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Results reveal that low-molecular-weight DNA synthesized by retron reverse transcriptase of Salmonella enterica is double-stranded with single-stranded overhangs unlike the more commonly produced single-stranded DNA by procaryotes. Data indicate that the plasmid containing three open reading frames confers phage resistance onto the host cell independent of double-stranded DNA synthesis.

The natural environment and water are among the sources of Campylobacter jejuni and Campylobacter coli . A limited number of protocols exist for the isolation of campylobacters in poorly filterable water. Therefore, the goal of our work was to find a more efficient method of Campylobacter isolation and detection from wastewater and surface water than the ISO standard. In the novel rapid culture method presented here, samples are centrifuged at high speed, and the resuspended pellet is inoculated on a filter, which is placed on Campylobacter selective mCCDA agar. The motile bacteria pass through the filter pores, and mCCDA agar suppresses the growth of background microbiota on behalf of campylobacters. This culture-based method is more efficient for the detection and isolation of Campylobacter jejuni and Campylobacter coli from poorly filterable water than the ISO 17995 standard. It also is less time-consuming, taking only 72 h and comprising three steps, while the ISO standard method requires five or six steps and 144-192 h. This novel culture method, based on high-speed centrifugation, bacterial motility, and selective cultivation conditions, can be used for the detection and isolation of various bacteria from water samples.

Background: In order to estimate the prevalence of plasmid borne colistin resistance and to characterize in detail the mcr -positive isolates, we carried out a sentinel testing survey on the intestinal carriage of plasmid-mediated colistin-resistant Enterobacteriaceae in hospitalized patients. Methods: Between June 2018 and September 2019, 1922 faecal samples from hospitalised patients were analysed by selective culture in presence of colistin (3.5 mg/L), and in parallel by direct detection of the mcr-1 to mcr-8 genes by qPCR. The mcr -positive isolates were characterised by whole-genome sequencing. Results: The prevalence of the mcr-1 gene was 0.21% ( n = 4/1922); the mcr-2 to 8 genes were not detected. The mcr-1 gene was found to be localised in the IncX4 ( n = 3) and IncHI2 ( n = 1) plasmid type. One Escherichia coli isolate was susceptible to colistin due to the inactivation of the mcr-1 gene through the insertion of the IS2 element; however, the colistin resistance was inducible by culture in low concentrations of colistin. One human mcr-1 positive E. coli isolate was related genetically to the mcr-1 E. coli isolate derived from turkey meat of Czech origin. Conclusions: mcr -mediated colistin resistance currently poses little threat to patients hospitalised in Czech healthcare settings. The presence of the mcr-1 gene in the human population has a possible link to domestically produced, retail meat.

The aim of our study was to determine complete nucleotide sequence of mcr-1- carrying plasmids from Enterobacterales isolates recovered from domestic and imported raw retailed meat and compare them with plasmids available at the GenBank sequence database. A set of 16 plasmids originating from Escherichia coli ( n = 13), Klebsiella pneumoniae ( n = 2), and Citrobacter braakii ( n = 1) were analyzed. In our previous study, data from whole genome sequencing showed that mcr-1 gene was located on plasmids of different incompatibility groups (IncHI2, IncI2, and IncX4). The IncI2 ( n = 3) and IncX4 ( n = 8) plasmids harbored mcr-1.1 gene only, whereas IncHI2 sequence type 4 plasmids ( n = 5) carried large multidrug resistance (MDR) regions. MDR regions of IncHI2 plasmids included additional antimicrobial resistance genes conferring resistance to β-lactams ( bla TEM-1 ), aminoglycosides [ aadA1, aadA2 , and aph(6)-Id ], macrolides [ mef (B)], tetracycline ( tetA, tetR ), and sulphonamides ( sul1, sul2 , and sul3 ). Likewise, IncHI2 plasmids carried several insertion sequences including IS 1 , IS 3 , IS 26 , IS 1326 , and IS Apl1 . In conclusion, our findings confirmed the involvement of IncX4, IncI2, and IncHI2 plasmids in the dissemination of mcr-1.1 gene in several environmental niches, as in samples of retail meat originating from different geographical regions. In contrast to IncX4 and IncI2, IncHI2 plasmids were more diverse and carried additional genes for resistance to heavy metals and multiple antimicrobials., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zelendova, Papagiannitsis, Valcek, Medvecky, Bitar, Hrabak, Gelbicova, Barakova, Kutilova, Karpiskova and Dolejska.)

Environmental adaptation of Listeria monocytogenes is a complex process involving various mechanisms that can contribute to their survival in the environment, further spreading throughout the food chain and the development of listeriosis. The aim of this study was to analyze whole-genome sequencing data in a set of 270 strains of L. monocytogenes derived from human listeriosis cases and food and environmental sources in order to compare the prevalence and type of genetic determinants encoding cadmium, arsenic, and benzalkonium chloride resistance. Most of the detected genes of cadmium (27.8%), arsenic (15.6%), and benzalkonium chloride (7.0%) resistance were located on mobile genetic elements, even in phylogenetically distant lineages I and II, which indicates the possibility of their horizontal spread. Although no differences were found in the prevalence of these genes between human and food strains, they have been detected sporadically in strains from the environment. Regarding cadmium resistance genes, cadA1C1_ Tn 5422 predominated, especially in clonal complexes (CCs) 121, 8, and 3 strains. At the same time, qacH_ Tn 6188 -encoding benzalkonium chloride resistance was most frequently detected in the genome of CC121 strains. Genes encoding arsenic resistance were detected mainly in strains CC2 (located on the chromosomal island LGI2) and CC9 (carried on Tn 554 ). The results indicated a relationship between the spread of genes encoding resistance to cadmium, arsenic, and benzalkonium chloride in certain serotypes and CCs and showed the need for a more extensive study of L. monocytogenes strains to better understand their ability to adapt to the food production environment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Gelbicova, Florianova, Hluchanova, Kalova, Korena, Strakova and Karpiskova.)

The microaerophilic pathogen Campylobacter jejuni is a leading bacterial cause of human gastroenteritis in developed countries. Even though it has a reputation as a fastidious organism, C. jejuni is widespread and can be easily isolated from various animals, food, and environmental sources. It is suggested that an ability to form biofilms is probably necessary for the survival of C. jejuni under harsh environmental conditions. The first step required for successful biofilm formation is adhesion to a suitable surface. Therefore, in this work, the degree of adhesion was evaluated, followed by characterization and quantification of biofilms using confocal laser scanning microscopy (CLSM). A total of 15 isolates of C. jejuni were used in the experiments (12 isolates from surface and waste waters, 1 human clinical, 1 food and 1 ACTT BAA-2151 collection strain, all samples originated from the Czech Republic). Regardless of the sample origin, all C. jejuni isolates were able to adhere to the polystyrene surface within 30 min, with the number of attached cells increasing with the time of incubation. The resulting data showed that all isolates were able to form complex voluminous biofilms after 24 h of cultivation. The average amount of biovolume ranged from 3.59 × 10 6 µm 3 to 17.50 × 10 6 µm 3 in isolates obtained from different sources of water, 16.79 × 10 6 µm 3 in the food isolate and 10.92 × 10 6 µm 3 in the collection strain. However, the highest amount of biomass was produced by the human clinical isolate (25.48 × 10 6 µm 3 ). Similar to the quantity, the architecture of the biofilms also differed, from a rugged flat monolayer of cells to large clustered structures. Further, all isolates were tested for the presence of the luxS gene, as the luxS /AI-2 (autoinducer-2) quorum sensing pathway has been previously connected with enhanced biofilm formation. Two isolates originated from surface waters did not possess the luxS gene. These isolates formed thinner and sparser biofilms lacking the presence of significant clusters. However, the ability to adhere to the surface was preserved. The sequencing of the luxS -containing fragments shown a high similarity of the luxS gene among the isolates., (Copyright © 2020 Shagieva, Teren, Michova, Strakova, Karpiskova and Demnerova.)

Here, we describe two plasmids carrying mcr-4.3 in two Acinetobacter baumannii strains isolated from imported food and a clinical sample. The comparative analysis of these plasmids, with two other plasmids reported in the NCBI database, highlighted the common origin of the plasmidic structure carrying mcr-4.3 This is the first case of the mcr-4.3 gene in a A. baumannii strain isolated from a clinical case in Europe. We hypothesize that food import is initiating the spread in Czech Republic., (Copyright © 2019 American Society for Microbiology.)

Staphylococcus aureus is a major food-borne pathogen due to the production of enterotoxin and is particularly prevalent in contaminated milk and dairy products. The lactic acid bacteria (LAB) are widely used as biocontrol agents in fermented foods which can inhibit pathogenic flora. In our work, we investigated the influence of three strains of LAB (Lactobacillus plantarum, Streptococcus thermophilus and Enterococcus durans) on the relative expression of three enterotoxin genes (sea, sec, sell) and eight virulence and/or regulatory genes (sarA, saeS, codY, srrA, rot, hld/RNAIII, agrA/RNAII, sigB) in two S. aureus strains (MW2 and Sa1612) in TSB and reduced-fat milk (1.5 %) at 30 °C over a 24-h period. The tested LAB and S. aureus strains proved to be mutually non-competitive or only slightly competitive during co-cultivation. In addition, under the above-mentioned conditions, differential gene expression between the S. aureus MW2 and Sa1612 strains was well documented. S. aureus growth was changed in mixed culture with LAB; however, its effect on the repression of sea and sec expression correlated with production of these virulence factors. In comparison, the presence of LAB strains generally inhibited the expression of sec, sell, sarA, seaS, agrA/RNAII and hld/RNAIII genes. The effect of LAB strains presence on the expression of sea, codY, srrA, rot and sigB genes was medium, time, LAB and S. aureus strain specific. SEA and SEC production was significantly reduced in milk compared to TSB in pure culture. After the 24-h cultivation, S. aureus MW2 and Sa1612 SEC production was 187 and 331 times lower in milk compared to TSB, respectively (0.07 and 0.39 ng/mL in milk, versus 13.1 and 129.2 ng/mL in TSB, respectively). At the same time S. aureus MW2 and Sa1612 SEA production was 77 and 68 times lower in milk compared to TSB, respectively (0.99 and 0.17 ng/mL in milk, versus 76.4 and 11.5 ng/mL in TSB, respectively). This study has revealed new insights into the interaction between S. aureus and LAB (L. plantarum, S. thermophilus, E. durans) on the level of the expression and/or production of S. aureus enterotoxins, regulatory and virulence genes in different media, including milk. This study provides data which may improve the quality of food production.

Soil and water are suggested to represent pivotal niches for the transmission of Listeria monocytogenes to plant material, animals, and the food chain. In the present study, 467 soil and 68 water samples were collected in 12 distinct geological and ecological sites in Austria from 2007 to 2009. Listeria was present in 30% and 26% of the investigated soil and water samples, respectively. Generally, the most dominant species in soil and water samples were Listeria seeligeri, L. innocua, and L. ivanovii. The human- and animal-pathogenic L. monocytogenes was isolated exclusively from 6% soil samples in regions A (mountainous region) and B (meadow). Distinct ecological preferences were observed for L. seeligeri and L. ivanovii, which were more often isolated from wildlife reserve region C (Lake Neusiedl) and from sites in proximity to wild and domestic ruminants (region A). The higher L. monocytogenes detection and antibiotic resistance rates in regions A and B could be explained by the proximity to agricultural land and urban environment. L. monocytogenes multilocus sequence typing corroborated this evidence since sequence type 37 (ST37), ST91, ST101, and ST517 were repeatedly isolated from regions A and B over several months. A higher L. monocytogenes detection and strain variability was observed during flooding of the river Schwarza (region A) and Danube (region B) in September 2007, indicating dispersion via watercourses., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

A case of fatal salmonellosis in a Eurasian eagle-owl (Bubo bubo) from Bursa Province (northwestern Turkey) is described. The organs of the bird were examined histopathologically and microbiologically. Macroscopic and microscopic findings were consistent with a Salmonella infection. Salmonella enterica subspecies enterica serovar Enteritidis (S. Enteritidis) phage type (PT) 21b was isolated from the liver and spleen in pure culture and from the intestine. The isolate was susceptible to amoxycillin/clavulanic acid, ampicillin, chloramphenicol, gentamicin, kanamycin, tetracycline, and trimethoprim/sulphamethoxazole. This is the first report of an isolation of salmonellae from a wild bird species from Turkey and the first time S. Enteritidis PT21b has been reported from Turkey.

The Czech Republic is a country in central Europe with a population of about 10 million inhabitants. Salmonellosis is the most commonly reported infectious intestinal disease. Until 1989 about 10 000 cases were reported each year, and similar numbers of S