Antimicrobial resistance has become a global issue and a threat to human and animal health. Contamination of poultry carcasses with meat-borne pathogens represents both an economic and a public ...health concern. The use of antimicrobial processing aids (APA) during poultry processing has contributed to an improvement in the microbiological quality of poultry carcasses. However, the extensive use of these decontaminants has raised concerns about their possible role in the co-selection of antibiotic-resistant bacteria. This topic is presented in the current review to provide an update on the information related to bacterial adaptation to APA used in poultry processing establishments, and to discuss the relationship between APA bacterial adaptation and the acquisition of a new resistance phenotype to therapeutic antimicrobials by bacteria. Common mechanisms such as active efflux and changes in membrane fluidity are the most documented mechanisms responsible for bacterial cross-resistance to APA and antimicrobials. Although most studies reported a bacterial resistance to antibiotics not reaching a clinical level, the under-exposure of bacteria to APA remains a concern in the poultry industry. Further research is needed to determine if APA used during poultry processing and therapeutic antimicrobials share common sites of action in bacteria and encounter similar mechanisms of resistance.
Antibiotics are used to fight bacterial infections. However, a selective pressure gave rise to bacteria resistant to antibiotics. This leaves scientists worried about the danger to human and animal ...health. Some strategies can be borrowed to reduce the use of antibiotics in chicken farms. Much research has been carried out to look for natural agents with similar beneficial effects of growth promoters. The aim of these alternatives is to maintain a low mortality rate, a good level of animal yield while preserving environment and consumer health. Among these, the most popular are probiotics, prebiotics, enzymes, organic acids, immunostimulants, bacteriocins, bacteriophages, phytogenic feed additives, phytoncides, nanoparticles and essential oils.
Salmonella is a foodborne pathogen commonly associated with poultry products. The aims of this work were to (i) estimate the impact of critical steps of the slaughter process on Salmonella detection ...from broiler chicken carcasses in two commercial poultry slaughter plants in Quebec, Canada; (ii) investigate the presence of Salmonella in the slaughter plant environment; (iii) describe, using a high-resolution melting (HRM) approach, the HRM Salmonella profiles and serotypes present on carcasses and in the slaughter plant environment; and (iv) evaluate whether the HRM flock status after chilling could be predicted by the flock status at previous steps of the slaughter process, the status of previous flocks, or the status of the processing environment, for the same HRM profile. Eight visits were conducted in each slaughter plant over a 6-month period. In total, 379 carcass rinsates from 79 flocks were collected at five critical steps of the slaughter process. Environmental samples were also collected from seven critical sites in each slaughter plant. The bleeding step was the most contaminated, with >92% positive carcasses. A decrease of the contamination along the slaughtering process was noted, with carcasses sampled after dry-air chilling showing ≤2.5% Salmonella prevalence. The most frequently isolated serotypes were Salmonella Heidelberg, Kentucky, and Schwarzengrund. The detection of the Salmonella Heidelberg 1-1-1 HRM profile on carcasses after chilling was significantly associated with its detection at previous steps of the slaughter process and in previously slaughtered flocks from other farms during a same sampling day. Results highlight the importance of the chilling step in the control of Salmonella on broiler chicken carcasses and the need to further describe and compare the competitive advantage of Salmonella serotypes to survive processing. The current study also illustrates the usefulness of HRM typing in investigating Salmonella contamination along the slaughter process.
In broiler chicken production, microbial populations on the eggshell surface following oviposition are still poorly characterized, though they may significantly impact both poultry and public health. ...The aim of this study was to describe the microbiota of both broiler breeder hens' feces and the surface of their eggs to assess the contribution of the parental fecal microbiota to the eggshell microbiota. A total of twelve breeder flocks in Quebec, Canada, were sampled at two different times, and a total of 940 feces and 16,400 egg surface samples were recovered. Using 16S rRNA gene sequencing, we showed that even if the microbiota of both feces and eggshells were mainly composed of the phyla Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes, the bacterial community compositions and structures differed between both types of samples. Our results also showed that both the sampling time and the flock identity significantly influenced the alpha- and the beta-diversities of the studied microbiomes. Using a Venn diagram, we showed that 1790 operational taxonomic units (OTUs) were shared between feces and eggshell samples. Sequences associated with genera of potentially pathogenic and spoilage bacteria,
,
,
,
,
,
,
,
, and
, were shared between sample types. Some OTUs highly represented in the fecal microbiota and associated with
and
genera, were absent from eggshells, suggesting a selection during the microbiota transfer and/or the potential role of environmental contamination. To the best of our knowledge, this is the first study using 16S rRNA sequencing to describe the contribution of the transfer from the fecal microbial ecosystem of laying breeder hens to the establishment of the microbiota on the surface of laid eggs, as well as the bacterial communities at both the broiler breeder feces and the eggshell levels.
Avian necrotic enteritis (NE) caused by Clostridium perfringens is a disease with a major economic impact, generating losses estimated to 6 billion of dollars annually for the poultry industry ...worldwide. The incidence of the disease is particularly on the rise in broiler chicken flocks eliminating the preventive use of antibiotics. To date, no alternative allows for the efficient prevention of NE and a control of the disease using a vaccinal strategy would be mostly prized. For this purpose, comparative and subtractive reverse vaccinology identifying putative immunogenic bacterial surface proteins is one of the most promising approaches.
A comparative genomic study was performed on 16 C. perfringens strains isolated from healthy broiler chickens and from broilers affected with necrotic enteritis. Results showed that the analyzed genomes were composed of 155,700 distinct proteins from which 13% were identified as extracellular, 65% as cytoplasmic and 22% as part of the bacterial membrane. The evaluation of the immunogenicity of these proteins was determined using the prediction software VaxiJen®.
For the most part, proteins with the highest scores were associated with an extracellular localisation. For all the proteins analyzed, the combination of both the immunogenicity score and the localisation prediction led to the selection of 12 candidate proteins that were mostly annotated as hypothetical proteins. We describe 6 potential candidates of higher interest due to their antigenic potential, their extracellular localisation, and their possible role in virulence of C. perfringens.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
is the most prevalent bacterial foodborne pathogen in humans. Given the wide genetic diversity of
strains found in poultry production, a better understanding of the relationships between these ...strains within chickens could lead to better control of this pathogen on farms. In this study, 14-day old broiler chickens were inoculated with two
strains (10
or 10
CFU of D2008b and 10
CFU of G2008b, alone or together) that were previously characterized
and that showed an opposite potential to compete for gut colonization in broilers. Liver samples and ileal and cecal contents were collected and used to count total
and to quantify the presence of each strain using a strain specific qPCR or PCR approach. Ileal tissue samples were also collected to analyze the relative expression level of tight junction proteins. While a 10
CFU inoculum of D2008b alone was not sufficient to induce intestinal colonization, this strain benefited from the G2008b colonization for its establishment in the gut and its extraintestinal spread. When the inoculum of D2008b was increased to 10
CFU - leading to its intestinal and hepatic colonization - a dominance of G2008b was measured in the gut and D2008b was found earlier in the liver for birds inoculated by both strains. In addition, a transcript level decrease of
,
and
at 7 dpi and a transcript level increase of
,
,
,
were observed at 21 dpi for groups of birds having livers contaminated by
. These discoveries suggest that
would alter the intestinal barrier function probably to facilitate the hepatic dissemination. By
co-culture assay, a growth arrest of D2008b was observed in the presence of G2008b after 48 h of culture. Based on these results, commensalism and competition seem to occur between both
strains, and the dynamics of
intestinal colonization and liver spread in broilers appear to be strain dependent. Further
experimentations should be conducted to elucidate the mechanisms of commensalism and competition between strains in order to develop adequate on-farm control strategies.
Since the ban or reduction on the use of antibiotic growth promoters (AGPs) in commercial broiler chickens in many countries, avian necrotic enteritis (NE) caused by Clostridium perfringens has ...re-emerged as one of the biggest threats for the poultry industry worldwide. While the toolbox for controlling NE in the absence of antibiotics consists of a limited number of alternatives for which the overall effectiveness has yet proven to be suboptimal, an effective vaccine would represent the best control strategy for this often-deadly disease. Using a comparative and subtractive reverse vaccinology approach, we previously identified 14 putative antigenic proteins unique to NE-causing strains of C. perfringens. In the current work, the in silico findings were confirmed by PCR and sequencing, and five vaccine candidate proteins were produced and purified subsequently. Among them, two candidates were hypothetical proteins, two candidates were prepilin proteins which are predicted to form the subunits of a pilus structure, and one candidate was a non-heme iron protein. Western blotting and ELISA results showed that immunization of broiler chickens with five of these proteins raised antibodies which can specifically recognize both the recombinant and native forms of the protein in pathogenic C. perfringens.
Foodborne diseases (FBDs) are a major worldwide public health concern. In the current context of globalization, it has become crucial to establish effective collaboration between countries to reduce ...the incidence of FBDs, by creating knowledge-sharing activities to address this challenge. However, despite the importance of this subject, there are limited opportunities for researchers from French-speaking countries to meet and exchange expertise in this field. Researchers from the Faculty of Veterinary Medicine of the Université de Montréal (Canada) and from the Faculty of Science, University of Abdelmalek Essaadi (Morocco) took the initiative to organize the first French-speaking edition of the conference on Good Hygiene Practices to Ensure Food Safety, that was held virtually on May 25 and 26, 2022. Attendees (n = 122) came from academic, food processing and government sectors. The conference was a great opportunity to showcase the practical application of the risk analysis paradigm, with concrete examples of food hazards, as well as the use of the latest high-throughput sequencing technologies as a tool for source attribution and molecular typing of some of the most important foodborne pathogens. In addition, the conference created a valuable forum for the exchange of knowledge between international food safety experts, particularly with respect to Canadian regulations compared with those of other countries. Interestingly, following the success of this first edition, the conference’s scientific committee has decided to continue organizing this event on a biannual basis, to provide a unique forum for French-speaking researchers to learn about the latest advances in food safety.
Bacterial contamination during meat processing is a concern for both food safety and for the shelf life of pork meat products. The gut microbiota of meat-producing animals is one of the most ...important sources of surface contamination of processed carcasses. This microbiota is recognized to vary between pigs from different farms and could thus be reflected on the bacterial contamination of carcasses at time of processing. In this study, the microbiota of 26 carcasses of pigs originating from different farms (i.e., batches) were compared to determine if an association could be observed between carcass surface microbiota (top and bottom) and the origin of slaughtered animals. The microbiota of the top and bottom carcass surface areas was analyzed by culturing classical indicator microorganisms (mesophilic aerobic bacteria, Enterobacteria,
, and lactic bacteria), by the detection of
, and by 16S rRNA gene sequencing. Culture results showed higher Enterobacteria,
, and lactic bacteria counts for the bottom areas of the carcasses (neck/chest/shoulder) when compared to the top areas.
was not detected in any samples. Globally, 16S rRNA gene sequencing showed a similar composition and diversity between the top and bottom carcass areas. Despite the presence of some genera associated with fecal contamination such as
, and
on the carcass surface, sequencing analysis suggested that there was no difference between the different batches of samples from the top and bottom areas of the carcasses. The primary processing therefore appears to cause a uniformization of the carcass global surface microbiota, with some specific bacteria being different depending on the carcass area sampled.
This study was carried out to evaluate the prevalence of Salmonella serogroups and serotypes and their virulence gene carriage in pig fecal samples from farms and slaughterhouses in some southern ...provinces of Vietnam. The presence of Salmonella was assessed based on culture enrichment of the collected samples and biochemical and serological analyses; 27.7% (51) of 184 samples were posititve for Salmonella. Based on the availability of antisera, serogroups were determined for 61% (31) of 51 isolates. Twenty isolates belonging to Salmonella serotypes Typhimurium (10 isolates), Anatum (8 isolates), Senftenberg (7 isolates), Paratyphi B (3 isolates), Paratyphi A (1 isolate), Montevideo (1 isolate), and Saintpaul (1 isolate) were further characterized by a multiplex PCR protocol targeting Salmonella invasion A and virulence plasmid C genes ( invA and spvC, respectively). Individual PCR assays were developed to detect genes for Salmonella enterotoxin ( stn) , Salmonella outer protein B ( sopB), and Salmonella fimbriae ( pef). Various carriage patterns were identified among tested isolates. The invA and sopB genes were found in all isolates, and the stn gene was found in 95% of the isolates. The spvC gene was found in only 5% of the Salmonella Typhimurium isolates. None of the isolates were positive for the pef gene. Among all isolates, the predominant genotypic virulence profile (virulotype) was characterized by the concomitant presence of invA, sopB, and stn in carrier strains. In contrast, two virulotypes comprising either invA, sopB, spvC, and stn or invA and sopB were identified for the Salmonella Typhimurium isolates. Virulotypes made up of multiple virulence genes were predominant in most Salmonella strains tested in this study, indicating that pigs might act as a reservoir for these virulent strains.
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