Order Spirochaetales
• Family Spirochaetaceae– Genera:
• Treponema• Borrelia
• Family Leptospiraceae– Genus Leptospira
• General characters:– Long (up to 250 µm),
thin (0.1-0.6 µm diameter), spirral/helically coiled
– High motility (flagella/axial filaments)
GenusTreponema
• Comensals: human upper respiratory mucosa, genital mucosa (e.g. Treponema phagedenis) – cultivable
• Pathogens: non-cultivable• Treponema pallidum
– ssp. pallidum – syphilis - STI
– ssp. endemicum – bejel (endemic syphilis) – Africa, Australia
– ssp. pertenue – pian – granulomatous skin lesions → degenerative lesions in lymph nodes and bones
• Treponema carateum – pinta – persistens skin lesions (papulae) → mutilating scars
Treponema pallidum
• Causative agent of syphilis• Transmission via:
– sexual intercourse– mother to child (transplacentar, intra-partum) – congenital
syphilis
• Evolution stages (if untreated):– Primary: 15 days after infecting contact; chancre – painless
ulceration at the entry site (penis, vagina, oral mucosa)– Secondary: 45 days after chancre; skin rash– Tertiary: after latency of 5-15 years; destructive lesions of CNS,
cardiovascular, muscles, bones, etc
Tertiary syphilis (patient is not infectious)
• 3 forms:– gummatous (15%): gummas = soft, tumor-like balls of
inflammation on the skin, bones, and liver – neurosyphilis (6.5%):
• Early: meningitis
• Late: general paresis / tabes dorsalis (myelopathy), dementia
– cardiovascular (10%): aortic aneurisms
Treponema pallidum- Laboratory diagnosis -
Collection of specimens:
• chancre secretion (primary syphilis)• secretion from skin lesions (secondary syphilis)
– choose most recent lesion, remove crust, press lesion in order to cause bleeding, collect serous exudate
• blood for serlogy (all stages)
Specimens from lesions must be examined asap (treponemae are not viable for a long time outside the body)
Treponema pallidum- Microscopy -
• Wet mount in dark field/contrast phase:
• shining treponemae, highly motile on the dark background of microscopic field
• Stained smears: e.g. Silver staining
ATTENTION: oral specimens might contain comensal treponemae!!
Treponema pallidum- Serology -
Diagnosis based on antigenic structure:– Cardiolipinic Ag – present in all treponemae + other bacteria– Proteic Ag (Reiter) – Genus-specific (present in all treponeame)– Treponema pallidum specfic Ag
Diagnostic tests:• Nonspecific (nontreponemic):
– VDRL (flocculation)– Bordet-Wasserman reaction (complement fixation)
• Specific (treponemic): – TPI (Treponema pallidum immobilization) test – passive hemagglutination
Treponema pallidum- Serology - continued
Nonspecific, nontreponemic tests:
VDRL
(Veneral Disease Research Laboratory, Atlanta, USA)
Principle: antibodies (anti-cardiolipin Ab) produced by a patient with syphilis react with an extract of ox heart; reaction visualized through foaming of the test tube fluid, or "flocculation".
Patient Ab react with bacterial components
Treponema pallidum- Serology - continued
Nonspecific, nontreponemic tests (continued):
Bordet-Wasserman test:
Principle: Ab in patient serum will inactivate serum complement in the presence of ”reagines” (produced by infected tissues in response to bacterial infection);
Treponema pallidum- Serology - continued
Specific treponemic tests
TPI (Treponema pallidum immobilization):• Principle: specific anti-Treponema pallidum Ab in patient
serum, in the presence of complement, immobilize actively motile T. pallidum obtained from testes of syphils infected rabbits
Passive hemagglutination:
• Principle: specific anti-Treponema pallidum Ab in patient serum cause agglutination of treponemic Ag adsorbed on the surface of red blood cells
Treponema pallidum- Antibiotic sensitivity -
• Penicillin – i.v.
• Alternatively (in case of allergy):– Doxycycline, tetracycline, azithromycin– OR – desensitization – to enable
administration of penicillin
• Pregnant women with syphilis must receive penicillin to prevent congenital syphilis
Order Spirochaetales
• Family Spirochaetaceae– Genera:
• Treponema
•Borrelia• Family
Leptospiraceae– Genus Leptospira
• General characters:– Long (up to 250 µm),
thin (0.1-0.6 µm diameter), spirral/helically coiled
– High motility (flagella/axial filaments)
Genus Borrelia
• Clinical significance: vector borne diseases
• Relapsing fever (Borrelia recurrentis) – lice, ticks
• Lyme disease (Borrelia burgdorferi) - ticks
Borrelia recurrentis
• Main causative agent of relapsing fever (also caused by other agents e.g. Rickettsia)
• Vectors: human lice (Pediculus corporis) + certain species of ticks
• Clinical aspect: sudden fever, chills, headache, nausea - for 2-9 days; symptoms reappear after 3-10 days; evolution continues with similar cycles
• Laboratory diagnosis: – detection of spirochetes in blood smear – ELISA – detection of specific Ab in patient serum
Borrelia burgdorferi
• Clinical significance: Lyme disease (boreliosis) – disease described for the 1st time in Lyme Connecticut USA 1976)
• Reservoir: birds, dogs, horses• Transmission via tick bites; incubation 1-3 weeks
Lyme borreliosis – ”disease with 1000 faces”- stages -
I. Erythema migrans:• 3-30 days after tick bite; • ”bull‘s eye” rash; may further
appear on other parts of the body
II. General dissemination: myocarditis, arthritis, lymphadenitis, neurologic symptoms (meningitis, meningoradiculitis)
III. Chronic relapsing arthritis (knee, elbow), chronic atrophic acrodermatitis (skin sclerosis and atrophy of limbs → generalised)
Borrelia burgdorferi- Laboratory diagnosis -
• ELISA for the detection of specific Ab (IgM and IgG) in patient serum
• Confirmatory tests: immunoblot (Western blot)
• Specific choice and sequence of tests – depends on stage of disease (described in diagnostic guidelines)
Lyme disease
TREATMENT:• early stages: doxycycline, amoxicillin, cefuroxime • later stages: intravenous ceftriaxone or penicillin
PREVENTION:
• Prevention of tick bites• Safe removal of ticks
• http://www.cdc.gov/lyme/prev/index.html
Order Spirochaetales
• Family Spirochaetaceae– Genera:
• Treponema• Borrelia
• Family Leptospiraceae– Genus Leptospira
• General characters:– Long (up to 250 µm),
thin (0.1-0.6 µm diameter), spirral/helically coiled
– High motility (flagella/axial filaments)
Genus Leptospira
General characters: • aerobic, helicoidal, flexible, 6-20 µm length, 0.1 µm
diameter, motile, terminal “hook” at each end
Species:
• Leptospira interrogans – pathogenic– Serotypes: L. canicola, L. icterohemorrhagiae, L. pomona, etc
• Leptospira biflexa – saprophitic – present in water
Genus Leptospira- Clinical significance -
• Zoonosis – domestic and wild animals• Human infection:
– contact with water, soil - contaminated with animal urine– occupational exposure: veterinarians, farmers, field workers,
hunters, etc– Germs may penetrate intact skin / microlesions → rapid blood
dissemination → organs (liver, kidney, eye), CSF
• Disease – Leptospirosis: mild clinical forms → severe icteric disease with hepatic & renal disfunctions
Leptospirosis- continued -
• Incubation: 3-30 days• First stage: germs present in blood and CSF ~ 1 week• Further stages: germs eliminated in urine – from 2nd
week; urine elimination persists 2-3 months
• Laboratory diagnosis:– Bacteriology– Serology– Experimental disease
Leptospirosis- Bacteriologic diagnosis -
• Collection of specimens: blood, CSF, urine, peritoneal fluid
• Specimens must be centrifuged to increase the chance of direct detection in sediment
• Microscopy:– Wet mounts examined in dark field– Immunofluorescence (fluorescent antibodies)
Leptospirosis- Bacteriologic diagnosis - continued
• Culture media: liquid/semisolid media containing blood + bovine serum + other ingredients– 1st week – blood culture (rarely positive growth)
– After 1st week – urine culture, experimental disease in animals– Incubation at room temperature, dark, very slow growth (6-14
days, up to 3-4 months) – not adequate for diagnostic purposes
• Serology: – microscopic agglutination with Leptospira antigens – ELISA