Drug-resistance of Enterobacter cloacae and Its Genes Encoding Aminoglycosides Modifying Enzymes / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To investigate the drug-resistance of Enterobacter cloacae(ECL) and its carrying rate of gene encoding aminoglycosides modifying enzymes(AMEs).METHODS Totally 132 clinically isolated ECL strains were identified with VITEK-32.Their drug susceptibility was tested with K-B disc diffusion.The presence of ESBLs and AmpC was tested with three dimensional test.The genes encoding AMEs were detected with PCR and confirmed by sequence.RESULTS All strains of ECL were susceptible to IMP and MER.The resistance rate to AMK,LVX,FEP,CFS and CIP was 21.2%,35.6%,37.9%,46.2% and 48.5%,respectively with gradually increasing.Their resistance rate to other antibiotics ranged from 50.0% to 87.7%.Among 132 strains of ECL,45 strains producing ESBLs,accounted for 34.1%,27 strains producing AmpC,accounted for 20.5%,11 strains producing ESBLs and AmpC,accounted for 8.3% and 49 strains producing neither ESBLs nor AmpC,accounted for 37.1%.Seven strains without positive detection of ESBLs were resistant to CTX and CAZ,but carried the genes of resistance to TEM and SHV.The detection rate of genes encoding AMEs was about 62.1%,among which subtypes of aac(6′)-Ⅰb dominated with detection rate of 51.5%.Meanwhile the detection rate of subtype aac(3)-Ⅰ,aac(3)-Ⅱ,aac(6′)-Ⅱ,ant(3″)-Ⅰ,ant(2″)-Ⅰ and aph(3′)-Ⅵ was 15.9%,12.9%,18.9%,37.1%,6.8% and 9.8%,respectively.The detection rate of carrying more than two types of AMEs was about 89.0%.There were 5 strains of presenting phenotypic resistance without detection of genes encoding AMEs.CONCLUSIONS The clinically isolated ECL strains are not only severe resistant to drug and but also multi-drug resistant.The carrying rate of genes encoding ESBLs,AmpC and AMEs is higher than estimated which is the leading cause of resistance to antibiotics.