Justyna Szulc

Microbiological Contamination at Workplaces in a Combined Heat and Power (CHP) Station Processing Plant Biomass

The aim of the study was to evaluate the microbial contamination at a plant biomass processing thermal power station (CHP). We found 2.42 × 103 CFU/m3 of bacteria and 1.37 × 104 CFU/m3 of fungi in the air; 2.30 × 107 CFU/g of bacteria and 4.46 × 105 CFU/g of fungi in the biomass; and 1.61 × 102 CFU/cm2 bacteria and 2.39 × 101 CFU/cm2 fungi in filtering facepiece respirators (FFRs). Using culture methods, we found 8 genera of mesophilic bacteria and 7 of fungi in the air; 10 genera each of bacteria and fungi in the biomass; and 2 and 5, respectively, on the FFRs. Metagenomic analysis (Illumina MiSeq) revealed the presence of 46 bacterial and 5 fungal genera on the FFRs, including potential pathogens Candida tropicalis, Escherichia coli, Prevotella sp., Aspergillus sp., Penicillium sp.). The ability of microorganisms to create a biofilm on the FFRs was confirmed using scanning electron microscopy (SEM). We also identified secondary metabolites in the biomass and FFRs, including fumigaclavines, quinocitrinines, sterigmatocistin, and 3-nitropropionic acid, which may be toxic to humans. Due to the presence of potential pathogens and mycotoxins, the level of microbiological contamination at workplaces in CHPs should be monitored.

Time-Dependent Antimicrobial Activity of Filtering Nonwovens with Gemini Surfactant-Based Biocides

Previous studies on nonwovens used for respiratory protective devices (RPDs) were related to equipment intended for short-term use. There is only limited research on the development of biocidal nonwoven fabrics for reusable RPDs that could be used safely in an industrial work environment where there is a risk of microbial growth. Moreover, a new group of biocides with high antimicrobial activity—gemini surfactants, has never been explored for textile’s application in previous studies. The aim of this study was to develop high-efficiency melt-blown nonwovens containing gemini surfactants with time-dependent biocidal activity, and to validate their antimicrobial properties under conditions simulating their use at a plant biomass-processing unit. A set of porous biocidal structures (SPBS) was prepared and applied to the melt-blown polypropylene (PP) nonwovens. The biocidal properties of the structures were triggered by humidity and had different activation rates. Scanning electron microscopy was used to undertake structural studies of the modified PP/SPBS nonwovens. In addition, simulation of plant biomass dust deposition on the nonwovens was performed. The biocidal activity of PP/SPBS nonwovens was evaluated following incubation with Escherichia coli and Aspergillus niger from the American Type Culture Collection, and with Pseudomonas fluorescens and Penicillium chrysogenum isolated from the biomass. PP/SPBS nonwovens exhibited antimicrobial activity to varying levels. Higher antimicrobial activity was noted for bacteria (R = 87.85–97.46%) and lower for moulds (R = 80.11–94.53%).

Dust at Various Workplaces—Microbiological and Toxicological Threats

The aim of the present study was to evaluate the relation between the chemical (analysis of elements and pH) and microbiological composition (culture and metagenomics analysis) of the dust at various workplaces (cement plant, composting plant, poultry farm, and cultivated area) and the cytotoxicity effect on the human adenocarcinoma lung epithelial adherent cell line A-549 (MTT assay test). Analysis of the Particulate Matter (PM) fraction showed that the dust concentration in cultivated areas exceeded the OELs. For the remaining workplaces examined, the dust concentration was lower than OELs limits. The number of microorganisms in the dust samples was 3.8 × 102–1.6 × 108 CFU/g bacteria and 1.5 × 102–6.5 × 106 CFU/g fungi. The highest number of microorganisms was noted for dust from cultivated areas (total number of bacteria, actinomycetes, P. fluorescens) and composting plants (xerophilic fungi and staphylococci), while the least number of microorganisms was observed for dust from cement plants. Many types of potentially pathogenic microorganisms have been identified, including bacteria, such as Bacillus, Actinomyces, Corynebacterium, Prevotella, Clostridium, and Rickettsia, and fungi, such as Alternaria, Cladosporium, Penicillium, and Aspergillus. The most cytotoxic to the human lung cell line A-549 was dust from cultivated areas (IC50 = 3.8 mg/mL after 72 h). The cytotoxicity of the tested dust samples depends on the PM concentration, the number of microorganisms, including potentially pathogenic genera, and the exposure time.

Microbial Growth on Dust-Loaded Filtering Materials Used for the Protection of Respiratory Tract as a Factor Affecting Filtration Efficiency

This work aims at understanding the effects of various dust-loading conditions and the type of nonwovens used in the construction of FFRs on the safe use of those protective devices in situations of exposure to biological agents. The survival of microorganisms (Escherichia coli, Candida albicans, and Aspergillus niger) in dust-loaded polypropylene nonwovens (melt-blown, spun-bonded, and needle-punched) was experimentally determined using microbiological quantitative method (AATCC TM 100-2004). Scanning electron microscope was used to assess biofilm formation on dust-loaded filtering nonwovens. The impact of the growth of microorganisms on filtration efficiency of nonwovens was analysed based on the measurements of penetration of sodium chloride particles (size range 7–270 nm). Results showed that tested microorganisms were able to survive on dust-loaded polypropylene filtering nonwovens. The survival rate of microorganisms and penetration of nanoparticles and submicron particles depended on the type of microorganism, as well as the type and the amount of dust, which indicates that both of those factors should be considered for FFR use recommendations.

Metabolic profiling of moulds with laser desorption/ionization mass spectrometry on gold nanoparticle enhanced target

Surface-assisted laser desorption/ionization mass spectrometry on gold nanoparticle enhanced target (AuNPET) technique was used for metabolomic analysis and secondary metabolites detection of two mould strains - Aspergillus versicolor and Penicillium chrysogenum in model conditions on microbiological malt extract agar medium. Results obtained with the use of AuNPET-based mass spectrometry technique were compared with traditional matrix-assisted laser desorption/ionization (MALDI) method based on α-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB) matrices. Gold nanoparticle enhanced target method enabled effective ionization of microbial cellular extract ingredients without interference from the matrix and also improved calibration of spectra resulting in the detection of much higher amount of characteristic metabolites for studied organisms than MALDI.

THREATS/RISKS IN POULTRY FARMS: MICROBIOLOGICAL CONTAMINANTS, DUST, ODOURS AND BIOLOGICAL METHOD FOR ELIMINATION

STRESZCZENIE Celem badań była ocena zagrożeń mikrobiologicznych odorowych i pyłowych w pomieszczeniach inwentarskich na fermach drobiu. Ponadto określono skuteczność biopreparatu i ekstraktu roślinnego Yucca schidigera w obniżaniu stężenia wybranych związków odorowych generowanych przez pomiot drobiowy oraz w higienizacji pomiotu. W pomieszczeniach inwentarskich zapylenie powietrza było wysokie i kształtowało się na poziomie 1,44 mg/ m3; dominowała frakcja pyłu PM10. Zarówno w pomiocie drobiowym oraz pyle osiadłym stwierdzono wysoką liczebność bakterii i grzybów na poziomie 106–1010 jtk/g. Na fermie drobiu nie odnotowano przekroczenia limitu dotyczącego liczby bakterii i grzybów w powietrzu. Odnotowane stężenia frakcji PM2,5 i PM10 były 18–20 razy wyższe niż dopuszczalne dla 24-godzinnej ekspozycji określone przez Światową Organizację Zdrowia. Wśród odorowych związków lotnych na fermach drobiu dominowały: amoniak, akroleina, metyloamina, kwas octowy, aldehyd octowy i formaldehyd. Ich stężenia były zmienne w zależności od rodzaju fermy i etapu cyklu produkcyjnego. Dopuszczalne stężenie amoniaku w powietrzu zostało przekroczone na fermie kur niosek I i II, natomiast stężenie dwutlenku węgla przekroczyło dopuszczalną wartość w trzecim etapie cyklu produkcyjnego na fermie brojlerów III i było zbliżone do limitu na fermie niosek I. Cytotoksyczność mieszaniny związków odorowych wobec komórek kurzych LMH maksymalnie wynosiła 45,7%, potwierdzono ją zmianami morfologicznymi komórek po działaniu związków odorowych (amoniaku, dii trimetyloaminy). Biopreparat mineralno-mikrobiologiczny wraz z ekstraktem Yucca schidigera zmniejszał ogólną liczbę drobnoustrojów o około 1 rząd wielkości w pomiocie drobiowym i obniżał stężenie związków odorowych o 37–70% w zależności od związku. Zastosowanie kolejno ekstraktu Y. schidigera, a następnie po 2 dniach biopreparatu może być skutecznym sposobem ograniczania zagrożeń mikrobiologicznych i odorowych na fermach drobiu.