Cotton and Surgical Face Masks in Community Settings: Bacterial Contamination and Face Mask Hygiene

Abstract

During the current COVID-19 pandemic, the use of face masks has become increasingly recommended and even mandatory in community settings. To evaluate the risk of bacterial cross-contamination, this study analyzed the bacterial bioburden of disposable surgical masks and homemade cotton masks, and surveyed the habits and face mask preferences of the Flemish population. Using culture approaches and 16S rRNA gene amplicon sequencing, we analyzed the microbial community on surgical and/or cotton face masks of 13 healthy volunteers after 4 h of wearing. Cotton and surgical masks contained on average 1.46 × 105 CFU/mask and 1.32 × 104 CFU/mask, respectively. Bacillus, Staphylococcus, and Acinetobacter spp. were mostly cultured from the masks and 43% of these isolates were resistant to ampicillin or erythromycin. Microbial profiling demonstrated a consistent difference between mask types. Cotton masks mainly contained Roseomonas, Paracoccus, and Enhydrobacter taxa and surgical masks Streptococcus and Staphylococcus. After 4 h of mask wearing, the microbiome of the anterior nares and the cheek showed a trend toward an altered beta-diversity. According to dedicated questions in the large-scale Corona survey of the University of Antwerp with almost 25,000 participants, only 21% of responders reported to clean their cotton face mask daily. Laboratory results indicated that the best mask cleaning methods were boiling at 100°C, washing at 60°C with detergent or ironing with a steam iron. Taken together, this study suggests that a considerable number of bacteria, including pathobionts and antibiotic resistant bacteria, accumulate on surgical and even more on cotton face masks after use. Based on our results, face masks should be properly disposed of or sterilized after intensive use. Clear guidelines for the general population are crucial to reduce the bacteria-related biosafety risk of face masks, and measures such as physical distancing and increased ventilation should not be neglected when promoting face mask use.

Bacterial contamination on the inner surface of the masks used by clinicians in a dental clinic

“…One study confirmed that pathogenic bacteria accumulated when both surgical and cotton masks were worn for more than 4 h, 11 and according to the Australian Dental Association (ADA) infection control guidelines, the filtration capacity of the mask starts to decrease after about 20 min, as moisture fills the inner and outer surfaces of the mask. 12 According to the World Health Organization (WHO) recommendations, medical masks are for a single use only, and once used, they should be discarded immediately.…”

Antibacterial Activity of Electrospun Polyacrylonitrile Copper Nanoparticle Nanofibers on Antibiotic Resistant Pathogens and Methicillin Resistant Staphylococcus aureus (MRSA)

“…CAP-causing microbes tend to remain on high contact surfaces for extended periods of time if they are not eliminated [34][35][36][37]. It is common for community acquired diseases, especially lung infections like CAP caused by S. aureus variations, to reside atop high contact surfaces such as masks, handles, or clothing [38][39][40].…”

Modification of face masks with zeolite imidazolate framework-8: A tool for hindering the spread of COVID-19 infection

“…Despite research like the aforementioned indicating the positive effect of wearing masks on the current pandemic, understanding of the influence of masks on the transmission of laboratory-diagnosed respiratory viruses remains incomplete [9] , [10] , [11] . For example, research on mask effectiveness [12] does not take into consideration that bacteria in human saliva and exhaled breath might constitute a biosafety concern [13] , particularly with long-term mask usage or mask reuse without appropriate disinfection. Hasan et al.…”