Study on the characteristics of clinical distribution and extended spectrum β-lactamases mediated antimicrobial resistance in Klebsiella pneumoniae

Objective To investigate the characteristics of clinical distribution and extended spectrum β-lactamases(ESBLs)mediated antimicrobial resistance in Klebsiella pneumoniae(K.pneumoniae). Methods Antimicrobial susceptibility tests, screening and confirmatory tests for ESBLs were done by Kirby-Bauer disk diffusions method, WHONET 5.4 software was used for data statistic analysis. Results A total of 336 strains of nonrepetitive K.pneumoniae were isolated betweem January 2008 and December 2010. Strains isolated from lower respiratory tract secretion, urine and blood were 149(44.3%),41(12.2%) and 40(11.9%) respectively. Infections with K.pneumoniae occurred in the department of hepatobiliary surgery, department of infective diseases and department of intensive care unit were 19.3%, 16.1% and 11.9% respectively. The total incident rate of ESBLs producing strains was 43.8%(147/336). ESBLs producing strains were resistant to most antimicrobial agents, and the resistant rates of them were significantly higher than that of the non-ESBLs producers(P 0.05). Conclusions K. pneumoniae cause principally infections of lower respiratory tract in clinic. ESBLs is one of the main mechanisms in which K. pneumoniae resist to β-lactams. ESBLs producing strains have the characteristic of multidrug resistant phenotypes. The antimicrobial agents for treating infections caused by K. pneumonia should be chosen according to the results of the antimicrobial susceptibility and ESBLs confirmatory tests.