Leptospira | Anatomy2Medicine
Leptospirosis Bacteria

Leptospira

    • Leptospira. interrogans
    • causes the disease leptospirosis.
  • Also called infectious jaundice, marsh fever, Weil disease, and swineherd’s disease (MCQ)
    • a slender (lepto = slender), tightly coiled, culturable spirochete
  • has a single, thin, axial filament and hooked ends that resemble umbrella handles(MCQ)
    • an obligate aerobe. (MCQ)
    • Many serovars have been characterized based upon polysaccharide differences in the LPS component in the outer membrane (MCQ)
    • sensitive to drying and disinfectants.
    • survive for weeks in slightly alkaline water.
  • Epidemiology and pathogenesis
      • Leptospirosis is essentially an animal disease that is coincidentally transmitted to humans, primarily by water or food contaminated with animal urine. (MCQ)
      • Entrance to the body can also occur via small skin abrasions or the conjunctiva. (MCQ)
    • Cultural characteristics:
  • grown in media enriched with rabbit serum
  • Liquid and semisolid media
  • Korthof’s, Stuart’s an, Fletcher’s media(MCQ)
      • Semisynthc media
  • EMJH (Ellinghausen, McCullough Johnson, Harris) (MCQ)
      • They are aerobic and microaerophilic.
      • Leptospires may be grown on the chorioallantoic membrane of chick embryos.
      • Bacterial contamination is a serious problem in isolating and maintaining leptospires in culture.
        • use of 5-fluorouracil has been recommend for the inhibition of contaminating bacteria in cultures
        • A simple method for obtaining cultures free a contaminants is to  inoculate the material intraperitoneally in guinea pigs and culture the heart blood collected ten minutes later.
  • Clinical significance- biphasic disease
  • First stage:
        • Fever occurs 1 to 2 weeks after infection, at which time spirochetes appear in the blood.
        • These symptoms decrease after about 1 week
      • Second stage
        • spirochetes reappear, accompanied by invasion of the liver, kidneys, and CNS.
        • This results in jaundice, hemorrhage, tissue necrosis, and/or aseptic meningitis.
        • lasts 3 or more weeks
        • involves a rise in circulating immunoglobulin M antibodies.
        • Protective immunity develops following disease, but it is serovar specific
  • Diagnosis and treatment
    • Although L. interrogans can be cultured,diagnosis is usually based on
      • serologic agglutination tests (MCQ)
      • visual demonstration of the spirochetes in urine, blood, or cerebrospinal fluid.
    • Penicillin or doxycycline (MCQ)
    • useful if administered during the first stage of the dis- ease,
    • ineffective later