Exposure to airborne mycotoxins: the riskiest working environments and tasks.

OBJECTIVES: There is growing interest in the role of airborne mycotoxins in occupational environments, however, their impact on human health still remains poorly investigated. This review aims to provide a comprehensive analysis of the existing literature on the occurrence of inhalable mycotoxins in working environments to investigate which sectors and tasks are at greater risk of exposure. METHODS: We have performed a systematic search in the PubMed, Scopus and Web of Science databases from 2010 to date, without limitation of geographic location. RESULTS: Database searches yielded 350 articles. After the removal of duplicates and applying our inclusion and exclusion criteria, 31 papers remained. Results show that the most exposed workers are those engaged in activities related to animal care and management and, in particular, in feeding tasks, while harvester cleaning seems to be the activity with the highest levels of exposure in agriculture. In healthcare settings mycotoxin concentrations are low but HVAC systems can be a source of contamination and this reinforces the relevance of further studies in this sector. The most common scenario is the exposure to multiple mycotoxins with variable concentrations depending on the working environment, the products handled or the tasks performed by workers. Some authors emphasize the importance of multi-approach sampling and analysis protocols to achieve an accurate and more realistic risk characterization. CONCLUSIONS: Results brought forward by this review can be utilized by health and safety professionals to recognize activities in which workers may be potentially exposed to airborne mycotoxins and thus undertake suitable preventive and protective measures.

A Pilot Study for Legionella pneumophila Volatilome Characterization Using a Gas Sensor Array and GC/MS Techniques.

Legionellosis is a generic term describing the pneumonic (Legionnaires' disease, LD) and non-pneumonic (Pontiac fever, PF) forms of infection with bacteria belonging to the genus Legionella. Currently, the techniques used to detect Legionella spp. in water samples have certain limitations and drawbacks, and thus, there is a need to identify new tools to carry out low-cost and rapid analysis. In this regard, several studies demonstrated that a volatolomics approach rapidly detects and discriminates different species of microorganisms via their volatile signature. In this paper, the volatile organic compounds (VOCs) pattern emitted in vitro by Legionella pneumophila cultures is characterized and compared to those produced by other Legionella species and by Pseudomonas aeruginosa, using a gas sensor array and gas chromatograph mass spectrometer (GC-MS). Bacterial cultures were measured at the 3rd and 7th day after the incubation. Sensor array data analyzed via the K-nearest neighbours (k-NN) algorithm showed a sensitivity to Legionella pneumophila identification at around 89%. On the other hand, GC-MS identified a bouquet of VOCs, mainly alcohols and ketones, that enable the differentiation of Legionella pneumophila in respect to other waterborne microorganisms.

Mapping Biological Risks Related to Necropsy Activities: Old Concerns and Novel Issues for the Safety of Health Professionals.

Nowadays only a few studies on biological and environmental risk among healthcare workers are available in literature. The present study aims to assess the health operator's risk of contact with microorganisms during necropsy activities, to evaluate the efficiency of current protections, to identify possible new sources of contact, and to point out possible preventive measures. In addition, considering the current pandemic scenario, the risk of transmission of SARS-CoV-2 infection in the dissection room is assessed. The objectives were pursued through two distinct monitoring campaigns carried out in different periods through sampling performed both on the corpses and at the environmental level.

Aspergillus Species Discrimination Using a Gas Sensor Array.

The efficiency of electronic noses in detecting and identifying microorganisms has been proven by several studies. Since volatile compounds change with the growth of colonies, the identification of strains is highly dependent on the growing conditions. In this paper, the effects of growth were investigated with different species of Aspergillus, which is one of the most studied microorganisms because of its implications in environmental and food safety. For this purpose, we used an electronic nose previously utilized for volatilome detection applications and based on eight porphyrins-functionalized quartz microbalances. The volatile organic compounds (VOCs) released by cultured fungi were measured at 3, 5, and 10 days after the incubation. The signals from the sensors showed that the pattern of VOCs evolve with time. In particular, the separation between the three studied strains progressively decreases with time. The three strains could still be identified despite the influence of culture time. Linear Discriminant Analysis (LDA) showed an overall accuracy of 88% and 71% in the training and test sets, respectively. These results indicate that the presence of microorganisms is detectable with respect to background, however, the difference between the strains changes with the incubation time.

Exposure to airborne endotoxin in Italian greenhouses: environmental analyses.

The peculiar characteristics of the greenhouses as confined spaces, microclimate and poor air exchange with the outside environment, encourage the development of a large number of biological agents. Endotoxin, is probably a major causative agent of occupational health problems. The objective of this study was to measure the concentrations of airborne endotoxin in greenhouses with different cultures. The influence of microclimate was studied in correlation with endotoxin levels and type of cultured vegetables. The data indicate that workers employed greenhouses are exposed to low levels of inhalable endotoxins; endotoxin concentrations do not correlate with the temperature and relative humidity values. A strong correlation between the leaf size and endotoxin concentration was observed. The mean concentration of endotoxins in the air of greenhouses is relatively low, however, there could be peaks of exposure during harvesting and eradication of broadleaf plants.

Validation of a high performance liquid chromatography-tandem mass spectrometry method for ß-hydroxy fatty acids as environmental markers of lipopolysaccharide.

The most commonly analytical method used for the assessment of the occupational exposure to airborne endotoxins is the LAL test, but other methods are reported in the literature. The objective of this work was to develop and validate a method using HPLC coupled to triple quadrupole mass spectrometer for the quantitative determination of ß-hydroxy-dodecanoic and ß-hydroxy-tetradecanoic acids as chemical markers of lipopolysaccharide in Gram-negative strains. Matrix effect was significant but compensated by the use of internal standard; accuracy was always more than 85% and variability always less than 10%. LOD and LLOQ were respectively 2.5 µg/l and 10 µg/l for ß-hydroxy-dodecanoic acid, 1 µg/l and 5 µg/l for ß-hydroxy-tetradecanoic acid. The analysis of different bacterial strains showed that samples contain ß-hydroxy-dodecanoic and ß-hydroxy-tetradecanoic acids in variable ratio, and therefore the sum of their concentrations was considered the chemical marker. The method showed a significant correlation of results with those of LAL-test on four bacterial strains.

Exposure to airborne culturable microorganisms and endotoxin in two Italian poultry slaughterhouses.

Even if slaughterhouses' workers handle large amounts of organic material and are potentially exposed to a wide range of biological agents, relatively little and not recent data are available. The main objective of this study was to characterize indoor concentrations of airborne bacteria, fungi, and endotoxin mod = Im (endotoxin∼Gram-negative*plant*filter) in two Italian poultry slaughterhouses. Air samples near air handling units inlets were also collected. Since there are not standardized protocols for endotoxin sampling and extraction procedures, an additional aim of the study was to compare the extraction efficiency of three different filter.. The study was also aimed at determining the correlation between concentrations of Gram-negative bacteria and endotoxin. In Plant A bacterial levels ranged from 17.5 to 2.6×10(3) CFU/m3. The highest concentrations were observed in evisceration area of chickens, between the automatic detachment of the neck and washing offal, and near birds coupling before hair-chilling. The highest mean value of Gram-negative (266.5 CFU/m3) was found near the washing offal of turkeys. In Plant B bacterial concentration ranged from 35 to 8×10(3) CFU/m3. The highest concentration. with the highest value of Gram-negative (248 CFU/m3), was found after defeathering. Fungal concentrations were overall lower than those found for bacteria (range: 0-205 CFU/m3 in Plant A and 0-146.2 CFU/m3 in Plant B). The microbial flora was dominated by Gram-negative and coagulase-negative staphylococci for bacteria and by species belonging to Cladosporium, Penicillium and Aspergillus genera for molds. The highest endotoxin concentrations were measured in washing offal for Plant A (range: 122.7-165.9 EU/m3) and after defeathering for Plant B (range: 0.83-38.85 EU/m3). In this study airborne microorganisms concentrations were lower than those found in similar occupational settings and below the occupational limits proposed by some authors. However, these microorganisms may exert adverse effects on exposed workers, in particular for those engaged in the early slaughtering stages, as evidenced by the presence of pathogenic species. The detection of pathogenic bacteria near AHU inlet may constitute a risk to public health and environmental pollution.

Indoor exposure to airborne endotoxin: a review of the literature on sampling and analysis methods.

Assessment of exposure to airborne endotoxins has been studied for several years, especially in occupational environments, but a large number of procedures are used for sampling and analysis. This lack of standardization makes it very difficult to compare results and set internationally accepted threshold limit values (TLVs) or occupational exposure limits (OELs) for endotoxin exposure. This paper reviews the methods reported, using advanced bibliographical search techniques: 82 papers published from 2004 to the present were selected to analyze methods for the assessment of human exposure to airborne endotoxins, with particular reference to occupational settings, and to examine their performance and critical points. Only few studies have focused on the standardization of sampling and analysis methods. The European Committee for Standardization Guidelines coincide with the procedures most frequently applied, but this does not guarantee the best results in terms of recovery and reproducibility. The factor that mainly affects endotoxin measurements is the extraction method, the main concern being the presence in the samples of a fraction insoluble in aqueous media. If substantial differences in the proportions of this fraction in different environments are confirmed in the future, the contribution of insoluble endotoxins cannot be neglected.

Multi-walled carbon nanotubes induce cytotoxicity and genotoxicity in human lung epithelial cells.

The increasing use of nanomaterials in consumer products highlights the importance of understanding their potential toxic effects. We evaluated cytotoxic and genotoxic/oxidative effects induced by commercial multi-walled carbon nanotubes (MWCNTs) on human lung epithelial (A549) cells treated with 5, 10, 40 and 100 µg ml⁻¹ for different exposure times. Scanning electron microscopy (SEM) analysis, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and lactate dehydrogenase (LDH) assays were performed to evaluate cytotoxicity. Fpg-modified comet assay was used to evaluate direct-oxidative DNA damage. LDH leakage was detected after 2, 4 and 24 h of exposure and viability reduction was revealed after 24 h. SEM analysis, performed after 4 and 24 h exposure, showed cell surface changes such as lower microvilli density, microvilli structure modifications and the presence of holes in plasma membrane. We found an induction of direct DNA damage after each exposure time and at all concentrations, statistically significant at 10 and 40 µg ml⁻¹ after 2 h, at 5, 10, 100 µg ml⁻¹ after 4 h and at 10 µg ml⁻¹ after 24 h exposure. However, oxidative DNA damage was not found. The results showed an induction of early cytotoxic effects such as loss of membrane integrity, surface morphological changes and MWCNT agglomerate entrance at all concentrations. We also demonstrated the ability of MWCNTs to induce early genotoxicity. This study emphasizes the suitability of our approach to evaluating simultaneously the early response of the cell membrane and DNA to different MWCNT concentrations and exposure times in cells of target organ. The findings contribute to elucidation of the mechanism by which MWCNTs cause toxic effects in an in vitro experimental model.

Evaluation of cytotoxic concentration-time response in A549 cells exposed to respirable alpha-quartz.

A causal pathway between quartz, silicosis and lung cancer has been postulated. The aim of our study was to assess cytotoxic effects induced in a human lung epithelial cell line (A549) by exposure to alpha-quartz. Cells were exposed to respirable alpha-quartz (SRM1878a, NIST) at 25, 50 or 100 microg ml(-1 )for 24 h and at 50 or 100 microg ml(-1) for 48 h. Cytotoxic effects were analyzed by scanning electron microscopy (SEM), apoptotic morphology analysis with Hoechst staining and lactate dehydrogenase (LDH) release assay. In cells exposed to alpha-quartz for 24 h, a concentration-dependent bleb development and in particular the localization of blebs at the cell edge at higher concentrations were observed. The blebbing phenomenon was more evident after 48 h of exposure to 50 or to 100 microg ml(-1) of alpha-quartz and large blebs were localized at the cell edge. At the same concentrations surface smoothing was also observed. Moreover the presence of holes and tears was detected at the highest concentration both at 24 and 48 h. Results of morphological analysis with Hoechst stain evidenced an increase concentration-time dependent of apoptotic cell percentage that was more marked after 48 h exposure to 100 microg ml(-1) and a prevalence of late apoptosis stage with the increase of exposure time and concentration. Cells exposed to 50 or 100 microg ml(-1) of alpha-quartz for 24 and 48 h produced a significant increase in LDH release. The concentration-time-dependent bleb induction evidenced by SEM correlates with the increase of apoptotic cells and LDH activity release, demonstrating the onset of cytotoxic effects in human lung cells exposed to alpha-quartz.

Cytotoxicity and DNA-damage in human lung epithelial cells exposed to respirable alpha-quartz.

Occupational exposure to respirable crystalline silica is associated with the development of silicosis, lung cancer and airways diseases. In order to assess cytotoxic effects and direct-oxidative DNA damage induced by short-term exposure to different doses of respirable alpha-quartz (NIST SRM1878a), we conducted a study using A549 cells. The cells were exposed to alpha-quartz at 25, 50, 100 microg/ml for 4 h and analysed by scanning electron microscope (SEM) and LDH release assay for cytotoxic effect evaluation. Cells were also exposed to 10, 25, 50, 100 microg/ml of alpha-quartz for 2 h and 4 h and analysed by Fpg comet test to evaluate direct and oxidative DNA damage. SEM observations of treated cells showed bleb development at lower doses and alterations of microvilli morphology at the highest dose. A slight LDH release was found only at 100 microg/ml. Fpg comet test showed a dose-related oxidative DNA damage in cells exposed for 2 h to quartz. Cells exposed for 4h at the same concentrations showed a dose-related direct DNA damage and the presence of oxidative DNA damage at lower doses. The bleb induction on cell surface evidenced by SEM at lower doses correlates with the presence of oxidative DNA damage at 4 h. The cell surface modifications observed by SEM at 100 microg/ml indicate that high doses of quartz induce more evident cytotoxic effects confirmed by LDH analysis and correlate with the genotoxicity showed by comet assay.

PI, GC, HP, and TF serum protein polymorphisms in Siena, Tuscany, Italy, with a review of data for Italy.

The genetic polymorphism of four serum proteins (PI, GC, HP, and TF) is analyzed in a sample of 200 unrelated individuals from the province of Siena, Tuscany, central Italy. Siena is traditionally divided into 17 Contrade, that act as social units. The aim of this report is to ascertain whether this peculiar organization has led to genetic differentiation among the inhabitants of each Contrada and from other populations of Italy. For this purpose, the frequencies of genetic markers found in Siena are also compared with those reported for the same serum proteins in Italy based on provincial samples from the literature. The statistical analyses (heterozygosity estimates, F-statistics, and cluster analysis) suggest that the Contrade represent only a cultural and historical institution without biological consequence and that the Italian population can be considered genetically homogeneous. Am. J. Hum. Biol. 9:629-646, 1997. © 1997 Wiley-Liss, Inc.