Characterization of extended spectrum β-lactamase-producing Klebsiella pneumoniae from Beijing, China

Fourteen clinical isolates of Klebsiella pneumoniae with extended-spectrum beta -lactamases (ESBLs) were detected by the double disk synergy test and the Etest ESBL strip. Co-resistances included high MICs for aminoglycosides, fluoroquinolones, tetracyclines, and trimethoprim/sulphamethoxazole. Co-resistance was not observed in five of the 14 strains. These isolates were all genetically distinct as determined by the automated ribotyping method. Isoelectric focusing documented the presence of multiple beta -lactamases (one to four per isolate) with pIs ranging from 5.4 to 8.4. The majority of isolates contained beta -lactamases with pI values of 7.6 and 8.4 consistent with SHV-type ESBLs and an Amp C enzyme, respectively. Emerging ESBL strains in K. pneumoniae compromise the use of agents such as cefotaxime, ceftriaxone, ceftazidime in China; leading to the expansion of quality infection control practices and formulary management programmes to minimize clonal expansion. (C) 2001 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.