Emergence of NDM-1-producing Sequence Type 773 Clone: Shift of Carbapenemase Molecular Epidemiology and Spread of 16S rRNA Methylase Genes in Korea.

Imipenemase (IMP)-6-producing sequence type (ST) 235 is a dominant clone of carbapenemase-producing (CPPAE) in Korea. As part of the Antimicrobial Resistance Surveillance System in Korea, we found an increase in the carbapenem resistance rate of isolates from blood cultures and a shift in the molecular epidemiology of CPPAE. A total of 212 non-duplicated blood isolates were obtained from nine general hospitals and two nursing homes. Twenty-four isolates were identified as CPPAE. We observed the emergence of the NDM-1 ST 773 clone (N=10), mostly from Gyeongsang Province. The IMP-6 ST 235 clone (N=11) was detected in all provinces. CPPAE isolates showed very high resistance rates to amikacin, and all NDM-1 strains carried . This is the first nationwide surveillance of the recently emerged NDM-1-producing ST773 clone in Korea. Continuous surveillance is necessary to prevent the infection and transmission of carbapenem- and amikacin-resistant in Korea.