Staphylococcus aureus Nasal Carriage among Medical Students at Damascus University, Syria

Background: Some healthcare workers, including medical students, are carriers of nasal Staphylococcus aureus and could pose as a nasal source of transmission. Objectives: The aims of the study are to determine the rate of nasal carriers of S. aureus among medical students in the different stages of the study (preclinical stage and clinical stage) and to determine the susceptibility pattern of isolated strains of S. aureus to some commonly used antibiotics. Materials and Methods: Nasal swabs were collected from 370 medical students. The antimicrobial susceptibility for commonly used antibiotics was determined for all positive isolates. Results: Nasal carriage among medical students in all stages was (21%), with a significant difference between the groups of preclinical and clinical stags. The high carriage rate of S. aureus was found in smoking and older students. The overall methicillin-resistant S. aureus (MRSA) carriage rate among all students was 8.3%. MRSA carriage had a high rate among S. aureus carrier students (39.7% of positive isolates were MRSA). A high rate of MRSA carriage was found in students of the clinical stage in comparison to premedical students. MRSA strains were highly resistant for most commonly used antibiotics: penicillin (100%), ampicillin (93.6%), amoxicillin/clavulanate (84%), erythromycin (74.2%), clindamycin (71%), and ceftriaxone (47%), while a moderate or low resistance rate was against ciprofloxacin and gentamycin (49.4%). Conclusion: The difference in the carriage rates of S. aureus among preclinical and clinical medical students was statistically insignificant. High rates of MRSA carriage were also detected among students of the clinical stage. MRSA strains in our study were highly resistant to most commonly used antibiotics.