Medical Microbiology and Immunology
• Dr. Floyd C. Knoop
– Department of Medical Microbiology and Immunology – Creighton University Medical Center
• Criss I, Room 528
• knoop@creighton.edu
© Dr. Floyd C. Knoop, 2005. All Rights Reserved
Spirochetes
• Read Talaro, 5th ed., pp. 629-639 • Lecture Objectives
– 1) Outline and describe the signs and symptoms of syphilis – 2) Differentiate the various stages of syphilis – 3) Discuss the treatment regimen for individuals in different stages of syphilis – 4) Assess the different tests used to diagnose syphilis – 5) Discuss the etiologic agent, mode of transmission, disease and diagnosis for Borrelia (relapsing fever; Lyme disease) and Leptospira (infectious jaundice) infections
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Spirochetes
• Treponema
– Treponema pallidum (syphilis)
• Borrelia
– Borrelia hermsii (relapsing fever) – Borrelia burgdorferi (Lyme disease)
• Leptospira
– Leptospira interrogans (infectious jaundice)
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Characteristics
• Long, slender, helically-shaped cells • Motile via axial filaments
– insert at end/wind around cell
• Gram-negative/difficult to view • Dark-field microscopy
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Spirochete - Blood Smear
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Leptospira
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Borrelia
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Treponema pallidum
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Treponema pallidum
Syphilis
– direct contact with lesions – 90% by sexual contact – congenital transfer
Symptoms occur in stages
– primary – secondary – latent – tertiary or late
Primary Syphilis
Single primary lesion on any cutaneous or mucous membrane surface
– base hard but painless = hard chancre – appears in 3 weeks/disappears 4-12 weeks – only diagnostic test = dark field microscopy
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Penile Chancre
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Labial Chancre
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Facial Chancre
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Chancre on Finger
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Secondary Syphilis
6 weeks-several months Cutaneous and mucous membrane lesions Majority of cases = macular skin rash Infectious, live treponemes
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Mucous Membrane Lesions
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Syphilitic Cutaneous Lesion
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Mucous Membrane/Cutaneous
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Mucous Membrane
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Latent Syphilis
Early latent period = 2 years or less, infectious lesions may reappear Late latent period = over 2 years, a noninfectious stage/may last a lifetime or result in tertiary syphilis
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Tertiary or Late Syphilis
• Noninfectious stage • Gummas- no treponemes, due to host response = granulomas =
– skin, subcutaneous tissue, deep tissue – bone = tibia = saber shin syndrome – neurosyphilis
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Tertiary/Late Syphilis
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Tertiary/Late Syphilis
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Tertiary/Late Syphilis Saber Shin
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Laboratory Diagnosis
• Examine exudate from lesions/dark field microscopy = only absolute diag test = primary, secondary, early latent • Immunofluorescence of exudate • Serological tests:
– VDRL/agglutination test for nonspecific treponemal antibody/primary or late = no – FTA (fluorescent treponemal antibody)/TPHA (T. pallidum hemagglutination) = more sens and specific
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Treatment
• Recommended Regimen for Adults:
– 1o, 2o and early latent benzathine penicillin G = 2.4 million units IM in a single dose – Late latent and 3o benzathine penicillin G = 7.2 million units total administered as 2.4 million units IM each at 1 week intervals – Neurosyphilis aqueous crystalline penicillin G 18-24 million units a day for 10-14 days
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Borrelia
• B. hermsii - N. America/tick/after 3-4 days = chills, fever/asymptomatic/relapse • B. burgdorferi - Lyme, Connecticut/tick/ stage 1 = “Bulls eye”/headache, fever, muscle aches/ stage 2 = weeks-months = arthritis/often in joint/neurological/ chronic infection • Diagnosis: stained blood smear/ELISA • Treatment: tetracycline, chloramphenicol
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Lyme Disease
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Compliments of CDC
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Lyme Disease - Bull’s Eye
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Lyme Disease
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1. Antibiotic treatment for 3-4 weeks with doxycycline or amoxicillin is generally effective in early disease. 2. Cefuroxime axetil or erythromycin can be used for persons allergic to penicillin or who cannot take tetracyclines. 3. Later disease, particularly with objective neurologic manifestations, may require treatment with intravenous ceftriaxone or penicillin for 4 weeks or more, depending on disease severity. 4. In later disease, treatment failures may occur and retreatment may be necessary. (The Medical Letter, Vol. 42(Issue 1077), May 1, 2000)
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Treatment
Leptospira
• L. interrogans - animal (rats, livestock) urine/water contact/infect skin abrasion or mucosal surface/chills, headache, severe muscular pain/infectious jaundice • Diagnosis: microscopic agglutination test • Treatment: penicillin, tetracycline
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What is the appropriate treatment for primary syphilis in adults?
A. benzathine penicillin G = 2.4 million units IM in a single dose B. benzathine penicillin G = 7.2 million units total administered as 2.4 million units IM each at 1 week intervals C. crystalline penicillin G 18-24 million units a day for 10-14 days D. tetracycline = 2.4 million units IM E. amoxicillin = 2.4 million units oral
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THANKS!!!
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