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.

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 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.

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.

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.

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.