Emergence of blaNDM-1 among Klebsiella pneumoniae ST15 and novel ST1031 clinical isolates in China

Abstract

The emergence of NDM-1 has become established as a major public health threat and represents a new and major challenge in the treatment of infectious diseases. A total of 39 carbapenem-resistant Enterobacteriaceae isolates collected from patients receiving care at 5 teaching hospitals in Jiangxi province, central China, were analyzed for carriage of resistance genes, including blaNDM-1. Two carbapenem-resistant Klebsiella pneumoniae isolates (NC12 and NC18) were found to harbor blaNDM-1. In addition to blaNDM-1, NC12 also carried blaSHV-1, while NC18 harbored additional resistance genes, including blaSHV-12, blaCTX-M-14, armA and blaTEM-1. NC12 and NC18 belonged to ST15 and novel ST1031 and were clonally unrelated. Carbapenem resistance for NC12 could be transferred to Escherichia coli recipients through conjugation and chemical transformation, while carbapenem resistance for NC18 was only transferred to E. coli recipients by chemical transformation. The EcoR1-digested DNA pattern of plasmids from the transformants of NC12 was identical to that for NC18. Taken together, this is the first report of blaNDM-1 carriage by K. pneumoniae clinical isolates in mainland China, indicating that blaNDM-1 is disseminated among Enterobacteriaceae in China. Systemic surveillance should focus on the dissemination of blaNDM-1 among Gram-negative clinical isolates, especially some major clones, such as K. pneumoniae ST15 which is a major clone among CTX-M-15–producing isolates.