[Research on genotyping of methicillin-resistant Staphylococcus aureus in China.]

To investigate the source and genetic background of methicillin-resistant Staphylococcus aureus in the year of 2006, in China.

From January to December 2006, a total number of 302 consecutive and non-repetitive methicillin-resistant Staphylococcus aureus were collected from 17 Teaching hospitals in 15 areas. Genotypes of SCCmec were determined by multiplex PCR and multilocus sequence typing (MLST) was used to type the house-keeping genes. The implementation of the spa typing method was straightforward, and the results obtained were reproducible, unambiguous, and easily interpreted.

All areas but Dalian harbored SCCmec III while Dalian harbored SCCmec II most. There were two strains in Guangzhou, harboring SCCmec IV. There were four strains of sequence type (ST), with ST239 accounted for 46.7% and ST5 accounted for 44.4%. ST59 accounted for 6.7% and ST88 accounted for 2.2%. There were fourteen strains of Spa typing, with t30 accounted for 52.6%; t37 accounted for 27.2%; t2 accounted for 12.9%; t632 accounted for 2.3%; t437 accounted for 1.3%; t570, t601 accounted for 0.7%; t377, t459, t796, t899, t1152, t2649 accounted for 0.3%; no-typing accounted for 0.3%, respectively. pvl gene was not detected.

The main clone strains were ST239-MRSA-SCCmec III-t30, ST5-MRSA-SCCmec II-t2, with unique geographic distributions across the whole nation.