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Bacterial and fungal isolation from face masks under the COVID-19 pandemic
Ah-Mee Park1, Sundar Khadka2, Fumitaka Sato2
1Department of Microbiology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan. ampk@med.kindai.ac.jp.
Abstract:
The COVID-19 pandemic has led people to wear face masks daily in public. Although the effectiveness of face masks against viral transmission has been extensively studied, there have been few reports on potential hygiene issues due to bacteria and fungi attached to the face masks. We aimed to (1) quantify and identify the bacteria and fungi attaching to the masks, and (2) investigate whether the mask-attached microbes could be associated with the types and usage of the masks and individual lifestyles. We surveyed 109 volunteers on their mask usage and lifestyles, and cultured bacteria and fungi from either the face-side or outer-side of their masks. The bacterial colony numbers were greater on the face-side than the outer-side; the fungal colony numbers were fewer on the face-side than the outer-side. A longer mask usage significantly increased the fungal colony numbers but not the bacterial colony numbers. Although most identified microbes were non-pathogenic in humans; Staphylococcus epidermidis, Staphylococcus aureus, and Cladosporium, we found several pathogenic microbes; Bacillus cereus, Staphylococcus saprophyticus, Aspergillus, and Microsporum. We also found no associations of mask-attached microbes with the transportation methods or gargling. We propose that immunocompromised people should avoid repeated use of masks to prevent microbial infection.
Insights
Daily face mask use can lead to bacterial and fungal growth. Longer mask wear increases fungi, posing a risk, especially for immunocompromised individuals. Reusable masks require careful hygiene management.
Area of Science:
- Microbiology
- Public Health
- Epidemiology
Background:
- The COVID-19 pandemic necessitated widespread daily face mask use.
- While mask efficacy against viral transmission is known, potential microbial contamination (bacteria, fungi) on masks is under-researched.
- Understanding mask-associated microbes is crucial for public health and hygiene.
Purpose of the Study:
- To quantify and identify bacteria and fungi on used face masks.
- To investigate links between mask microbes, mask type, usage duration, and individual lifestyles.
- To assess the public health implications of microbial contamination on face masks.
Main Methods:
- Surveyed 109 volunteers on mask usage and lifestyle factors.
- Cultured bacteria and fungi from the inner (face-side) and outer surfaces of used face masks.
- Identified microbial species using standard microbiological techniques.
Main Results:
- Bacterial colonies were more numerous on the mask's inner surface compared to the outer surface.
- Fungal colonies were less numerous on the inner surface than the outer surface.
- Extended mask usage correlated with increased fungal growth, but not bacterial growth. Pathogenic microbes like Staphylococcus aureus and Aspergillus were identified.
Conclusions:
- Face masks can harbor diverse microbial communities, including potentially pathogenic species.
- Prolonged mask use may promote fungal proliferation, posing a risk.
- Immunocompromised individuals should exercise caution with reusable masks to prevent potential microbial infections.
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