Purpose: Klebsiella pneumoniae  carbapenemase (KPC)-producing K. pneumoniae  bacteria causes nosocomial infections worldwide. However, KPC-producing K. pneumoniae  outbreak has never been reported in Shandong Province, China. The purpose of our study was to elucidate the epidemiological and drug resistance mechanisms of KPC-producing K. pneumoniae  strains collected from a large teaching hospital in Shandong during the outbreak. Moreover, we attempted to characterize the genetic environment and phylogenetic analysis of bla _KPC-2 in outbreak isolates.
Methods: We monitored a 64-day outbreak of infection in a general hospital in Shandong Province, and the bacteria causing the infection were all ST11-type K. pneumoniae . The genotype correlation of KPC-producing K. pneumoniae  isolates was assessed by whole-genome sequencing (WGS) phylogenetic analysis. Subsequent studies included antibiotic susceptibility testing, multilocus sequence typing (MLST) and S1-pulsed-field gel electrophoresis (S1-PFGE), Southern blot hybridization.
Results: From February 1, 2018 to April 5, 2018, 14 KPC-producing K. pneumoniae  isolates from different wards were collected. All 14 isolates were resistant to carbapenems and carried the extended-spectrum β-lactamase (ESBL) gene as well as fosA , and sul  genes. Whole-genome analysis showed that all 14 the outbreak isolates were all ST11 type. The bla _KPC-2 carrying plasmids were all belong to IncFII_K2 type, and the size ranged from 94 kb to 368 kb.
Conclusion: As far as we know, this report first describes the genomics characterization of KPC-2-producing K. pneumoniae  outbreak isolates from Shandong Province, China. In our study, these isolates appeared to be cloned, and ST11 K. pneumoniae  was the major clone caused the outbreak. Therefore, routine surveillance of such strains in this region is urgently warranted.
Keywords: Klebsiella pneumoniae , ST11, whole-genome sequencing, SNP, outbreak, IncFII_K2