Molecular epidemiology of klebsiella pneumoniae producing KPC-17 and NDM-1 carbapenemases in Southern Taiwan

Introduction The carbapenem-resistant Klebsiella pneumoniae (CRKP)- mediated infections have increasing incidence globally. Particularly, two carbapenemase-producing KP (CPKP) subclasses, Klebsiella pneumoniae carbapenemase-2 (KPC-2) and New Delhi metallo- β-lactamase-1 (NDM-1), have been identified worldwide. Moreover, KPC-17 has been identified exclusively in Taiwan, which has emerged as a public health problem at Chiali district in Tainan, a city in southern Taiwan. Methods A prospective genetic survey for CRKP was conducted at a regional Hospital A in Tainan city for 5 years from January, 2014 through November, 2018. The multilocus sequence typing (MLST) using the DNA sequences of internal fragments of multiple housekeeping gens was used to reveal the sequence type (ST) of CPKP isolates. Pulsotype of pulsed-field gel electrophoresis (PFGE) was used to increases the discrimination power of genotyping. Results We collected a total of 413 non-repetitive CRKP isolates. The genetic analysis revealed two carbapenemase genes, predominantly bla_KPC-17 (n = 206, 49.9%) and rarely bla_NDM-1 (n = 43, 10.4%), both of which (defined CPKP group) were responsible for resistance in 60.3% of the CRKP strains. The other CRKP isolates (39.7%) were presumed to be partially associated with outer membrane porin defect. MLST revealed the ST of CPKP isolates harboring bla_KPC-17 was exclusively ST11, whereas those isolates harboring bla_NDM-1 belonged to diverse ST types, including a major clone of ST681 and others (ST656, ST611, ST307, ST11, ST5, etc.), suggesting difference in epidemiology between KPC-17 and NDM-1 isolates. Epidemiological analysis was consistent with PFGE pulsotypes. Although the outbreak of KPC-17 strains which first peaked in 2014 (May-July) has been controlled, it recurred in May, 2915, and May, 2016 and had predominated from July 2017 through November, 2018. Meanwhile, another outbreak of NDM-1 isolates had happened during the 2016-2017 influenza season from October, 2016 to May, 2017. Conclusion While KPC-2 isolates widely spread in the world, KPC-17 strains have been prevalent at Tainan city in southern Taiwan. Molecular epidemiology was different in the two CPKP lineages of KPC-17 and NDM-1. There was clonal dissemination of ST11 responsible for KPC-17 strains, whereas NDM-1 isolates mainly belonged to diverse genotypes.