Is methicillin-resistant Staphylococcus aureus involved in community acquired skin and soft tissue infections?

BACKGROUND: To improve the empiric antimicrobial therapy of community-acquired (CA) skin and soft tissue infections (SSTIs), it is necessary to generate data on the current spectrum and susceptibility profile of associated bacteria. CA methicillin-resistant Staphylococcus aureus (CA MRSA) is increasingly being reported in SSTIs in India and globally. AIMS: The present study was undertaken to determine the bacterial profile of CA-SSTIs, to know the contribution of MRSA in these infections, to determine inducible clindamycin resistance in S. aureus and to compare the resistance patterns of isolates from hospital-acquired (HA) SSTIs. MATERIALS AND METHODS: Eight hundred and twenty patients with CA SSTIs were prospectively studied. Pus samples were cultured and antimicrobial susceptibility pattern determined. Inducible clindamycin resistance was detected by D-test. Laboratory records were analyzed retrospectively to generate data on HA SSTIs. RESULTS: 619 isolates were recovered in CA-SSTIs, of which S. aureus (73%) and Streptococci (12%) were the most common. Pseudomonas aeruginosa (28%) and Acinetobacter spp (18%) were the predominant HA-SSTI pathogens. Susceptibility of CA S. aureus to antibiotics tested was, penicillin (6%), co-trimoxazole (20%), ciprofloxacin (37%), cefazolin (100%), erythromycin (84%), clindamycin (97%), gentamicin (94%) and fusidic acid (95%). No MRSA was found in CA SSTIs whereas 45% of HA S. aureus strains were methicillin-resistant. HA strains demonstrated significantly higher resistance as compared to their CA counterparts (P<0.001). D test was positive in 22% of CA S. aureus tested. CONCLUSIONS: In CA SSTIs, methicillin-susceptible S. aureus is the predominant pathogen. Penicillinase-resistant penicillins, clindamycin and erythromycin in that order can be used as suitable antimicrobials for empiric therapy. D test should be carried out routinely. No CA MRSA was detected in the present series.