D-Test as a tool to detect the frequency of clindamycin resistance in community acquired and hospital acquired methicillin resistant Staphylococcus aureus infections (MRSA).

Abstract

Objectives: D-Test as a tool to detect the frequency of clindamycin resistance in community acquired and hospital acquired methicillin resistant Staphylococcus aureus infections. Study Design: A cross-sectional study. Setting: Microbiology department of BMSI, JPMC, Karachi. Period: January 2015 till December 2015. Material & Methods: Pus samples from deep wounds, skin lesions, abscesses, postoperative wounds from surgical, medical wards and OPDs were collected. MRSA testing and susceptibility testing for antibiotics was done according to CLSI2014. The frequency of inducible clindamycin resistance was detected by D-Test of the CA-MRSA and HA-MRSA. Result: In a total of 402 S. aurous isolates, 253 (62.93%) were methicillin-sensitive and 149 (37.06%) were methicillin-resistant. Out of 149 MRSA, 106 (71.14%) were HA-MRSA and 43(28.85%) were CA-MRSA. Among the HA-MRSA, 63(59.8%) were resistant to clindamycin while with D-Test, it increased to 78(73.58%). Out of 43 CA-MRSA, 9 (21.6%) were clindamycin resistant, while with D-Test, the resistance to clindamycin increased to 13 (30.23%). Conclusion: Inducible clindamycin-resistant strains may lead to clindamycin treatment failure in patients with S. aureus infection. Therefore, D-test should be done in priority to detect inducible clindamycin resistance in S. aurous.