Characteristics of OXA-48-Producing Escherichia coli, Enterobacter cloacae and Klebsiella oxytoca from a Chinese Hospital

Objectives: The OXA-48-like enzymes are mainly produced by various enterobacteriaceae. The aim of this study was to investigate the characteristics of OXA-48-producing Escherichia coli, Enterobacter cloacae and Klebsiella oxytoca from China.
Methods: Carbapenemase genes (bla_VIM, bla_OXA-48, bla_KPC, bla_IMPand bla_NDM) were screened by PCR and subsequent amplicons sequencing. Genetic relationship was investigated by pulsed field gel electrophoresis and multilocus sequence typing. The size and incompatibility types of bla_OXA-48-carrying plasmids were analyzed by the S1-PFGE, Southern blot and multiple PCR.
Results: Several OXA-48-producing enterobacterial isolates were collected, including three E. coli, three E. cloacae and one K. oxytoca. All isolates exhibited low-levels of carbapenem resistance or even were susceptible to imipenem and meropenem. The E. coli isolates belonged to ST156, ST648 and ST3554, while the E. cloacae were ST418 and ST414, respectively. All isolates harbored the same ~60 kb IncL/M bla_OXA-48-carrying plasmid.
Conclusions: This is the first report of OXA-48-producing E. cloacae ST414 and ST418 worldwide, and OXA-48- producing K. oxytoca in China. Although the bla_OXA-48 gene prevalence is at a low frequency in China, the blaOXA-48- carrying plasmid has spread among different enterobacteriaceae species.