PREVALENCE OF STAPHYLOCOCCUS AUREUS NASAL CARRIAGE IN ASYMPTOMATIC OTHERWISE HEALTHY INDIVIDUALS

Abstract

Staphylococcus aureus is a bacterium that can colonize many surfaces and cause various infections, including skin and bloodstream infections. Although it can be asymptomatic, nasal colonization with S.aureus is a risk factor for serious staphylococcal infections, such as surgical site infections, bacteremia, skinand soft tissue infections, etc. The aim of this study was to determine the prevalence of S. aureus nasal colonization among medical students aged 19-21 years old who have not undergone clinical rotations. Nasal
swabs were taken from both nostrils and immediately plated onto 5% sheep blood agar and identified using a Staphaurex™ Latex Agglutination Test. We found that 10/59 students (16.9%) carry S. aureus in their nostrils, while the rest showed mixed growth of Coagulase negative Staphylococci and Corynebacterium spp. Additionally, 1/10 of S. aureus colonizers showed pure growth of S. aureus. Antibiotic susceptibility testing on the isolated S. aureusshowed 100% sensitivity against either Ciprofloxacin, Gentamicin, and
Linezolid; sensitivity of 90%, 80%, 70%, 40%, and 30% against Cefoxitin,
Trimethoprim/Sulfamethoxazole, Clindamycin, Azithromycin, and Penicillin, respectively. It is noteworthy that 1/10 (10%) of S.aureus isolate was MRSA (Methicillin Resistant Staphylococcus aureus). The prevalence of S. aureus nasal carriage in asymptomatic otherwise healthy individuals is relatively high, and caution is needed as they may act as a source of infection to people who are at risk for severe S. aureus infections.

Keywords: staphylococcus aureus, prevalence, medical students