Salmonella typhimurium (Salmonella enterica subsp. enterica serovar Typhimurium)

  • General information

    • the following information is not yet verified
      General information
      An isolate is confirmed as Salmonella when the specific O serogroup has been determined and biochemical identification has been completed

      Family: Enterobacteriaceae

      Natural habitats
      Salmonella is ubiquitous in animal populations, and human illness is usually linked to foods of animal origin.

      Salmonellosis also is transmitted by direct contact with animals, by nonanimal foods, by water, and occasionally, by human contact.

      Clinical significance
      Strains of Salmonella are categorized as typhoidal and nontyphoidal.

      Nontyphoidal infection
      Usually cause an intestinal infection (accompanied by diarrhea, fever and abdominal cramps) that often lasts one week or longer.
      They can also cause extra intestinal infections, e.g., bacteremia, urinary tract infection, or osteomyelitis, especially in immunocompromised persons.

  • Gram stain

    • the following information is not yet verified
      Gram negative rods,

      2-5 x 0.7-1.5 μm

  • Culture characteristics

    • the following information is not yet verified

      Facultative anaerobic

      Selective media for the isolation of Salmonella and Shigella from clinical specimens

      XLD / xylose lysine desoxycholate agar
      Salmonella cannot ferment xylose ► red colonies, possible with black discoloration.
      Enterobacteriaceae ferment xylose ► yellow colonies

      HEK / hektoen agar
      These bacteria grow with green to blue-green colonies on the agar, possible with black discoloration.

      Colonies are 1-3 mm, usually the S-type, they are large, gray-white and smooth.

      After subculturing there are also R-type ("rough" form), these are grainy, with an irregular surface and a serrated edge.

      McConkey colonies are pale, non lactose fermenter

      BBAØ growth

      Salmonella can be further identified by its possession of somatic (O) and flagellar (h) antigen.

  • Characteristics

  • References

    • James Versalovic et al.(2011) Manual of Clinical Microbiology 10th Edition

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