Molecular Characterization of Community- and Healthcare-Associated Methicillin-Resistant Staphylococcus aureus Isolates in Southern Taiwan

A growing tendency for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) to be involved in nosocomial infections was reported. The predominance of SCC mec type IV or V CA-MRSA in soft tissue infection has also been indicated in Northern Taiwan. To establish basic information about the molecular characteristics of MRSA in our region, a total of 102 MRSA isolates were collected and characterized by an array of typing methods. Healthcare-associated MRSA (HA-MRSA) were found to be more resistant to levofloxacin ( p =0.016) and moxifloxacin ( p =0.015) than CA-MRSA. However, no difference was found in each and overall SCC mec type distribution between the two MRSA groups. Type I (8.7% vs. 2.6%) was more frequently found in CA-MRSA, whereas type V was more often observed in HA-MRSA (24.4% vs. 8.7%). No difference was found in the dichotomous group of PVL , SCC mec type IV, V, and IV/V between the two MRSA groups. Twenty-seven distinct spa types were identified; t437 and t1081 were the predominant types in our isolates. Moreover, 12 novel spa types with extremely low global frequency were detected in our isolates. SCC mec type III and IV were the major subtypes in the MRSA we collected. The t1081 clones all belonged to HA-MRSA and mostly to SCC mec type V (71.4%). CA-MRSA t437 clones were mostly SCC mec type IV strains (71.4%), but HA-MRSA t437 clones were predominantly SCC mec type IV (42.1%) and III (36.8%). Our findings support a difference in the molecular characteristics of CA-MRSA and HA-MRSA that may reflect various clonal origins in our isolates.