Linezolid resistance mechanisms and molecular epidemiology of clinical isolates of methicillin-resistant coagulase-negative staphylococci
10.3760/cma.j.issn.0254-5101.2012.06.010
- VernacularTitle:耐甲氧西林凝固酶阴性葡萄球菌对利奈唑胺的耐药机制及分子流行病学研究
- Author:
Jiachang CAI
;
Hongwei ZHOU
;
Yanyan HU
;
Rong ZHANG
;
Gongxiang CHEN
- Publication Type:Journal Article
- Keywords:
Staphylococci;
Linezolid;
Antibiotic resistance;
23S rRNA;
cfr
- From:
Chinese Journal of Microbiology and Immunology
2012;32(6):532-536
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the linezolid resistance mechanisms and molecular epidemiology of clinical isolates of methicillin-resistant coagulase-negative staphylococci (MRCoNS).Methods Seventeen MRCoNS,including 10 S.capitis,4 S.cohnii,2 S.haemolyticus,and 1 S.sciuri with various levels of linezolid resistance were isolated from intensive care units in our hospital from March to August 2011. Minimal inhibitory concentration (MIC) was determined by E-test method. Pulsed-field gel electrophoresis was performed to analyze the molecular epidemiology.PCRs and DNA sequencing were preformed to investigate the mechanisms of linezolid resistance in MRCoNS.Results Nine S.capitis with linezolid MIC of ＞256 μg/ml were indistinguishable,and another S.capitis with linezolid MIC of 4 μg/ml was closely related.Four S.cohnii with linezolid MIC of ＞256 μg/ml were belonged to the same clonal strain.MIC of linezolid for S.sciuri was 64 μg/ml,and were 4 μg/ml and 6 μg/ml for 2 S.haemolyticus,respectively.A commom G2576T mutation and a novel C2104T mutation were identified in 9 S.capitis with linezolid MIC of ＞256 μg/ml by DNA sequence analysis of domain V of the 23S rRNA gene.cfr gene was deteeted in all staphylococci except a S.sciuri whose 23S rRNA gene contained the G2576T mutation.Conclusion It is the first report of linezolid-resistant clinical isolates of staphylococci in China.Linezolid resistance in MRCoNS is related to the presence of DNA mutation in domain V of the 23S rRNA gene and cfr gene.It's a clonally dissemination of linezolid-resistant MRCoNS in intensive care units of our hospital.
