Pig fecal and tonsil contamination of Yersinia enterocolita in one French slaughterhouse

Pig is considered to be the main animal reservoir of human pathogenic Yersinia enterocolitica strains which is frequently isolated from tonsils, but can also be found in the feces and onto carcasses. In France, while the main pathogenic biotypes are known for humans, few data are available regarding their prevalence in the pork chain production, and generally focus on tonsils contamination

In vitro characterization of the ability of Yersinia enterocolitica BT4 to colonize pigs and stainless steel surfaces

Yersiniosis is, after campylobacteriosis and salmonellosis, the third most frequently reported zoonosis in Europe. Humans become infected with Y. enterocolitica through the consumption of undercooked pork and raw food having been in contact with contaminated surfaces. Pigs, the main reservoir for human pathogenic strains, do not develop clinical signs. In France and worldwide, biotype 4 (BT4) is the biotype the most frequently isolated from both pigs and clinical yersiniosis. In this study, a collection of 26 pathogenic BT4 strains isolated from pig tonsils was used to investigate their ability to adhere and invade intestinal pig cells (IPEC-J2) and to adhere to abiotic surfaces (stainless steel coupons) using two in vitro tests. Regression analysis was performed between data sets obtained from IPECJ2 cells assays versus stainless steel assays. All BT4 strains were able to adhere and invade IPEC-J2 cells. However, the results showed heterogeneity between strains with respect to their ability to adhere to IPECJ2 cells, with a percentage of adhesion varying from 9% to more than 90%. The BT4 population displayed a more homogeneous ability to invade IPECJ2 cells with percentages varying from 10% to 26%. The BT4 strains displayed a great ability to adhere to the stainless steel surface, percentage of adhesion varying from 0.3% to 4.2%. No correlation was observed between IPEC-J2 cell adhesion, cell invasion and adhesion to the stainless steel surface (R² \u3c 0.02). In conclusion, these results reflect the ability of the different BT4 strains to colonize the intestinal tract of pigs and to contaminate the stainless steel surfaces of the food processing environment

Impact of cleaning and disinfection procedures on microbial ecology and Salmonella antimicrobial resistance in a pig slaughterhouse

International audienceTo guarantee food safety, a better deciphering of ecology and adaptation strategies of bacterial pathogens such as Salmonella in food environments is crucial. The role of food processing conditions such as cleaning and disinfection procedures on antimicrobial resistance emergence should especially be investigated. In this work, the prevalence and antimicrobial resistance of Salmonella and the microbial ecology of associated surfaces communities were investigated in a pig slaughterhouse before and after cleaning and disinfection procedures. Salmonella were detected in 67% of samples and isolates characterization revealed the presence of 15 PFGE-patterns belonging to five serotypes: S.4,5,12:i:-, Rissen, Typhimurium, Infantis and Derby. Resistance to ampicillin, sulfamethoxazole, tetracycline and/or chloramphenicol was detected depending on serotypes. 16S rRNA-based bacterial diversity analyses showed that Salmonella surface associated communities were highly dominated by the Moraxellaceae family with a clear site-specific composition suggesting a persistent colonization of the pig slaughterhouse. Cleaning and disinfection procedures did not lead to a modification of Salmonella susceptibility to antimicrobials in this short-term study but they tended to significantly reduce bacterial diversity and favored some genera such as Rothia and Psychrobacter. Such data participate to the construction of a comprehensive view of Salmonella ecology and antimicrobial resistance emergence in food environments in relation with cleaning and disinfection procedures

Tell me if you prefer bovine or poultry sectors and I’ll tell you who you are: Characterization of Salmonella enterica subsp. enterica serovar Mbandaka in France

IntroductionIn north-western France, Salmonella enterica susp. enterica serovar Mbandaka (S. Mbandaka) is most frequently isolated from bovine and dairy samples. While this serovar most often results in asymptomatic carriage, for a number of years it has caused episodes of abortions, which have serious economic consequences for the sector. Interestingly, this serovar is also isolated from Gallus gallus in the same geographic zone. Despite its prevalence in bovines in north-western France, S. Mbandaka has not been broadly studied at the genomic level, and its prevalence and host adaptation are still not fully understood.MethodsIn this study, we analyzed the genomic diversity of 304 strains of S. Mbandaka isolated from the bovine and poultry sectors in this area over a period of 5 years. A phylogenetic analysis was carried out and two approaches were followed to identify conserved genes and mutations related to host associations. The first approach targeted the genes compiled in the MEGARESv2, Resfinder, VFDB and SPI databases. Plasmid and phage contents were also investigated. The second approach refers to an in-house algorithm developed for this study that computes sensitivity, specificity, and accuracy of accessory genes and core variants according to predefined genomes groups.Results and discussionAll the analyzed strains belong to the multi-locus sequence type profile ST413, and the phylogenomic analysis revealed main clustering by host (bovine and poultry), emphasizing the circulation of 12 different major clones, of which seven circulate in poultry and five in the bovine sector in France and a likely food production chain adaptation of these clones. All strains present resistance determinants including heavy metals and biocides that could explain the ability of this serovar to survive and persist in the environment, within herds, and in food processing plants. To explore the wild animal contribution to the spread of this serovar in north-western France, we retrieved S. Mbandaka genomes isolated from wild birds from EnteroBase and included them in the phylogenomic analysis together with our collection. Lastly, screening of accessory genes and major variants allowed us to identify conserved specific mutations characteristic of each major cluster. These mutations could be used to design useful probes for food safety surveillance

Caractérisation taxonomique et dynamique de la flore bactérienne de surface de munsters (rôle antagoniste d'isolats corynéformes issus de la flore résiliente contre Listeria)

PARIS-AgroParisTech Centre Paris (751052302) / SudocSudocFranceF

Pig fecal and tonsil contamination of Yersinia enterocolita in one French slaughterhouse

Pig is considered to be the main animal reservoir of human pathogenic Yersinia enterocolitica strains which is frequently isolated from tonsils, but can also be found in the feces and onto carcasses. In France, while the main pathogenic biotypes are known for humans, few data are available regarding their prevalence in the pork chain production, and generally focus on tonsils contamination.</p

In vitro characterization of the ability of Yersinia enterocolitica BT4 to colonize pigs and stainless steel surfaces

Yersiniosis is, after campylobacteriosis and salmonellosis, the third most frequently reported zoonosis in Europe. Humans become infected with Y. enterocolitica through the consumption of undercooked pork and raw food having been in contact with contaminated surfaces. Pigs, the main reservoir for human pathogenic strains, do not develop clinical signs. In France and worldwide, biotype 4 (BT4) is the biotype the most frequently isolated from both pigs and clinical yersiniosis. In this study, a collection of 26 pathogenic BT4 strains isolated from pig tonsils was used to investigate their ability to adhere and invade intestinal pig cells (IPEC-J2) and to adhere to abiotic surfaces (stainless steel coupons) using two in vitro tests. Regression analysis was performed between data sets obtained from IPECJ2 cells assays versus stainless steel assays. All BT4 strains were able to adhere and invade IPEC-J2 cells. However, the results showed heterogeneity between strains with respect to their ability to adhere to IPECJ2 cells, with a percentage of adhesion varying from 9% to more than 90%. The BT4 population displayed a more homogeneous ability to invade IPECJ2 cells with percentages varying from 10% to 26%. The BT4 strains displayed a great ability to adhere to the stainless steel surface, percentage of adhesion varying from 0.3% to 4.2%. No correlation was observed between IPEC-J2 cell adhesion, cell invasion and adhesion to the stainless steel surface (R² < 0.02). In conclusion, these results reflect the ability of the different BT4 strains to colonize the intestinal tract of pigs and to contaminate the stainless steel surfaces of the food processing environment.</p

Population Genetic Structure of Listeria monocytogenes Strains Isolated From the Pig and Pork Production Chain in France

Listeria monocytogenes is an ubiquitous pathogenic bacterium, transmissible to humans through the consumption of contaminated food. The pork production sector has been hit hard by a series of L. monocytogenes-related food poisoning outbreaks in France. An overview of the diversity of strains circulating at all levels of the pork production chain, from pig farming (PF) to finished food products (FFP), is needed to identify the contamination routes and improve food safety. Until now, no typing data has been available on strains isolated across the entire pig and pork production chain. Here, we analyzed the population genetic structure of 687 L. monocytogenes strains isolated over the last 20 years in virtually all the French départements from three compartments of this production sector: PF, the food processing environment (FPE), and FFP. The genetic structure was described based on Multilocus sequence typing (MLST) clonal complexes (CCs). The CCs were obtained by mapping the PFGE profiles of the strains. The distribution of CCs was compared firstly between the three compartments and then with CCs obtained from 1106 strains isolated from other food production sectors in France. The predominant CCs of pig and pork strains were not equally distributed among the three compartments: the CC37, CC59, and CC77 strains, rarely found in FPE and FFP, were prevalent in PF. The two most prevalent CCs in the FPE and FFP compartments, CC9 and CC121, were rarely or never detected in PF. No CC was exclusively associated with the pork sector. Three CCs (CC5, CC6, and CC2) were considered ubiquitous, because they were observed in comparable proportions in all food production sectors. The two most prevalent CCs in all sectors were CC9 and CC121, but their distribution was disparate. CC9 was associated with meat products and food products combining several food categories, whereas CC121 was not associated with any given sector. Based on these results, CC121 is likely able to colonize a larger diversity of food products than CC9. Both CCs being associated with the food production suggests, that certain processing steps, such as slaughtering or stabilization treatments, favor their settlement and the recontamination of the food produced

Reduced susceptibilities to biocides and resistance to antibiotics in food-associated bacteria following exposure to quaternary ammonium compounds

International audienceAims: Our aim was to assess the effects of step-wise exposure to didecyl dimethyl ammonium chloride (DDAC) on the antimicrobial (antibiotics and biocides) susceptibilities of food-associated bacterial strains. Methods and Results: Adaptive responses of bacterial strains were investigated by exposing the strains daily to increasing subinhibitory concentrations of DDAC for 7 days. Following adaptation to DDAC, a threefold increase in the minimum inhibitory concentration (MIC) values for this biocide was observed in 48% of the Escherichia coli and Listeria monocytogenes strains, and 3% of the Salmonella strains. Reduced susceptibility to other biocides was found with the most important increase in MIC for benzalkonium chloride (BC) and a commercial biocide formulation (Galox Horizon) containing DDAC and glutaraldehyde, for all species except Salmonella. Increase in antibiotic MIC values was more pronounced in E. coli in terms of antibiotic numbers and of magnitude (from 4- to 32-fold increase) and, to a lesser extent, in Salmonella strains. Most of these strains had acquired resistance to ampicillin, cefotaxime, ceftazidime, chloramphenicol and ciprofloxacin. Conclusions: The effects of exposure to DDAC on biocides and antibiotics susceptibilities depend upon the bacteria species. Significance and Impact of the Study: Extensive use of DDAC at subinhibitory concentrations may lead to the development of antibiotic-resistant bacteria and may represent a public health issue

Complete Genome Sequence of Salmonella enterica subsp. enterica Serotype Derby, Associated with the Pork Sector in France

International audienceIn the European Union, Salmonella enterica subsp. enterica serovar Derby is the most abundant serotype isolated from pork. Recent studies have shown that this serotype is polyphyletic. However, one main genomic lineage, characterized by sequence type 40 (ST40), the presence of the Salmonella pathogenicity island 23, and showing resistance to streptomycin, sulphonamides, and tetracycline (STR-SSS-TET), is pork associated. Here, we describe the complete genome sequence of a strain from this lineage isolated in France