%0 Journal Article
%T Comparison of the effectiveness of core genome multilocus sequence typing and polymerase chain reaction-based open reading frame typing in tracing nosocomial methicillin-resistant Staphylococcus aureus transmission.
%A Mitsumoto-Kaseida F
%A Murata M
%A Ota K
%A Kaku N
%A Kosai K
%A Hasegawa H
%A Hayashi J
%A Yanagihara K
%J J Infect Chemother
%V 0
%N 0
%D 2024 Jul 4
%M 38969102
%F 2.065
%R 10.1016/j.jiac.2024.07.001
%X <B>BACKGROUND: </B>A clonal shift from staphylococcal cassette chromosome mec (SCCmec) type II/ST5 methicillin-resistant Staphylococcus aureus (MRSA) to SCCmec type IV/clonal complex (CC)1 MRSA has occurred rapidly in Japan. Our previous research in a geriatric hospital found SCCmec type IV/CC1 MRSA prevalence in long-term care wards. Due to intensive personal care requirements, frequent contact with healthcare providers can potentially cause unintentional nosocomial MRSA transmission. We performed polymerase chain reaction-based open reading frame typing (POT) and core genome multilocus sequence typing (cgMLST) to investigate the occurrence of nosocomial transmission and to compare the results of these methods.<BR><B>METHODS: </B>POT and whole genome sequencing were performed in 83 MRSA isolates. Commercial automated software (Ridom SeqSphere+) was used to perform cgMLST. MRSA isolates with 0-8 allelic differences were considered related, and medical records were consulted in these cases.<BR><B>RESULTS: </B>SCCmec type IV/CC1 MRSA was the most frequently detected clone (n = 56, 67.5 %), which was divided into 14 POT types, followed by SCCmec type I/ST8 (n = 9) and SCCmec type IV/ST8 (n = 8). Identical POT types were found across 7 of 11 wards. However, cgMLST analysis identified only three cases (six strains) of high genetic similarity, indicating nosocomial transmission; only one involved SCCmec type IV/CC1 (two strains). The mean allelic difference in the core genomes between strains with identical POT types in the same ward was 55.3 ± 22.0.<BR><B>CONCLUSIONS: </B>The cgMLST method proved more effective for identifying nosocomial transmissions compared to POT, highlighting its utility in tracking MRSA spread in healthcare settings.