Study On Detection Of AmpC Enzyme And Analysis Of AmpC Gene In Enterobacter Cloacae

Objective To investigate the status of resistance and the influence of the expression of high-level AmpC β-lactamase of Enterobacter Cloacae from Kunming. To discuss the relationship between drug resistance and AmpC gene . Methods K—B tests were performed to detect the susceptibility of antimicrobial agents, AmpC β -lactamase in Enterobacter Cloacae was detected by three-dimensional test ,phenotype screening method ,FCC double inhibitors diffused synergy test.The ampC and ampD Gene was detected by PCR.Gene mutation was detected by DNA sequencing. Result The sensitive rates of 74 strains olny to Impenam and Cefepime was high , but to other antimicrobial agents were lower. the detection rate of high-level AmpC β -lactamase were 28.4%, 35.1%,37.8% by three-dimensional test,phenotype screening method , FCC double inhibitors diffused synergy test, respectively .Three method has not significantly difference. The drug resistant rates of strains producing AmpC β-lactamase was significantly lower than that of strains not producing AmpC β-lactamase. The rate of positive ampC and ampD Gene were 89.2%,86.5%, respectively. The necleotide sequences and deduced amino acid sequences of 4 high-level AmpC β-lactamase strains were compared with E .cloacae p99. The sequences of strains showed homologous of 99% with E .cloacae p99 and their deduced amino acid sequences had site directed mutagenesis of Ala-58-Pro . Compared with E.cloacael4, the ampD genes of 4 high-level AmpC β-lactamase strains had point mutations and amino acid alterations such as Phe-63→ Tyr,Ala-68→Ser, Met-101→ Lys.Conclusion The resistant status of Enterobacter Cloacae from Kunming is severe. The important reason of drug resistant was the high level high-level AmpC β-lactamase produced by Enterobacter Cloacae. Compared with three-dimensional test, phenotype screening andFCC double inhibitors diffused synergy test has not significantly difference and can be easy to use in clinical laboratories. The existent of structure gene ampC was aboard in Enterobacter Cloacae and the mutation regulative gene ampD of Enterobacter Cloacae may be associated with its drug resistance.