First Imported Case of Skin Infection Caused by PVL-positive ST30 Community-Associated Methicillin-Resistant Staphylococcus aureus Clone in a Returning Korean Traveler from the Philippines
A previously healthy 30-yr-old Korean woman presented with fever and painful swelling in her right buttock for 5 days in January 2012. The symptoms started the day after she had felt like insect-bite on her right buttock, while traveling in the Philippines. After coming back to Korea, she had taken cefaclor for four days without any improvement of buttock lesion. On admission, she had normal temperature (36.3℃), pulse rate of 110 beats/min, blood pressure of 114/72 mmHg, and respiratory rate of 20 breaths/min. Physical examination showed around 3 cm-sized carbuncle on her right buttock with spontaneously draining pus through a small central opening. Laboratory tests showed 8,340 leukocytes/µL, hemoglobin 13.9 g/dL, platelet 243,000/µL, and C-reactive protein (CRP) 0.03 mg/dL. Cefazolin was empirically started along with local curettage and irrigation. Culture of the aspirated pus grew MRSA. Antimicrobial susceptibility testing by minimum inhibitory concentration (MIC) determination according to guidelines of the Clinical and Laboratory Standards Institute () showed that this MRSA strain was susceptible to gentamicin, ciprofloxacin, clindamycin, erythromycin, rifampicin, tetracycline, cotrimoxazole, and fusidic acid. MIC of vancomycin was 1 mg/L. Antibiotic regimen was changed to vancomycin and continued for 6 days with clinical improvement. She was cured after further use of oral clindamycin for 5 days.\nAn MRSA strain isolated from the patient was molecularly characterized and compared with the reference strains. Multilocus sequence typing (MLST) was carried out by PCR amplification and sequencing of seven housekeeping genes (arcC, aroE, glpF, gmk, pta, tpi, and yqiL) as previously described (). The allelic profiles and sequence types (ST) were assigned by the MLST web site (). SCCmec types were determined by the multiplex PCR method (). Presence of the lukF-PV and lukS-PV genes encoding the components of the PVL toxin was screened as previously described (). The spa typing was performed as previously described (). The spa type was determined by using Ridom SpaServer (). The isolate was determined to be PVL-positive ST30-MRSA-IV, and it belonged to spa type t019.\nPulsed-field gel electrophoresis (PFGE) was performed as described previously (). The PFGE patterns were analyzed using GelCompar II software (Applied Maths, Belgium), and compared to those of the ST30-MRSA-IV reference strains (P01-SAU-05-41 and P01-SAU-05-66; Asian Bacterial Bank, Asia Pacific Foundation for Infectious Diseases, Seoul, Korea), which had been previously collected from the Philippines by the Asian Network for Surveillance of Resistant Pathogens (ANSORP) for MRSA surveillance during the period from 2004 to 2006 (), and the USA300 strain (NRS384), which had been obtained from the Network on Antimicrobial Resistance in Staphylococcus aureus (NARSA), supported under NIAID/NIH contract #HHSN2722 0070 0055C, and ST72-MRSA-IV strain (K01-SAU-04-1325; Asian Bacterial Bank, Asia Pacific Foundation for Infectious Diseases, Seoul, Korea) (). Analysis of the PFGE patterns showed that the isolate from the patient showed 83.3% similarity compared to those of the ST30-MRSA-IV reference strains collected from the Philippines.