ST9 MRSA strains carrying a variant of type IX SCCmec identified in the Thai community
1 Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
2 Department of Infection Control Science, Graduate School of Medicine, Juntendo University, Tokyo, Japan
3 Department of Bacteriology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo Bunkyo-ku, Tokyo 113-8421, Japan
4 Research and Diagnostic Center of Emerging Infectious Diseases and Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
5 Veterinary Research and Development (Upper Northeastern) Center, Khon Kaen, Thailand
BMC Infectious Diseases 2013, 13:214 doi:10.1186/1471-2334-13-214Published: 11 May 2013
Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in Thailand occur most frequently in healthcare facilities. However, reports of community-associated MRSA are limited.
We characterized 14 MRSA isolates from outpatients (O-1 to O-14) by phenotypic and genotypic methods and compared them with 5 isolates from inpatients (I-1 to I-5). Thai MRSA isolates from a healthcare worker (N-1) and a pig (P-1) were also included as ST9 MRSA strains from other sources.
All MRSA isolates from the outpatients and inpatients were multidrug-resistant (resistant to ≥3 classes of antimicrobials). All of them except strains O-2 and I-3 carried type III SCCmec and belonged to agrI, coagulase IV, spa type t037 or t233, which related to ST239. The strain O-2 (JCSC6690) carried type IX SCCmec and belonged to agrII, coagulaseXIc, spa type t337 and ST9, whereas the strain I-3 carried a type III SCCmec and belonged to ST1429. Nucleotide sequence determination revealed that the type IX SCCmec element in strain O-2 was distinct from that in a Thai ST398 strain (JCSC6943) previously identified in 2011; nucleotide identities of ccrA and ccrB were 93 and 91%, respectively and several open reading frames (ORFs) at the joining regions were different. PCR experiments suggested that strain O-2 and N-1 carried similar SCCmec element, whereas that of strain P-1 was different, suggesting that distinct ST9-MRSA–IX clones might be spreading in this province.
The SCCmecIX-ST9 MRSA clones of distinct SCCmec subtypes might have emerged in the Thai community and might also have disseminated into the hospital.