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Ma X, Kaw HY, Yu J, Yang Q, Zhu L, Wang W. The intracellular concentrations of fluoroquinolones determined the antibiotic resistance response of Escherichia coli. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:134057. [PMID: 38508108 DOI: 10.1016/j.jhazmat.2024.134057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 02/27/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024]
Abstract
The extensive consumption of antibiotics has been reported to significantly promote the generation of antibiotic resistance (ABR), however, a quantitative causal relationship between antibiotic exposure and ABR response is absent. This study aimed to pinpoint the accurate regulatory concentration of fluoroquinolones (FQs) and to understand the biochemical mechanism of the mutual action between FQ exposure and FQ resistance response. Highly sensitive analytical methods were developed by using UPLC-MS/MS to determine the total residual, extracellular residual, total intracellular, intracellular residual and intracellular degraded concentration of three representative FQs, including ciprofloxacin (CIP), ofloxacin (OFL) and norfloxacin (NOR), with detection limits in the range of 0.002-0.057 μg/L, and recoveries in the range of 80-93%. The MICs of Escherichia coli (E. coli) were 7.0-31.4-fold of the respective MIC0 after 40-day FQ exposure, and significant negative associations were discovered between the intracellular (residual, degraded or the sum) FQ concentrations and FQ resistance. Transcriptional expression and whole-genome sequencing results indicated that reduced membrane permeability and enhanced multi-drug efflux pumps contributed to the decreasing intracellular concentration. These results unveiled the pivotal role of intracellular concentration in triggering FQ resistance, providing important information to understand the dose-response relationship between FQ exposure and FQ resistance response, and ascertain the target dose metric of FQs for eliminating FQ resistance crisis.
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Affiliation(s)
- Xuejing Ma
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Han Yeong Kaw
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Jing Yu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Qi Yang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Lizhong Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Wei Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China.
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2
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Rahman Z, McLaws M, Thomas T. Genomic characterization of extended-spectrum beta-lactamase-producing and carbapenem-resistant Escherichia coli from urban wastewater in Australia. Microbiologyopen 2024; 13:e1403. [PMID: 38488803 PMCID: PMC10941799 DOI: 10.1002/mbo3.1403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
This study investigates extended-spectrum beta-lactamase-producing and carbapenem-resistant Escherichia coli isolates from Sydney's wastewater. These isolates exhibit resistance to critical antibiotics and harbor novel resistance mechanisms. The findings highlight the importance of wastewater-based surveillance in monitoring resistance beyond the clinical setting.
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Affiliation(s)
- Zillur Rahman
- School of Biological, Earth and Environmental Sciences, Centre for Marine Science and InnovationUNSW SydneySydneyNew South WalesAustralia
| | - Mary‐Louise McLaws
- School of Population HealthUNSW SydneySydneyNew South WalesAustralia
- UNSW Global Water InstituteUNSW SydneySydneyNew South WalesAustralia
| | - Torsten Thomas
- School of Biological, Earth and Environmental Sciences, Centre for Marine Science and InnovationUNSW SydneySydneyNew South WalesAustralia
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3
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Hemez C, Clarelli F, Palmer AC, Bleis C, Abel S, Chindelevitch L, Cohen T, Abel zur Wiesch P. Mechanisms of antibiotic action shape the fitness landscapes of resistance mutations. Comput Struct Biotechnol J 2022; 20:4688-4703. [PMID: 36147681 PMCID: PMC9463365 DOI: 10.1016/j.csbj.2022.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/12/2022] [Accepted: 08/12/2022] [Indexed: 11/15/2022] Open
Abstract
Antibiotic-resistant pathogens are a major public health threat. A deeper understanding of how an antibiotic's mechanism of action influences the emergence of resistance would aid in the design of new drugs and help to preserve the effectiveness of existing ones. To this end, we developed a model that links bacterial population dynamics with antibiotic-target binding kinetics. Our approach allows us to derive mechanistic insights on drug activity from population-scale experimental data and to quantify the interplay between drug mechanism and resistance selection. We find that both bacteriostatic and bactericidal agents can be equally effective at suppressing the selection of resistant mutants, but that key determinants of resistance selection are the relationships between the number of drug-inactivated targets within a cell and the rates of cellular growth and death. We also show that heterogeneous drug-target binding within a population enables resistant bacteria to evolve fitness-improving secondary mutations even when drug doses remain above the resistant strain's minimum inhibitory concentration. Our work suggests that antibiotic doses beyond this "secondary mutation selection window" could safeguard against the emergence of high-fitness resistant strains during treatment.
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Affiliation(s)
- Colin Hemez
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Graduate Program in Biophysics, Harvard University, Boston, MA 02115, USA
- Corresponding authors at: Broad Institute, 75 Ames St, Room 3035, Cambridge, MA 02412, USA (C. Hemez). Department of Pharmacy, UiT – The Arctic University of Norway, 9019 Tromsø, Norway (P. Abel zur Wiesch).
| | - Fabrizio Clarelli
- Department of Pharmacy, UiT – The Arctic University of Norway, 9019 Tromsø, Norway
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Adam C. Palmer
- Department of Pharmacology, Computational Medicine Program, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Christina Bleis
- Department of Pharmacy, UiT – The Arctic University of Norway, 9019 Tromsø, Norway
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Sören Abel
- Department of Pharmacy, UiT – The Arctic University of Norway, 9019 Tromsø, Norway
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
- Division of Infection Control, Norwegian Institute of Public Health, Oslo 0318, Norway
| | - Leonid Chindelevitch
- Department of Infectious Disease Epidemiology, Imperial College, London SW7 2AZ, UK
| | - Theodore Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA
| | - Pia Abel zur Wiesch
- Department of Pharmacy, UiT – The Arctic University of Norway, 9019 Tromsø, Norway
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
- Division of Infection Control, Norwegian Institute of Public Health, Oslo 0318, Norway
- Corresponding authors at: Broad Institute, 75 Ames St, Room 3035, Cambridge, MA 02412, USA (C. Hemez). Department of Pharmacy, UiT – The Arctic University of Norway, 9019 Tromsø, Norway (P. Abel zur Wiesch).
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4
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Onishi R, Shigemura K, Osawa K, Yang YM, Maeda K, Tanimoto H, Kado M, Fang SB, Sung SY, Miyara T, Fujisawa M. Impact on quinolone resistance of plasmid-mediated quinolone resistance gene and mutations in quinolone resistance-determining regions in extended spectrum beta lactamase-producing Klebsiella pneumoniae isolated from urinary tract infection patients. Pathog Dis 2022; 80:6649813. [PMID: 35878410 DOI: 10.1093/femspd/ftac030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/25/2022] [Accepted: 07/21/2022] [Indexed: 11/13/2022] Open
Abstract
Klebsiella pneumoniae is a typical pathogen in urinary tract infections (UTI), and the emergence of extended spectrum beta-lactamase (ESBL)-producing strains has been frequently reported, accompanied by higher quinolone resistance rates. There are two major mechanisms of quinolone resistance, mutations in quinolone resistance-determining regions (QRDR) and the presence of the plasmid-mediated quinolone resistance (PMQR) genes. This study aimed to investigate quinolone resistance among 105 ESBL-producing K. pneumoniae specimens isolated from UTI patients in Indonesia. These were characterized for antimicrobial resistance to nalidixic acid, ciprofloxacin and levofloxacin, QRDR mutations in gyrA and parC and the presence of PMQR genes. We found that 84.8% of the collected isolates were resistant to at least one of the quinolones. QRDR mutation in gyrA was observed in 49.5% of these strains and parC mutations in 61.0%. PMQR genes were identified in 84.8% of strains. The QRDR mutations clearly had a greater effect on resistance than the PMQR genes. In conclusion, we found high quinolone resistance rates in Indonesian ESBL-producing K. pneumoniae, in which QRDR mutation played a major role.
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Affiliation(s)
- Reo Onishi
- Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe, 654-0142, Japan
| | - Katsumi Shigemura
- Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe, 654-0142, Japan.,Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Kayo Osawa
- Department of Medical Technology, Kobe Tokiwa University, 2-6-2 Otani-cho, Nagata-ku, Kobe, 653-0838, Japan
| | - Young-Min Yang
- Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Koki Maeda
- Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Hiroshi Tanimoto
- Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe, 654-0142, Japan
| | - Mitsuki Kado
- Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe, 654-0142, Japan
| | - Shiuh-Bin Fang
- Department of Pediatrics, Division of Pediatric Gastroenterology and Hepatology, Shuang Ho Hospital, Taipei Medical University, 291 Jhong Jheng Road, Jhong Ho District, New Taipei City, 23561, Taiwan.,Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, 250, Wu Hsing Street, Hsin Yi District, Taipei, 11031, Taiwan
| | - Shian-Ying Sung
- International Ph.D. Program for Translational Science, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan
| | - Takayuki Miyara
- Department of Infection Control and Prevention, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Masato Fujisawa
- Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
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5
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Mounsey O, Schubert H, Findlay J, Morley K, Puddy EF, Gould VC, North P, Bowker KE, Williams OM, Williams PB, Barrett DC, Cogan TA, Turner KM, MacGowan AP, Reyher KK, Avison MB. Limited phylogenetic overlap between fluoroquinolone-resistant Escherichia coli isolated on dairy farms and those causing bacteriuria in humans living in the same geographical region. J Antimicrob Chemother 2021; 76:3144-3150. [PMID: 34450630 PMCID: PMC8598280 DOI: 10.1093/jac/dkab310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 08/03/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Our primary aim was to test whether cattle-associated fluoroquinolone-resistant (FQ-R) Escherichia coli found on dairy farms are closely phylogenetically related to those causing bacteriuria in humans living in the same 50 × 50 km geographical region suggestive of farm-human sharing. Another aim was to identify risk factors for the presence of FQ-R E. coli on dairy farms. METHODS FQ-R E. coli were isolated during 2017-18 from 42 dairy farms and from community urine samples. Forty-two cattle and 489 human urinary isolates were subjected to WGS, allowing phylogenetic comparisons. Risk factors were identified using a Bayesian regularization approach. RESULTS Of 489 FQ-R human isolates, 255 were also third-generation-cephalosporin-resistant, with strong genetic linkage between aac(6')Ib-cr and blaCTX-M-15. We identified possible farm-human sharing for pairs of ST744 and ST162 isolates, but minimal core genome SNP distances were larger between farm-human pairs of ST744 and ST162 isolates (71 and 63 SNPs, respectively) than between pairs of isolates from different farms (7 and 3 SNPs, respectively). Total farm fluoroquinolone use showed a positive association with the odds of isolating FQ-R E. coli, while total dry cow therapy use showed a negative association. CONCLUSIONS This work suggests that FQ-R E. coli found on dairy farms have a limited impact on community bacteriuria within the local human population. Reducing fluoroquinolone use may reduce the on-farm prevalence of FQ-R E. coli and this reduction may be greater when dry cow therapy is targeted to the ecology of resistant E. coli on the farm.
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Affiliation(s)
- Oliver Mounsey
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, UK
| | - Hannah Schubert
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Jacqueline Findlay
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, UK
| | - Katy Morley
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Emma F Puddy
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, UK
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Virginia C Gould
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, UK
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Paul North
- Department of Microbiology, Infection Sciences, Southmead Hospital, North Bristol NHS Trust, Bristol, UK
| | - Karen E Bowker
- Department of Microbiology, Infection Sciences, Southmead Hospital, North Bristol NHS Trust, Bristol, UK
| | - O Martin Williams
- Bristol Royal Infirmary, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
| | - Philip B Williams
- Bristol Royal Infirmary, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
| | - David C Barrett
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Tristan A Cogan
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Katy M Turner
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Alasdair P MacGowan
- Department of Microbiology, Infection Sciences, Southmead Hospital, North Bristol NHS Trust, Bristol, UK
| | | | - Matthew B Avison
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, UK
- Corresponding author. E-mail:
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6
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Helgesen E, Sætre F, Skarstad K. Topoisomerase IV tracks behind the replication fork and the SeqA complex during DNA replication in Escherichia coli. Sci Rep 2021; 11:474. [PMID: 33436807 PMCID: PMC7803763 DOI: 10.1038/s41598-020-80043-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 12/11/2020] [Indexed: 11/13/2022] Open
Abstract
Topoisomerase IV (TopoIV) is a vital bacterial enzyme which disentangles newly replicated DNA and enables segregation of daughter chromosomes. In bacteria, DNA replication and segregation are concurrent processes. This means that TopoIV must continually remove inter-DNA linkages during replication. There exists a short time lag of about 10–20 min between replication and segregation in which the daughter chromosomes are intertwined. Exactly where TopoIV binds during the cell cycle has been the subject of much debate. We show here that TopoIV localizes to the origin proximal side of the fork trailing protein SeqA and follows the movement pattern of the replication machinery in the cell.
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Affiliation(s)
- Emily Helgesen
- Department of Microbiology, Molecular Microbiology, Oslo University Hospital, P.O. Box 4950, 0424, Oslo, Norway. .,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Frank Sætre
- Department of Microbiology, Molecular Microbiology, Oslo University Hospital, P.O. Box 4950, 0424, Oslo, Norway.,Department of Pathology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kirsten Skarstad
- Department of Microbiology, Molecular Microbiology, Oslo University Hospital, P.O. Box 4950, 0424, Oslo, Norway
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7
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Turner AK, Eckert SE, Turner DJ, Yasir M, Webber MA, Charles IG, Parkhill J, Wain J. A whole-genome screen identifies Salmonella enterica serovar Typhi genes involved in fluoroquinolone susceptibility. J Antimicrob Chemother 2020; 75:2516-2525. [PMID: 32514543 PMCID: PMC7443733 DOI: 10.1093/jac/dkaa204] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/31/2020] [Accepted: 04/21/2020] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVES A whole-genome screen at sub-gene resolution was performed to identify candidate loci that contribute to enhanced or diminished ciprofloxacin susceptibility in Salmonella enterica serovar Typhi. METHODS A pool of over 1 million transposon insertion mutants of an S. Typhi Ty2 derivative were grown in a sub-MIC concentration of ciprofloxacin, or without ciprofloxacin. Transposon-directed insertion site sequencing (TraDIS) identified relative differences between the mutants that grew following the ciprofloxacin treatment compared with the untreated mutant pool, thereby indicating which mutations contribute to gain or loss of ciprofloxacin susceptibility. RESULTS Approximately 88% of the S. Typhi strain's 4895 annotated genes were assayed, and at least 116 were identified as contributing to gain or loss of ciprofloxacin susceptibility. Many of the identified genes are known to influence susceptibility to ciprofloxacin, thereby providing method validation. Genes were identified that were not known previously to be involved in susceptibility, and some of these had no previously known phenotype. Susceptibility to ciprofloxacin was enhanced by insertion mutations in genes coding for efflux, other surface-associated functions, DNA repair and expression regulation, including phoP, barA and marA. Insertion mutations that diminished susceptibility were predominantly in genes coding for surface polysaccharide biosynthesis and regulatory genes, including slyA, emrR, envZ and cpxR. CONCLUSIONS A genomics approach has identified novel contributors to gain or loss of ciprofloxacin susceptibility in S. Typhi, expanding our understanding of the impact of fluoroquinolones on bacteria and of mechanisms that may contribute to resistance. The data also demonstrate the power of the TraDIS technology for antibacterial research.
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Affiliation(s)
- A Keith Turner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Sabine E Eckert
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Daniel J Turner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- Oxford Nanopore Technologies Ltd, Gosling Building, Edmund Halley Road, Oxford Science Park OX4 4DQ, UK
| | - Muhammud Yasir
- Quadram Institute, Norwich Research Park, Colney, Norwich NR4 7UA, UK
| | - Mark A Webber
- Quadram Institute, Norwich Research Park, Colney, Norwich NR4 7UA, UK
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Ian G Charles
- Quadram Institute, Norwich Research Park, Colney, Norwich NR4 7UA, UK
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Julian Parkhill
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK
| | - John Wain
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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8
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Ching C, Orubu ESF, Sutradhar I, Wirtz VJ, Boucher HW, Zaman MH. Bacterial antibiotic resistance development and mutagenesis following exposure to subinhibitory concentrations of fluoroquinolones in vitro: a systematic review of the literature. JAC Antimicrob Resist 2020; 2:dlaa068. [PMID: 34223024 PMCID: PMC8210091 DOI: 10.1093/jacamr/dlaa068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/15/2020] [Indexed: 12/09/2022] Open
Abstract
BACKGROUND Understanding social and scientific drivers of antibiotic resistance is critical to help preserve antibiotic efficacy. These drivers include exposure to subinhibitory antibiotic concentrations in the environment and clinic. OBJECTIVES To summarize and quantify the relationship between subinhibitory fluoroquinolone exposure and antibiotic resistance and mutagenesis to better understand resistance patterns and mechanisms. METHODS Following PRISMA guidelines, PubMed, Web of Science and Embase were searched for primary in vitro experimental studies on subinhibitory fluoroquinolone exposure and bacterial antibiotic resistance and mutagenesis, from earliest available dates through to 2018 without language limitation. A specifically developed non-weighted tool was used to assess risk of bias. RESULTS Evidence from 62 eligible studies showed that subinhibitory fluoroquinolone exposure results in increased resistance to the selecting fluoroquinolone. Most increases in MIC were low (median minimum of 3.7-fold and median maximum of 32-fold) and may not be considered clinically relevant. Mechanistically, resistance is partly explained by target mutations but also changes in drug efflux. Collaterally, resistance to other fluoroquinolones and unrelated antibiotic classes also develops. The mean ± SD quality score for all studies was 2.6 ± 1.8 with a range of 0 (highest score) to 7 (lowest score). CONCLUSIONS Low and moderate levels of resistance and efflux changes can create an opportunity for higher-level resistance or MDR. Future studies, to elucidate the genetic regulation of specific resistance mechanisms, and increased policies, including surveillance of low-level resistance changes or genomic surveillance of efflux pump genes and regulators, could serve as a predictor of MDR development.
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Affiliation(s)
- Carly Ching
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Ebiowei S F Orubu
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Institute for Health System Innovation & Policy, Boston University, Boston, MA, USA
| | - Indorica Sutradhar
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Veronika J Wirtz
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | - Helen W Boucher
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA, USA
| | - Muhammad H Zaman
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Howard Hughes Medical Institute, Boston University, Boston, MA, USA
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9
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The mutational landscape of quinolone resistance in Escherichia coli. PLoS One 2019; 14:e0224650. [PMID: 31689338 PMCID: PMC6830822 DOI: 10.1371/journal.pone.0224650] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 10/19/2019] [Indexed: 11/19/2022] Open
Abstract
The evolution of antibiotic resistance is influenced by a variety of factors, including the availability of resistance mutations, and the pleiotropic effects of such mutations. Here, we isolate and characterize chromosomal quinolone resistance mutations in E. coli, in order to gain a systematic understanding of the rate and consequences of resistance to this important class of drugs. We isolated over fifty spontaneous resistance mutants on nalidixic acid, ciprofloxacin, and levofloxacin. This set of mutants includes known resistance mutations in gyrA, gyrB, and marR, as well as two novel gyrB mutations. We find that, for most mutations, resistance tends to be higher to nalidixic acid than relative to the other two drugs. Resistance mutations had deleterious impacts on one or more growth parameters, suggesting that quinolone resistance mutations are generally costly. Our findings suggest that the prevalence of specific gyrA alleles amongst clinical isolates are driven by high levels of resistance, at no more cost than other resistance alleles.
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10
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Gupta SK, Sharma P, McMillan EA, Jackson CR, Hiott LM, Woodley T, Humayoun SB, Barrett JB, Frye JG, McClelland M. Genomic comparison of diverse Salmonella serovars isolated from swine. PLoS One 2019; 14:e0224518. [PMID: 31675365 PMCID: PMC6824618 DOI: 10.1371/journal.pone.0224518] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/15/2019] [Indexed: 12/19/2022] Open
Abstract
Food animals act as a reservoir for many foodborne pathogens. Salmonella enterica is one of the leading pathogens that cause food borne illness in a broad host range including animals and humans. They can also be associated with a single host species or a subset of hosts, due to genetic factors associated with colonization and infection. Adult swine are often asymptomatic carriers of a broad range of Salmonella servoars and can act as an important reservoir of infections for humans. In order to understand the genetic variations among different Salmonella serovars, Whole Genome Sequences (WGS) of fourteen Salmonella serovars from swine products were analyzed. More than 75% of the genes were part of the core genome in each isolate and the higher fraction of gene assign to different functional categories in dispensable genes indicated that these genes acquired for better adaptability and diversity. High concordance (97%) was detected between phenotypically confirmed antibiotic resistances and identified antibiotic resistance genes from WGS. The resistance determinants were mainly located on mobile genetic elements (MGE) on plasmids or integrated into the chromosome. Most of known and putative virulence genes were part of the core genome, but a small fraction were detected on MGE. Predicted integrated phage were highly diverse and many harbored virulence, metal resistance, or antibiotic resistance genes. CRISPR (Clustered regularly interspaced short palindromic repeats) patterns revealed the common ancestry or infection history among Salmonella serovars. Overall genomic analysis revealed a great deal of diversity among Salmonella serovars due to acquired genes that enable them to thrive and survive during infection.
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Affiliation(s)
- Sushim K. Gupta
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - Poonam Sharma
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - Elizabeth A. McMillan
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
| | - Charlene R. Jackson
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - Lari M. Hiott
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - Tiffanie Woodley
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - Shaheen B. Humayoun
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - John B. Barrett
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
| | - Jonathan G. Frye
- Bacterial Epidemiology and Antimicrobial Resistance Unit, USDA-ARS, Athens, GA, United States of America
- * E-mail:
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA, United States of America
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Le-Vo HN, Tran PTB, Le L, Matsumoto Y, Motooka D, Nakamura S, Jones JW, Iida T, Cao V. Complex Class 1 Integron in a Clinical Escherichia coli Strain From Vietnam Carrying Both mcr-1 and bla NDM-1. Front Microbiol 2019; 10:2472. [PMID: 31736911 PMCID: PMC6834847 DOI: 10.3389/fmicb.2019.02472] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/15/2019] [Indexed: 11/13/2022] Open
Abstract
The co-production of MCR and carbapenemase in Enterobacteriaceae has been previously reported. Here, we describe a clinical strain of Escherichia coli from Vietnam carrying both mcr-1 and bla NDM-1. Whole-genome sequencing showed that the genome of this strain consists of a 4,975,832-bp chromosome and four plasmids. The mcr-1 and bla NDM-1 genes are located on IncI2 and IncA/C2-type plasmids, respectively. Genetic analysis revealed the presence of a multidrug-resistant region with the structure of a novel complex class 1 integron including a class 1 integron region bearing two 5' conserved segments and one 3' conserved segment and two complete structures of ISCR1. The complex integron contains aminoglycoside resistance genes aadA2, aadB, strA, strB, and aphA6, quinolone resistance gene qnrA1, extended-spectrum β-lactamase gene bla OXA- 4, and a Tn125-like transposon bearing bla NDM-1. In addition, the dfrA12-gcuF-aadA2-cmlA1-aadA1-qacH gene cassette array belonging to the sul3-type integron was also identified, but the region found downstream of the gene cassette array is the IS440-tet(M)-IS26 element instead of the sul3 gene. The results further support that Enterobacteriaceae isolates co-harboring mcr and bla NDM are widely being distributed. The structural characteristics of the complex integron reveal that ISCR1 elements play an important role in the mobilization of bla NDM-1 and the development of multidrug-resistant regions.
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Affiliation(s)
- Hong-Ngoc Le-Vo
- Department of Immunology and Microbiology, Pasteur Institute in Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Phuong Thi-Bich Tran
- Department of Immunology and Microbiology, Pasteur Institute in Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Lien Le
- Department of Immunology and Microbiology, Pasteur Institute in Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Yuki Matsumoto
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Daisuke Motooka
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Shota Nakamura
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - James W Jones
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Tetsuya Iida
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Van Cao
- Department of Immunology and Microbiology, Pasteur Institute in Ho Chi Minh City, Ho Chi Minh City, Vietnam
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DEHBANIPOUR R, KHANAHMAD H, SEDIGHI M, BIALVAEI AZAHEDI, FAGHRI J. High prevalence of fluoroquinolone-resistant Escherichia coli strains isolated from urine clinical samples. JOURNAL OF PREVENTIVE MEDICINE AND HYGIENE 2019; 60:E25-E30. [PMID: 31041407 PMCID: PMC6477561 DOI: 10.15167/2421-4248/jpmh2019.60.1.884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 12/12/2018] [Indexed: 11/16/2022]
Abstract
Background Fluoroquinolone resistant Escherichia coli isolates have become an important challenge in healthcare settings in Iran. In this study, we have determined Fluoroquinolone resistant E. coli isolates (from both outpatients and inpatients) and evaluated mutations of gyrA and parC within the quinolone resistance-determining regions (QRDR) of these clinical isolates. Materials and methods Clinical isolates were recovered from the urine sample of patients with urinary tract infections admitted at Alzahra hospital, Iran, between September and February 2013. We assessed antimicrobial susceptibility of all isolates and determined mutations in QRDR of gyrA and parC genes from 13 fluoroquinolone-resistant isolates by DNA sequencing. Results A total of 135 E. coli strains were obtained from 135 patients (91 outpatients and 44 inpatients). The resistance rate of fluoroquinolones (Ciprofloxacin, Norfloxacin and Ofloxacin) among our strains was 45.2%. Two E. coli isolates were shown just a single mutation, but other isolates possessed 2-5 mutations in gyrA and parC genes. Mutations in the QRDR regions of gyrA were at positions Ser83 and Asp87 and parC at positions Ser80, Glu84, Gly78. Conclusions Ciprofloxacin is the most common antimicrobial agent used for treating urinary tract infections (UTIs) in healthcare settings in Iran. Accumulation of different substitutions in the QRDR regions of gyrA and parC confers high-level resistance of fluoroquinolones in clinical isolates.
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Affiliation(s)
- R. DEHBANIPOUR
- Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - H. KHANAHMAD
- Department of Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - M. SEDIGHI
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - A. ZAHEDI BIALVAEI
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - J. FAGHRI
- Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
- Jamshid Faghri, Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran - Tel/Fax +983137922421 - E-mail:
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Ostrer L, Khodursky RF, Johnson JR, Hiasa H, Khodursky A. Analysis of mutational patterns in quinolone resistance-determining regions of GyrA and ParC of clinical isolates. Int J Antimicrob Agents 2018; 53:318-324. [PMID: 30582984 DOI: 10.1016/j.ijantimicag.2018.12.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/15/2018] [Indexed: 01/03/2023]
Abstract
Fluoroquinolone (FQ)-resistant bacteria pose a major global health threat. Unanalysed genomic data from thousands of sequenced microbes likely contain important hints regarding the evolution of FQ resistance, yet this information lies fallow. Here we analysed the co-occurrence patterns of quinolone resistance mutations in genes encoding the FQ drug targets DNA gyrase (gyrase) and topoisomerase IV (topo-IV) from 36,402 bacterial genomes, representing 10 Gram-positive and 10 Gram-negative species. For 19 species, the likeliest routes toward resistance mutations in both targets were determined, and for 5 species those mutations necessary and sufficient to predict FQ resistance were also determined. Target mutation hierarchy was fixed in all examined Gram-negative species, with gyrase being the primary and topo-IV the secondary quinolone target, as well as in six of nine Gram-positive species, with topo-IV being the primary and gyrase the secondary target. By contrast, in three Gram-positive species (Staphylococcus haemolyticus, Streptococcus pneumoniae and Streptococcus suis), under some conditions gyrase became the primary and topo-IV the secondary target. The path through individual resistance mutations varied by species. Both linear and branched paths were identified in Gram-positive and Gram-negative organisms alike. Finally, FQ resistance could be predicted based solely on target gene quinolone resistance mutations for Acinetobacter baumannii, Escherichia coli and Staphylococcus aureus, but not Klebsiella pneumoniae or Pseudomonas aeruginosa. These findings have important implications both for sequence-based diagnostics and for understanding the emergence of FQ resistance.
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Affiliation(s)
- Lev Ostrer
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, St Paul, MN, USA
| | - Rachel F Khodursky
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, St Paul, MN, USA
| | | | - Hiroshi Hiasa
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN, USA
| | - Arkady Khodursky
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, St Paul, MN, USA.
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14
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Resistance profile of clinically relevant bacterial isolates against fluoroquinolone in Ethiopia: a systematic review and meta-analysis. BMC Pharmacol Toxicol 2018; 19:86. [PMID: 30541613 PMCID: PMC6292079 DOI: 10.1186/s40360-018-0274-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/22/2018] [Indexed: 11/13/2022] Open
Abstract
Background Fluoroquinolones are among the most frequently utilized antibacterial agents in developing countries like Ethiopia. Ciprofloxacin has become the most prescribed drug within this class and remains as one of the top three antibacterial agents prescribed in Ethiopia. However, several studies indicated that there is a gradual increase of antibacterial resistance. Therefore, this meta-analysis aimed to quantitatively estimate the prevalence of ciprofloxacin resistance bacterial isolates in Ethiopia. Methods Literature search was conducted from electronic databases and indexing services including EMBASE (Ovid interface), PubMed/MEDLINE, Google Scholar, Science Direct and WorldCat. Data were extracted with structured format prepared in Microsoft Excel and exported to STATA 15.0 software for the analyses. Pooled estimation of outcomes was performed with DerSimonian-Laird random-effects model at 95% confidence level. Degree of heterogeneity of studies was presented with I2 statistics. Publication bias was conducted with comprehensive meta-analysis version 3 software and presented with funnel plots of standard error supplemented by Begg’s and Egger’s tests. The study protocol has been registered on PROSPERO with reference number ID: CRD42018097047. Results A total of 37 studies were included for this study. The pooled prevalence of resistance in selected gram-positive bacterial isolates against ciprofloxacin was found to be 19.0% (95% confidence interval [CI]: 15.0, 23.0). The degree of resistance among Staphylococcus aureus, Coagulase negative Staphyloccoci (CoNS), Enterococcus faecalis and Group B Streptococci (GBS) was found to be 18.6, 21.6, 23.9, and 7.40%, respectively. The pooled prevalence of resistance in gram-negative bacteria was about 21.0% (95% CI: 17, 25). Higher estimates were observed in Neisseria gonorrhea (48.1%), Escherichia coli (24.3%) and Klebsiella pneumonia (23.2%). Subgroup analysis indicated that blood and urine were found to be a major source of resistant S. aureus isolates. Urine was also a major source of resistant strains for CoNS, Klebsiella and Proteus species. Conclusion Among gram-positive bacteria, high prevalence of resistance was observed in E. faecalis and CoNS whereas relatively low estimate of resistance was observed among GBS isolates. Within gram-negative bacteria, nearly half of isolates in N. gonorrhoea were found ciprofloxacin resistant. From enterobacteriaceae isolates, K. pneumonia and E. coli showed higher estimates of ciprofloxacin resistance. Electronic supplementary material The online version of this article (10.1186/s40360-018-0274-6) contains supplementary material, which is available to authorized users.
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15
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Mutations in DNA gyrase and topoisomerase genes linked to fluoroquinolone resistance in Salmonella Typhimurium of animal origin in India. J Glob Antimicrob Resist 2018; 15:268-270. [PMID: 30312828 DOI: 10.1016/j.jgar.2018.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 10/02/2018] [Accepted: 10/02/2018] [Indexed: 11/23/2022] Open
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16
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Gerasyuto AI, Arnold MA, Wang J, Chen G, Zhang X, Smith S, Woll MG, Baird J, Zhang N, Almstead NG, Narasimhan J, Peddi S, Dumble M, Sheedy J, Weetall M, Branstrom AA, Prasad JVN, Karp GM. Discovery and Optimization of Indolyl-Containing 4-Hydroxy-2-Pyridone Type II DNA Topoisomerase Inhibitors Active against Multidrug Resistant Gram-negative Bacteria. J Med Chem 2018; 61:4456-4475. [PMID: 29727185 PMCID: PMC5991783 DOI: 10.1021/acs.jmedchem.8b00114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There exists an urgent medical need to identify new chemical entities (NCEs) targeting multidrug resistant (MDR) bacterial infections, particularly those caused by Gram-negative pathogens. 4-Hydroxy-2-pyridones represent a novel class of nonfluoroquinolone inhibitors of bacterial type II topoisomerases active against MDR Gram-negative bacteria. Herein, we report on the discovery and structure-activity relationships of a series of fused indolyl-containing 4-hydroxy-2-pyridones with improved in vitro antibacterial activity against fluoroquinolone resistant strains. Compounds 6o and 6v are representative of this class, targeting both bacterial DNA gyrase and topoisomerase IV (Topo IV). In an abbreviated susceptibility screen, compounds 6o and 6v showed improved MIC90 values against Escherichia coli (0.5-1 μg/mL) and Acinetobacter baumannii (8-16 μg/mL) compared to the precursor compounds. In a murine septicemia model, both compounds showed complete protection in mice infected with a lethal dose of E. coli.
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Affiliation(s)
- Aleksey I Gerasyuto
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Michael A Arnold
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Jiashi Wang
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Guangming Chen
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Xiaoyan Zhang
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Sean Smith
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Matthew G Woll
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - John Baird
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Nanjing Zhang
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Neil G Almstead
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Jana Narasimhan
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Srinivasa Peddi
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Melissa Dumble
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Josephine Sheedy
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Marla Weetall
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Arthur A Branstrom
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - J V N Prasad
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
| | - Gary M Karp
- PTC Therapeutics, Inc. , 100 Corporate Court , South Plainfield , New Jersey 07080 , United States
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17
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Schuldiner S. The Escherichia coli effluxome. Res Microbiol 2018; 169:357-362. [PMID: 29574104 DOI: 10.1016/j.resmic.2018.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 11/30/2022]
Abstract
Multidrug transporters function in a coordinated mode to provide an essential first-line defense mechanism that prevents antibiotics from reaching lethal concentrations, until a number of stable efficient adaptations occur that allow survival. Single-component efflux transporters remove the toxic compounds from the cytoplasm to the periplasmic space where TolC-dependent transporters expel them from the cell. The close interaction between the two types of transporters ensures handling of a wide range of xenobiotics and prevents rapid leak of the hydrophobic substrates back into the cell. In this review, we discuss the concept of the bacterial effluxome of the Gram-negative Escherichia coli that is the entire set of transporters expressed at a given time, under defined conditions. The process of identification of its members and the elucidation of the nature of the interactions throw a novel light on the roles of transporters in bacterial physiology and drug resistance development. We anticipate that the concept of an effluxome where each member contributes to the removal of noxious chemicals from the cell should contribute to improving the present strategy of searching for transport inhibitors as adjuvants of existing antibiotics and provide novel targets for this urgent undertaking.
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Affiliation(s)
- Shimon Schuldiner
- Department of Biological Chemistry, Institute of Life Sciences, Silberman Bldg. 1-339, Edmond J. Safra Campus, Hebrew University of Jerusalem, Givat Ram, Jerusalem, 91904, Israel.
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18
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Affiliation(s)
- Zachary C. Conley
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Truston J. Bodine
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, United States of America
| | - Andrew Chou
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, United States of America
| | - Lynn Zechiedrich
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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19
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Arnold MA, Gerasyuto AI, Wang J, Du W, Gorske YJK, Arasu T, Baird J, Almstead NG, Narasimhan J, Peddi S, Ginzburg O, Lue SW, Hedrick J, Sheedy J, Lagaud G, Branstrom AA, Weetall M, Prasad JVNV, Karp GM. 4-Hydroxy-2-pyridones: Discovery and evaluation of a novel class of antibacterial agents targeting DNA synthesis. Bioorg Med Chem Lett 2017; 27:5014-5021. [PMID: 29032026 DOI: 10.1016/j.bmcl.2017.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/27/2017] [Accepted: 10/04/2017] [Indexed: 01/01/2023]
Abstract
The continued emergence of bacteria resistant to current standard of care antibiotics presents a rapidly growing threat to public health. New chemical entities (NCEs) to treat these serious infections are desperately needed. Herein we report the discovery, synthesis, SAR and in vivo efficacy of a novel series of 4-hydroxy-2-pyridones exhibiting activity against Gram-negative pathogens. Compound 1c, derived from the N-debenzylation of 1b, preferentially inhibits bacterial DNA synthesis as determined by standard macromolecular synthesis assays. The structural features of the 4-hydroxy-2-pyridone scaffold required for antibacterial activity were explored and compound 6q, identified through further optimization of the series, had an MIC90 value of 8 μg/mL against a panel of highly resistant strains of E. coli. In a murine septicemia model, compound 6q exhibited a PD50 of 8 mg/kg in mice infected with a lethal dose of E. coli. This novel series of 4-hydroxy-2-pyridones serves as an excellent starting point for the identification of NCEs treating Gram-negative infections.
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Affiliation(s)
- Michael A Arnold
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA.
| | - Aleksey I Gerasyuto
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jiashi Wang
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Wu Du
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Yi Jin Kim Gorske
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Tamil Arasu
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - John Baird
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Neil G Almstead
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jana Narasimhan
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Srinivasa Peddi
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Olya Ginzburg
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Stanley W Lue
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jean Hedrick
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Josephine Sheedy
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Guy Lagaud
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Arthur A Branstrom
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Marla Weetall
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - J V N Vara Prasad
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Gary M Karp
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
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20
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Li J, Hao H, Cheng G, Wang X, Ahmed S, Shabbir MAB, Liu Z, Dai M, Yuan Z. The effects of different enrofloxacin dosages on clinical efficacy and resistance development in chickens experimentally infected with Salmonella Typhimurium. Sci Rep 2017; 7:11676. [PMID: 28916830 PMCID: PMC5601478 DOI: 10.1038/s41598-017-12294-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 09/07/2017] [Indexed: 12/05/2022] Open
Abstract
To investigate the optimal dosage which can improve clinical efficacy and minimize resistance, pharmacokinetics/pharmacodynamics model of enrofloxacin was established. Effect of enrofloxacin treatments on clearance of Salmonella in experimentally infected chickens and simultaneously resistance selection in Salmonella and coliforms were evaluated in three treatment groups (100, PK/PD designed dosage of 4, 0.1 mg/kg b.w.) and a control group. Treatment duration was three rounds of 7-day treatment alternated with 7-day withdrawal. Results showed that 100 mg/kg b.w. of enrofloxacin completely eradicated Salmonella, but resistant coliforms (4.0-60.8%) were selected from the end of the second round's withdrawal period till the end of the experiment (days 28-42). PK/PD based dosage (4 mg/kg b.w.) effectively reduced Salmonella for the first treatment duration. However upon cessation of medication, Salmonella repopulated chickens and persisted till the end with reduced susceptibility (MICCIP = 0.03-0.25 mg/L). Low frequency (5-9.5%) of resistant coliforms was selected (days 39-42). Enrofloxacin at dosage of 0.1 mg/kg b.w. was not able to eliminate Salmonella and selected coliforms with slight decreased susceptibility (MICENR = 0.25 mg/L). In conclusion, short time treatment (7 days) of enrofloxacin at high dosage (100 mg/kg b.w.) could be effective in treating Salmonella infection while minimizing resistance selection in both Salmonella and coliforms.
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Affiliation(s)
- Jun Li
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Haihong Hao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan, China.
| | - Guyue Cheng
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan, China
| | - Xu Wang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan, China
| | - Saeed Ahmed
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Muhammad Abu Bakr Shabbir
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Zhenli Liu
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Menghong Dai
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan, China.
| | - Zonghui Yuan
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China.
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan, China.
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
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Matsumura Y, Noguchi T, Tanaka M, Kanahashi T, Yamamoto M, Nagao M, Takakura S, Ichiyama S. Population structure of Japanese extraintestinal pathogenic Escherichia coli and its relationship with antimicrobial resistance. J Antimicrob Chemother 2017; 72:1040-1049. [PMID: 28077674 DOI: 10.1093/jac/dkw530] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/10/2016] [Indexed: 12/23/2022] Open
Abstract
Objectives To define the population structure of extraintestinal pathogenic Escherichia coli (ExPEC) in Japan and its relationship with antimicrobial resistance and the major resistance mechanisms for fluoroquinolones and β-lactams, we designed a multicentre prospective study. Methods A total of 329 ExPEC isolates were collected at 10 Japanese acute-care hospitals during December 2014. We defined the clonal groups of ExPEC by fumC and fimH sequencing (CH typing). Antimicrobial susceptibility testing of 18 agents and the detection of mutations in quinolone resistance-determining regions (QRDRs) and β-lactamases were performed. Results Among the study isolates, 103 CH types were found, and CH40-30 (25%) and another 10 CH types (35% in total) constituted the major ExPEC population. Ciprofloxacin non-susceptibility, ESBLs and MDR phenotypes were found in 34%, 22% and 33%, respectively. CH40-30, corresponding to the C/H30 clade of the global pandemic ST131 clone, was associated with four QRDR mutations (100%) and bla CTX-M (60%) and was the most frequent type in 15 antimicrobial-non-susceptible populations (dominating 39%-75% of each population, the highest prevalence for ciprofloxacin), the ESBL producers (70%) and the MDR isolates (59%). Isolates that were non-susceptible to nalidixic acid and low-level resistant to ciprofloxacin with one or two QRDR mutations represented 16% of the study isolates and were distributed among the eight major and non-major CH types. Conclusions More than half of the ExPEC population in Japan consisted of 11 major clones. Of these clones, the CH40-30-ST131-C/H30 clone was the predominant antimicrobial-resistant population. The presence of major clones with low-level ciprofloxacin resistance supports the potential future success of a non-ST131 fluoroquinolone-resistant clone.
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Machuca J, Recacha E, Briales A, Díaz-de-Alba P, Blazquez J, Pascual Á, Rodríguez-Martínez JM. Cellular Response to Ciprofloxacin in Low-Level Quinolone-Resistant Escherichia coli. Front Microbiol 2017; 8:1370. [PMID: 28769919 PMCID: PMC5516121 DOI: 10.3389/fmicb.2017.01370] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/05/2017] [Indexed: 11/13/2022] Open
Abstract
Bactericidal activity of quinolones has been related to a combination of DNA fragmentation, reactive oxygen species (ROS) production and programmed cell death (PCD) systems. The underlying molecular systems responsible for reducing bactericidal effect during antimicrobial therapy in low-level quinolone resistance (LLQR) phenotypes need to be clarified. To do this and also define possible new antimicrobial targets, the transcriptome profile of isogenic Escherichia coli harboring quinolone resistance mechanisms in the presence of a clinical relevant concentration of ciprofloxacin was evaluated. A marked differential response to ciprofloxacin of either up- or downregulation was observed in LLQR strains. Multiple genes implicated in ROS modulation (related to the TCA cycle, aerobic respiration and detoxification systems) were upregulated (sdhC up to 63.5-fold) in mutants with LLQR. SOS system components were downregulated (recA up to 30.7-fold). yihE, a protective kinase coding for PCD, was also upregulated (up to 5.2-fold). SdhC inhibition sensitized LLQR phenotypes (up to ΔLog = 2.3 after 24 h). At clinically relevant concentrations of ciprofloxacin, gene expression patterns in critical systems to bacterial survival and mutant development were significantly modified in LLQR phenotypes. Chemical inhibition of SdhC (succinate dehydrogenase) validated modulation of ROS as an interesting target for bacterial sensitization.
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Affiliation(s)
- Jesús Machuca
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
| | - Esther Recacha
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
| | - Alejandra Briales
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
- Departamento de Microbiología, Universidad de SevillaSevilla, Spain
| | - Paula Díaz-de-Alba
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
| | - Jesús Blazquez
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Álvaro Pascual
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
| | - José-Manuel Rodríguez-Martínez
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
- Departamento de Microbiología, Universidad de SevillaSevilla, Spain
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van Opijnen T, Dedrick S, Bento J. Strain Dependent Genetic Networks for Antibiotic-Sensitivity in a Bacterial Pathogen with a Large Pan-Genome. PLoS Pathog 2016; 12:e1005869. [PMID: 27607357 PMCID: PMC5015961 DOI: 10.1371/journal.ppat.1005869] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/15/2016] [Indexed: 11/19/2022] Open
Abstract
The interaction between an antibiotic and bacterium is not merely restricted to the drug and its direct target, rather antibiotic induced stress seems to resonate through the bacterium, creating selective pressures that drive the emergence of adaptive mutations not only in the direct target, but in genes involved in many different fundamental processes as well. Surprisingly, it has been shown that adaptive mutations do not necessarily have the same effect in all species, indicating that the genetic background influences how phenotypes are manifested. However, to what extent the genetic background affects the manner in which a bacterium experiences antibiotic stress, and how this stress is processed is unclear. Here we employ the genome-wide tool Tn-Seq to construct daptomycin-sensitivity profiles for two strains of the bacterial pathogen Streptococcus pneumoniae. Remarkably, over half of the genes that are important for dealing with antibiotic-induced stress in one strain are dispensable in another. By confirming over 100 genotype-phenotype relationships, probing potassium-loss, employing genetic interaction mapping as well as temporal gene-expression experiments we reveal genome-wide conditionally important/essential genes, we discover roles for genes with unknown function, and uncover parts of the antibiotic's mode-of-action. Moreover, by mapping the underlying genomic network for two query genes we encounter little conservation in network connectivity between strains as well as profound differences in regulatory relationships. Our approach uniquely enables genome-wide fitness comparisons across strains, facilitating the discovery that antibiotic responses are complex events that can vary widely between strains, which suggests that in some cases the emergence of resistance could be strain specific and at least for species with a large pan-genome less predictable.
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Affiliation(s)
- Tim van Opijnen
- Boston College, Biology Department, Chestnut Hill, Massachusetts, United States of America
| | - Sandra Dedrick
- Boston College, Biology Department, Chestnut Hill, Massachusetts, United States of America
| | - José Bento
- Boston College, Computer Science Department, Massachusetts, United States of America
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A Transporter Interactome Is Essential for the Acquisition of Antimicrobial Resistance to Antibiotics. PLoS One 2016; 11:e0152917. [PMID: 27050393 PMCID: PMC4822809 DOI: 10.1371/journal.pone.0152917] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 03/21/2016] [Indexed: 01/12/2023] Open
Abstract
Awareness of the problem of antimicrobial resistance (AMR) has escalated and drug-resistant infections are named among the most urgent problems facing clinicians today. Our experiments here identify a transporter interactome and portray its essential function in acquisition of antimicrobial resistance. By exposing E. coli cells to consecutive increasing concentrations of the fluoroquinolone norfloxacin we generated in the laboratory highly resistant strains that carry multiple mutations, most of them identical to those identified in clinical isolates. With this experimental paradigm, we show that the MDTs function in a coordinated mode to provide an essential first-line defense mechanism, preventing the drug reaching lethal concentrations, until a number of stable efficient alterations occur that allow survival. Single-component efflux transporters remove the toxic compounds from the cytoplasm to the periplasmic space where TolC-dependent transporters expel them from the cell. We postulate a close interaction between the two types of transporters to prevent rapid leak of the hydrophobic substrates back into the cell. The findings change the prevalent concept that in Gram-negative bacteria a single multidrug transporter, AcrAB-TolC type, is responsible for the resistance. The concept of a functional interactome, the process of identification of its members, the elucidation of the nature of the interactions and its role in cell physiology will change the existing paradigms in the field. We anticipate that our work will have an impact on the present strategy searching for inhibitors of AcrAB-TolC as adjuvants of existing antibiotics and provide novel targets for this urgent undertaking.
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Thompson CN, Thieu NTV, Vinh PV, Duc AN, Wolbers M, Vinh H, Campbell JI, Ngoc DTT, Hoang NVM, Thanh TH, The HC, Nguyen TNT, Lan NPH, Parry CM, Chau NVV, Thwaites G, Thanh DP, Baker S. Clinical implications of reduced susceptibility to fluoroquinolones in paediatric Shigella sonnei and Shigella flexneri infections. J Antimicrob Chemother 2015; 71:807-15. [PMID: 26679253 PMCID: PMC4743702 DOI: 10.1093/jac/dkv400] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/26/2015] [Indexed: 11/25/2022] Open
Abstract
Objectives We aimed to quantify the impact of fluoroquinolone resistance on the clinical outcome of paediatric shigellosis patients treated with fluoroquinolones in southern Vietnam. Such information is important to inform therapeutic management for infections caused by this increasingly drug-resistant pathogen, responsible for high morbidity and mortality in young children globally. Methods Clinical information and bacterial isolates were derived from a randomized controlled trial comparing gatifloxacin with ciprofloxacin for the treatment of paediatric shigellosis. Time–kill experiments were performed to evaluate the impact of MIC on the in vitro growth of Shigella and Cox regression modelling was used to compare clinical outcome between treatments and Shigella species. Results Shigella flexneri patients treated with gatifloxacin had significantly worse outcomes than those treated with ciprofloxacin. However, the MICs of fluoroquinolones were not significantly associated with poorer outcome. The presence of S83L and A87T mutations in the gyrA gene significantly increased MICs of fluoroquinolones. Finally, elevated MICs and the presence of the qnrS gene allowed Shigella to replicate efficiently in vitro in high concentrations of ciprofloxacin. Conclusions We found that below the CLSI breakpoint, there was no association between MIC and clinical outcome in paediatric shigellosis infections. However, S. flexneri patients had worse clinical outcomes when treated with gatifloxacin in this study regardless of MIC. Additionally, Shigella harbouring the qnrS gene are able to replicate efficiently in high concentrations of ciprofloxacin and we hypothesize that such strains possess a competitive advantage against fluoroquinolone-susceptible strains due to enhanced shedding and transmission.
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Affiliation(s)
- Corinne N Thompson
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK The London School of Hygiene and Tropical Medicine, London, UK
| | - Nga Tran Vu Thieu
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Anh Nguyen Duc
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Marcel Wolbers
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Ha Vinh
- The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - James I Campbell
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Dung Tran Thi Ngoc
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Nguyen Van Minh Hoang
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Hao Chung The
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - To Nguyen Thi Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Nguyen Phu Huong Lan
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Christopher M Parry
- The London School of Hygiene and Tropical Medicine, London, UK School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | | | - Guy Thwaites
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Duy Pham Thanh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Stephen Baker
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK The London School of Hygiene and Tropical Medicine, London, UK
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26
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Sousa CF, Ferreira M, Abreu B, Medforth CJ, Gameiro P. Interactions of a non-fluorescent fluoroquinolone with biological membrane models: A multi-technique approach. Int J Pharm 2015; 495:761-70. [PMID: 26392242 DOI: 10.1016/j.ijpharm.2015.09.037] [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: 06/13/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 11/30/2022]
Abstract
Fluoroquinolones are antibiotics which act by penetrating into bacterial cells and inhibiting enzymes related to DNA replication, and metal complexes of these drugs have recently been investigated as one approach to counteracting bacterial resistance. In this work, we apply a multi-technique approach to studying the partition coefficient (Kp) for the non-fluorescent third-generation fluoroquinolone sparfloxacin or its copper-complex with lipid membrane models of Gram-negative bacteria. The techniques investigated are UV-vis absorption and (19)F NMR spectroscopies together with quenching of a fluorescent probe present in the lipids (using steady-state and time-resolved methods). (19)F NMR spectroscopy has previously been used to determine the Kp values of fluorinated drugs but in the case of sparfloxacin did not yield useful data. However, similar Kp values for sparfloxacin or its copper-complex were obtained for the absorption and fluorescence quenching methods confirming the usefulness of a multi-technique approach. The Kp values measured for sparfloxacin were significantly higher than those found for other fluoroquinolones. In addition, similar Kp values were found for sparfloxacin and copper-complex suggesting that in contrast to other fluoroquinolones hydrophobic diffusion occurs readily for both of these molecules.
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Affiliation(s)
- Carla F Sousa
- Requimte/UCIBIO, Departmento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal
| | - Mariana Ferreira
- Requimte/UCIBIO, Departmento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal
| | - Bárbara Abreu
- Requimte/UCIBIO, Departmento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal
| | - Craig J Medforth
- Requimte/UCIBIO, Departmento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal
| | - Paula Gameiro
- Requimte/UCIBIO, Departmento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal.
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27
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Machuca J, Briales A, Díaz-de-Alba P, Martínez-Martínez L, Rodríguez-Martínez JM, Pascual Á. Comparison of clinical categories for Escherichia coli harboring specific qnr and chromosomal-mediated fluoroquinolone resistance determinants according to CLSI and EUCAST. Enferm Infecc Microbiol Clin 2015; 34:188-90. [PMID: 25772329 DOI: 10.1016/j.eimc.2015.01.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/19/2015] [Accepted: 01/30/2015] [Indexed: 11/17/2022]
Abstract
EUCAST breakpoints are more restrictive than those defined by CLSI. This study highlights the discrepancies between CLSI and EUCAST in a well characterized isogenic Escherichia coli collection and their correlations with specific quinolone resistance mechanisms. The greatest number of discrepancies was observed in strains containing 2-4 resistance mechanisms (MIC values on the borderline of clinical resistance). Bearing in mind that quinolones are concentration dependent antimicrobial agents, small changes in MIC may have relevant consequences for treatment outcomes.
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Affiliation(s)
- Jesús Machuca
- Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena, Seville, Spain
| | - Alejandra Briales
- Department of Microbiology, University of Seville, Seville, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Luis Martínez-Martínez
- Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain; University Hospital Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain; Department of Molecular Biology, University of Cantabria, Santander, Spain
| | - José-Manuel Rodríguez-Martínez
- Department of Microbiology, University of Seville, Seville, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain.
| | - Álvaro Pascual
- Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena, Seville, Spain; Department of Microbiology, University of Seville, Seville, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
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Phenotypic and molecular characterization of extended-spectrum beta-lactamase-producing Escherichia coli in Bangladesh. PLoS One 2014; 9:e108735. [PMID: 25302491 PMCID: PMC4193765 DOI: 10.1371/journal.pone.0108735] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 09/04/2014] [Indexed: 12/05/2022] Open
Abstract
Background Resistance to cephalosporins in Enterobacteriaceae is mainly due to the production of extended-spectrum beta-lactamase (ESBL). Little is known about ESBL-producing bacteria in Bangladesh. Therefore, the study presents results of phenotypic and molecular characterization of ESBL-producing Escherichia coli from hospitals in Bangladesh. Methods A total of 339 E. coli isolated from patients with urinary tract and wound infections attending three different medical hospitals in urban and rural areas of Bangladesh between 2003–2007 were screened for ESBL-production by the double disk diffusion test. Isolates with ESBL-phenotype were further characterized by antibiotic susceptibility testing, PCR and sequencing of different β-lactamase and virulence genes, serotyping, and XbaI-macrorestriction followed by pulsed-field gel electrophoresis (PFGE). Results We identified 40 E. coli with ESBL phenotype. These isolates were resistant to ceftriaxone, ceftazidime, cefotaxime, aztreonam, cefepime, and nalidixic acid but remained susceptible to imipenem. All but one isolate were additionally resistant to ciprofloxacin, and 3 isolates were resistant to cefoxitin. ESBL genes of blaCTX-M-1-group were detected in all isolates; blaTEM-type and blaOXA-1-type genes were detected in 33 (82.5%) and 19 (47.5%) isolates, respectively. Virulence genes that are present in diarrhoeagenic E. coli were not found. Class-1 integron was present in 20 (50%) isolates. All the ESBL-producing E. coli isolates harbored plasmids ranging between 1.1 and 120 MDa. PFGE-typing revealed 26 different pulsotypes, but identical pulsotype showed 6 isolates of serotype O25:H4. Conclusion The prevalence of multidrug-resistant ESBL-producing E. coli isolates appears to be high and the majority of the isolates were positive for blaCTX-M. Although there was genetic heterogeneity among isolates, presence of a cluster of isolates belonging to serotype O25:H4 indicates dissemination of the pandemic uropathogenic E. coli clone in Bangladesh.
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Azmi IJ, Khajanchi BK, Akter F, Hasan TN, Shahnaij M, Akter M, Banik A, Sultana H, Hossain MA, Ahmed MK, Faruque SM, Talukder KA. Fluoroquinolone resistance mechanisms of Shigella flexneri isolated in Bangladesh. PLoS One 2014; 9:e102533. [PMID: 25028972 PMCID: PMC4100904 DOI: 10.1371/journal.pone.0102533] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 06/19/2014] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To investigate the prevalence and mechanisms of fluoroquinolone resistance in Shigella species isolated in Bangladesh and to compare with similar strains isolated in China. METHODS A total of 3789 Shigella isolates collected from Clinical Microbiology Laboratory of icddr,b, during 2004-2010 were analyzed for antibiotic susceptibility. Analysis of plasmids, plasmid-mediated quinolone-resistance genes, PFGE, and sequencing of genes of the quinolone-resistance-determining regions (QRDR) were conducted in representative strains isolated in Bangladesh and compared with strains isolated in Zhengding, China. In addition, the role of efflux-pump was studied by using the efflux-pump inhibitor carbonyl cyanide-m-chlorophenylhydrazone (CCCP). RESULTS Resistance to ciprofloxacin in Shigella species increased from 0% in 2004 to 44% in 2010 and S. flexneri was the predominant species. Of Shigella spp, ciprofloxacin resistant (CipR) strains were mostly found among S. flexneri (8.3%), followed by S. sonnei (1.5%). Within S. flexneri (n = 2181), 14.5% were resistance to ciprofloxacin of which serotype 2a was predominant (96%). MIC of ciprofloxacin, norfloxacin, and ofloxacin were 6-32 mg/L, 8-32 mg/L, and 8-24 mg/L, respectively in S. flexneri 2a isolates. Sequencing of QRDR genes of resistant isolates showed double mutations in gyrA gene (Ser83Leu, Asp87Asn/Gly) and single mutation in parC gene (Ser80Ile). A difference in amino acid substitution at position 87 was found between strains isolated in Bangladesh (Asp87Asn) and China (Asp87Gly) except for one. A novel mutation at position 211 (His→Tyr) in gyrA gene was detected only in the Bangladeshi strains. Susceptibility to ciprofloxacin was increased by the presence of CCCP indicating the involvement of energy dependent active efflux pumps. A single PFGE type was found in isolates from Bangladesh and China suggesting their genetic relatedness. CONCLUSIONS Emergence of fluoroquinolone resistance in Shigella undermines a major challenge in current treatment strategies which needs to be followed up by using empirical therapeutic strategies.
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Affiliation(s)
- Ishrat J. Azmi
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Bijay K. Khajanchi
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Fatema Akter
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Trisheeta N. Hasan
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mohammad Shahnaij
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mahmuda Akter
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Atanu Banik
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Halima Sultana
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mohammad A. Hossain
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mohammad K. Ahmed
- Drug Testing Laboratory, Institute of Public Health, Dhaka, Bangladesh
| | - Shah M. Faruque
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Kaisar A. Talukder
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
- * E-mail:
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Redgrave LS, Sutton SB, Webber MA, Piddock LJV. Fluoroquinolone resistance: mechanisms, impact on bacteria, and role in evolutionary success. Trends Microbiol 2014; 22:438-45. [PMID: 24842194 DOI: 10.1016/j.tim.2014.04.007] [Citation(s) in RCA: 571] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/11/2014] [Accepted: 04/16/2014] [Indexed: 12/12/2022]
Abstract
Quinolone and fluoroquinolone antibiotics are potent, broad-spectrum agents commonly used to treat a range of infections. Resistance to these agents is multifactorial and can be via one or a combination of target-site gene mutations, increased production of multidrug-resistance (MDR) efflux pumps, modifying enzymes, and/or target-protection proteins. Fluoroquinolone-resistant clinical isolates of bacteria have emerged readily and recent data have shown that resistance to this class of antibiotics can have diverse, species-dependent impacts on host-strain fitness. Here we outline the impacts of quinolone-resistance mutations in relation to the fitness and evolutionary success of mutant strains.
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Affiliation(s)
- Liam S Redgrave
- School of Immunity and Infection, Institute of Microbiology and Infection, Biosciences Building, University Road West, University of Birmingham, Birmingham B15 2TT, UK
| | - Sam B Sutton
- School of Immunity and Infection, Institute of Microbiology and Infection, Biosciences Building, University Road West, University of Birmingham, Birmingham B15 2TT, UK
| | - Mark A Webber
- School of Immunity and Infection, Institute of Microbiology and Infection, Biosciences Building, University Road West, University of Birmingham, Birmingham B15 2TT, UK
| | - Laura J V Piddock
- School of Immunity and Infection, Institute of Microbiology and Infection, Biosciences Building, University Road West, University of Birmingham, Birmingham B15 2TT, UK.
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Elkhatib W, Haynes V, Noreddin A. Microbiological Appraisal of Levofloxacin Activity AgainstPseudomonas aeruginosaBiofilm in Combination with Different Calcium Channel BlockersIn Vitro. J Chemother 2013; 21:135-43. [DOI: 10.1179/joc.2009.21.2.135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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32
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Swick MC, Evangelista MA, Bodine TJ, Easton-Marks JR, Barth P, Shah MJ, Bormann Chung CA, Stanley S, McLaughlin SF, Lee CC, Sheth V, Doan Q, Hamill RJ, Steffen D, Becnel LB, Sucgang R, Zechiedrich L. Novel Conserved Genotypes Correspond to Antibiotic Resistance Phenotypes of E. coli Clinical Isolates. PLoS One 2013; 8:e65961. [PMID: 23824211 PMCID: PMC3688849 DOI: 10.1371/journal.pone.0065961] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 05/03/2013] [Indexed: 11/20/2022] Open
Abstract
Current efforts to understand antibiotic resistance on the whole genome scale tend to focus on known genes even as high throughput sequencing strategies uncover novel mechanisms. To identify genomic variations associated with antibiotic resistance, we employed a modified genome-wide association study; we sequenced genomic DNA from pools of E. coli clinical isolates with similar antibiotic resistance phenotypes using SOLiD technology to uncover single nucleotide polymorphisms (SNPs) unanimously conserved in each pool. The multidrug-resistant pools were genotypically similar to SMS-3-5, a previously sequenced multidrug-resistant isolate from a polluted environment. The similarity was evenly spread across the entire genome and not limited to plasmid or pathogenicity island loci. Among the pools of clinical isolates, genomic variation was concentrated adjacent to previously reported inversion and duplication differences between the SMS-3-5 isolate and the drug-susceptible laboratory strain, DH10B. SNPs that result in non-synonymous changes in gyrA (encoding the well-known S83L allele associated with fluoroquinolone resistance), mutM, ligB, and recG were unanimously conserved in every fluoroquinolone-resistant pool. Alleles of the latter three genes are tightly linked among most sequenced E. coli genomes, and had not been implicated in antibiotic resistance previously. The changes in these genes map to amino acid positions in alpha helices that are involved in DNA binding. Plasmid-encoded complementation of null strains with either allelic variant of mutM or ligB resulted in variable responses to ultraviolet light or hydrogen peroxide treatment as markers of induced DNA damage, indicating their importance in DNA metabolism and revealing a potential mechanism for fluoroquinolone resistance. Our approach uncovered evidence that additional DNA binding enzymes may contribute to fluoroquinolone resistance and further implicate environmental bacteria as a reservoir for antibiotic resistance.
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Affiliation(s)
- Michelle C. Swick
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael A. Evangelista
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, Texas, United States of America
| | - Truston J. Bodine
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jeremy R. Easton-Marks
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas, United States of America
- Biomedical Informatics Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Patrick Barth
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, Texas, United States of America
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Minita J. Shah
- Life Technologies, Beverly, Massachusetts, United States of America
| | | | - Sarah Stanley
- Life Technologies, Beverly, Massachusetts, United States of America
| | | | - Clarence C. Lee
- Life Technologies, Beverly, Massachusetts, United States of America
| | - Vrunda Sheth
- Life Technologies, Beverly, Massachusetts, United States of America
| | - Quynh Doan
- Life Technologies, Foster City, California, United States of America
| | - Richard J. Hamill
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - David Steffen
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas, United States of America
- Biomedical Informatics Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lauren B. Becnel
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas, United States of America
- Biomedical Informatics Group, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard Sucgang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, Texas, United States of America
- * E-mail: (RS); (LZ)
| | - Lynn Zechiedrich
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (RS); (LZ)
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Molecular characterization of extraintestinal Escherichia coli isolates in Japan: relationship between sequence types and mutation patterns of quinolone resistance-determining regions analyzed by pyrosequencing. J Clin Microbiol 2013; 51:1692-8. [PMID: 23515543 DOI: 10.1128/jcm.03049-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection from fluoroquinolone-resistant Enterobacteriaceae is an increasing health problem worldwide. In the present study, we developed a pyrosequencing-based high-throughput method for analyzing the nucleotide sequence of the quinolone resistance-determining regions (QRDRs) of gyrA and parC. By using this method, we successfully determined the QRDR sequences of 139 out of 140 clinical Escherichia coli isolates, 28% of which were nonsusceptible to ciprofloxacin. Sequence results obtained by the pyrosequencing method were in complete agreement with those obtained by the Sanger method. All fluoroquinolone-resistant isolates (n = 35; 25%) contained mutations leading to three or four amino acid substitutions in the QRDRs. In contrast, all isolates lacking a mutation in the QRDR (n = 81; 57%) were susceptible to ciprofloxacin, levofloxacin, and nalidixic acid. The qnr determinants, namely, the qnrA, qnrB, and qnrS genes, were not detected in the isolates, and the aac(6')-Ib-cr gene was detected in 2 (1.4%) of the isolates. Multilocus sequence typing of 34 randomly selected isolates revealed that sequence type 131 (ST131) (n = 7; 20%) is the most prevalent lineage and is significantly resistant to quinolones (P < 0.01). The genetic background of quinolone-susceptible isolates seemed more diverse, and interestingly, neighboring STs of ST131 in the phylogenetic tree were all susceptible to ciprofloxacin. In conclusion, our investigation reveals the relationship between fluoroquinolone resistance caused by mutations of QRDRs and the population structure of clinical extraintestinal E. coli isolates. This high-throughput method for analyzing QRDR mutations by pyrosequencing is a powerful tool for epidemiological studies of fluoroquinolone resistance in bacteria.
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Adachi F, Yamamoto A, Takakura KI, Kawahara R. Occurrence of fluoroquinolones and fluoroquinolone-resistance genes in the aquatic environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 444:508-514. [PMID: 23291652 DOI: 10.1016/j.scitotenv.2012.11.077] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 11/12/2012] [Accepted: 11/22/2012] [Indexed: 06/01/2023]
Abstract
Fluoroquinolones (FQs) have been detected in aquatic environments in several countries. Long-term exposure to low levels of antimicrobial agents provides selective pressure, which might alter the sensitivity of bacteria to antimicrobial agents in the environment. Here, we examined FQ levels and the resistance of Escherichia coli (E. coli) to FQs by phenotyping and genotyping. In the aquatic environment in Osaka, Japan, ciprofloxacin, enoxacin, enfloxacin, lomefloxacin, norfloxacin, and ofloxacin were detected in concentrations ranging from 0.1 to 570 ng L(-1). FQ-resistant E. coli were also found. Although no obvious correlation was detected between the concentration of FQs and the presence of FQ-resistant E. coli, FQ-resistant E. coli were detected in samples along with FQs, particularly ciprofloxacin and ofloxacin. Most FQ-resistant E. coli carried mutations in gyrA, parC, and parE in quinolone resistance-determining regions. No mutations in gyrB were detected in any isolates. Amino acid changes in these isolates were quite similar to those in clinical isolates. Six strains carried the plasmid-mediated quinolone resistance determinant qnrS1 and expressed low susceptibility to ciprofloxacin and nalidixic acid: the minimum inhibitory concentrations ranged from 0.25 μg mL(-1) for ciprofloxacin, and from 8 to 16 μg mL(-1) for nalidixic acid. This finding confirmed that plasmids containing qnr genes themselves did not confer full resistance to quinolones. Because plasmids are responsible for much of the horizontal gene transfer, these genes may transfer and spread in the environment. To our knowledge, this is the first report of plasmid-mediated quinolone resistance determinant qnrS1 in the aquatic environment, and this investigation provides baseline data on antimicrobial resistance profiles in the Osaka area.
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Affiliation(s)
- Fumie Adachi
- Osaka Prefectural Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka 537-0025, Japan
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Fu Y, Zhang W, Wang H, Zhao S, Chen Y, Meng F, Zhang Y, Xu H, Chen X, Zhang F. Specific patterns of gyrA mutations determine the resistance difference to ciprofloxacin and levofloxacin in Klebsiella pneumoniae and Escherichia coli. BMC Infect Dis 2013; 13:8. [PMID: 23295059 PMCID: PMC3576228 DOI: 10.1186/1471-2334-13-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 01/02/2013] [Indexed: 02/04/2023] Open
Abstract
Background Wide use of ciprofloxacin and levofloxacin has often led to increased resistance. The resistance rate to these two agents varies in different clinical isolates of Enterobacteriaceae. Mutations of GyrA within the quinolone resistance-determining regions have been found to be the main mechanism for quinolone resistance in Enterobacteriaceae. It has been shown that only some of the mutations in the gyrA gene identified from clinical sources were involved in fluoroquinolone resistance. Whether different patterns of gyrA mutation are related to antimicrobial resistance against ciprofloxacin and levofloxacin is unclear. Methods The minimum inhibitory concentration (MIC) of ciprofloxacin and levofloxacin were determined by the agar dilution method followed by PCR amplification and sequencing of the quinolone resistance determining region of gyrA to identify all the mutation types. The correlation between fluoroquinolone resistance and the individual mutation type was analyzed. Results Resistance differences between ciprofloxacin and levofloxacin were found in 327 isolates of K. pneumoniae and E. coli in Harbin, China and in the isolates reported in PubMed publications. GyrA mutations were found in both susceptible and resistant isolates. For the isolates with QRDR mutations, the resistance rates to ciprofloxacin and levofloxacin were also statistically different. Among the 14 patterns of alterations, two single mutations (Ser83Tyr and Ser83Ile), and three double mutations (Ser83Leu+Asp87Asn, Ser83Leu+Asp87Tyr and Ser83Phe+Asp87Asn) were associated with both ciprofloxacin and levofloxacin resistance. Two single mutations (Ser83Phe and Ser83Leu) were related with ciprofloxacin resistance but not to levofloxacin. Resistance difference between ciprofloxacin and levofloxacin in isolates harboring mutation Ser83Leu+Asp87Asn were of statistical significance among all Enterobacteriaceae (P<0.001). Conclusions Resistance rate to ciprofloxacin and levofloxacin were statistically different among clinical isolates of Enterobacteriaceae harboring GyrA mutations. Ser83Leu+Asp87Asn may account for the antimicrobial resistance difference between ciprofloxacin and levofloxacin.
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Affiliation(s)
- Yingmei Fu
- Department of Microbiology, Heilongjiang Province Key Laboratory for Immunity and infection, Pathogenic biology, Bio-pharmaceutical Key Laboratory of Ministry of Education, Harbin Medical University, 157 Baojian Road, Harbin 150086, China
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Han J, Wang Y, Sahin O, Shen Z, Guo B, Shen J, Zhang Q. A fluoroquinolone resistance associated mutation in gyrA Affects DNA supercoiling in Campylobacter jejuni. Front Cell Infect Microbiol 2012; 2:21. [PMID: 22919613 PMCID: PMC3417464 DOI: 10.3389/fcimb.2012.00021] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/14/2012] [Indexed: 01/23/2023] Open
Abstract
The prevalence of fluoroquinolone (FQ)-resistant Campylobacter has become a concern for public health. To facilitate the control of FQ-resistant (FQR) Campylobacter, it is necessary to understand the impact of FQR on the fitness of Campylobacter in its natural hosts as understanding fitness will help to determine and predict the persistence of FQRCampylobacter. Previously it was shown that acquisition of resistance to FQ antimicrobials enhanced the in vivo fitness of FQRCampylobacter. In this study, we confirmed the role of the Thr-86-Ile mutation in GyrA in modulating Campylobacter fitness by reverting the mutation to the wild-type (WT) allele, which resulted in the loss of the fitness advantage. Additionally, we determined if the resistance-conferring GyrA mutations alter the enzymatic function of the DNA gyrase. Recombinant WT gyrase and mutant gyrases with three different types of mutations (Thr-86-Ile, Thr-86-Lys, and Asp-90-Asn), which are associated with FQR in Campylobacter, were generated in E. coli and compared for their supercoiling activities using an in vitro assay. The mutant gyrase with the Thr-86-Ile change showed a greatly reduced supercoiling activity compared with the WT gyrase, while other mutant gyrases did not show an altered supercoiling. Furthermore, we measured DNA supercoiling within Campylobacter cells using a reporter plasmid. Consistent with the results from the in vitro supercoiling assay, the FQR mutant carrying the Thr-86-Ile change in GyrA showed much less DNA supercoiling than the WT strain and the mutant strains carrying other mutations. Together, these results indicate that the Thr-86-Ile mutation, which is predominant in clinical FQRCampylobacter, modulates DNA supercoiling homeostasis in FQRCampylobacter.
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Affiliation(s)
- Jing Han
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University Ames, IA, USA
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Temporal interplay between efflux pumps and target mutations in development of antibiotic resistance in Escherichia coli. Antimicrob Agents Chemother 2012; 56:1680-5. [PMID: 22232279 DOI: 10.1128/aac.05693-11] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence of resistance presents a debilitating change in the management of infectious diseases. Currently, the temporal relationship and interplay between various mechanisms of drug resistance are not well understood. A thorough understanding of the resistance development process is needed to facilitate rational design of countermeasure strategies. Using an in vitro hollow-fiber infection model that simulates human drug treatment, we examined the appearance of efflux pump (acrAB) overexpression and target topoisomerase gene (gyrA and parC) mutations over time in the emergence of quinolone resistance in Escherichia coli. Drug-resistant isolates recovered early (24 h) had 2- to 8-fold elevation in the MIC due to acrAB overexpression, but no point mutations were noted. In contrast, high-level (≥ 64× MIC) resistant isolates with target site mutations (gyrA S83L with or without parC E84K) were selected more readily after 120 h, and regression of acrAB overexpression was observed at 240 h. Using a similar dosing selection pressure, the emergence of levofloxacin resistance was delayed in a strain with acrAB deleted compared to the isogenic parent. The role of efflux pumps in bacterial resistance development may have been underappreciated. Our data revealed the interplay between two mechanisms of quinolone resistance and provided a new mechanistic framework in the development of high-level resistance. Early low-level levofloxacin resistance conferred by acrAB overexpression preceded and facilitated high-level resistance development mediated by target site mutation(s). If this interpretation is correct, then these findings represent a paradigm shift in the way quinolone resistance is thought to develop.
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Gebru E, Damte D, Choi MJ, Lee SJ, Kim YH, Park SC. Mutant prevention concentration and phenotypic and molecular basis of fluoroquinolone resistance in clinical isolates and in vitro-selected mutants of Escherichia coli from dogs. Vet Microbiol 2012; 154:384-94. [DOI: 10.1016/j.vetmic.2011.07.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 07/25/2011] [Accepted: 07/27/2011] [Indexed: 11/26/2022]
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Lamikanra A, Crowe JL, Lijek RS, Odetoyin BW, Wain J, Aboderin AO, Okeke IN. Rapid evolution of fluoroquinolone-resistant Escherichia coli in Nigeria is temporally associated with fluoroquinolone use. BMC Infect Dis 2011; 11:312. [PMID: 22060770 PMCID: PMC3226678 DOI: 10.1186/1471-2334-11-312] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Accepted: 11/07/2011] [Indexed: 11/25/2022] Open
Abstract
Background Antibiotic resistance has necessitated fluoroquinolone use but little is known about the selective forces and resistance trajectory in malaria-endemic settings, where selection from the antimalarial chloroquine for fluoroquinolone-resistant bacteria has been proposed. Methods Antimicrobial resistance was studied in fecal Escherichia coli isolates in a Nigerian community. Quinolone-resistance determining regions of gyrA and parC were sequenced in nalidixic acid resistant strains and horizontally-transmitted quinolone-resistance genes were sought by PCR. Antimicrobial prescription practices were compared with antimicrobial resistance rates over a period spanning three decades. Results Before 2005, quinolone resistance was limited to low-level nalixidic acid resistance in fewer than 4% of E. coli isolates. In 2005, the proportion of isolates demonstrating low-level quinolone resistance due to elevated efflux increased and high-level quinolone resistance and resistance to the fluoroquinolones appeared. Fluoroquinolone resistance was attributable to single nucleotide polymorphisms in quinolone target genes gyrA and/or parC. By 2009, 35 (34.5%) of isolates were quinolone non-susceptible with nine carrying gyrA and parC SNPs and six bearing identical qnrS1 alleles. The antimalarial chloroquine was heavily used throughout the entire period but E. coli with quinolone-specific resistance mechanisms were only detected in the final half decade, immediately following the introduction of the fluoroquinolone antibacterial ciprofloxacin. Conclusions Fluoroquinolones, and not chloroquine, appear to be the selective force for fluoroquinolone-resistant fecal E. coli in this setting. Rapid evolution to resistance following fluoroquinolone introduction points the need to implement resistant containment strategies when new antibacterials are introduced into resource-poor settings with high infectious disease burdens.
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Affiliation(s)
- Adebayo Lamikanra
- Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
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Christiansen N, Nielsen L, Jakobsen L, Stegger M, Hansen LH, Frimodt-Møller N. Fluoroquinolone resistance mechanisms in urinary tract pathogenic Escherichia coli isolated during rapidly increasing fluoroquinolone consumption in a low-use country. Microb Drug Resist 2011; 17:395-406. [PMID: 21668371 DOI: 10.1089/mdr.2011.0015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Resistance to ciprofloxacin in Escherichia coli from urinary tract infections (UTI) in Denmark is increasing parallel to increased use of fluoroquinolones both in Denmark and in other European countries. The objective was to investigate the occurrence of ciprofloxacin resistance mechanisms, phenotypic coresistance, and if ciprofloxacin resistance was caused by clonal spread or to individual mutational events in a collection of consecutively obtained E. coli submitted to a clinical microbiology department at a Danish hospital. One hundred four UTI-related E. coli resistant toward nalidixic acid by disc diffusion were typed by Pulsed Field Gel Electrophoresis (PFGE) with XbaI. One isolate representing each PFGE type and only one patient (n = 77) were investigated for point mutations in sequenced PCR amplicons of the four topoisomerase genes; qnr genes by use of PCR; aac(6')-Ib-cr by BtsCI restriction of PCR products; and efflux using efflux pump inhibitors in a broth dilution assay. Minimal inhibitory concentration (MIC) was determined for 21 antibacterial agents, including ciprofloxacin. Of the 77 isolates, the majority were resistant to ciprofloxacin (91%) and multiresistant (resistant to ≥ 3 antimicrobial classes, 83%). Ciprofloxacin-resistant isolates showed at least one target mutation. A significant, positive correlation was found regarding MIC of ciprofloxacin and the number of target mutations. Efflux was found as a resistance mechanism in 77% of isolates tested (n = 60). The aac(6')-Ib-cr gene was detected on plasmids from five isolates showing ciprofloxacin MICs >512 mg/L. No overall clonal relationship among isolates was found according to PFGE. Target modification is the dominating fluoroquinolone resistance mechanism often found in combination with efflux and sometimes aac(6')-Ib-cr. In Denmark, increasing ciprofloxacin resistance in E. coli is mainly due to mutational events and not to spread of clones.
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Affiliation(s)
- Nina Christiansen
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen S, Denmark
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Rodriguez-Martinez JM, Briales A, Velasco C, Diaz de Alba P, Martinez-Martinez L, Pascual A. Discrepancies in fluoroquinolone clinical categories between the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and CLSI for Escherichia coli harbouring qnr genes and mutations in gyrA and parC. J Antimicrob Chemother 2011; 66:1405-7. [DOI: 10.1093/jac/dkr117] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Namboodiri SS, Opintan JA, Lijek RS, Newman MJ, Okeke IN. Quinolone resistance in Escherichia coli from Accra, Ghana. BMC Microbiol 2011; 11:44. [PMID: 21352598 PMCID: PMC3051878 DOI: 10.1186/1471-2180-11-44] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 02/27/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Antimicrobial resistance is under-documented and commensal Escherichia coli can be used as indicator organisms to study the resistance in the community. We sought to determine the prevalence of resistance to broad-spectrum antimicrobials with particular focus on the quinolones, which have recently been introduced in parts of Africa, including Ghana. RESULTS Forty (13.7%) of 293 E. coli isolates evaluated were nalidixic acid-resistant. Thirteen (52%) of 2006 and 2007 isolates and 10 (66.7%) of 2008 isolates were also resistant to ciprofloxacin. All but one of the quinolone-resistant isolates were resistant to three or more other antimicrobial classes. Sequencing the quinolone-resistance determining regions of gyrA and parC, which encode quinolone targets, revealed that 28 quinolone-resistant E. coli harboured a substitution at position 83 of the gyrA gene product and 20 of these isolates had other gyrA and/or parC substitutions. Horizontally-acquired quinolone-resistance genes qnrB1, qnrB2, qnrS1 or qepA were detected in 12 of the isolates. In spite of considerable overall diversity among E. coli from Ghana, as evaluated by multilocus sequence typing, 15 quinolone-resistant E. coli belonged to sequence type complex 10. Five of these isolates carried qnrS1 alleles. CONCLUSIONS Quinolone-resistant E. coli are commonly present in the faecal flora of Accra residents. The isolates have evolved resistance through multiple mechanisms and belong to very few lineages, suggesting clonal expansion. Containment strategies to limit the spread of quinolone-resistant E. coli need to be deployed to conserve quinolone effectiveness and promote alternatives to their use.
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In vitro effect of qnrA1, qnrB1, and qnrS1 genes on fluoroquinolone activity against isogenic Escherichia coli isolates with mutations in gyrA and parC. Antimicrob Agents Chemother 2010; 55:1266-9. [PMID: 21173174 DOI: 10.1128/aac.00927-10] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This article provides an analysis of the in vitro effect of qnrA1, qnrB1, and qnrS1 genes, combined with quinolone-resistant Ser83Leu substitutions in GyrA and/or Ser80Arg in ParC, on fluoroquinolone (FQ) resistance in isogenic Escherichia coli strains. The association of Ser83Leu substitution in GyrA, Ser80Arg substitution in ParC, and qnr gene expression increased the MIC of ciprofloxacin to 2 μg/ml. qnr genes present in E. coli that harbored a Ser83Leu substitution in GyrA increased mutant prevention concentration (MPC) values to 8 to 32 μg/ml. qnr gene expression in E. coli may play an important role in selecting for one-step FQ-resistant mutants.
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Use of an in vitro pharmacodynamic model to derive a moxifloxacin regimen that optimizes kill of Yersinia pestis and prevents emergence of resistance. Antimicrob Agents Chemother 2010; 55:822-30. [PMID: 21115791 DOI: 10.1128/aac.00818-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yersinia pestis, the causative agent of bubonic, septicemic, and pneumonic plague, is classified as a CDC category A bioterrorism pathogen. Streptomycin and doxycycline are the "gold standards" for the treatment of plague. However, streptomycin is not available in many countries, and Y. pestis isolates resistant to streptomycin and doxycycline occur naturally and have been generated in laboratories. Moxifloxacin is a fluoroquinolone antibiotic that demonstrates potent activity against Y. pestis in in vitro and animal infection models. However, the dose and frequency of administration of moxifloxacin that would be predicted to optimize treatment efficacy in humans while preventing the emergence of resistance are unknown. Therefore, dose range and dose fractionation studies for moxifloxacin were conducted for Y. pestis in an in vitro pharmacodynamic model in which the half-lives of moxifloxacin in human serum were simulated so as to identify the lowest drug exposure and the schedule of administration that are linked with killing of Y. pestis and with the suppression of resistance. In the dose range studies, simulated moxifloxacin regimens of ≥175 mg/day killed drug-susceptible bacteria without resistance amplification. Dose fractionation studies demonstrated that the AUC (area under the concentration-time curve)/MIC ratio predicted kill of drug-susceptible Y. pestis, while the C(max) (maximum concentration of the drug in serum)/MIC ratio was linked to resistance prevention. Monte Carlo simulations predicted that moxifloxacin at 400 mg/day would successfully treat human infection due to Y. pestis in 99.8% of subjects and would prevent resistance amplification. We conclude that in an in vitro pharmacodynamic model, the clinically prescribed moxifloxacin regimen of 400 mg/day is predicted to be highly effective for the treatment of Y. pestis infections in humans. Studies of moxifloxacin in animal models of plague are warranted.
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High percentage of resistance to ciprofloxacin and qnrB19 gene identified in urinary isolates of extended-spectrum β-lactamase–producing Escherichia coli in Madrid, Spain. Diagn Microbiol Infect Dis 2010; 67:380-3. [DOI: 10.1016/j.diagmicrobio.2010.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/26/2010] [Accepted: 03/16/2010] [Indexed: 11/23/2022]
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Johnsen L, Weigel C, von Kries J, Møller M, Skarstad K. A novel DNA gyrase inhibitor rescues Escherichia coli dnaAcos mutant cells from lethal hyperinitiation. J Antimicrob Chemother 2010; 65:924-30. [PMID: 20228083 DOI: 10.1093/jac/dkq071] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES In order to search for novel antibacterial compounds we used a previously developed screening strain designed specifically to discover inhibitors of the bacterial initiator protein, DnaA. This strain (SF53) is not viable at 30 degrees C due to overinitiation. Therefore, compounds that are able to restore growth to SF53 cells are likely to cause either partial or complete inhibition of DnaA function. In this study we used SF53 cells to screen the Library of Pharmacologically Active Compounds (LOPAC). METHODS An SF53 screen of LOPAC in 384-well plates was performed. The effects of compounds identified as positive were studied further by growth assays specific for replication proteins as well as an in vitro assay of the activity of purified DNA gyrase. RESULTS One of the compounds that tested positive in this screening was the benzazepine derivate (+/-)-6-chloro-PB hydrobromide (S143). We found that the substance did not target DnaA directly, but that it most probably reduces overinitiation by inhibiting DNA gyrase. Benzazepines have not previously been reported as gyrase inhibitors. CONCLUSIONS These findings indicate that a screening with SF53 will be able to identify compounds that also target other replication proteins (in addition to DnaA). Screening of LOPAC with SF53 cells led to the discovery of a novel DNA gyrase inhibitor.
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Affiliation(s)
- Line Johnsen
- Department of Cell Biology, Institute of Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, 0310 Oslo, Norway.
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Singh R, Ledesma KR, Chang KT, Hou JG, Prince RA, Tam VH. Pharmacodynamics of moxifloxacin against a high inoculum of Escherichia coli in an in vitro infection model. J Antimicrob Chemother 2009; 64:556-62. [PMID: 19589810 DOI: 10.1093/jac/dkp247] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Escherichia coli is the leading bacterial species implicated in intra-abdominal infections. In these infections a high bacterial burden with pre-existing resistant mutants are likely to be encountered and resistance could be amplified with suboptimal dosing. Our objective was to investigate the pharmacodynamics of moxifloxacin against a high inoculum of E. coli using an in vitro hollow fibre infection model (HFIM). METHODS Three wild-type strains of E. coli (ATCC 25922, MG1655 and EC28044) were studied by exposing approximately 2 x 10(8) cfu/mL (20 mL) to escalating dosing regimens of moxifloxacin (ranging from 30 to 400 mg, once daily). Serial samples were obtained from HFIM over 120 h to enumerate the total and resistant subpopulation. Quinolone resistance-determining regions of gyrA and parC of resistant isolates were sequenced to confirm the mechanism of resistance. RESULTS The pre-exposure MIC of the three wild-type strains was 0.0625 mg/L. Simulated moxifloxacin concentration profiles in HFIM were satisfactory (r(2) >or= 0.94). Placebo experiments revealed natural mutants, but no resistance amplification. Regrowth and resistance amplification was observed between 30 mg/day (AUC/MIC = 47) and 80 mg/day dose (AUC/MIC = 117). Sustained bacterial suppression was achieved at >or=120 mg/day dose (AUC/MIC = 180). Point mutations in gyrA (D87G or S83L) were detected in resistant isolates. CONCLUSIONS Our results suggest that suboptimal dosing may facilitate resistance amplification in a high inoculum of E. coli. The clinical dose of moxifloxacin (400 mg/day) was adequate to suppress resistance development in three wild-type strains. Clinical relevance of these findings warrants further in vivo investigation.
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Affiliation(s)
- Renu Singh
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX, USA
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Almahmoud I, Kay E, Schneider D, Maurin M. Mutational paths towards increased fluoroquinolone resistance in Legionella pneumophila. J Antimicrob Chemother 2009; 64:284-93. [PMID: 19474069 DOI: 10.1093/jac/dkp173] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Fluoroquinolone resistance has been poorly studied in Legionella pneumophila, an intracellular pathogen responsible for legionellosis. Our goal was to further characterize molecular mechanisms involved in fluoroquinolone resistance in this species. METHODS Eight independent lineages were founded from a common fluoroquinolone-susceptible L. pneumophila ancestor and propagated by serial passages in moxifloxacin-containing culture medium. We identified the substituted mutations that affected the DNA topoisomerase II-encoding genes, determined the order of substitution of the mutations leading to the stepwise MIC increases of moxifloxacin over evolutionary time and demonstrated their direct involvement in the resistance process. RESULTS Adaptation occurred through parallel stepwise increases in the moxifloxacin MICs up to 512-fold the MIC for the parental strain. Mutations affected the topoisomerase II-encoding genes gyrA, parC and gyrB, reflecting a high degree of genetic parallelism across the independent lineages. During evolution, the T83I change in GyrA occurred first, followed by G78D or S80R in ParC and D87N in GyrA, or S464Y or D426N in GyrB. By constructing isogenic strains, we showed that the progressive increase in resistance was linked to a precise order of mutation substitution, but also to the co-existence of several subpopulations of bacteria bearing different mutations. CONCLUSIONS Specific mutational trajectories were identified, strongly suggesting that intermolecular epistatic interactions between DNA topoisomerases underlie the mechanism of fluoroquinolone resistance in L. pneumophila. Our results suggest that L. pneumophila has strong potential to become resistant to fluoroquinolone compounds and warrant further investigation of resistance in clinical and environmental strains of this pathogen.
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Affiliation(s)
- Iyad Almahmoud
- Laboratoire Adaptation et Pathogénie des Micro-organismes, Université Joseph Fourier Grenoble 1, Institut Jean Roget, Campus Santé, Domaine de la Merci, BP 170, F-38042 Grenoble cedex 9, France
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Lysnyansky I, Gerchman I, Perk S, Levisohn S. Molecular Characterization and Typing of Enrofloxacin-Resistant Clinical Isolates of Mycoplasma gallisepticum. Avian Dis 2008; 52:685-9. [DOI: 10.1637/8386-063008-resnote.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Mechanisms accounting for fluoroquinolone resistance in Escherichia coli clinical isolates. Antimicrob Agents Chemother 2008; 53:235-41. [PMID: 18838592 DOI: 10.1128/aac.00665-08] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fluoroquinolone MICs are increased through the acquisition of chromosomal mutations in the genes encoding gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE), increased levels of the multidrug efflux pump AcrAB, and the plasmid-borne genes aac(6')-Ib-cr and the qnr variants in Escherichia coli. In the accompanying report, we found that ciprofloxacin, gatifloxacin, levofloxacin, and norfloxacin MICs for fluoroquinolone-resistant E. coli clinical isolates were very high and widely varied (L. Becnel Boyd, M. J. Maynard, S. K. Morgan-Linnell, L. B. Horton, R. Sucgang, R. J. Hamill, J. Rojo Jimenez, J. Versalovic, D. Steffen, and L. Zechiedrich, Antimicrob. Agents Chemother. 53:229-234, 2009). Here, we sequenced gyrA, gyrB, parC, and parE; screened for aac(6')-Ib-cr and qnrA; and quantified AcrA levels in E. coli isolates for which patient sex, age, location, and site of infection were known. We found that (i) all fluoroquinolone-resistant isolates had gyrA mutations; (ii) approximately 85% of gyrA mutants also had parC mutations; (iii) the ciprofloxacin and norfloxacin MICs for isolates harboring aac(6')-Ib-cr ( approximately 23%) were significantly higher, but the gatifloxacin and levofloxacin MICs were not; (iv) no isolate had qnrA; and (v) approximately 33% of the fluoroquinolone-resistant isolates had increased AcrA levels. Increased AcrA correlated with nonsusceptibility to the fluoroquinolones but did not correlate with nonsusceptibility to any other antimicrobial agents reported from hospital antibiograms. Known mechanisms accounted for the fluoroquinolone MICs of 50 to 70% of the isolates; the remaining included isolates for which the MICs were up to 1,500-fold higher than expected. Thus, additional, unknown fluoroquinolone resistance mechanisms must be present in some clinical isolates.
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