Determination of Antimicrobial Resistance Pattern in Methicillin-Resistant Staphylococcus saprophyticus and Staphylococcus epidermidis and Detection of Resistance Genes to Clindamycin and Erythromycin

Background and Aims: Clindamycin is one of the selective drugs for treatment of staphylococcal infections. Molecular methods can complete phenotypic methods to diagnosis induction resistance to clindamycin. The aim of this study was to identify the genes responsible for the resistance to clindamycin and erythromycin, and determine their antibiotic resistance pattern. Materials and Methods: ۱۰۰ isolates of Staphylococcus epidermidis and Staphylococcus saprophyticus were isolated from ۴۶۶ different clinical specimens using biochemical tests. Using the disc diffusion method, Antibiogram susceptibility test was conducted to determinate lincosamides and tetracycline resistance pattern. Then  ermA, ermB, ermC and msrA genes were identified and investigated by PCR method. Results: Out of ۱۰۰ strains of coagulase-negative staphylococci isolated from clinical specimens, ۵ isolates were identified as S. saprophyticus (۵%) and ۵۵ isolates of S. epidermidis (۵۵%), respectively. Out of the ۵ isolated of S. saprophyticus, ۲ (۴۰%) isolates were resistant to methicillin and one (۲۰%) isolate had D phenotype. In addition, ۱ isolate had ermA gene and ۱ isolate had ermB. Out of the ۵۵ isolates of S. epidermidis, ۲۵ (۴۵.۴۵%) isolates were resistant to methicillin, of which nine (۳۶%) isolates had D phenotype. Also, ۴ (۱۶%) isolates had ermA gene, ۳ (۱۲%) isolates had ermB, ۶ (۲۴%) isolates had ermC and ۱ (۴%) isolate was carrying the msrA.  Conclusions: The phenotypic pattern of resistance to macrolide- lincosamides groups does not have a high degree of accuracy in detecting methicillin-resistant MLSB strains.

Keywords:

Staphylococcus saprophyticus , Staphylococcus epidermidis , Methicillin resistance , Macrolides , Lincosamides , استافیلوکوکوس ساپروفیتیکوس , استافیلوکوکوس اپیدرمیدیس , مقاومت به متی سیلین , ماکرولید , لینکوزامید