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Inhibition of pathogenic Salmonella enteritidis growth mediated by Escherichia coli microcin J25 producing strains
V Portrait1, S Gendron-Gaillard, G Cottenceau
1Laboratoire de Génie Protéique et Cellulaire, Université de La Rochelle, France.
Abstract:
For the first time, microcin-producing strains showing inhibitory activities against enteropathogen Salmonella enteritidis were isolated from poultry intestinal contents. Among the numerous strains isolated, two strains of Escherichia coli, named J02 and J03, showing the greatest activities against S. enteritidis, were studied. Biochemical tests and purification identified the main antagonist compound produced as microcin J25. In order to evaluate the protective potential of E. coli J02 and J03 against S. enteritidis infection, the ability of these strains to inhibit growth of S. enteritidis was investigated in mixed culture. A strong antagonist activity was obtained with a preculture phase of the active strain in minimal medium before incubation with S. enteritidis. In a bioreactor experiment simulating the chicken gastric and intestinal tract environment, a mixture of the two strains E. coli J02 and J03, provided an enhanced inhibitory effect. Microcinogenic strain activities were not affected by bile, pancreatic enzymes addition, or acidic conditions. These results suggest the relevant role of microcin-producing microorganisms in microbial intestinal ecology. To conclude, this study shows that microcin J25 strains could exert a beneficial protective effect against S. enteritidis growth in situ.
Insights
Poultry intestinal bacteria, including Escherichia coli strains J02 and J03, produce microcin J25, inhibiting Salmonella enteritidis. These microcin-producing strains show protective potential against Salmonella infection in simulated gut environments.
Area of Science:
- Microbiology
- Bacteriology
- Poultry Science
Background:
- Enteropathogenic bacteria like Salmonella enteritidis pose a significant threat to poultry health.
- Microcins are ribosomally synthesized peptides with antimicrobial activity, but their role in poultry gut ecology is not fully understood.
Purpose of the Study:
- To isolate and characterize microcin-producing bacteria from poultry intestines with inhibitory activity against Salmonella enteritidis.
- To evaluate the potential of identified Escherichia coli strains and their microcin J25 production for controlling Salmonella enteritidis.
Main Methods:
- Isolation and screening of microcin-producing bacteria from poultry intestinal contents.
- Identification of antagonist compounds using biochemical tests and purification.
- In vitro inhibition assays in mixed cultures and bioreactor simulations of the chicken gastrointestinal tract.
- Assessment of microcin activity under various conditions (bile, pancreatic enzymes, acidic pH).
Main Results:
- Two Escherichia coli strains, J02 and J03, were isolated, exhibiting strong inhibitory activity against Salmonella enteritidis.
- The primary antimicrobial compound produced by these strains was identified as microcin J25.
- Enhanced inhibition of Salmonella enteritidis was observed when E. coli J02 and J03 were cultured together in a simulated gut environment.
- Microcin J25 activity remained stable under simulated gastric and intestinal conditions, including acidic pH and the presence of bile and pancreatic enzymes.
Conclusions:
- Microcin-producing Escherichia coli strains, specifically those producing microcin J25, can effectively inhibit Salmonella enteritidis in poultry.
- These findings highlight the potential of microcinogenic bacteria as probiotics for controlling Salmonella infections in poultry.
- Microcin-producing microorganisms play a relevant role in maintaining intestinal microbial ecology and could offer a beneficial protective effect against enteropathogens.