aim of this study was to characterize carbapenem resistance in 89 clinical strains of P. aeruginosa isolated from three hospitals in western Algeria between October 2009 and November 2012. Minimum inhibitory concentrations (MICs) of imipenem were determined by the Etest method. Screening for metallo-β-lactamase (MβL) was performed using Etest MβL strips, and a PCR was conducted to detect carbapenemase-encoding genes. The amplification of the oprD gene followed by a sequencing reaction was performed for all strains resistant to imipenem. The clonality of 53 P. aeruginosa strains was demonstrated using multilocus sequence typing (MLST). Among the 89 isolates, 35 (39.33%) were found to be resistant to IMP (MICs ≥16 μg/ml). The blaVIM-2 gene was detected in two strains. The remaining imipenem-resistant isolates showed the presence of oprD mutations. The MLST analysis differentiated strains into various clones and the strains from the same clone had an identical sequence of the oprD gene. We report the second detection in 2010 of blaVIM-2 in Algerian P. aeruginosa strains. We also found that oprD mutations were the major determinant of high-level imipenem resistance. We demonstrate that these oprD mutations can be used as a tool to study the clonality in P. aeruginosa isolates.
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Affiliation(s)
- Imane Sefraoui
- 1 Aix-Marseille Université , Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, Inserm 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Marseille, France
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29
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Pseudomonas aeruginosa outer membrane vesicles modulate host immune responses by targeting the Toll-like receptor 4 signaling pathway. Infect Immun 2013; 81:4509-18. [PMID: 24082079 DOI: 10.1128/iai.01008-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bacteria can naturally secrete outer membrane vesicles (OMVs) as pathogenic factors, while these vesicles may also serve as immunologic regulators if appropriately prepared. However, it is largely unknown whether Pseudomonas aeruginosa OMVs can activate inflammatory responses and whether immunization with OMVs can provide immune protection against subsequent infection. We purified and identified OMVs, which were then used to infect lung epithelial cells in vitro as well as C57BL/6J mice to investigate the immune response and the underlying signaling pathway. The results showed that OMVs generated from P. aeruginosa wild-type strain PAO1 were more cytotoxic to alveolar epithelial cells than those from quorum-sensing (QS)-deficient strain PAO1-ΔlasR. The levels of Toll-like receptor 4 (TLR4) and proinflammatory cytokines, including interleukin-1β (IL-1β) and IL-6, increased following OMV infection. Compared with lipopolysaccharide (LPS), lysed OMVs in which the membrane structures were broken induced a weak immune response. Furthermore, expression levels of TLR4-mediated responders (i.e., cytokines) were markedly downregulated by the TLR4 inhibitor E5564. Active immunization with OMVs or passive transfer of sera with a high cytokine quantity acquired from OMV-immunized mice could protect healthy mice against subsequent lethal PAO1 challenges (1.5 × 10(11) CFU). Collectively, these findings indicate that naturally secreted P. aeruginosa OMVs may trigger significant inflammatory responses via the TLR4 signaling pathway and protect mice against pseudomonal lung infection.
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Kataoka H, Ida T, Ishii Y, Tateda K, Oguri T, Yoshida A, Okuzumi K, Oishi T, Tsukahara M, Mori SI, Yoneyama A, Araoka H, Mitsuda T, Sumitomo M, Moriya K, Goto M, Nakamori Y, Shibayama A, Ohmagari N, Sato T, Yamaguchi K. Analysis of the influence of drug resistance factors on the efficacy of combinations of antibiotics for multidrug-resistant Pseudomonas aeruginosa isolated from hospitals located in the suburbs of Kanto area, Japan. J Glob Antimicrob Resist 2013; 1:91-96. [PMID: 27873584 DOI: 10.1016/j.jgar.2013.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/04/2013] [Accepted: 03/07/2013] [Indexed: 11/17/2022] Open
Abstract
Infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa are very difficult to treat. The aim of this study was to develop more effective treatments by investigating in vitro the effects of combinations of antibiotics against 47 MDR P. aeruginosa isolates harbouring various resistance factors. The isolates included 41 (87%) metallo-β-lactamase (MBL)-positive strains, 37 (79%) strains with mutations in OprD and 46 (98%) strains carrying the genes encoding aminoglycoside-modifying enzymes (AMEs). The quinolone resistance-determining region was mutated in all of the strains. These strains were classified into 16 groups according to amplified fragment length polymorphism and resistance factors. The effects of combinations of antibiotics on 16 representative strains were determined using a 'Break-point Checkerboard Plate' assay. Combinations of amikacin+aztreonam (coverage rate, 81.3%) and arbekacin+aztreonam (93.8%) inhibited growth. In contrast, combinations of ciprofloxacin+meropenem (6.3%) and ciprofloxacin+ceftazidime (12.5%) were much less effective. Aztreonam and arbekacin (or amikacin) are not substrates for MBLs and AMEs, respectively. We conclude that the combined effects of these drugs were possibly because of resistance factors.
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Affiliation(s)
- Hiroshi Kataoka
- Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., Tokyo 104 8002, Japan
| | - Takashi Ida
- Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., Tokyo 104 8002, Japan
| | - Yoshikazu Ishii
- Department of Microbiology and Infectious Diseases, Faculty of Medicine, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143 8540, Japan.
| | - Kazuhiro Tateda
- Department of Microbiology and Infectious Diseases, Faculty of Medicine, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143 8540, Japan
| | | | | | | | - Tsuyoshi Oishi
- Tokyo Medical University Ibaraki Medical Center, Ibaraki 300 0395, Japan
| | - Miyuki Tsukahara
- Tokyo Medical University Ibaraki Medical Center, Ibaraki 300 0395, Japan
| | | | - Akiko Yoneyama
- Department of Infectious Diseases, Toranomon Hospital, Tokyo 105 8470, Japan
| | - Hideki Araoka
- Department of Infectious Diseases, Toranomon Hospital, Tokyo 105 8470, Japan
| | | | | | - Kyoji Moriya
- Graduate School of Medicine, The University of Tokyo, Tokyo 113 8655, Japan
| | - Mieko Goto
- Graduate School of Medicine, The University of Tokyo, Tokyo 113 8655, Japan
| | - Yoshitaka Nakamori
- Department of Respiratory Diseases, Misyuku Hospital, Tokyo 153 051, Japan
| | - Akiyoshi Shibayama
- Department of Respiratory Diseases, Misyuku Hospital, Tokyo 153 051, Japan
| | | | - Tomoaki Sato
- Shizuoka Cancer Center, Shizuoka 411 8777, Japan
| | - Keizo Yamaguchi
- Department of Microbiology and Infectious Diseases, Faculty of Medicine, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143 8540, Japan
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Fournier D, Richardot C, Müller E, Robert-Nicoud M, Llanes C, Plésiat P, Jeannot K. Complexity of resistance mechanisms to imipenem in intensive care unit strains of Pseudomonas aeruginosa. J Antimicrob Chemother 2013; 68:1772-80. [DOI: 10.1093/jac/dkt098] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Adaptive and mutational resistance: role of porins and efflux pumps in drug resistance. Clin Microbiol Rev 2013; 25:661-81. [PMID: 23034325 DOI: 10.1128/cmr.00043-12] [Citation(s) in RCA: 530] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The substantial use of antibiotics in the clinic, combined with a dearth of new antibiotic classes, has led to a gradual increase in the resistance of bacterial pathogens to these compounds. Among the various mechanisms by which bacteria endure the action of antibiotics, those affecting influx and efflux are of particular importance, as they limit the interaction of the drug with its intracellular targets and, consequently, its deleterious effects on the cell. This review evaluates the impact of porins and efflux pumps on two major types of resistance, namely, mutational and adaptive types of resistance, both of which are regarded as key phenomena in the global rise of antibiotic resistance among pathogenic microorganisms. In particular, we explain how adaptive and mutational events can dramatically influence the outcome of antibiotic therapy by altering the mechanisms of influx and efflux of antibiotics. The identification of porins and pumps as major resistance markers has opened new possibilities for the development of novel therapeutic strategies directed specifically against these mechanisms.
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Alterations of OprD in carbapenem-intermediate and -susceptible strains of Pseudomonas aeruginosa isolated from patients with bacteremia in a Spanish multicenter study. Antimicrob Agents Chemother 2012; 56:1703-13. [PMID: 22290967 DOI: 10.1128/aac.05451-11] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We investigated the presence of OprD mutations in 60 strains of metallo-ß-lactamase-negative Pseudomonas aeruginosa intermediately susceptible (IS [n = 12]; MIC = 8 μg/ml) or susceptible (S [n = 48]; MICs ≤ 1 to 4 μg/ml) to imipenem and/or meropenem that were isolated from patients with bacteremia in order to evaluate their impact on carbapenem susceptibility profiles. The presence of mutations in oprD was detected by sequencing analysis. OprD expression was assessed by both outer membrane protein (OMP) analysis and real-time PCR (RT-PCR). Fourteen (23%) isolates had an OprD identical to that of PAO1, and OprD modifications were detected in 46 isolates (77%). Isolates were classified as OprD "full-length types" (T1 [n = 40, including both wild-type OprD and variants showing several polymorphisms]) and OprD "deficient types" (T2 [n = 3 for OprD frameshift mutations] and T3 [n = 17 for premature stop codons in oprD]). RT-PCR showed that 5 OprD type T1 isolates presented reduced transcription of oprD (0.1- to 0.4-fold compared to PAO1), while oprD levels increased more than 2-fold over that seen with PAO1 in 4 OprD type T1 isolates. A total of 50% of the isolates belonging to OprD "deficient types" were susceptible to both carbapenems, and 40% were susceptible to meropenem and intermediately susceptible to imipenem. Only one isolate (5%) within this group was intermediately susceptible to both carbapenems, and one (5%) was susceptible to imipenem and intermediately susceptible to meropenem. We concluded that OprD inactivating mutations in clinical isolates of P. aeruginosa are not restricted only to carbapenem-resistant isolates but are also found in isolates with imipenem or meropenem MICs of only 0.06 to 4 μg/ml.
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Eren E, Vijayaraghavan J, Liu J, Cheneke BR, Touw DS, Lepore BW, Indic M, Movileanu L, van den Berg B. Substrate specificity within a family of outer membrane carboxylate channels. PLoS Biol 2012; 10:e1001242. [PMID: 22272184 PMCID: PMC3260308 DOI: 10.1371/journal.pbio.1001242] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 11/30/2011] [Indexed: 12/20/2022] Open
Abstract
Characterization of a large family of outer membrane channels from gram-negative bacteria suggest how they can thrive in nutrient-poor environments and how channel inactivation can contribute to antibiotic resistance. Many Gram-negative bacteria, including human pathogens such as Pseudomonas aeruginosa, do not have large-channel porins. This results in an outer membrane (OM) that is highly impermeable to small polar molecules, making the bacteria intrinsically resistant towards many antibiotics. In such microorganisms, the majority of small molecules are taken up by members of the OprD outer membrane protein family. Here we show that OprD channels require a carboxyl group in the substrate for efficient transport, and based on this we have renamed the family Occ, for outer membrane carboxylate channels. We further show that Occ channels can be divided into two subfamilies, based on their very different substrate specificities. Our results rationalize how certain bacteria can efficiently take up a variety of substrates under nutrient-poor conditions without compromising membrane permeability. In addition, they explain how channel inactivation in response to antibiotics can cause resistance but does not lead to decreased fitness. Emerging antibiotic resistance in the treatment of infectious disease is an increasing problem that urgently requires new drug development. In Gram-negative bacteria, the outer membrane (OM) prevents permeation of small molecules, including antibiotics. A family of channel-forming proteins, called OprD proteins, are present in the OM to enable uptake of nutrients required for growth and cellular function. Since these channels also transport antibiotics, understanding how molecules are recognized and transported by these proteins should enable the design of more effective antibiotics. Here, we have characterized by biophysical and biochemical methods the structures and substrate-specificities of nine members of the OprD channel family of a common multidrug-resistant pathogen, Pseudomonas aeruginosa. Because we demonstrate that efficient passage through these channels requires the presence of a carboxyl group in the substrate, we renamed this channel family outer membrane carboxylate channels, or Occ. This broad substrate specificity suggests that such efficient transport allows bacteria to thrive in nutrient-poor environments. We also show markedly varied substrate specificities among the family members, especially for antibiotics, suggesting that mutation of a single channel can result in antibiotic resistance. These results provide the framework for studying the interaction of antibiotics with OM uptake channels, which will facilitate the development of more permeable and thus effective drugs.
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Affiliation(s)
- Elif Eren
- University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America
| | - Jagamya Vijayaraghavan
- University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America
| | - Jiaming Liu
- Syracuse University, Department of Physics, Syracuse, New York, United States of America
| | - Belete R. Cheneke
- Syracuse University, Department of Physics, Syracuse, New York, United States of America
| | - Debra S. Touw
- University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America
| | - Bryan W. Lepore
- University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America
| | - Mridhu Indic
- University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America
| | - Liviu Movileanu
- Syracuse University, Department of Physics, Syracuse, New York, United States of America
| | - Bert van den Berg
- University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America
- * E-mail:
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Altered antibiotic transport in OmpC mutants isolated from a series of clinical strains of multi-drug resistant E. coli. PLoS One 2011; 6:e25825. [PMID: 22053181 PMCID: PMC3203869 DOI: 10.1371/journal.pone.0025825] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/11/2011] [Indexed: 11/19/2022] Open
Abstract
Antibiotic-resistant bacteria, particularly Gram negative species, present significant health care challenges. The permeation of antibiotics through the outer membrane is largely effected by the porin superfamily, changes in which contribute to antibiotic resistance. A series of antibiotic resistant E. coli isolates were obtained from a patient during serial treatment with various antibiotics. The sequence of OmpC changed at three positions during treatment giving rise to a total of four OmpC variants (denoted OmpC20, OmpC26, OmpC28 and OmpC33, in which OmpC20 was derived from the first clinical isolate). We demonstrate that expression of the OmpC K12 porin in the clinical isolates lowers the MIC, consistent with modified porin function contributing to drug resistance. By a range of assays we have established that the three mutations that occur between OmpC20 and OmpC33 modify transport of both small molecules and antibiotics across the outer membrane. This results in the modulation of resistance to antibiotics, particularly cefotaxime. Small ion unitary conductance measurements of the isolated porins do not show significant differences between isolates. Thus, resistance does not appear to arise from major changes in pore size. Crystal structures of all four OmpC clinical mutants and molecular dynamics simulations also show that the pore size is essentially unchanged. Molecular dynamics simulations suggest that perturbation of the transverse electrostatic field at the constriction zone reduces cefotaxime passage through the pore, consistent with laboratory and clinical data. This subtle modification of the transverse electric field is a very different source of resistance than occlusion of the pore or wholesale destruction of the transverse field and points to a new mechanism by which porins may modulate antibiotic passage through the outer membrane.
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Horizontal gene transfer and assortative recombination within the Acinetobacter baumannii clinical population provide genetic diversity at the single carO gene, encoding a major outer membrane protein channel. J Bacteriol 2011; 193:4736-48. [PMID: 21764928 DOI: 10.1128/jb.01533-10] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We described previously the presence in Acinetobacter baumannii of a novel outer membrane (OM) protein, CarO, which functions as an L-ornithine OM channel and whose loss was concomitant with increased carbapenem resistance among clonally related nosocomial isolates of this opportunistic pathogen. Here, we describe the existence of extensive genetic diversity at the carO gene within the A. baumannii clinical population. The systematic analysis of carO sequences from A. baumannii isolates obtained from public hospitals in Argentina revealed the existence of four highly polymorphic carO variants among them. Sequence polymorphism between the different A. baumannii CarO variants was concentrated in three well-defined protein regions that superimposed mostly to predicted surface-exposed loops. Polymorphism among A. baumannii CarO variants was manifested in differential electrophoretic mobilities, antigenic properties, abilities to form stable oligomeric structures, and l-ornithine influx abilities through the A. baumannii OM under in vivo conditions. Incongruence between the phylogenies of the clinical A. baumannii isolates analyzed and those of the carO variants they harbor suggests the existence of assortative (entire-gene) carO recombinational exchange within the A. baumannii population. Exchange of carO variants possessing differential characteristics mediated by horizontal gene transfer may constitute an A. baumannii population strategy to survive radically changing environmental conditions, such as the leap from inanimate sources to human hosts and vice versa, persistence in a compromised host, and/or survival in health care facilities.
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