SEF17 fimbriae are essential for the convoluted colonial morphology of Salmonella enteritidis

• Published in: FEMS microbiology letters 1997-08, Vol.153 (1), p.33-42
• Main Authors: Allen-Vercoe, E, Dibb-Fuller, M, Thorns, C.J, Woodward, M.J
• Format: Article
• Language: English
• Subjects: Agar; Ampicillin; animal diseases; animal health; Animals; Antigens; bacterial infections; Bacterial Proteins - analysis; Chickens; Colonies; Colony morphology; Congo Red; Culture Media; Environmental stress; Extracellular matrix; Fimbriae; Fimbriae Proteins; Fimbriae, Bacterial - chemistry; Fimbriae, Bacterial - ultrastructure; Flagella; food contamination; Genotype & phenotype; Genotypes; human health and safety; Immunoelectron microscopy; medicine; Microbiology; Microscopy; Molecular Sequence Data; Morphology; Multigene Family; Mutagenesis, Insertional; Phenotype; Phenotypes; Pili; poultry products; Salmonella; Salmonella enteritidis; Salmonella enteritidis - cytology; Salmonella enteritidis - genetics; Salmonella enteritidis - pathogenicity; Salmonellosis; SEF17; Virulence
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.1997.tb10460.x

Salmonella enteritidis isolated from poultry infections generated a convoluted colonial morphology after 48 h growth on colonisation factor antigen (CFA) agar at 25 degrees C. A mutant enteritidis defective for the elaboration of the SEF17 fimbria antigen, in which the agf gene cluster was inactivated by insertion of an ampicillin resistance gene cassette, and other wild-type S. enteritidis transduced to this genotype failed to produce convoluted colonies. However, growth of SEF17- mutants at 25 degrees C on CFA agar supplemented with 0.001% Congo red resulted in partial recovery of the phenotype. Immunoelectron microscopy demonstrated that copious amounts of the SEF17 fimbria antigen were present in the extracellular matrix of convoluted colonies of wild-type virulent S. enteriridis isolates. Bacteria were often hyperflagellated also. Immunoelectron microscopy of SEF17- mutants grown on CFA agar+0.00l% Congo red demonstrated the elaboration of an as yet undefined fimbria structure. Isolates of S. enteritidis which were described previously as avirulent and sensitive to environmental stress failed to express SEF17 or produce convoluted colonies. These data indicate an essential role for SEF17, and possibly for another fimbria and flagella, in the generation of the convoluted colonial phenotype. The relationship between virulence and colonial phenotype is discussed.