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SpirochetesSpirochetes
Dr. Jyotsna AgarwalDr. Jyotsna Agarwal
Dept. MicrobiologyDept. Microbiology
KGMUKGMU
Classification of spirochetesClassification of spirochetes
• Spirochetes are thin, elongated, spirally twisted, Gram negative bacteria
• There are 11 genera in this group • Some are pathogens, but most are
free-living, and are actually pretty common in the environment.
3 genera have human pathogensTreponema, Borrelia, leptospira
Treponema (25 species)-Relatively short, slender, fine spirals.Associated with venereal and non venerealdiseases, some are non pathogenic Treponema pallidum causes syphilis- venereal
disease- STD.
Syphilis - T. pallidum
• History- ancient disease, Columbus crew
• Reservoir- humans only known natural host.
• Name syphilis from a poem describing a shepherd boy
• Transmission- sexual route- venereal
• Syphilis is not very contagious; a person has 1/10 chance of becoming infected after contact with an infected person
• In some stages, it is less contagious
• Syphilis is conventionally divided into Syphilis is conventionally divided into following stages:following stages:
Primary, Secondary, Latent, TertiaryPrimary, Secondary, Latent, Tertiary
–Staging has prognostic and therapeutic implications.
Primary syphilis• 5 to 80 days after contact (sexual), a
chancre develops at point of contact- external genitalia
• Chancre is an inflammatory lesion containing spirochetes & lymphocytes.
• It is painless, well circumscribed, indurated, heals spontaneously after ~10 – 40 days leaving a thin scar.(also called hard chancre)
• Regional lymph nodes are enlarged and non tender
• Even before appearance of chancre, treponema spread from site of entry via blood/lymph.
• Multiple chancre may be seen in immunodefficient patients.
• Once this heals patient remains asymptomatic till secondary stage
Secondary syphilis
• 2 - 12 weeks after primary lesion heals, generalized symptoms of disseminated infection occur due to multiplication and dissemination of treponemes
• Fever, headache, sore throat and enlarged lymph nodes develop
• Papular skin rash develops on body and lesions appear on palms and soles of feet also
• Abundant spirochetes in skin lesions- Abundant spirochetes in skin lesions- most infectious stagemost infectious stage
• Intensity of lesions in secondary syphilis Intensity of lesions in secondary syphilis variesvaries
• Can Heal spontaneously in months to Can Heal spontaneously in months to yearsyears
• Variable course spontaneous cure latent stage go to 3rd stage
Latent Syphilis
• Absence of clinical symptoms
• 3 possible outcomes
Persist for life
Tertiary syphilis
Cure
Tertiary syphilis
• 2-20 years later• Steady tissue destruction- Chronic
granulomata formation- Gumma, lesions contain very few treponema
• Cardiovascular system/CNS• ~1/3 die
Late tertiary or quaternary syphilis-
• Tabes dorsalis- dorsal column of spinal cord
• GPI- dementia
Congenital Syphilis
• Fetus susceptible after 4th month IU life
• 40% fetal death
• Hutchinson's Triad
peg teeth
interstitial keratitis
8th nerve destruction- deafness
Treponema pallidum bacteria• It is slender and tightly coiled,
measuring 5 to 15 µm long by 0.09 to 0.18µm wide
• They have a characteristic motility on dark field microscopy- cork screw
• This is due to axial fibrils, similar to flagella, varying numbers
• T. pallidum has not been cultured in vivo.
• It is rapidly inactivated by:
Drying, Heat, Cold
• Transmission is by direct contact or
congenitally
DiagnosisDiagnosis
Clinical- based on symptoms, history Clinical- based on symptoms, history
LaboratoryLaboratory
• Darkfield examinationDarkfield examination
Wear gloves, Clean the lesion with Wear gloves, Clean the lesion with saline gauze, press it gently and saline gauze, press it gently and collect exudate on a slide and examine collect exudate on a slide and examine in darkground microscope.in darkground microscope.
Serologic tests Non Specific/Non treponemal
• A reactive material from beef heart called cardiolipin is used as antigen
• It reacts with “reagin” antibodies that develop in syphilis
• Also called Standard test for Syphilis(STS)
VDRL• This is a slide flocculation test to
detect antibodies in patients serum using cardiolipin as antigen
11oo 1/3 + 1/3 +22o o 95% +95% +latent +/-latent +/-
Other Non treponemal tests• Kahn’s- Tube flocculation test• Wasserman test- Complement
fixation• RPR- rapid plasma reagin testBiological false positives- BFP• Acute infections, major trauma,
autoimmune conditions like SLE, • Leprosy, malaria
Specific - treponemal testsSpecific - treponemal tests
Using T. pallidum antigen to detect antibodies in Using T. pallidum antigen to detect antibodies in patients serum patients serum
• Treponema pallidum immobilization- TPITreponema pallidum immobilization- TPI• Fluorescent treponemal Antibody (FTA)Fluorescent treponemal Antibody (FTA)• T pallidum haemagglutination (TPHA)T pallidum haemagglutination (TPHA)
11oo 80% + 80% +22oo & 3 & 3oo >95% + >95% +latent >99% +latent >99% +
Treatment
• Penicillin is drug of choice
• Duration of tretment varies according to clinical stage of disease
• If allergic to penicillin- Ceftriaxone
Summary
• Treponema pallidum bacteria: characters
• Syphilis disease: mode of transmissison
• Clinical stages
• Diagnostic tests: STS / Specific tests
• Utility of tests / BFP