The increase in incidence of variety of
infections due to Staphylococcus aureus and especially methicillin resistant Staphylococcus aureus has highlighted on the need for better agents to treat such
infections. Also the resistance to
antimicrobial agents among staphylococci is an increasing problem. The
macrolide-lincosamide-
streptogramin B (MLS(B)) groups of
antibiotics are commonly used in the treatment of
staphylococcal infections with
clindamycin being the preferred agent. This study demonstrates a simple phenotypic method (D-test) for detecting inducible
clindamycin resistance in
erythromycin resistant strains of staphylococcus aureus &
coagulase negative Staphylococcus. A total of 181
erythromycin resistant staphylococcal isolates were obtained from various clinical specimens. Among the Staphylococcus aureus isolates, 38 (25.4%) were methicillin resistant Staphylococcus aureus (MRSA) and 112 (74.6%) were
methicillin sensitive staphylococcus aureus (MSSA). Constitutive resistance was seen in 56 (37.3%) of isolates. Of these 18 (47.4%) were MRSA and 38 (33.9%) were MSSA. Inducible resistance was seen in 25 (16.6%) isolates, in which 11(28.9%) were methicillin resistant Staphylococcus aureus & 14 (12.6%) were
methicillin sensitive staphylococcus aureus. It is likely that the true percentage of
clindamycin resistance is being underestimated, since testing for inducible resistance is not being routinely performed. So the test should be done routinely in all the labs to avoid therapeutic failures.