First Reported Nosocomial Outbreak Of NDM-5-Producing Klebsiella pneumoniae In A Neonatal Unit In China

Purpose: Carbapenem-resistant Klebsiella pneumoniae (CRKP) have emerged worldwide and also being a major threat to children and neonate. In this study, we describe a nosocomial outbreak of NDM-5-producing Klebsiella pneumoniae in neonatal unit of a teaching hospital in China from September 2015 to September 2016. Patients and methods: We collected 12 carbapenem-resistant K. pneumoniae outbreak strains from 12 newborns and characterized these isolates for their antimicrobial susceptibility, clone relationships, and multi-locus sequence types using vitek-2 compact system, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Resistant genes were detected by using PCR and sequencing. Plasmid conjugation experiment was carried out to determine the transferability of carbapenem resistance. PCR-based replicon typing (PBRT), S1 nuclease-PFGE, and southern blotting were conducted for plasmid profiling. Results: All 12 K. pneumoniae isolates were resistant to carbapenems and carried bla NDM-5 , bla TEM-1 and bla SHV-11 . Furthermore, PFGE analysis showed that NDM-5-producing K. pneumoniae were clonally related and MLST assigned them to sequence type 337. Conjugative assays showed that plasmids harboring bla NDM-5 gene were self-transmissible. Plasmid analysis suggested that all bla NDM-5 gene located on a ∼45 kb IncX3 type plasmid. Conclusion: To the best of our knowledge, this is the first report of a clone outbreak of bla NDM-5 -carrying K. pneumoniae isolates from neonates. There is an urgent need for effective infection control measures to prevent bla NDM-5 variants from becoming epidemic in the neonates in the future.