Search

Listeria monocytogenes is not only a pathogen causing a serious food-borne disease in humans but can also occur as a saprophyte in the natural environment. This study aimed to evaluate the occurrence of L. monocytogenes obtained from the natural environment of the Czech Republic (hereinafter Czechia) and Slovakia in 2016-2018 and to compare the clonal relationship of strains circulating in the environment with the strains originating from the food chain and humans. Altogether, 217 samples of mud, surface water, vegetation and soil were collected in 61 locations. Samples were processed according to the modified EN ISO 11290-1 standard. The obtained L. monocytogenes isolates were characterised using serotyping, macrorestriction analysis, followed by pulsed-field gel electrophoresis, whole genome sequencing (WGS), and antimicrobial susceptibility testing. L. monocytogenes were detected in 8.8% of the examined samples and were isolated in 15 locations, mainly from the mud from the banks of the surface water sources. Altogether, 25 L. monocytogenes strains were obtained from 19 positive samples. Serotypes 1/2a, 4b, and 1/2b were detected among the strains. Twenty combined AscI/ApaI pulsotypes were obtained by macrorestriction analysis. Altogether, 12 sequence types (STs) were detected using Multi-locus sequence typing (MLST) by WGS, with ST451 being the most frequent. The core genome MLST analysis revealed a heterogeneous population of environmental strains. No phenotype resistance was detected by antimicrobial susceptibility testing. Screening of antimicrobial-resistance genes using the platform ResFinder revealed the genes fosX in 24 isolates and blaTEM-116 in one isolate. The occurrence of L. monocytogenes in various samples from natural environments within wide altitude range during different seasons of the year may highlight this bacterium's remarkable adaptability and exceptional tolerance to external factors. Serotype distribution of the strains circulating in the natural environment of Czechia and Slovakia seems to reflect distribution in the human population more than in the food chain. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes (Lm) is a ubiquitous bacterium that causes listeriosis, a serious foodborne illness. In the nature-to-human transmission route, Lm can prosper in various ecological niches. Soil and decaying organic matter are its primary reservoirs. Certain clonal complexes (CCs) are over-represented in food production and represent a challenge to food safety. To gain new understanding of Lm adaptation mechanisms in food, the genetic background of strains found in animals and environment should be investigated in comparison to that of food strains. Twenty-one partners, including food, environment, veterinary and public health laboratories, constructed a dataset of 1484 genomes originating from Lm strains collected in 19 European countries. This dataset encompasses a large number of CCs occurring worldwide, covers many diverse habitats and is balanced between ecological compartments and geographic regions. The dataset presented here will contribute to improve our understanding of Lm ecology and should aid in the surveillance of Lm. This dataset provides a basis for the discovery of the genetic traits underlying Lm adaptation to different ecological niches. Measurement(s) whole genome sequencing Technology Type(s) Illumina Sequencing Factor Type(s) Multi-locus sequence types • Geographic location • Animal associated environment isolates • Food product and food production environment isolates Sample Characteristic - Organism Listeria monocytogenes Sample Characteristic - Environment Farm • Ruminant • Agricultural soil • Wild animals • food processing building • dairy food product • meat or meat product (from mammal) (us cfr) • chicken meat food product • fish food product • vegetable or vegetable product (us cfr) Sample Characteristic - Location Europe [ABSTRACT FROM AUTHOR]

This study was focused on characterization of the genetic diversity of Listeria monocytogenes isolated from packed fresh rabbit meat obtained from one producer via retail outlets. The partial aim was to compare the characteristics of a suspect persistent strain with strains from human cases. The occurrence of L. monocytogenes in vacuum-packed rabbit meat was monitored during 2013 to 2016. All strains were characterized by serotyping, pulsed-field gel electrophoresis, and multilocus sequence typing (MLST). Selected strains, which represented each year, were analyzed using the whole genome sequencing method. L. monocytogenes was detected in 21 (38%) of 56 originally packed rabbit meat samples from one food producer during the whole monitored period. All strains showed the identical serotype (1/2a), AscI/ApaI pulsotype (735/2), and sequence type (ST451). The clonal similarity of strains from rabbit meat was also confirmed on the basis of core genome MLST (on 1,701 loci). This fact suggests the occurrence of a suspect persistent strain in the meat processing plant. Results of core genome MLST enabled us to unambiguously exclude rabbit meat as a source of listeriosis in humans caused by the indistinguishable AscI/ApaI pulsotype and sequence type, although all strains carried all genes important for the virulence of L. monocytogenes. No specific genes that may be associated with its persistence in the food processing environment were detected among the tested strains of ST451. [ABSTRACT FROM AUTHOR]

Staphylococci from the Staphylococcus intermedius-Staphylococcus hyicus species group include numerous animal pathogens and are an important reservoir of virulence and antimicrobial resistance determinants. Due to their pathogenic potential, they are possible causative agents of zoonoses in humans; therefore, it is important to address the properties of these strains. Here we used a polyphasic taxonomic approach to characterize the coagulase-negative staphylococcal strain NRL/St 03/464T, isolated from the nostrils of a healthy laboratory rat during a microbiological screening of laboratory animals. The 16S rRNA sequence, MALDI-TOF mass spectrometry and positive urea hydrolysis and beta-glucuronidase tests clearly distinguished it from closely related Staphylococcus spp. All analyses have consistently shown that the closest relative is Staphylococcus chromogenes; however, values of digital DNA-DNA hybridization <35.3% and an average nucleotide identity <81.4% confirmed that the analyzed strain is a distinct Staphylococcus species. Whole-genome sequencing and expert annotation of the genome revealed the presence of novel variable genetic elements, including two plasmids named pSR9025A and pSR9025B, prophages, genomic islands and a composite transposon that may confer selective advantages to other bacteria and enhance their survival. Based on phenotypic, phylogenetic and genomic data obtained in this study, the strain NRL/St 03/464T (= CCM 9025T = LMG 31873T = DSM 111348T) represents a novel species with the suggested name Staphylococcus ratti sp. nov. [ABSTRACT FROM AUTHOR]