Exposure to resistant fungi across working environments and time.

Antifungal resistance has emerged as a significant health concern with increasing reports of resistant variants in previously susceptible species. At present, little is known about occupational exposure to antifungal-resistant fungi. This study aimed to investigate Danish workers' occupational exposure to airborne fungi resistant to first-line treatment drugs. A retrospective study was performed on a unique collection of personal exposure samples gathered over a twenty-year period from Danish working environments, in sectors including agriculture, animal handling, waste management, and healthcare. A total of 669 samples were cultivated at 37 °C and fungal colonies were identified using MALDI-TOF MS. Subsequently, identification was confirmed by amplicon sequencing the genes of calmodulin and beta-tubulin to unveil potential cryptic species. Infectious fungi (495 isolates from 23 species) were tested for resistance against Itraconazole, Voriconazole, Posaconazole, and Amphotericin B. Working environments were highly variable in the overall fungal exposure, and showed vastly different species compositions. Resistance was found in 30 isolates of the species Aspergillus fumigatus (4 of 251 isolates), A. nidulans (2 of 13), A. niger complex (19 of 131), A. versicolor (3 of 18), and A. lentulus (2 of 2). Sequence analysis revealed several cryptic species within the A. niger complex including A. tubingensis, A. luchuensis, and A. phoenicis. Among the resistant A. fumigatus isolates, two contained the well-described TR34/L98H mutation in the cyp51A gene and promoter region, while the remainder harbored silent mutations. The results indicate that the working environment significantly contributes to exposure to resistant fungi, with particularly biofuel plant workers experiencing high exposure. Differences in the prevalence of resistance across working environments may be linked to the underlying species composition.

A cross-sectional study on occupational exposure to microorganisms, endotoxin, hydrogen sulfide, and dust during work at drilling waste treatment plants.

This cross-sectional study aims to obtain knowledge about workers' exposure to airborne dust, bacterial and fungal species, endotoxin, biofilm formation, and hydrogen sulfide (H2S) in drilling waste treatment plants. In total, 408 full-shift personal samples, 66 work areas, 40 drilling waste, and reference (outdoor air and seawater) samples were analyzed. Some workers were exposed to high levels of endotoxin (207 EU/m3), bacteria (3.8 × 104 colony forming units (CFU)/m3 and 9.8 × 104 DNA copies/m3), or fungi (1.4 × 107 CFU/m3 and 3,600 copies/m3). The exposure levels to endotoxin, bacteria, and peaks of H2S were dependent on the treatment technique. All types of drilling waste contained large concentrations of bacteria compared to the seawater references. Elevated concentrations of airborne bacteria were found close to drilling waste basins. In total, 116, 146, and 112 different bacterial species were found in workers' exposure, work areas, and the drilling waste, respectively. An overlap in bacterial species found in the drilling waste and air (personal and work area) samples was found. Of the bacterial species found, 49 are classified as human pathogens such as Escherichia coli, Enterobacter cloacae, and Klebsiella oxytoca. In total, 44 fungal species were found in the working environment, and 6 of these are classified as human pathogens such as Aspergillus fumigatus. In conclusion, across the drilling waste treatment plants, human pathogens were present in the drilling waste, and workers' exposure was affected by the drilling waste treated at the plants with elevated exposure to endotoxin and bacteria. Elevated exposure was related to working as apprentices or chemical engineers, and working with cleaning, or slop water, and working in the daytime.

A cohort study of wastewater treatment plant workers: Association between levels of biomarkers of systemic inflammation and exposure to bacteria and fungi, and endotoxin as measured using two methods.

Work in wastewater treatment plants (WWTPs) can be associated with exposure to airborne microorganisms and endotoxin from the working environment. The aim of this study was to obtain knowledge about whether serum levels of the markers of systemic inflammation, C-reactive protein (CRP) and serum amyloid A (SAA), are associated with personal exposure to endotoxin, measured using the Limulus (endotoxinLimulus) and the rFC (endotoxinrFC) assays, as well as bacteria and fungi in a cohort of WWTP workers. Exposure and blood samples were collected for 11 workers over one year. Exposure to endotoxinLimulus-day and endotoxinrFC-day correlated significantly (r = 0.80, p<0.0001, n = 104), but endotoxinLimulus-day was 4.4 (Geometric mean (GM) value) times higher than endotoxinrFC-day (p<0.0001). The endotoxinLimulus-day, endotoxinrFC-day, bacteria, and fungal exposure as well as serum levels of CRP-day (GM=1.4 mg/l) and SAA-day (GM=12 mg/l) differed between workers. Serum levels of SAAday correlated significantly with CRPday (r = 0.30, p = 0.0068). The serum levels of CRPday were associated significantly with exposure to endotoxinLimulus-day. Exposure, SAA and CRP data were also analyzed as av. of each season, and SAAseason was associated positively and significantly with endotoxinLimulus-season and endotoxinrFC-season and negatively with fungalseason exposure. In conclusion, CRPday was associated with the endotoxinLimulus-day and SAAseason with endotoxinLimulus-season and endotoxinrFC-season exposure. Thus, we hereby document that WWTP workers are exposed to airborne endotoxin which seems to have a negative impact on their health.