Relationship of multidrug-resistant gene and extended-spectrum carbapenem-resistance in Staphylococcus aureus

摘要

The aim of this study was to determine the relationship between phenotypic antimicrobial susceptibility patterns and extended-spectrum,carbapenem-resistance genes.A total of 109 clinical Staphilococcus aureus strains were subjected to 19 antimicrobial susceptibility tests.Resistance to methicillin(mecA),penicillin(blaTEM),and tetracycline(tetM)was detected.We compared the presence of the blaTEM genes with extended-spectrum,carbapenem-related genes and identified the types of SCCmec genes.Of 109 clinical S.aureus strains,62(56.88%)had methicillin resistance and 60 strains carried mecA.The prevalence of blaTEM and tetM genes was 81.65%and 37.61%,respectively.The most predominant SCCmec type was SCCmec type Ⅱ 28/60(46.67%),in 60 mecA-positive methicillin-resistant S.aureus(MRSA)isolates.The SCCmec prevalence rates were type ⅣA 30.00%(18/60),type Ⅳb 8.33%(5/60),type Ⅳd 6.67%(4/60),and non-typable 8.33%(5/60).Sixty of the 109(55.05%)MRSA isolates were positive for extended-spectrum carbapenems(31/60)(51.67%),cephalosporins 40/60(66.67%)and carbapenems 31/60(51.67%).The predominant SCCmec type II demonstrated more carbapenem-resistance than the ⅣA,Ⅳb and Ⅳd types.