| Accurate detection and therapeutic challenges are still on the debate for methicillin-resistant Staphylococcus
aureus (MRSA). Working on clindamycin, researchers serendipitously spotted the D test and the era of macrolidelincosamide (ML) resistance commenced. We aimed to i) assess usage of other antibiotics other than cefoxitin for
the detection of MRSA, ii) evaluate various surrogate therapeutic options, and iii) determine phenotypic and
genotypic aspects of inducible and constitutive clindamycin resistance in S. aureus. Disk diffusion agar assay and
molecular method were used to assess MRSA detection. Efficacy of linezolid, vancomycin, mupirocin, teicoplanin, fusidic acid, and rifampin was analyzed by E-test. Various phenotypes of macrolide-lincosamidestreptogramin B (MLSB) resistance were detected by performing D-test followed by PCR assay for ermA, ermB
and ermC genes coding for macrolide resistance. The cefoxitin disc yielded the best sensitivity value (100%) over
oxacillin, imipenem, and meropenem. All isolates were completely sensitive to linezolid and teicoplanin. Among
MRSA isolates, 6.2%, 1.5%, and 17.1% strains had intermediate and complete resistance to vancomycin, fusidic
acid, and rifampin respectively. Fifty-six isolates were clindamycin susceptible and diverse resistance outlooks
were the major outcome of our study with 20.6% isolates demonstrated two distinct induction phenotypes (D and
D+) and 45% isolates showed non-induction (HD,R) phenotypes. ermA gene alone and in combination with ermC
was found to be more prevalent among inducible as well as constitutive clindamycin- resistant isolates. |