Prevalence and drug-resistant characteristics of aac ( 6' ) -Ib- cr gene in common enterobacteriaceae clinical isolates

Abstract

Objective To investigate the prevalence of aac (6')-Ib-cr gene in clinical isolates of Klebsiella pneumoniae and Escherichia coli,and analyze the drug-resitant charactcristios of positive aac ( 6' ) - ib- cr isolates of fluoroquinolones,aminoglyeosides and cephalosporins.Methods aac ( 6' ) -Ib gene were detected by PCR.Positive PCR products of aac(6')-Ib were digested with BtsCI and sequencing to identify aac(6')-Ib-cr; analyze the resistance to fluoroquinolones,aminoglycosides and cephalosporins in isolates containig aac( 6 ' ) -Ib-cr gene with statistical methods.Results aac( 6' ) -Ib -cr gene was detected in 12.6 ％ ( 3 0 / 2 3 8 ) of Klebsiella pneumoniae isolates and 18.8 ％ ( 1 3 / 6 9 ) of Escherichia coli isolates; the resistance rates of ciprofloxacin in positive and negative aac (6')-Ib-cr isolates were 72.1％ (31/43) and 48.1％ (127/264),the difference was statistically significant (x2 =8.52,P ＜ 0.05 ).The resistance rate of amikacin in positive aac ( 6' ) -Ib-cr of Klebsiella pneumoniae isolates was significantly higher than negative isolates(x2 =4.25,P ＜ 0.05 ).All the isolates displayed a high resistant rate to gentamicin and cephalosporins which else showed multidrug resistance,regardless the carrying of aac (6')-Ib-cr gene,which showed no significant difference.Conclusion In the region,aac (6')-Ib-cr gene was both detected in Klebsiella pneumoniae and Escherichia coli clinical isolates; The resistance rate to ciprofloxacin in positive aac (6')-Ib-cr isolates was significantly higher than negative isolates,so did to amikacin in Klebsiella pneumonia isolates,which had statistical significance,the resistance rate and the multiple resistance rate of common used cephalosporins in whether positive or negative aac(6')-Ib-cr isolates were high,which has no statistically significant. Key words: Ciprofloxacin; aac( 6')-Ib-cr; Multidrug resistance