Assessment of fungal hazards in archives based on nasal swab samples

Abstract

BACKGROUND AND AIM Scientists are looking for exposure indicators that could accurately describe the impact of bioaerosols on workers’ health. Especially useful in this regard seems to be the swabs collected from the nose or nasopharynx, which represent easy to obtain biological samples. The aim of this study was to identify a mycobiota occurring in the upper respiratory tract of archive workers as a result of work shift exposure. METHODS Eleven workers from three archives and two libraries participated in this study. Each of them was equipped with a personal measurement set consist of CIS sampler to check the concentration of inhalable dust and, after work shift, the swab samples from nasal cavity were collected. Qualitative mycobiota analysis was performed using culture-based method and isolated pathogens were additionally diagnosed based on MALDI-TOF MS. RESULTS The average fungal concentration in swab samples was 43 CFU/ml, (SD=59). In turn, the concentrations of airborne fungi were very variable and depended on the place of measurement (mean value: 2916 CFU/m³, SD=3051). The qualitative analysis of the samples revealed the presence of 33 fungal species belonging to 17 genera. The swab samples were dominated by the yeast of Candida genus and filamentous fungi from Penicillium and Aspergillus genera. It was shown that 59% of identified fungal strains were simultaneously present in the air at workplaces and in the nasal cavities of employees. Two isolated fungal genera, i.e., Aspergillus and Microsporum, represent human pathogens classified in risk group 2, according to the Commission Directive (EU) 2019/1833. CONCLUSIONS As airborne fungi in archives and libraries can colonize the upper respiratory tract of workers, the microbiologcal analysis of nasal swabs can be a precise tool to assess the exposure to biological aerosol in this working environment. KEYWORDS archive workers, exposure assessment, fungal aerosols, nasal swabs