Staphylococcus aureus como modelo de testagem da eficácia das máscaras utilizadas em sala de aula de curso da saúde em Belo Horizonte – MG

Abstract

This study evaluated the effectiveness of masks as a protective barrier against droplets and splashes that could contain different pathogens. For this purpose, a model employing Staphylococcus aureus was used to evaluate the effectiveness of the masks. In this model, the participating volunteers quantified bacteria droplets under two conditions: with and without masks. Three types of masks were tested: cloth, surgical, and PFF-2. Forty volunteers were selected and positioned at a distance of 30 centimeters from the plate containing the mannitol agar culture medium. For 60 seconds, in a standardized manner, they uttered words facing the plate using the mask and then without using it. A microorganism count and the microbial control efficacy of the three types of masks were performed. The colonies collected on mannitol agar medium were stained by Gram, and the biochemical tests of catalase, toluidine blue DNAse, coagulase test, and antibiogram were performed. It was observed that the use of a mask, even if it is made of fabric, is more effective as a protective barrier against different pathogenic microorganisms than not using any mask or filtering piece. There was a significant difference in filtering the three models used by the volunteers in this study. The cloth mask was the one that least filtered the microdroplets emitted by the volunteers on the plates, just being more effective to the practice without a mask, in which the highest number of grown colonies and the colonies that were most positive in the biochemical tests performed. The surgical mask proved an effective barrier, filtering most of the microdroplets and reaching a low level of colonies grown on the plates. Moreover, finally, the PFF-2 proved to be an excellent barrier against the microdroplets, filtering and blocking the possible pathogenic microorganisms expelled by the volunteers on the plates.