Molecular characteristics of extended spectrum β-lactamase and carbapenemase genes carried by carbapenem-resistant Enterobacter cloacae in a Chinese university hospital

Background/aim: In recent years, the increase in the prevalence of carbapenem-resistant Enterobacter cloacae (CREC) has been significant and has become a global problem. The aim of this study is to characterize CREC extended spectrum beta-lactamases (ESBLs) and CREC carbapenemase genes and evaluate the risk factors for CREC infections in a university hospital in China. Materials and methods: The identification and assessment of the antimicrobial susceptibility of CREC isolates were performed using a VITEK-2 compact system. Clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE). beta-Lactamase genes were examined using polymerase chain reaction and nucleotide sequencing. Results: A total of 64 CREC isolates were included in the study. The rate of CREC infections significantly increased between 2009 and 2012. Among the CREC isolates, 39 (60.9%) isolates possessed ESBL genes, and 49 (76.6%) carried carbapenemase genes; blaSHV-12 and blaKPC-2 were the most common genes, respectively. PFGE showed that there were no obvious clonal associations between these CREC isolates, except for 3 isolates. A univariate analysis demonstrated that prior treatment with antibiotics, intravascular catheterization, urinary catheterization, mechanical ventilation, and parenteral nutrition were significant risk factors for CREC infections. Conclusion: The emergence and increase of CREC infections is worrisome. Effective measures should be taken to control the spread of CREC.