Outbreak Of Bla_NDM-1 Producing K.pneumoniae ST1224 In Neonates In Neonatal Wards And Bla_NDM-1 Producing Enterobacter Cloacaes ST177 In Adults In A Intensive Care Unit In A Hospital,China

Objective To analyze resistance genes and molecular epidemiology of carbapenem resistant Enterobacter cloacaes and Klebsiella pneumonia isolates so as to provide guidance for nosocominal infection control and prevention.Methods Total 17 carbapenem-resistant stains,including 10 E.Cloacaes and 7Klebsiella pneumoniaes were isolated from three hospitals in china.These isolates were identified by Vitek 2 compact?Bio Merieux?,and the antibiotic susceptibilities tests?AST?were done by using VITEK-2 compact system and E-Tests.The putative metallo-?-lactamase?MBL?producers of these 17 stains were detected by IPM/EDTA E-tests.The drug resistance genes of carbapenems,ESBLs,Amp C,Quinolone and Fosfomycin resistant genes were done by PCR,and confirmed by Sequence Alignment.Pulsed field gel electrophoresis?PFGE?and multilocus sequence typing?MLST?were performed to analyze clonal relatedness of 10 E.Cloacaes and 7 Klebsiella pneumoniaes.The transferability of plasmids were determined by conjugation experiments and Southern blot hybridization.Results All of 17 strains were positive MBL E-tests and carried a couple of drug resistance genes,including bla_NDM-1,CMY-6,DHA-1,SHV-12,ACT-35,TEM-1,qnr B,qnr S1 and fos A.The ten isolates of Enterobacter cloacaes were categorized into three PFGE types,and belonged to ST177?8 isolates,YG1⁶,YG8⁹?,ST51?one isolate,YG7?and ST418?one isolate,YG10?,respectively.Out of seven Klebsiella pneumoniae strains,five ST1224 K.pneumoniaes are categorized into one type,and other two ST478 K.pneumoniae isolates belonged to a different clone.The Southern blot hybridization and PCR-based replicon typing revealed that plasmids which carried the bla_NDM-1 gene in 17 isolates were successfully transferred to E.coli J53 Azi R by conjugation experiments and that bla_NDM-1 genes were located on a 140 kb Inc A/C plasmid in K.pneumoniae stains and 50 kb Inc F? plasmid in Enterobacter cloacaes isolates,respectively.Conclusion Our results demonstrated that there were two outbreak of bla_NDM-1producing K.pneumoniae ST1224 and bla_NDM-1 producing Enterobacter cloacaes ST177 as well.To our knowledge,this is the first report in worldwide.Therefore there is an urgent need on strengthening the surveillance of carbapenem-resistant enterobacteriaceae and proventing the spread of nosocominal infection.