title: Detection of metallo-β-lactamase genes in clinically isolated Klebsiella pneumoniae and Klebsiella oxytoca.
abstract: We detected and characterized metallo-β-lactamase genes (blaIMP-1 and blaIMP-11) in third generation cephalosporin-resistant Klebsiella pneumoniae and Klebsiella oxytoca isolated at Showa University Hospital between January 1, 2011 and December 31, 2012. The cephalosporin-resistant K pneumoniae strains were frequently isolated from the urine, while one strain of K. pneumoniae, which was resistant to carbapenem, was isolated from the stool. We analyzed the phenotypes and genotypes of the metallo-β-lactamase genes from the 16 strains of cephalosporin-resistant-K pneumoniae and 6 strains of -K. oxytoca isolated from the same ward. The minimum inhibitory concentrations of imipenem were below 4 µg/ml in 21 out of the 22 isolated strains. The double disc synergy test using ceftazidime and sodium mercaptoacetic acid revealed enlargements in the inhibitory zones of 14 of the 16 strains of K. pneumoniae and all 6 strains of K. oxytoca. Metallo-β-lactamase genes were detected in all of the tested strains, with blaIMP-1 in 3 K. pneumoniae and 1 K. oxytoca, blaIMP-11 in 13 K pneumoniae and 4 K. oxytoca, and both blaIMP-1 and blaIMP-11 in one K. oxytoca. Our results indicate that third generation cephalosporin-resistant and imipenem-susceptible K. pneumoniae and K. oxytoca possess the metallo-β-lactamase gene. The active surveillance of metallo-β-lactamase genes should be performed in clinical laboratories. (Original).
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Tateno
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yasuhara
authors.forename: Emi
authors.initials: E
authors.lastname: Sugano
authors.forename: Sachiko
authors.initials: S
authors.lastname: Tahara
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Ugajin
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Fukuchi
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015780:Carbapenems / Q000494:pharmacology; D005838:Genotype; D006801:Humans; D041121:Klebsiella oxytoca / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D001618:beta-Lactamases