Molecular Characteristics of Community-Acquired Methicillin-ResistantStaphylococcus aureusin Hokkaido, Northern Main Island of Japan: Identification of Sequence Types 6 and 59 Panton-Valentine Leucocidin–Positive Community-Acquired Methicillin-ResistantStaphylococcus aureus

Abstract

Prevalence and molecular characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) were studied in Hokkaido, the main northern island of Japan. Among the 1,015 S. aureus isolates derived from clinical specimens of outpatients collected in 2009, methicillin resistance gene mecA was detected in 189 isolates (18.6%). The most frequent staphylococcal cassette chromosome mec (SCCmec) type in MRSA was II (83.1%), followed by IV (6.9%) and V (3.2%). MRSA with type II-SCCmec showed multiple drug resistance and harbored various toxin and virulence factor genes except for Panton-Valentine leucocidin (PVL) gene. These isolates were mostly classified into sequence type 5 (ST5) (or other STs in CC5) and coagulase genotype II and were thus genetically similar to hospital-acquired MRSA, which have been predominating in Japan (New York/Japan clone). PVL gene was detected in three MRSA strains belonging to ST6 (two strains) and ST59 (one strain), having type IVa- and Vt-SCCmec, respectively, and also in two methicillin-susceptible S. aureus ST121 and ST188. The arcA gene within the arginine catabolic mobile element (ACME) was detected in the two PVL-negative ST5 MRSA strains, which had type IIa- or V-SCCmec. The PVL gene-positive ST6 and ST59 CA-MRSA strains were susceptible to more antimicrobials and had less virulence factor genes than the PVL-negative ST5 MRSA, including the ACME-arcA-positive strains. In the present study, ST6 was identified as a lineage of PVL-positive CA-MRSA, the ACME-arcA was first detected in ST5 MRSA with type V-SCCmec, and ST59 Taiwanese CA-MRSA strain was isolated in Hokkaido for the first time. These findings suggest a potential spread of these emerging CA-MRSA clones in Japan.

StaphylococcalCassette Chromosomemec(SCCmec) Typing of Methicillin-ResistantStaphylococcus aureusStrains Isolated from Community- and Hospital-Acquired Infections

“…Furthermore, a similar prevalence rate (54%) was reported by Moghadami Based on SCCmec typing, MRSA strains are classified into 5 different allotypes, 2 of which have been identified in Asian countries. The clonotype II is distributed in Japan and Korea, whereas clonotype III is predominant in some other Asian countries, such as Saudi Arabia, India, China, and Thailand (8,27,28). We used SCCmec typing to monitor the epidemiology of MRSA isolates, collected from hospital-and community-acquired infections.…”

“…SCCmec typing is a polymerase chain reaction (PCR)-based method, which is essential for characterization of MRSA clones in epidemiological studies and provides important information about the mobile genetic elements of methicillin resistance (8,9). SCCmec is an element involved in the horizontal transfer of resistant genes among Staphylococcus strains.…”

Characterization of Staphylococcus aureus Strains Associated with Food Poisoning in Shenzhen, China

“…Within the MLST database, prior to 2004, all of the isolates of ST6 were methicillin-susceptible Staphylococcus aureus (MSSA) isolates from Australia, the United Kingdom, Thailand, Japan, and Gambia. The ST6 MRSA strain has rarely been isolated, but community-associated MRSA (CA-MRSA) clones were reported in Kuwait hospitals (32), Japan (12), and Lebanon (31). According to previous research, ST6 is not the predominant S. aureus lineage that is observed in hospitals and animals in China (6,8,9,35,36,38,40,41).…”

Novel Structures and Temporal Changes of Arginine Catabolic Mobile Elements in Methicillin-Resistant Staphylococcus aureus Genotypes ST5-MRSA-II and ST764-MRSA-II in Japan

“…Clinical isolates were collected at various hospitals in Hokkaido from February 2008 to December 2011 (9,10,17). Only one isolate per patient was used as a study subject.…”