Methicillin-Resistant Staphylococci (MRS): Carriage and Antibiotic Resistance Patterns in College Students

Asymptomatic carriage of methicillin-resistant Staphylococci (MRS) may allow for the unseen dissemination of antibiotic-resistant strains through the population. This study investigates the prevalence and epidemiological risk factors that contribute to the spread of MRS in a university setting in Amman, Jordan. A cross-sectional questionnaire-based study was performed in December 2019. Five hundred and four students enrolled in the study and provided skin and nasal swabs. Swabs were then processed to isolate MRS on Mannitol Salt Agar (MSA) + 4 µg/ml oxacillin. Isolates were tested for their antibiotic susceptibility using the disc diffusion assay. Epidemiological risk assessment was performed using the Chi-square test and univariate and multivariant analysis. The percentage carriage of MRS in the 504 students was 40.4%. The carriage rate of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) from the skin and nasal areas was 13.5% and 26.9%, respectively. The percentage of male carriers was significantly higher than females, and the only identified epidemiological risk factor related to the carriage was attendance at a fitness club. All MRS isolates were resistant to oxacillin (100%), cefoxitin (45.5%), erythromycin (35.2%), gentamycin (10.2%), ciprofloxacin (12.7%), nitrofurantoin (12.2%), linezolid (7.8%), amikacin (1.47%), and Vancomycin (0.49%). 42% of MRS expressed a multiple antibiotic resistance (MAR) index above 0.2. Three isolates expressed a MAR index of 0.8. MRS has been exhibited to be present in an otherwise healthy population of students, which may then act as a reservoir for MAR strains.