Evolution and virulence of Panton-Valentine leukocidin-positive ST30 methicillin-resistant Staphylococcus aureus in the past 30 years in Japan

• Published in: Biomedical Research 2012, Vol.33(2), pp.97-109
• Main Authors: Isobe, Hirokazu, Takano, Tomomi, Nishiyama, Akihito, Hung, Wei-Chun, Kuniyuki, Shuichi, Shibuya, Yasuhiro, Reva, Ivan, Yabe, Shizuka, Iwao, Yasuhisa, Higuchi, Wataru, Khokhlova, Olga E, Okubo, Takeshi, Yamamoto, Tatsuo
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Bacterial Toxins - genetics; Cell Line; Child; Child, Preschool; Drug resistance; Drug Resistance, Multiple, Bacterial; Electrophoresis, Gel, Pulsed-Field; Evolution; Evolution, Molecular; Exotoxins - genetics; Female; Gel electrophoresis; Genes, Bacterial; Genetic Linkage; Genotypes; History, 20th Century; History, 21st Century; Hospitals; Host-Pathogen Interactions; Humans; Imipenem; Infant; Infection; leukocidin; Leukocidins - genetics; Male; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Methicillin-Resistant Staphylococcus aureus - pathogenicity; Middle Aged; Minimum inhibitory concentration; Multidrug resistance; Oxacillin; Phages; Phenotype; Phylogeny; Pneumonia; sea gene; Staphylococcal Infections - history; Staphylococcal Infections - microbiology; Staphylococcus aureus; Transcription, Genetic; Virulence; Virulence - genetics
• ISSN: 0388-6107; 1880-313X
• DOI: 10.2220/biomedres.33.97

Methicillin-resistant Staphylococcus aureus (MRSA) includes hospital-acquired MRSA (HAMRSA) and community-acquired MRSA (CA-MRSA). Panton-Valentine leukocidin (PVL)-positive multilocus sequence type 30 (ST30) MRSA is one of worldwide CA-MRSA, which has also persisted in Japan since the 1980s. However, unexpectedly, it was not the same ST30 clone throughout. Before 2000, it was HA-MRSA with spa43 and φSa3sea (phage Sa3 carrying the sea gene) and only one PVL-positive MRSA in Japan; in the 1980s, ST30 MRSA accounted for 23.5% of HA-MRSA, showed multidrug resistance, had high MICs for oxacillin and imipenem, and caused decubitus and pneumonia in hospitalized patients. A dynamic clonal change (spa43/φSa3sea→ spa19) occurred around 2000-2002. A rare spa43/φSa3sea/SCCmecI-IE25923 genotype also emerged. After 2002, the prevalent spa19 clone was CA-MRSA; it accounted for only 0.3% (or less) of MRSA in hospitals but 7.6% of CA-MRSA. Since 2007, PVL-positive CA-MRSA with other ST types (such as ST8, ST22, and ST59) also emerged in Japan, albeit at a low frequency. ST30/spa19 CA-MRSA occasionally caused severe invasive infections and a novel ST1335/spa19 genotype emerged. These ST30/spa19 CA-MRSA and variants were identified by pulsed field gel electrophoresis. Further analysis revealed that PVL-positive ST30/spa19 CA-MRSA is a highlyvirulent, successful clone, having a potential of clonal expansion.