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Binding of Salmonella strains to immobilized intestinal mucosal preparations from broiler chickens
S E Craven1, N A Cox, J S Bailey
1Poultry Microbiological Safety Research Unit, R. B. Russell Agricultural Research Center, Athens, Georgia 30613.
Abstract:
The binding kinetics of radiolabeled Salmonella california 1989/O (mannose-sensitive hemagglutinin-positive [MSHA+]) to immobilized mucus or enterocytes isolated from broiler ceca and inhibition of binding by D-mannose and sodium metaperiodate were characteristic of adherence of mannose-sensitive type 1 fimbriae of bacteria to eukaryotic mannose-containing receptors. Binding by radiolabeled strains 1989/O (in the presence of D-mannose) and S. typhimurium S 7471 N (MSHA-, non-fimbriated) indicated non-specific binding that was characterized by less binding to enterocytes and mucus and lack of inhibition by carbohydrates or prior treatment with sodium metaperiodate. Inhibition of non-specific binding to enterocytes by pretreatment with various enzymes or by the presence of tetramethylurea or p-nitrophenol (known to disrupt hydrophobic interactions) indicate involvement of multiple sites and hydrophobic bonding. Strain-specific outer-membrane preparations inhibited non-specific binding to a greater extent than did lipopolysaccharide, Escherichia coli outer-membrane preparations, or bovine serum albumin.
Insights
Salmonella binding to chicken gut cells involves mannose-sensitive type 1 fimbriae, similar to bacterial adherence to mannose receptors. Non-specific binding also occurs, influenced by hydrophobic interactions and multiple binding sites.
Area of Science:
- Microbiology
- Bacterial Adherence Mechanisms
- Poultry Gut Health
Background:
- Bacterial fimbriae mediate adherence to host cells, crucial for colonization and infection.
- Mannose-sensitive type 1 fimbriae are common bacterial adhesins interacting with mannose receptors.
- Understanding Salmonella adherence in poultry is vital for food safety and animal health.
Purpose of the Study:
- To characterize the binding kinetics of Salmonella california 1989/O to broiler cecal enterocytes and mucus.
- To differentiate specific mannose-sensitive adherence from non-specific binding mechanisms.
- To identify factors influencing Salmonella binding to the poultry gut.
Main Methods:
- Radiolabeling of Salmonella california 1989/O and Salmonella typhimurium S 7471 N strains.
- Binding assays using immobilized mucus and enterocytes isolated from broiler ceca.
- Inhibition studies using D-mannose, sodium metaperiodate, enzymes, and various chemical agents.
Main Results:
- Specific binding of Salmonella california 1989/O was mannose-sensitive, characteristic of type 1 fimbriae adherence.
- Non-specific binding by non-fimbriated or D-mannose-treated Salmonella was observed, with reduced affinity for enterocytes and mucus.
- Non-specific binding involved multiple sites and hydrophobic interactions, partially inhibited by strain-specific outer-membrane preparations.
Conclusions:
- Salmonella adherence to broiler cecal cells involves both specific mannose-sensitive fimbrial interactions and non-specific mechanisms.
- Non-specific binding is complex, involving hydrophobic forces and potentially multiple bacterial surface components.
- These findings contribute to understanding Salmonella colonization dynamics in poultry, with implications for control strategies.