Metallo-beta-lactamase-producing Enterobacteriaceae isolates in a university hospital in Taiwan: prevalence of IMP-8 in Enterobacter cloacae and first identification of VIM-2 in Citrobacter freundii.
A total of 9082 clinical isolates of Enterobacteriaceae other than Klebsiella spp. collected in 1999 and 2000 at a university hospital in Taiwan were investigated for the production of metallo- beta-lactamases (MBLs). Thirty-six (2.9%) of the 1261 Enterobacter cloacae isolates and one (0.3%) of the 340 Citrobacter freundii isolates were found to carry bla(IMP-8) and bla(VIM-2), respectively, by colony hybridization, PCR and sequence analysis. The IMP-8 producers were recovered from 20 patients and four of them had recently transferred from other hospitals, implying spread of IMP-8-producing E. cloacae among different healthcare settings. Of the 20 non-repetitive IMP-8 producers, 17 (85%) isolates also harboured bla(SHV-12), which was on the same transferable plasmids with bla(IMP-8). The bla(VIM-2)-positive isolate and all non-repetitive bla(IMP-8)-positive isolates appeared susceptible to imipenem (MICs < 8 mg/L) and meropenem (MICs < 4 mg/L), indicating the difficulty in detection of MBLs in Enterobacteriaceae by routine susceptibility testing. Ribotyping of the IMP-8-producing E. cloacae isolates indicated that the dissemination of bla(IMP-8) was due largely to the spread of an epidemic clone, but horizontal transfer among unrelated strains also occurred.
D016971:Citrobacter freundii / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D016972:Enterobacter cloacae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004755:Enterobacteriaceae / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000706:statistics & numerical data; D013624:Taiwan / Q000453:epidemiology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
C436760:IMP-8 enzyme; C425108:beta-lactamase bla(vim-2); D001618:beta-Lactamases