SPIROCHETES

• contains the genus Leptospira


  family Leptospiraceae
• contains Borrelia and Treponema


  family Spirochaetaceae
• spirochetes


  are slender, flexuous, helically shaped, unicellular bacteria ranging from 0.1 to 0.5 μm wide and from 5 to 20 μm long, with one or more complete turns in the helix.
• fibrils


  termed the periplasmic flagella
• also known as axial fibrils, axial filaments, endoflagella, and periplasmic fibril that areresponsible for motility.


  periplasmic flagella
• Treponema


  reproduce via transverse fission
• Leptospira and Borrelia


  divide by the more common binary fission
• Leptospira


  — are tightly coiled, thin, flexible spirochetes, 0.1 μm wide and 5 to 15 μm long

  — One or both ends of the organism have hooks rather than tapering off.

  — Their motion is rapid and rotational.

  — impregnated with silver and visualized

  — visible by dark field, phase contrast, and immunofluorescent microscopy
• Leptospires


  are obligately aerobic and can be grown in artificial media
• artificial media


  Fletcher's semisolid

  Stuart liquid

  Johnson-Harris (EMJH) Ellinghausen-McCullough semisolid media.
• L. interrogans


  — The incubation period of leptospirosis is usually 10 to 12 days but ranges from 3 to 30 days

  — hepatic, renal, and central nervous system involvemen
• Weil disease


  Severe systemic disease includes renal failure, hepatic failure, and intravascular disease and can result in death.
• 1 week to 3 weeks


  Duration of the illness of L. interrogans that varies from less than
• immunoglobulin M (IgM)


  antibodies are detected within 1 week after onset of disease
• Immunoglobulin G (IgG)


  antibodies are usually detectable 1 month or more after infection.
• natural host, leptospires live in the ___ and are ___

  lumen of renal tubules

  excreted in the urine
• principal animal reservoirs of L. interrogans

  Dogs, rats, and other rodents
• leptospires have been shown to be susceptible in vitro to

  streptomycin, tetracycline, doxycycline, and macrolide antimicrobials
• genus Borrelia


  Most species cause relapsing fever, with the notable exception of Lyme borreliosis,
• Lyme borreliosis


  caused by several species in the Borrelia burgdorferi sensu lato complex.
• arthropod-borne


  The spirals vary in number from 3 to 10 per organism and are much less tightly coiled than those of the leptospires
• — borreliae stain easily and can be visualized by bright field microscopy

  — cultivated in the clinical laboratory

  Kelly medium
• Borrelia recurrentis and Similar Borreliae

  — relapsing fever is characterized by acute febrile episodes that subside spontaneously but tend to recur over a period of weeks

  — evade complement
• tick-borne


  endemic relapsing fever
• louse-borne


  epidemic relapsing fever
• are the drugs of choice Borrelia recurrentis and Similar Borreliae

  tetracyclines
• Jarisch-Herxheimer reaction


  patients treated with antimicrobial agents experience fever, chills, headache, and myalgia believed to be caused by the sudden release of endotoxin from the spirochetes, a condition referred
• BORRELIA BURGDORFERI
• Lyme borreliosis


  is a complex disease that can generally be divided into three stages.
• localized (stage 1)


  erythema migrans (EM), the classic skin lesion that is normally found at the site of the tick bite
• Stage 2 is early disseminated


  secondary skin lesions, migratory joint and bone pain, alarming neurologic and cardiac pathology, splenomegaly, and severe malaise and fatigue
• late persistent infections (stage 3)

  — focus on the cardiac, musculoskeletal, and neurologic systems

  — Organisms are transmitted via the bite of infected Ixodes ticks
• Doxycycline and amoxicillin


  are equally effective in treating early stages of Lyme disease without complications.
• TREPONEMES


  — thin, spiral organisms about 0.1 to 0.2 μm in thickness and 6 to 20 μm in length

  — seen very easily using dark field microscopy.

  — The spirals are regular and angular, with 4 to 14 spirals per organism

  — The cells are motile, with graceful flexuous movements in liquid
• are inserted into each end of the cell

  Three periplasmic flagella
• TREPONEMA PALLIDUM SUBSP. PALLIDUM


  has the ability to cross intact mucous membranes and the placenta, disseminate throughout the body, and infect almost any organ system.
• Clinical Manifestations
• causes syphilis


  Treponema pallidum subsp. pallidum
• Treponema pallidum subsp. pallidum


  — direct sexual contact, transplacental transmission to a fetus, resulting in congenital syphilis.

  — wide variety of clinical manifestations, which gave rise to the name the "great imitator."
• tests for treponema pallidum

  Venereal Disease Research Laboratory (VDRL) and Rapid Plasma Reagin (RPR tests)