New Delhi Metallo-β-Lactamase 1(NDM-1), the Dominant Carbapenemase Detected in Carbapenem-Resistant Enterobacter cloacae from Henan Province, China.
PLoS One. 2015 Aug 11;10(8):e0135044.
Liu C1, Qin S2, Xu H1, Xu L1, Zhao D2, Liu X3, Lang S4, Feng X1, Liu HM2.
1Department of clinical laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, PR China; Henan province Key Laboratory of Medicine, Zhengzhou, PR China.
2School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, PR China.
3Department of clinical laboratory, The central hospital of Zhumadian city, Zhumadian, PR China.
4Department of clinical laboratory, The central hospital of Sanmenxia city, Sanmenxia, PR China.
The emergence of New Delhi metallo-β-lactamase 1 (NDM-1) has become established as a major public health threat and represents a new challenge in the treatment of infectious diseases.
In this study, we report a high incidence and endemic spread of NDM-1-producing carbapenem-resistant Enterobacter cloacae isolates in Henan province, China.
Eight (72.7%) out of eleven non-duplicated carbapenem-resistant E. cloacae isolates collected between June 2011 and May 2013 were identified as NDM-1 positive.
The blaNDM-1 gene surrounded by an entire ISAba125 element and a bleomycin resistance gene bleMBL in these isolates were carried by diverse conjugatable plasmids (IncA/C, IncN, IncHI2 and untypeable) ranging from ~55 to ~360 kb.
Molecular epidemiology analysis revealed that three NDM-1-producing E. cloacae belonged to the same multilocus sequence type (ST), ST120, two of which were classified as extensively drug-resistant (XDR) isolates susceptible only to tigecycline and colistin.
The two XDR ST120 E. cloacae isolates co-harbored blaNDM-1, armA and fosA3 genes and could transfer resistance to carbapenems, fosfomycin and aminoglycosides simultaneously via a conjugation experiment.
Our study demonstrated NDM-1 was the most prevalent metallo-β-lactamase (MBL) among carbapenem-resistant E. cloacae isolates and identified a potential endemic clone of ST120 in Henan province.
These findings highlight the need for enhanced efforts to monitor the further spread of NDM-1 and XDR ST120 E. cloacae in this region.