Staphylococcus aureus burden of worn face mask at different time usage among undergraduate preclinical medical students.

Abstract

Background:
The prolonged use of face masks has become routine in both healthcare and community settings, particularly following the COVID-19 pandemic. While face masks are effective in preventing respiratory infections, extended usage without appropriate hygiene may promote bacterial accumulation, potentially disrupting the skin and nasal microbiome and increasing the risk of self-contamination and infection.

Objective:
This study aimed to evaluate bacterial contamination on surgical face masks worn for different durations and to assess the presence of Staphylococcus aureus as an indicator of contamination risk among undergraduate preclinical medical students.

Methods:
A quantitative descriptive study was conducted involving 30 randomly selected preclinical undergraduate medical students. Participants wore new disposable surgical face masks for four hours and seven hours on separate days during routine academic activities. The face-side of each mask was swabbed and cultured on Mannitol Salt Agar (MSA). Colony-forming units (CFU) were enumerated, followed by Gram staining and coagulase testing to identify Staphylococcus aureus. Statistical analysis was performed using paired-sample t-tests with a significance level set at p < 0.05.

Results:
The total bacterial load on face masks increased significantly with prolonged wearing time. Masks worn for seven hours showed a higher mean total colony count compared to those worn for four hours (p < 0.05). Notably, yellow colonies indicative of Staphylococcus aureus increased by 83.33% between four and seven hours of mask usage. Coagulase testing confirmed the presence of S. aureus, highlighting a greater contamination risk associated with extended mask use.

Conclusion:
Prolonged use of face masks is associated with a significant increase in bacterial contamination, particularly Staphylococcus aureus. These findings emphasize the importance of proper mask hygiene and timely replacement to minimize self-contamination risks. The study provides practical insights for infection prevention among medical students and underscores the need for further research to establish optimal safe durations for face mask usage.