Miscellaneous Bacterial Agents of Disease

The Spirochetes

Spirochetes 

Major human pathogen: - Treponema F.treponemataceae - Leptospira F.treponemataceae - Borrelia F.treponemataceae Spirochaetaceae : commensals of human and animals

Spirochetes  

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Typical gram negative cell wall Well developed periplasmic space that encloses the flagella Rotating and crawling motion Order Spirochaetales 2 family 5 genera

Treponema        

Thin regular coiled cells (5-15µ l -0.2 µ w) Oral cavity, IT, and perigenital regions Pathogens are restrict parasite Treponematoses T.p. pallidum :Venereal and congenital syphilis T.p.endimicum: Bejel T.p.pertenue: Yaws Treponema carateum: Pinta

Treponema 

Infection

skin

Tissue

marked by periods of healing interspersed with relapses

Treponema pallidum 

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The terms syphilis first appeared in a poem entitled” Syphilis sive Morbus Gallicus” by Fracastorius(1530) about a mythical shepherd whose name eventually become synonymous with the disease from which he suffered. Shaudinn & Hoffmann 1905 Strict human disease

Treponema pallidum Epidemiology and transmission: -Extremely sensitive and fastidious bacterium -Rapidly destroyed by heat, drying, disinfectants, soap, high O2 tension, and PH changes -Risk of infection from and infected sexual partner is 12% to 30% -Less common are passage to the fetus in utero and laboratory or medical accidents. - blood transfusion or exposure to fomites is rare.

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Treponema pallidum   

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Pathogenesis and host response: ID 57 organisms Direct contact with mucous membranes or abraded skin Local multiplication and penetration to capillaries Within a short times move to circulation and then to tissue targets.

Treponema pallidum 

Clinical manifestations: Untreated syphilis is marked by distinct clinical stages ♥ Primary syphilis ♥ Secondary syphilis ♥ Tertiary syphilis

Primary syphilis     

Incubation period of 9 days to 3 months Appearance of hard chancre at the site of inoculation Most chancres appear on the internal and external genitalia 20% occur on the lips, oral cavity, nipples, fingers or around the rectum The chancres heals spontaneously without scaring in 3 to 6 weeks.

Secondary syphilis 

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About 3 weeks to 6 month( 6 weeks) after the chancre heals Fever, headache and sore throat Lymphadenopathy and peculiar red or brown rash that breaks out on all skin surfaces including palm and soles Disappear spontaneously in a few weeks.

Latency and tertiary syphilis    

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About 30% of infections enter to this stage Numerous pathologic complications Cardiovascular syphilis Painful swollen syphilitic tumors called gummas develop in liver, skin, bone, and cartilage Neurosyphilis (sever headache, convulsions, mental disorders, paralysis and dementia,blindness destruction of parts of spinal cord)

Congenital syphilis Most common in 2th and 3rd trimester.  Inhibits fetal growth  Disrupt critical periods of development  Mild  Spontaneous miscarriage or stillbirth  Early congenital syphilis from birth to 2 years of age: - Nasal discharges, skin eruption and loss, bone deformation and Nervous system abnormalities 

Congenital syphilis 

Late congenital syphilis: _ unusual assortment of stigmata in bones, eyes, inner ear (deafness), and joints(periostitis) _ Hutchinson’s teeth

Clinical and laboratory diagnosis         

Chancre and patient history Rapid test Dark-field microscopy Wet mount preparation Immunofluorescence staining with monoclonal antibodies VDRL RPR MHA-TP FTA-ABS

Syphilis rapid test

FTA-ABS

VDRL and RPR Positive reaction

Negative reaction

VDRL and RPR

Syphilis 

Prevention: complete treatment of patients isolation of infectious reservoirs Good hygiene Use of condom

Nonsyphilitic Treponematoses

Non sexually transmitted treponematoses

Bejel ,Yaws ,Pinta   

Treponema pallidum endimicum Treponema pallidum pertenue Treponema carateum

Bejel ,Yaws ,Pinta Resemble to syphilis in effects Found in tropical and subtropical areas of the world Unsanitary living condition Morphologically indistinguishable from T.p.p Do not grow in artificial media

Bejel (endemic syphilis )    

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T.p.edemicum Nonvenereal childhood syphilis Africa, Middle east, and South east Asia Ulcers of skin and mucous and sometimes viscera Penicillin

Yaws    

T.P.Pertenue Children of tropical area Mother Yaws in legs and lower trunk Diagnosis and treatment is similar to syphilis

Pinta       

T.carateum Chronic skin infection Rural areas of Mexico, Columbia, Cuba, Philippine Nonulcerated extra genital papules reminiscent of psoriasis or leprosy Hyperkeratosis Depigmentation Diagnosis and treatment similar to syphilis