Is methicillin-resistant Staphylococcus aureus involved in community acquired skin and soft tissue infections? Experience from a tertiary care centre in Mumbai.

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.