Dataset Information

Molecular characteristics of ofloxacin mono-resistant Mycobacterium tuberculosis isolates from new and previously treated tuberculosis patients.

ABSTRACT: BACKGROUND:Ofloxacin (OFX) resistant Mycobacterium tuberculosis (MTB) isolates have been increasingly observed and are a major concern in recent years. This study investigated the genetic mutations associated with OFX resistance among clinical OFX mono-resistant MTB isolates from new and previously treated tuberculosis patients. METHODS:A total of 50 unrelated OFX mono-resistant MTB isolates were analyzed. For all isolates, the quinolone resistance determining regions of gyrA and gyrB were PCR amplified and sequenced. RESULTS:Single mutations in the quinolone resistance determining regions of gyrA (positions D94A, G, N, and Y; A90V; and S91P) and gyrB (positions T539A and E540D) were observed in 62% (31/50) and 4% (2/50) of all OFX mono-resistant isolates, respectively. No differences were detected between the proportions of isolates with mutations in gyrA/gyrB from new and previously treated tuberculosis patients (P=.820). CONCLUSIONS:Although mutations in gyrB were rare, they were as important as mutations in gyrA in predicting OFX resistance in MTB in Tianjin, China.

SUBMITTER: Wang Z

PROVIDER: S-EPMC6817024 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

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Molecular characteristics of ofloxacin mono-resistant Mycobacterium tuberculosis isolates from new and previously treated tuberculosis patients.

Wang Zhirui Z Xie Tong T Mu Cheng C Wang Chunhua C Ju Hanfang H Zhao Hui H Sun Rui R

Journal of clinical laboratory analysis 20170320 1

<h4>Background</h4>Ofloxacin (OFX) resistant Mycobacterium tuberculosis (MTB) isolates have been increasingly observed and are a major concern in recent years. This study investigated the genetic mutations associated with OFX resistance among clinical OFX mono-resistant MTB isolates from new and previously treated tuberculosis patients.<h4>Methods</h4>A total of 50 unrelated OFX mono-resistant MTB isolates were analyzed. For all isolates, the quinolone resistance determining regions of gyrA and ...[more]

PMID: 28317169

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Project description:Carbapenem-resistant Enterobacterales (CRE), specifically those resistant to only ertapenem among carbapenems (ETP-mono-resistant), are increasingly reported, while the optimal therapy options remain uncertain. To investigate the prevalence and characteristics of ETP-mono-resistant CRE, CRE strains were systematically collected from 102 hospitals across China between 2018 and 2021. A 1:1 randomized matching study was conducted with ETP-mono-resistant strains to meropenem- and/or imipenem-resistant (MEM/IPM-resistant) strains. Antimicrobial susceptibility testing, whole-genome sequencing, carbapenem-hydrolysing activity and the expression of carbapenemase genes were determined. In total, 18.8% of CRE strains were ETP-mono-resistant, with relatively low ertapenem MIC values. ETP-mono-resistant strains exhibited enhanced susceptibility to β-lactams, β-lactam/β-lactamase inhibitor combinations, levofloxacin, fosfomycin, amikacin and polymyxin than MEM/IPM-resistant strains (P < 0.05). Phylogenetic analysis revealed high genetic diversity among ETP-mono-resistant strains. Extended-spectrum β-lactamases (ESBLs) and/or AmpC, as well as porin mutations, were identified as potential major mechanisms mediating ETP-mono-resistance, while the presence of carbapenemases was found to be the key factor distinguishing the carbapenem-resistant phenotypes between the two groups (P < 0.001). Compared with the MEM/IPM-resistant group, limited carbapenemase-producing CRE (CP-CRE) strains in the ETP-mono-resistant group showed a significantly lower prevalence of ESBLs and porin mutations, along with reduced expression of carbapenemase. Remarkably, spot assays combined with modified carbapenem inactivation method indicated that ETP-mono-resistant CP-CRE isolates grew at meropenem concentrations eightfold above their corresponding MIC values, accompanied by rapidly enhanced carbapenem-hydrolysing ability. These findings illustrate that ETP-mono-resistant CRE strains are relatively prevalent and that caution should be exercised when using meropenem alone for treatment. The detection of carbapenemase should be prioritized.

Dataset Information

Molecular characteristics of ofloxacin mono-resistant Mycobacterium tuberculosis isolates from new and previously treated tuberculosis patients.

Publications

Molecular characteristics of ofloxacin mono-resistant Mycobacterium tuberculosis isolates from new and previously treated tuberculosis patients.

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