Extended Spectum β-Lactamases Producing E.coli and K.pneumoniae:Their Distribution and Resistance to Antimicrobial Agent

OBJECTIVE To investigate the prevalence and resistance of extended spectram β-lactamases(ESBLs) producers in Escherichia coli and Klebsiella pneumoniae.METHODS ESBLs producing strains were screened by double disk test and confirmed by the NCCLS confirmatory test.Susceptibility test to antimicrobial agents was performed by disk diffusion method and analyzed by WHONET 5.3 and Excel.RESULTS The isolated ratio of ESBLs producing E.coli and K.pneumoniae increased from 14% and 15% in 1999 to 30.1% and 30.4% in 2002.Bacteremia caused by the two kinds of ESBLs producers accounted for 30.2% and 30.4%,respectively.ESBLs producing K.pneumoniae and(ESBLs) producing E.coli were 19.8% and 14.0% for outpatient and 26.6% and 31.6% for inpatient.The resistance of(E.coli) to 17 kinds of agents was similar,no matter it was isolated from blood,urine or sputum.Susceptibility of(ESBLs) producing E.coli and K.pneumoniae in urine to cefoperazone/sulbactam,and piperacillin/tazobactam were 85% and 65.2%,66.6% and 29.4%,although to other 15 agents there were no difference.None of the(isolates) showed resistance to imipenem.CONCLUSIONS There is an increasing trend of ESBLs producing E.coli and K.pneumoniae(isolated) from various kinds of specimens and from different wards.It is important for clinical physicians to understand the distribution and the resistance characteristics of ESBLs producing E.coli and(K.pneumoniae) to antibiotics.