Dissemination of extensively drug-resistant and KPC-2 producing Klebsiella pneumoniae isolated from bloodstream infections.

INTRODUCTION Bloodstream infections (BSIs) are serious diseases associated with high mortality, especially when caused by extensively drug-resistant (XDR) Klebsiella pneumoniae. The prevalence and pandemic strains of extended-spectrum beta-lactamase (ESBL)-producing K. pneumoniae isolated from blood cultures of patients with BSIs were determined at Sir Run Run Shaw Hospital, China. METHODOLOGY A total of 24 XDR K. pneumoniae were isolated from blood cultures, and the clinical data of the patients were analyzed retrospectively. Bacterial species identification and antimicrobial susceptibility testing were performed using VITEK2 and E-test methods, respectively. Common ESBL-resistant genes were amplified and sequenced after the validation of a modified Hodge test. Strain homology was also analyzed by pulsed-field gel electrophoresis (PFGE). RESULTS All of the isolates were resistant to 10 antimicrobial agents. Several strains showed partial sensitivity to aminoglycosides, but all showed sensitivity to polymyxin and tigecycline. All strains were Klebsiella pneumoniae carbapenemase (KPC-2) producing, and carried two or three ESBL-resistant genes, which belonged to 13 PFGE clones (A-M). The overall mortality rate in patients was as high as 29.2%. CONCLUSIONS KPC-2-producing K. pneumoniae BSIs are associated with high mortality rates. Our observations suggest that KPC-2 and ESBL-producing K. pneumoniae might be responsible for the clonal dissemination of extensively drug-resistant isolates in our hospital.