Objective. The objective of this study was to get insight into the clonal structure of CA-MRSA isolates from both carriers and infections, in patients without health care exposures.
Methods. The study was performed on 39 isolates sent to the National Medicines Institute (NMI) during one year survey. The isolates were re-identified in NMI to the species level. The clonal structure of the isolates was studied by MLVF and PFGE, MLST, spa-typing and SCCmec typing. Detection of the PVL coding gene was also performed by PCR.
Results. Thirty-six isolates were confirmed to belong to S.aureus species. MLST revealed 8 different clones among isolates. In this regard 5, 2, 1, 16, 1, 5, 1 and 1 strain of ST5-IV, ST8-IV, ST30-IV, ST45-IV, ST74-IV, ST338-V, ST121-IV and single locus variant (SLV) of ST25-IV, respectively, were detected. Four isolates were characterised as ST8-IB. The PVL coding gene was detected in all isolates belonging to ST8-IV, ST30-IV, ST338-V and ST121-IV.
Conclusions. Among the MRSA strains studied, no MRSA sharing the background of the major European CA-MRSA clone, ST80 was detected. MRSA clones of ST5-IV, ST8-IV, ST30-IV, ST45-IV, ST74-IV and ST338-V have been recently reported to spread in the communities in many parts of the world. Clone ST121 has been often associated with MSSA in a carrier state and some of the isolates belonging to ST121 harboured PVL gene, whereas other did not. The emergence of ST121-IV, PVL-positive clone may be the result of a local SCCmec acquisition by a PVL-positive, ST121-MSSA strain.