Macrolide, lincosamide and streptogramin type B (MLSB) antibiotics are important in the treatment of Staphylococcus aureus infections and existence of isolates with ability to resist against MLSB antibiotics is worrisome. Routine testing of staphylococcal isolates for inducible clindamycin resistance (ICR) is advocated by the Clinical Laboratory Standards Institute (CLSI). Automated system Vitek 2 offers a panel that detects inducible clindamycin resistance directly. it is easy and more cost-effective than the more labor-intensive CLSI reference methods. Objectives: Evaluation the utility of automated vitek-2 system in detection of inducible clindamycin resistance S. aureus compared to D zone test and detection the prevalence of erm A and erm C genes among isolated strains. Method: 25 clinical staphylococcus aureus isolates (Erythromycin intermediate and resistant, Clindamycin susceptible) were examined for ICR both by D- test and Vitek-2 system. multiplex PCR was performed for the isolates to detect ermA and ermC genes. Results: Out of the 25 isolates, ICR was detected by Vitek-2 in 11 isolates (44%). Two of the isolates were not detected by Vitek-2 but confirmed by D-test. sensitivity, specificity, positive and negative predictive values were calculated as 85.7%, 100%, 100% and 84.6% respectively. erm C and A genes were detected in (40%) and (24%) of the studied isolates respectively. Both C and A genes were detected in (12%). Conclusion: Vitek-2 is considered a potentially reliable test for detection of ICR, further studies are recommended on large number of isolates. [ |
