Clindamycin: An adjunct option in drug-resistant staphylococcal infections

Abstract

Introduction: The emergence of methicillin resistance among staphylococcal infections has led to increasing demand for the use of safe and effective agents to treat such infections. Clindamycin is one such drug which is gaining the interest of clinicians because of its excellent pharmacokinetic properties. However, the widespread use of macrolide–lincosamide–streptogramin B antibiotics has led to inducible or constitutive resistance which is a major concern. In vitro routine tests for clindamycin, susceptibility may fail to detect inducible clindamycin resistance leading to treatment failure, thus requiring a simple D test to detect such resistance on a routine basis. Aim of the Study: The aim of this study was to find the prevalence of inducible clindamycin resistance in Staphylococcus aureus isolates from various clinical samples. Materials and Methods: One thousand isolates isolates of S. aureus obtained from various clinical samples were subjected to routine antibiotic susceptibility testing including cefoxitin (30 μg) using the Kirby–Bauer disk diffusion method. Inducible clindamycin resistance was tested by the “D test” as per CLSI guidelines. Results and Conclusion: Out of 1000 isolates of S. aureus, 556 (55.6%) were methicillin-sensitive S. aureus and 444 (44.4%) were methicillin-resistant S. aureus (MRSA). The total percentage of inducible clindamycin resistance was found to be 21.9%. Inducible clindamycin resistance was found to be higher among MRSA making treatment of such infections more difficult. D test is a simple test which can be included in routine testing of antibiotic susceptibility for staphylococcal isolates to detect inducible clindamycin resistance so as to avoid treatment failure and aid in the judicious use of this drug.