Detection and analysis of bacteria producing extended spectrum β-lactamases in children with lower respiratory tract infection.

OBJECTIVE To investigate the distribution and resistance of extended spectrum β-lactamases(ESBLs) producing bacteria in children with lower respiratory tract infection.METHODS Totally 148 strains of Klebsiella pneumoniae and Escherichia coli were isolated from the sputum specimens which collected from lower respiratory tract infection of children in our hospital from Jan 2007 to Sep 2009.ESBLs-producing strains were detected and their susceptibilities to all antimicrobial agents were determined according to criteria of CLSI.RESULTS Among the isolated 51 strains of ESBLs-producing bacteria(34.5%),35 strains were of K.pneumoniae(36.1%) and 16 strains of E.coli(31.4%).The resistant rate of ESBLs-producing strains to most antibiotics was higher than that of non ESBLs-producing strains.The drug-resistance rates of ESBLs-producing strains against amoxicillin,ticarcillin,piperacillin,cefalothin,cefuroxime,cefotaxime,ceftazidime,and cefepime were 100.0%.To ESBLs-producing K.pneumoniae and E.coli,carbapenems(imipenem and meropenem) were the most active antimicrobial agents(all 100.0% susceptible).The susceptibility of ESBLs-producing K.pneumoniae and E.coli to piperacillin-tazobactam,amikacin,ciprofloxacin and cefoxitin was 100.0% and 93.7%,94.3% and 81.2%,91.4% and 62.5%,82.9% and 75.0,respectively%.CONCLUSIONS ESBLs-producing K.pneumoniae and E.coli are important pathogenic bacteria in lower respiratory tract infections in children.There is a multi-drug resistance to the varied antibiotics.The first choice to treat ESBLs producting bacteria,is to select carbapenem antibiotics.