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  • Some serotypes tend to be more species specific, whereas others can affect a wide range of species. For example:
  • Salmonella enteritidis
  • Salmonella typhimurium
    • Widespread in most species.
  • Salmonella dublin
  • Cattle
  • Salmonella cholerae suis
  • Salmonella montevideo
    • Produces outbreaks from contaminated imported meat and bone meal.


Overview

  • Important member of the enterobacteria
  • Cause disease in humans and animals
  • Oral transmission
  • Reservior of infection in poulty, pigs, rodents, cattle, dogs
  • Cause enteritis and systemic infection (septicaemia and abortion)
  • Salmonella may be carried sub-clinically
  • Some human strains cause enteric fever (S. Typhi causes typhoid), also gastroenteritis, septicaemia or bacteraemia

Characteristics

  • Facultative intracellular pathogens
  • Non-lactose fermentor
  • Do not produce urease or indole from tryptophan
  • Utlise citrate as a carbon source
  • Usually produce hydrogen sulphide
  • Most motile with flagellae (H antigen)
  • H antigen can be in phase 1 or phase 2, depending on a genetic switch allowing for one of the H antigen genes to be transcribed

Classification

  • Single species, Salmonella enterica
  • Over 2400 pathogenic serotypes or serovars identified
  • Grouped into 9 groups according to O antigen (lipopolysaccharide) by the Kauffmann-White scheme - determined by slide agglutination of the bacteria with specific antisera
  • Categorised into serovars depending on and H (flagellar) antigen, e.g. Salmonella enterica subspecies enterica serovar Tymphimurium; must also determine phase of H antigen

Pathogenesis

Clinical infections

Diagnosis

Treatment

Control