[ODP2] 1. Taxonomy / Epidemiology / Infectious diseases -b. Epidemiology and molecular epidemiology

[ODP-011] Molecular epidemiology of MRSA isolates from bloodstream infections in northern Japan

Meiji Soe Aung¹, Noriko Urushibara¹, Mitsuyo Kawaguchiya¹, Masahiko Ito², Satoshi Habadera², Mina Hirose³, Nobumichi Kobayashi¹ (¹Dept. Hygiene, Sapporo Med. Univ., ²Sapporo Clin. Lab. Inc., ³Dept. Pediatr. Dentistry, Health Sci. Univ. Hokkaido)

BACKGROUND: MRSA is one of the major leading causes of bloodstream infections (BSIs). This study was conducted to explore the molecular epidemiological characteristics of MRSA from BSIs in northern Japan.
METHODS: A total of 277 MRSA isolates were collected from blood samples of patients in medical facilities in Hokkaido, for a two-year period from August 2017. Genotypes, virulence factors/drug-resistance profile, and structure of SCCmec complex were analyzed by PCR and sequencing analysis.
RESULTS: The dominant genotype was SCCmec-IIa, coagulase genotype (coa) IIa, ST5/ST764/ST2389 (n=171, 61.7%), followed by SCCmec-IVa (n=78, 28.2%), and IVl (n=10, 3.6%). Among the MRSA-IVa, 5.1% (14 isolates) had genetic features identical to USA300 clone (ST8/coa-IIIa/spa-t008 having PVL genes in φSa2USA and ACME-I), while PVL/ACME-negative MRSA-IVa isolates were assigned into ‍coa-IIa/IIIa/VIIa/VIIb, with coa-VIIa/spa-t1784/ST1 being dominant. SCCmec-IVl isolates belonged to coa-IIIa/CC8, harboring spj. Spermidine N-acetyltransferase gene (speG), which is typically present in ACME-I of USA300 clone, was identified in two isolates, ACME-II’-positive ST764-MRSA-IIa and ACME-negative ST1-MRSA-IVa.
CONCLUSION: Our present study revealed clonal diversity in MRSA from BSI in northern Japan, with potential increase in prevalence of ST8-USA300 MRSA clones.