Sccmec Type Ix In A Community-Acquired Methicillin-Resistant Staphylococcus Aureus Isolate: First Report In A Patient From Thailand

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is mostly associated with hospital, whereas community-acquired MRSA (CA-MRSA) infections in Thailand have been uncommon. The present study aimed to investigate 14 MRSA strains isolated from outpatients of a university hospital in Thailand. Methods: Fourteen MRSA isolates were collected between September 2005 and March 2006 from outpatients of a university hospital inThailand. Minimum inhibitory concentrations (MICs) of six antimicrobial agents: vancomycin, cefazolin, oxacillin, cefoxitin, tetracycline, erythromycin and ofloxacin were determined using an agar dilution method. Genotypic studies such as SCCmec type, coagulase typ, agr type, spa type, multilocus sequence type (MLST) were performed using PCR and subsequent nucleotide sequences. Pulsed-field gel electrophoresis (PFGE) of SmaI-digested chromosomal DNA was also performed. Results: All 14 MRSA were multidrug-resistant with high MICs of cefazolin, oxacillin, cefoxitin, tetracycline and erythromycin (32- >64 μg/ml), however all isolates were susceptible to vancomycin (MIC 1-2 μg/ml). Of the 14 isolates, 13 carried type III SCCmec and belonged to ST239, coagulase type IV, agr I and spa type-t037 but one isolate was t233. The remaining isolate (strain JCSC6690) carried a new SCCmec element, class C2 mec gene complex with ccrA1B1, type XIc coagulase, agr II, spa type-t337 and ST9. PFGE of the 14 isolates showed that 12 isolates gave similar bands pattern to a hospital acquired-MRSA (HA-MRSA) from the same hospital. The other isolates with spa type t337 and t233 showed a unique DNA profile. The Panton-Valentine Leukocidin gene was not found in these isolates. The strain JCSC6690 was isolated in March of 2006, from a 2-year-old boy underlined with atopic dermatitis, attended the hospital because of suffering from chronic impetigo at left foot. The patient achieved good recovery after receiving cefaclor. He had never been admitted in a hospital during the former year. Nucleotide sequencing of the 57 kb region at the downstream of orfX revealed a novel SCCmec carrying type I ccr gene complex and classC2 mec gene complex. Conclusion: We reported a real community acquired-MRSA (CA-MRSA) from a patient in Thailand with SCCmec type IX - ST9 which carried class C2 mec gene complex and ccrA1B1.