Identification of an NDM-5-producing Escherichia coli Sequence Type 167 in a Neonatal Patient in China

Emergence of New Delhi metallo-β-lactamase-producing Enterobacteriaceae has become a challenging threat to public health. Two carbapenem-resistant Escherichia coli, strain QD28 and QD29, were recovered from the aspirating sputum of a neonate and the urine of an adult in a Chinese hospital in 2013. Molecular typing revealed that both isolates belonged to the sequence type 167, but they were clonally diverse. Both isolates exhibited resistance to carbapenems, cephalosporins, ciprofloxacin, gentamicin, piperacillin-tazobactam and trimethoprim-sulfamethoxazole. In addition, strain QD28 was also resistant to aztreonam, and strain QD29 was resistant to amikacin, fosfomycin and minocycline. Antimicrobial resistance gene screening revealed that strain QD28 harbored aac(6′)-Ib, bla(CTX-M-14), bla(NDM-5), bla(TEM-1) and sul1 genes, and strain QD29 harbored aac(6′)-Ib, bla(CTX-M-3), bla(NDM-5), bla(TEM-1), rmtB, sul1 and sul2 genes. The bla(NDM-5) gene was found to be located on a 46-kb plasmid in two isolates, and further sequence analysis showed that this plasmid was highly similar to the previously reported IncX3 plasmid pNDM-MGR194 in India. This is the first identification of bla(NDM-5)-carrying E. coli in the neonatal infection.