Surgical masks as source of bacterial contamination during operative procedures

Abstract

BackgroundSurgical masks (SMs) are used to reduce bacterial shedding from the mouth, nose and face. This study aimed to investigate whether SMs may be a potential source of bacterial shedding leading to an increased risk of surgical site infection.MethodsBacterial contamination of the SMs was tested by making an impression of the external surface of the mask on sterile culture media immediately. We investigated the difference in bacterial counts between the SMs worn by surgeons and those placed unused in the operating room (OR), and the bacterial count variation with indicated wearing time. Moreover, the difference in bacterial counts on the external surface between the first and second layers of double-layered SMs was also assessed.ResultsThe bacterial count on the surface of SMs increased with extended operating times; significant difference was found between the 4- to 6-hour and 0-hour groups (p < 0.05). When we analysed the bacterial counts from the same surgeon, a significant increase was noted in the 2-hours group. Moreover, the bacterial counts were significantly higher among the surgeons than the OR. Additionally, the bacterial count of the external surface of the second mask was significantly higher than that of the first one.ConclusionsThe source of bacterial contamination in SMs was the body surface of the surgeons rather than the OR environment. Moreover, we recommend that surgeons should change the mask after each operation, especially those beyond 2 hours. Double-layered SMs or those with excellent filtration function may also be a better alternative.The translational potential of this articleThis study provides strong evidence for the identification that SMs as source of bacterial contamination during operative procedures, which should be a cause for alarm and attention in the prevention of surgical site infection in clinical practice.

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“…Inclusion criteria were (1) study type: RCT (including cluster‐randomized trial) and nonrandomized controlled study; (2) participants: humans with influenza (including pandemic strains, seasonal influenza A or B viruses and zoonotic viruses such as swine or avian influenza), and other respiratory viral infections (as a proxy for influenza); (3) intervention and comparator: N95 respirators versus surgical masks; (4) primary outcome: laboratory‐confirmed influenza; (5) secondary outcomes: laboratory‐confirmed respiratory viral infections, laboratory‐confirmed bacterial colonization, laboratory‐confirmed respiratory infection, and influenzalike illness; and (6) settings: hospital or community. RCTs were selected due to the potential possibility of high evidence level.…”

Community Masks During the SARS-CoV-2 Pandemic: Filtration Efficacy and Air Resistance

“…(20) Mathematical models to assess the likely effectiveness of facemasks on the reproduction number (R) have highlighted the importance of the filtration efficacy. (26) The third-party and self-contamination risk increases with the working life of a protective mask (27,28) ; therefore, a regular change or a regular cleaning is mandatory. It is assumed that the moisture in the mask cloth as well as the contamination rate of the mask with airborne pathogens increases significantly with longer use of the masks.…”

“…(29) Infectious particles from the mask surface could be further spread by contact or re-aerosolization causing self-infection or infection of others. (27)(28)(29) With regard to the change intervals and hygienic preparation, it is advisable not to exceed a total wearing time of 6 hours. (27) The mask should then be disinfected.…”

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