The study of plasmid-mediated quionlone resistance gene qnr in Enterobacteriaceae / 中华检验医学杂志

ABSTRACT

Objective To explore distribution and genetypes of plasmid-mediated quionlone resistance genes qnrA.qnrB and qnrS in Enterobacteriaceae isolates iu Renmin Hospital of Wuhan University.Methods The qnrA,qnrB and qnrS genes in Enterobaeteriaceae isolates including nonrepetitive 129 isolates of E.coli.13 isolates of E.cloacae and 37 isolates of k pneunoniae were detected by PCR.Antibiotic suseeptibility testing for 15 antibiotics were also performed by K.B in virto.MICs of ciprofloxacin were determined by agar dilution methed.Plasmid conjugatable test wag applied to examine whether qnrA,qnrB and qnrS genes were located in conjugatable plasmid.For qnr-positive strains,integrase I and SHV-1,TEM-1,CTX-M,OXA-I,OXA-Ⅱ,OXA-Ⅲ,DHA and EBC β-lactamases genes were examined.Results 25 qnr-positive isolates were detected among 179 Enterobaeteriaceae isolates,including 6 qnrA-positive isolates,9 qnrB-positive isolates and 10 qnrS-positive isolates,which were presented in 3.35%.5.02%,and 5.59%respectively.All positive isolates were susceptible to imipenem but resistance to some other drugs.2 qnrA-positive isolates and 4 qnrB-positive isolates of them were susceptible to Quinolones.The plasmid wag eonjugatable in 2 qnrA-positive isolates and 4 isolates carrrying qnrB and qnrS.23 qnrA-positive isolates harbored type 1 Integrase,but one isolate with both qnrB and qnrS did not carry Type 1 Integrage.14 isolates of them were TEM-1 producing strains.6 isolates were OXA-Ⅲ-producing strains.and 7 isolates of them were EBC-producing strains.Conciusions In HuBei province,a low prevalence of qnrA,qnrB and qnrS wag determined in Enterebacteriaceae isolates.Muhidrng-resistance was found in qnr-pesitive isolates and qnr genes were detected in quinolone susceptible strains.Extendedspectrum β-lactamages could be presented in qnr-positive isolates too.