Investigating cross‐contamination by yeast strains from dental solid waste to waste‐handling workers by DNA sequencing

Abstract

Trying to widen the discussion on the risks associated with dental waste, this study proposed to investigate and genetically compare yeast isolates recovered from dental solid waste and waste workers. Three samples were collected from workers' hands, nasal mucosa, and professional clothing (days 0, 30, and 180), and two from dental waste (days 0 and 180). Slide culture, microscopy, antifungal drug susceptibility, intersimple sequence repeat analysis, and amplification and sequencing of internal transcribed spacer regions were performed. Yeast strains were recovered from all waste workers' sites, including professional clothes, and from waste. Antifungal susceptibility testing demonstrated that some yeast recovered from employees and waste exhibited nonsusceptible profiles. The dendrogram demonstrated the presence of three major clusters based on similarity matrix and UPGMA grouping method. Two branches displayed 100% similarity: three strains of Candida guilliermondii isolated from different employees, working in opposite work shifts, and from diverse sites grouped in one part of branch 1 and cluster 3 that included two samples of Candida albicans recovered from waste and the hand of one waste worker. The results suggested the possibility of cross‐contamination from dental waste to waste workers and reinforce the need of training programs focused on better waste management routines.

Environmental reservoirs of the drug-resistant pathogenic yeast Candida auris

“…Contaminated clinical solid waste is a proven pathway for the introduction of pathogenic microorganisms into the environment [65], and clinical wastes contaminated with pathogenic species of Candida, e.g., C. albicans, C. glabrata, and C. parapsilosis, have previously been reported [66]. C. auris shows an increased ability to persist on dry inanimate surfaces compared to C. albicans [67] and can persist in biofilms on inanimate surfaces, e.g., plastics, for significant periods [68][69][70].…”

Health and Environmental Impact of Hospital Wastes: Systematic Review

“…Vieira et al [28] were able to demonstrate the possibility of cross-contamination between dental waste and the handlers of this waste, by highlighting strains of yeast recovered from dental waste treatment sites, including professional clothing, and in dental waste. Finally, a major but not yet resolved concern about the use of dental amalgam is its potential impact on the health of the population given its widespread use in dentistry.…”

“…Overall, the main terms used were "Medical waste" or "Clinical waste" [22][23][24], "Solid hospital waste" [25], "Healthcare waste" [26,27]. Other publications have studied a specific typology of waste, such as "Solid dental waste" [28,29] and "Regulated medical waste/Red bag waste" [30].…”