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International Journal of Food... Jan 2019The aim of the study was to determine antimicrobial resistance and genotypic characteristics of L. monocytogenes isolated from food of animal origin from different parts...
The aim of the study was to determine antimicrobial resistance and genotypic characteristics of L. monocytogenes isolated from food of animal origin from different parts of Poland during years 2013-2016. A total of 146 isolates were tested using a microbroth dilution method, whereas virulence genes and molecular serogroups were identified by PCR. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) methods were used to analyze the genotypic relationship of the strains. Altogether, 102 pulsotypes grouped into 7 clusters and 24 sequence types, including 3 new types, were identified. Most of the strains clustered into individual patterns were originated from different food products and were isolated in different geographical regions at various time. L. monocytogenes was mostly resistant to oxacilin (90.4% strains), clindamycin (54.1%) and ceftriaxone (49.3%). A multiresistance patterns, mainly to ceftriaxone, oxacillin together with other antimicrobials, were observed among 27.4% strains. Antimicrobial resistance and presence of virulence genes suggest that food of animal origin contaminated with L. monocytogenes may present a risk for public health.
Topics: Anti-Bacterial Agents; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Food Microbiology; Genotype; Listeria monocytogenes; Multilocus Sequence Typing; Poland; Polymerase Chain Reaction; Serogroup
PubMed: 30189331
DOI: 10.1016/j.ijfoodmicro.2018.08.029 -
Applied and Environmental Microbiology Aug 2020Interactions between and food-associated or environmental bacteria are critical not only for the growth but also for a number of key biological processes of the...
Differential Modulation of Listeria monocytogenes Fitness, Virulence, and Transcription of Virulence-Associated Genes in Response to the Presence of Different Microorganisms.
Interactions between and food-associated or environmental bacteria are critical not only for the growth but also for a number of key biological processes of the microorganism. In this regard, limited information exists on the impact of other microorganisms on the virulence of In this study, the growth of was evaluated in a single culture or in coculture with , , , or in tryptic soy broth (10°C/10 days and 37°C/24 h). Transcriptional levels of 9 key virulence genes (, , , , , , , , and ) and invasion efficiency and intracellular growth in Caco-2 cells were determined for following growth in mono- or coculture for 3 days at 10°C or 9 h at 37°C. The growth of was negatively affected by the presence of and , while the effect of cell-to-cell contact on growth was dependent on the competing microorganism. Cocultivation affected the virulence properties of in a microorganism-specific manner, with mainly enhancing and reducing the invasion of the pathogen in Caco-2 cells. Assessment of the mRNA levels of virulence genes in the presence of the four tested bacteria revealed a complex pattern in which the observed up- or downregulation was only partially correlated with growth or virulence and mainly suggested that may display a microorganism-specific transcriptional response. is the etiological agent of the severe foodborne disease listeriosis. Important insight regarding the physiology and the infection biology of this microorganism has been acquired in the past 20 years. However, despite the fact that coexists with various microorganisms throughout its life cycle and during transmission from the environment to foods and then to the host, there is still limited knowledge related to the impact of surrounding microorganisms on ' biological functions. In this study, we showed that modulates specific biological activities (i.e., growth and virulence potential) as a response to coexisting microorganisms and differentially alters the expression of virulence-associated genes when confronted with different bacterial genera and species. Our work suggests that the interaction with different bacteria plays a key role in the survival strategies of and supports the need to incorporate biotic factors into the research conducted to identify mechanisms deployed by this organism for establishment in different environments.
Topics: Bacterial Physiological Phenomena; Gene Expression Regulation, Bacterial; Genetic Fitness; Listeria monocytogenes; Species Specificity; Transcription, Genetic; Virulence
PubMed: 32591377
DOI: 10.1128/AEM.01165-20 -
International Journal of Food... Oct 2018The aim of this research was to investigate the occurrence of Listeria monocytogenes in fish and fish processing plant and to determine their transmission, virulence and...
The aim of this research was to investigate the occurrence of Listeria monocytogenes in fish and fish processing plant and to determine their transmission, virulence and antibiotic resistance. L. monocytogenes was isolated according to the ISO 11290-1. The identification of L. monocytogenes was confirmed by multiplex PCR method. Genetic similarity of L. monocytogenes strains was determined with the Pulsed-Filed Gene Electrophoresis (PFGE) method. The multiplex PCR was used for identification of L. monocytogenes serogroups and detection of selected virulence genes (actA, fbpA, hlyA, iap, inlA, inlB, mpl, plcA, plcB, prfA). The L. monocytogens isolates susceptibility to penicillin, ampicillin, meropenem, erythromycin, trimethoprim/sulfamethoxazole was evaluated with disc diffusion method according to EUCAST v. 7.1. The presence of 237 L. monocytogenes isolates (before genetic similarity assessment) in 614 examined samples was confirmed. After strain differentiation by PFGE techniques the presence of 161 genetically different strains were confirmed. The genetic similarity of the examined isolates suggested that the source of the L. monocytogenes strains were fishes originating from farms. All tested strains possessed all detected virulence genes. Among examined strains, the most (26, 38.6%) belonged to the group 1/2a-3a. The most of tested strains were resistant to erythromycin (47.1%) and trimethoprim/sulfamethoxazole (47.1%).
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Fishes; Food Handling; Food Microbiology; Listeria monocytogenes; Serogroup; Virulence Factors
PubMed: 29929178
DOI: 10.1016/j.ijfoodmicro.2018.06.011 -
Food Microbiology Oct 2020In this study, thirteen batches of broiler chicken from an integrated Italian poultry company were investigated for the detection of Listeria monocytogenes. The...
In this study, thirteen batches of broiler chicken from an integrated Italian poultry company were investigated for the detection of Listeria monocytogenes. The prevalence was evaluated in faeces samples at farm level and after transport, caecal contents and carcass neck skin from 2 slaughterhouses (M1 and M2), for a total of 2080 samples, throughout a 27-month period. No positive results were recorded in faeces, while the overall prevalence of contamination in carcass neck skin was 26.7%. Then, 123 isolates out of 139 positive skin samples, with the prevalent serotypes 4b (76%) and 1/2b (94%) from slaughterhouses M1 and M2 respectively, were PFGE characterized, showing the presence of 18 different pulsotypes and 8 genetic clusters. The same pulsotypes were found in carcasses from different farms, but slaughtered in the same abattoir, highlighting the environmental origin of contamination. The persistence of the pathogen over long time seemed to be very likely, considering that undistinguishable pulsotypes were found in carcasses slaughtered in the same slaughterhouse after periods up to 18 months long. The implementation of cleaning and sanitation at slaughterhouse level could represent the main factor for the control of such pathogen in the poultry meat processing line.
Topics: Abattoirs; Animals; Chickens; Farms; Feces; Food Contamination; Food Handling; Food Microbiology; Italy; Listeria monocytogenes; Poultry; Prevalence; Serogroup; Skin
PubMed: 32539961
DOI: 10.1016/j.fm.2020.103533 -
Food Microbiology Oct 2018The classical definition of a disease outbreak is the occurrence of cases of disease in excess of what would normally be expected in a community, geographical area or... (Review)
Review
The classical definition of a disease outbreak is the occurrence of cases of disease in excess of what would normally be expected in a community, geographical area or time period. The establishment of an outbreak then starts with the identification of an incidence of cases above the normally expected threshold during a given time period. Subsequently, the cases are examined using a variety of subtyping methods to identify potential linkages. As listeriosis disease has a long incubation period, relating a single source or multiple sources of contaminated food to clinical disease is challenging and time consuming. The vast majority of human listeriosis cases are caused by three serotypes, 1/2a, 1/2b, and 4b. Thus serotyping of isolates from suspected foods and clinical samples, although useful for eliminating some food sources, has a very limited discriminatory power. The advent of faster and more affordable sequencing technology, coupled with increased computational power, has permitted comparisons of whole Listeria genome sequences from isolates recovered from clinical, food, and environmental sources. These analyses made it possible to identify outbreaks and the source much more accurately and faster, thus leading to a reduction in number of illnesses as well as a reduction in economic losses. Initial DNA sequence information also facilitated the development of a simple molecular serotype protocol which allowed for the identification of major disease causing serotypes of L. monocytogenes, including a clade of 4b variant (4bV) strains of L. monocytogenes involved in at least 3 more recent listeriosis outbreaks in the US. Furthermore, data generated using whole genome sequence (WGS) analyses was successfully utilized to develop a pan-genomic DNA microarray as well as a single nucleotide polymorphism (SNP) based analysis. Herein, we present and compare, the two recently developed sub-typing technologies and discuss how these methods are not only important in outbreak investigations, but could also shed light on possible adaptations to different foods and environments.
Topics: Disease Outbreaks; Genotype; Humans; Listeria monocytogenes; Listeriosis; Phylogeny; Serogroup
PubMed: 30056958
DOI: 10.1016/j.fm.2017.06.013 -
Foodborne Pathogens and Disease Jul 2015Products from three broiler abattoirs were sampled for Listeria species to evaluate the changes in the prevalence and contamination rates at two stages of processing....
Products from three broiler abattoirs were sampled for Listeria species to evaluate the changes in the prevalence and contamination rates at two stages of processing. Sampling was performed at the evisceration stage and at the end of processing after packaging and refrigerating at 4°C for 24 h. A total of 212 samples were collected; 52 were from abattoir A, and 80 samples each were collected from abattoirs B and C. Among all samples, 99 (46.7%) tested positive for Listeria, including L. monocytogenes 19 (8.9%), L. innocua 69 (32.5%), L. grayi 10 (4.7%), and L. welshimeri 1 (0.5%). The L. monocytogenes contamination rate varied from 5% to 11.5% in the 3 abattoirs. L. innocua was the most common species identified and was found in 8.8% of the samples from abattoir A and 33.7% of the samples from both abattoirs B and C. Twenty-six of the L. monocytogenes isolates obtained from positive samples were subjected to serotyping by multiplex polymerase chain reaction and characterization by the pulsed-field gel electrophoresis (PFGE) method using two cutting enzymes, ApaI and AscI. Three molecular serogroups were identified: IIa, IIb, and IVb. Serogroup IIa was common to all abattoirs, and serogroups IIb and IVb were found only in abattoir C. The 10 different obtained PFGE profiles were grouped into 7 clusters; some of these clusters were common to the 3 abattoirs, and others were specific to the abattoirs in which they were identified. This study revealed a high prevalence of Listeria spp., particularly L. monocytogenes, in raw broilers. This high incidence presents a risk to consumers due to the potential occurrence of cross-contamination with other foods in domestic refrigerators and the ability of these microorganisms to survive in undercooked products.
Topics: Abattoirs; Animals; Bacterial Proteins; Chickens; Colony Count, Microbial; Electrophoresis, Gel, Pulsed-Field; Food Contamination; Food Handling; Food Microbiology; Listeria monocytogenes; Serotyping
PubMed: 25942617
DOI: 10.1089/fpd.2014.1904 -
Food Science and Technology... Dec 2014Listeria-infecting bacteriophages (listeriaphages) can be used to control Listeria monocytogenes in the food industry. However, the sensitivity of many of seafood-borne...
Listeria-infecting bacteriophages (listeriaphages) can be used to control Listeria monocytogenes in the food industry. However, the sensitivity of many of seafood-borne Listeria strains to phages has not been reported. This research investigated the host ranges of three listeriaphages (FWLLm1, FWLLm3 and FWLLm5) by the formation of lytic zones and plaques on host lawns and in vitro lysis kinetics of listeriaphage FWLLm3. The study also predicted the phage titres required to lyse host cells. The host ranges of the phages were determined using 50 L. monocytogenes strains, of which 48 were isolated from the seafood industry and two from clinical cases. Of the 50 strains, 36 were tested at 25 and 30 ℃ and the remainder (14) at 15 and 25 ℃. Based on the formation of either discrete plaques or lytic zones (host kill zones), the host ranges of FWLLm1, FWLLm3 and FWLLm5 were about 87%, 81% and 87%, respectively, at 25 ℃. Six L. monocytogenes strains from the seafood environment were insensitive to all three phages, while the other seafood strains (42) were phage-sensitive. The adsorption rate constant (k value) of listeriaphage FWLLm3 was between 1.2 × 10(-9) and 1.6 × 10(-9 )ml/min across four host strains in tryptic soy broth at 25 ℃. The cultures (at 3-4 log colony-forming unit (CFU/ml) were completely lysed (<1 log CFU/ml) when cultures were infected with FWLLm3 at > 8.7 log phage-forming units (PFU/ml) for 30 min. Re-growth of phage-infected cultures was not detected after 24 h. The effective empirical phage titre was similar to the calculated titre using a kinetic model. Results indicate the potential use of the three phages for controlling L. monocytogenes strains in seafood processing environments.
Topics: Animals; Bacteriophages; Host Specificity; Host-Pathogen Interactions; Listeria monocytogenes; Seafood
PubMed: 23908393
DOI: 10.1177/1082013213497211 -
Foodborne Pathogens and Disease Mar 2021Persistence of in retail deli environments is a serious food safety issue, potentially leading to cross-contamination of ready-to-eat foods such as deli meats, salads,...
Genomic and Transcriptomic Analysis of Biofilm Formation in Persistent and Transient Isolates from the Retail Deli Environment Does Not Yield Insight into Persistence Mechanisms.
Persistence of in retail deli environments is a serious food safety issue, potentially leading to cross-contamination of ready-to-eat foods such as deli meats, salads, and cheeses. We previously discovered strong evidence of persistence in delis across multiple states. We hypothesized that this was correlated with isolates' innate characteristics, such as biofilm-forming capacity or gene differences. To test this hypothesis, we sequenced the genomes of 21 isolates previously collected longitudinally from the retail deli environment. Isolates were chosen to represent varying attachment capacity and sanitizer tolerance as well as persistence or transience. We used single-nucleotide polymorphism analysis to characterize the isolates' genetic relationships and used BLAST to search the isolates' genomes for antibiotic resistance elements, quaternary ammonium tolerance genes, and stress survival islets. We further chose four isolates for RNA-sequencing analysis and compared their global biofilm transcriptome with their global planktonic transcriptome. We did not find genetic content that explained persistence. The presence of stress survival islet-1 correlated to increased attachment capacity ( < 0.05), but not persistence. Further, the presence of sanitizer tolerance elements was not significantly correlated with phenotypic sanitizer tolerance. Analysis of biofilm versus planktonic gene expression did not show the expected differences in gene expression patterns. Overall, persistence in the deli environment is likely a matter of poor sanitation and/or facility design, rather than isolates' biofilm-forming capacity, sanitizer tolerance, or genomic content.
Topics: Animals; Biofilms; Food Microbiology; Genome, Bacterial; Listeria monocytogenes; Meat Products; Transcriptome
PubMed: 33227214
DOI: 10.1089/fpd.2020.2817 -
Emerging Microbes & Infections 2019is a high risk pathogen which can cause invasive diseases in humans. We previously reported that black-headed gulls from Dianchi Lake of Kunming carrying , while the...
is a high risk pathogen which can cause invasive diseases in humans. We previously reported that black-headed gulls from Dianchi Lake of Kunming carrying , while the characteristics of these isolates and the relationship with habitats of migratory gulls have not been explored. In this study, we investigated the prevalence and molecular characteristics of from black-headed gulls in Dianchi Lake, and phylogenetic analysis based on core genome SNPs was used to determine the genetic relationship of the strains from Dianchi Lake and other regions. Occurrence of in black-headed gull feces in 2016, 2017 and 2018 was 1.0%, 1.0% and 0.6% respectively. The predominant serotype of 28 isolates was 4b, while the predominant sequence types were ST145 and ST201. Based on their prevalence and genomic relationships, ST5 and ST87 were likely to be sourced locally while ST145 and ST201 were likely to be non-local. may travel along the bird migration route leading to transmission over a large geographical span carried by black-headed gull. Although the prevalence of was low, its carriage by the migratory black-headed gulls poses potential public health risks in regions where the migratory birds passage and reside.
Topics: Animals; Bird Diseases; Carrier State; Charadriiformes; China; Disease Transmission, Infectious; Genetic Variation; Genotype; Lakes; Leptospirosis; Listeria monocytogenes; Molecular Epidemiology; Phylogeny; Polymorphism, Single Nucleotide; Prevalence; Sequence Analysis, DNA; Serogroup
PubMed: 31393224
DOI: 10.1080/22221751.2019.1647764 -
Journal of Dairy Science Nov 2019Listeria monocytogenes can survive and grow in a variety of environments, including refrigeration, making it difficult to control and highlighting the importance of...
Listeria monocytogenes can survive and grow in a variety of environments, including refrigeration, making it difficult to control and highlighting the importance of optimizing control strategies against this pathogen. Listeria phages are attractive biocontrol agents because phages bind to specific wall teichoic acids (WTA) on the bacterial cell wall, inhibiting pathogens without disrupting the normal microbiota or structure of the food. Common stresses found on dairy products can affect cell wall composition and structure and subsequently affect the efficiency of control strategies that target the cell wall. The goal of this study was to determine the effect of a range of pH and temperatures on the effectiveness of a commercial phage cocktail treatment against several strains of L. monocytogenes in a cheese matrix. We developed a laboratory-scale cheese model that was made at different pH, treated with phage, and then inoculated with L. monocytogenes. Cheeses were incubated at 6, 14, or 22°C for 14 d, and bacterial counts were determined on d 1, 7, and 14. Our data show that phage treatment has a limited ability to reduce L. monocytogenes counts at each temperature tested; however, it was more effective on specific strains of L. monocytogenes when cheese was stored at higher temperatures. More specifically, the average counts of L. monocytogenes on phage-treated cheese stored at 22°C were significantly lower than those on phage-treated cheese stored at 6 or 14°C. Similarly, phage treatment was significantly more effective at inhibiting L. monocytogenes on cheese made at higher pH (6 and 6.5) compared with counts on cheese made at pH 5.5, where L. monocytogenes did not grow. Furthermore, serotype was found to affect the susceptibility of L. monocytogenes to phage treatment; serotype 1/2 strains showed significantly higher susceptibility to phage treatment than serotype 4b strains. Overall, our results suggest the importance of considering the efficacy of phage under conditions (i.e., temperature and pH) specific to a given food matrix when applying interventions against this important foodborne pathogen.
Topics: Animals; Bacterial Load; Bacteriophages; Cheese; Food Microbiology; Humans; Hydrogen-Ion Concentration; Least-Squares Analysis; Listeria monocytogenes; Serogroup; Temperature; Time Factors
PubMed: 31477293
DOI: 10.3168/jds.2019-16474