Significance of MRSA strains in community associated skin and soft tissue infections

The study was conducted to determine the antibiotic susceptibility profile of community-associated methicillin resistant Staphylococcus aureus (CAMRSA) strains isolated from infections. S. aureus strains were isolated from clinical specimens using the standard procedures. CDC definition was used to classify CAMRSA. Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method. Double disk diffusion method (D-test) was used to detect inducible macrolide, lincosamide and streptogramin_B resistance (inducible MLS_B resistance). A total of 83 CAMRSA were isolated from abscesses and other skin infections in persons without known risk factors for MRSA infection. All CAMRSA were susceptible to vancomycin. Out of 83 CAMRSA, 13 (15.65%) were D-test positive (inducible MLS_B positive) and 6 (7.23%) were positive for constitutive MLS_B resistance. Eight strains (9.63%) were resistant to tetracycline and 26 (31.32%) strains were resistant to erythromycin. Increased rate of inducible clindamycin resistance among CAMRSA indicates the importance of identification of such strains by D test to avoid treatment failure when clindamycin is used.