Inducible clindamycin resistance in Staphylococcus aureus strains isolated from clinical samples.

Abstract

Background: Staphylococcus aureus is commensal flora but it can lead minor skin infections to life threatening conditions such as endocarditis, pneumonia and septicemia. Spread of multi drug resistance MRSA, therapeutic options become severely limited. Clindamycin can be an alternative option for use in the increasing drug resistance among the staphylococci. However, resistance to clindamycin can be missed in the laboratory, unless look specially thus necessitating the need to detect such resistance by a simple D test on routine basis. Objectives: To find clindamycin resistance among clinical isolates of S aureus by disk-approximation test (D-test) and to establish methicillin resistant Staphylococcus aureus (MRSA) isolates and its relationship with inducible clindamycin resistance. Materials and Methods: S. aureus isolated from various clinical specimens in microbiology unit BP Koirala Institute of Health Sciences hospital, Nepal from 8 th March 2012 to 10 th September 2012 was studied. Isolation and identification of organism was done by standard microbiological technique. S aureus resistant to erythromycin Kirby Baur disk diffusion test and phenotypic expression on inducible resistance was assessed using D-test. Results : Among 300 S. aureus 41% were methicillin resistant. MRSA demonstrated 11.6% constitutive MLSBc. D test positive inducible resistance (MLSBi) found to be 24.59% and (22.4%) were MS type among MRSA isolates. Conclusion: It was found 11.6% of isolates were inducible resistance to clindamycin, thus highlighting, whenever clindamycin is intended to be used for S. aureus infections, D-test should be performed to facilitate the appropriate treatment of patients.