Mechanism of resistance and antibacterial susceptibility in ESBL-phenotype Klebsiella pneumoniae and Klebsiella oxytoca isolated between 2000 and 2010 in Japan.

Mechanism of resistance and antibacterial susceptibility in ESBL-phenotype Klebsiella pneumoniae and Klebsiella oxytoca isolated between 2000 and 2010 in Japan. J Med Microbiol. 2015 Mar 26; Authors: Sato T, Hara T, Horiyama T, Kanazawa S, Yamaguchi T, Maki H Abstract Clinical isolates of Klebsiella pneumoniae and Klebsiella oxytoca collected from 20 Japanese medical facilities between 2000 and 2010 were analyzed to evaluate the mechanisms of resistance and antibacterial susceptibilities to 14 antimicrobials. Overall, 8 of 484 (1.6%) K. pneumoniae and 19 of 359 (5.3%) K. oxytoca were determined to be extended-spectrum β-lactamase (ESBL)-phenotype isolates, and the identified ESBLs among the K. pneumoniae isolates were CTX-M-2, -3, -14, and -15 and SHV-12. In contrast, overproduction of chromosomal β-lactamase OXY-2, which was due to a distinct mutation at -10 promoter regions of this gene, conferred the ESBL-phenotype to all the K. oxytoca isolates except one. Based on the CLSI breakpoints, all the ESBL-phenotype K. pneumoniae were susceptible to doripenem, flomoxef, moxalactam (latamoxef), cefmetazole and tazobactam/piperacillin, whereas the ESBL-phenotype K. oxytoca were susceptible to ceftazidime and ceftibuten in addition to the above, with the exception of tazobactam/piperacillin. Among the oral antimicrobials, ceftibuten was relatively effective against both ESBL-phenotype Klebsiella species compared with levofloxacin and amo...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research