Browsing by Author "Cencek, Tomasz"

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    Enterobacteriaceae in Sewage Sludge and Digestate Intended for Soil Fertilization
    (MDPI, 2024) Wójcik-Fatla, Angelina; Farian, Ewelina; Kowalczyk, Katarzyna; Sroka, Jacek; Skowron, Piotr; Siebielec, Grzegorz; Zdybel, Jolanta Małgorzata; Jadczyszyn, Tamara; Cencek, Tomasz
    Substances of organic origin are seeing increasing use in agriculture as rich sources of nutrients for plants. The aim of this study was to determine the microbiological contamination of sewage sludge and digestate to assess their safe use as fertilizers in Poland. The assessment of microbial soil, sewage sludge and digestate contamination was based on the total number of mesophilic bacteria and Gram-negative bacteria from the Enterobacteriaceae family. The presence of Escherichia coli and Salmonella spp. was identified via culture and the presence of Enterobacteriaceae species was determined via biochemical and molecular methods. In laboratory conditions, the survival of E. coli in soil fertilized with sewage sludge or digestate inoculated with a reference strain was determined. The average concentration of Enterobacteriaceae in soil, sewage sludge and digestate samples was 1.1 × 104 CFU/g, 9.4 × 105 CFU/g and 5.6 × 106 CFU/g, respectively. Escherichia coli was detected in all sample types. From the soil samples, Serratia, Enterobacter, Pantoea, Citrobacter and Pseudomonas genera were identified the most frequently, while in sewage sludge and digestate, E. coli was predominant. Based on the results of our laboratory experiment, it can be concluded that after three weeks, fertilization with organic waste in acceptable doses does not significantly increase soil contamination with Enterobacteriaceae.
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    Genetic diversity, virulence factors and drug resistance of Pantoea strains isolated from samples of fresh fruits, vegetables and soil
    (Państwowy Instytut Weterynaryjny - Państwowy Instytut Badawczy, 2025-09-13) Fabian, Ewelina ; Kowalczyk, Katarzyna; Kłapeć, Teresa; Sroka, Jacek; Skowron, Piotr ; Siebielec, Grzegorz; Jadczyszyn, Tamara ; Zdybel, Jolanta Małgorzata ; Cencek, Tomasz ; Wójcik-Fatla, Angelina
    Pantoea is a genus of Gram-negative bacteria from the Erwiniaceae family. These bacteria are opportunistic human pathogens which are widely distributed in plants and soil. This study aimed to reveal the genetic diversity of Pantoea isolates from food and soil, characterise them biochemically and evaluate their drug resistance. Material and Methods: Thirty Pantoea strains were isolated from fresh fruit (n = 2), fresh and minimally processed vegetables (n = 12) and soil samples (n = 16). The genomic DNA was isolated from cultures on nutrient agar, and species were identified by amplification of 16S ribosomal RNA and housekeeping gene fragments and confirmed by sequencing. Virulence gene presence was determined by amplification of the hcp (haemolysin-coregulated protein), vgrG (glycine-valine repeat sequence G), acrA (anti–clustered regularly interspaced short palindromic repeat protein A) and acrB genes. Isolate drug resistance was tested using the disc-diffusion and gradient strip methods. The presence of Ambler class C (AmpC) β-lactamase (βL) and extended-spectrum (ES) βL resistance genes was tested for. Results: Five species were identified: P. agglomerans (n = 24), P. ananatis (n = 1), P. eucalypti (n = 1), P. conspicua (n = 1) and P. vagans (n = 2). The hcp and vrgG virulence genes were detected in 7 and 1 strain, respectively. All strains showed high resistance to cephazolin and cephuroxime, and more than half did so to ampicillin. The production of AmpC βL and ESβL was confirmed in 22 and 25 strains, respectively. Three strains of the Pantoea bacteria, including P. ananatis from leeks and P. agglomerans from arugula and soil, showed resistance to three or more antimicrobial classes. Conclusion: Pantoea spp., including multidrug-resistant strains, in fresh foods pose a potential risk of infection to consumers.