Microbial Occupational Exposure Assessments in Sawmills—A Review

Abstract

The composition of airborne microflora in sawmills may vary to a great degree depending on the kind of timber being processed and the technology of production being used. Cases of allergy alveolitis and asthma have been reported in woodworkers who were exposed to wood dust largely infected with microorganisms. The aim of this review article is to identify studies where the microbial occupational exposure assessment was performed in sawmills and the characteristics of the contamination found, as well as to identify which sampling methods and assays were applied. This study reports the search of available data published regarding microbial occupational exposure assessment in environmental samples from sawmills, following the Preferred Reporting Items for Systematic Reviews (PRISMA) methodology. The most used sampling method was air sampling, impaction being the most common method. Regarding analytical procedures for microbial characterization, morphological identification of fungi and bacteria was the most frequent approach. Screening for fungal susceptibility to azoles was performed in two studies and four studies applied molecular tools. Regarding microbial contamination, high fungal levels were frequent, as well as high bacteria levels. Fungal identification evidenced Penicillium as the most frequent genera followed by Aspergillus sp. Mycotoxins were not assessed in any of the analyzed studies. Microbial occupational exposure assessment in sawmills is crucial to allow this risk characterization and management.

Development of an Indexed Score to Identify the Most Suitable Sampling Method to Assess Occupational Exposure to Fungi

“…Settled dust is considered a passive sampling method that has been described as being more repeatable than active sampling procedures in terms of anticipating microbial levels in indoor air [8,19]. It has also been documented as an environmental support for bacterial development, making it a bacterial contamination reservoir [8,29].…”

“…Settled dust is considered a passive sampling method that has been described as being more repeatable than active sampling procedures in terms of anticipating microbial levels in indoor air [8,19]. It has also been documented as an environmental support for bacterial development, making it a bacterial contamination reservoir [8,29]. Depending on the location and surroundings of a workplace or facility, as well as the occupants and their activities, dust contains a wide range of components in various proportions [30].…”

“…In fact, the use of culture-dependent methods is vital to predict potential health risks since microbial viability affects inflammatory and cytotoxic responses [1,2]. Additionally, it Atmosphere 2022, 13, 1123 2 of 12 requires obtaining fungal isolates to characterize the resistance azole profile from a specific occupational environment [5,7,8].…”

“…Microbial determination procedures can be accomplished by diverse techniques. Regarding sampling methods for bioaerosols assessment, air sampling is recurrent [8], and the impaction method is the most frequently used [9,10]. This sampling approach relies exclusively on culture-based methods [8], enabling microorganisms' quantification and identification [11][12][13].…”

“…Regarding sampling methods for bioaerosols assessment, air sampling is recurrent [8], and the impaction method is the most frequently used [9,10]. This sampling approach relies exclusively on culture-based methods [8], enabling microorganisms' quantification and identification [11][12][13]. However, since it can only evaluate culturable microorganisms, the microbial counts may be undervalued due to the short sampling time or the conditions set on the sampling device, since high velocity of the air flow may result in cell damage, compromising the microorganisms' viability [12,13].…”