Related Experiment Videos
Outer membrane characteristics of Salmonella enteritidis phage type 4 growing in chickens
1Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UK.
Abstract:
Strains of Salmonella enteritidis belonging to phage type 4 (SE4) were grown in the peritoneal cavities of chickens, and without subculture on laboratory media examined for inducible in vivo phenotypic characteristics. These bacteria expressed three major outer membrane proteins (OMPs) of 33, 35 and 36 kilodaltons (kDa), and iron regulated OMPs of 74, 78 and 81 kDa. Bacteria growing in vivo did not express flagella, or fimbriae with a subunit molecular mass of 14 kDa (14 kDa fimbriae). Two OMPs of 55 and 23 kDa, expressed during culture in nutrient broth, were repressed during growth in chickens. Possession of a 38 MDa 'mouse virulence' plasmid did not influence the expression of OMPs, flagella or fimbriae. It was concluded that strains of SE4 growing in chicken tissues, use an enterobactin mediated iron uptake system to obtain ferric ions, do not express flagella or 14 kDa fimbriae and appear not to express novel OMPs involved in survival in vivo.
Insights
Salmonella enteritidis phage type 4 (SE4) grown in chickens showed specific outer membrane proteins and repressed flagella/fimbriae. Iron uptake systems were utilized for survival in vivo.
Area of Science:
- Microbiology
- Immunology
- Veterinary Science
Background:
- Salmonella enteritidis is a significant foodborne pathogen.
- Understanding in vivo bacterial adaptation is crucial for controlling infections.
Purpose of the Study:
- To investigate the in vivo phenotypic characteristics of Salmonella enteritidis phage type 4 (SE4) grown in chicken peritoneal cavities.
- To identify changes in outer membrane protein (OMP) expression, flagella, and fimbriae during chicken infection.
Main Methods:
- Culturing SE4 strains in chicken peritoneal cavities without laboratory subculturing.
- Analyzing bacterial outer membrane proteins (OMPs) using molecular mass.
- Assessing flagella and fimbriae expression.
- Investigating the role of a 'mouse virulence' plasmid.
Main Results:
- SE4 expressed major OMPs (33, 35, 36 kDa) and iron-regulated OMPs (74, 78, 81 kDa) in vivo.
- Flagella and 14 kDa fimbriae were not expressed by bacteria growing in vivo.
- OMPs of 55 and 23 kDa, seen in nutrient broth, were repressed in chickens.
- A 38 MDa 'mouse virulence' plasmid did not affect OMP, flagella, or fimbriae expression.
Conclusions:
- SE4 utilizes an enterobactin-mediated iron uptake system in chickens.
- SE4 does not express flagella or 14 kDa fimbriae during chicken infection.
- No novel OMPs were identified as essential for SE4 survival in vivo under these conditions.