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Spirochetes and Neisseria (Gram negative) Lecture 36. Faculty: Dr. Alvin Fox. Spirochete Axial filament Treponema pallidum Syphilis Chancre Primary lesion Darkfield microscopy Secondary Lesion Tertiary Lesion Anti-cardiolipin antibodies Anti-treponemal antibodies.
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SpirochetesandNeisseria(Gram negative)Lecture 36 Faculty: Dr. Alvin Fox
Spirochete Axial filament Treponema pallidum Syphilis Chancre Primary lesion Darkfield microscopy Secondary Lesion Tertiary Lesion Anti-cardiolipin antibodies Anti-treponemal antibodies Borrelia burgdorferi Lyme disease Relapsing fever (other borrelia) Leptospira (leptospirosis) Neisseria Thayer Martin agar Oxidase test N. gonorrhoeae Gonorrhea N. meningitidis Meningitis Key Words
SPIROCHETES Treponema, Borrelia and Leptospira
Spirochetes • Gram negative • long, thin, helical, motile • axial filaments • locomotion • between peptidoglycan layer/outer membrane • runs parallel
www.orl.cz/choroby/ustni/jazyk/zanet/1 Histology: Treponema pallidum - testis infected rabbit
Treponema pallidum • transmission • genital/genital • in utero or during birth
Syphilis • chronic • slowly progressive
Secondary (2-10 weeks later) • - systemic spread • - flu-like symptoms • - skin, particularly • - many organisms • - Highly infectious
Tertiary • several years later • rare • skin • central nervous system • delayed hypersensitivity • few organisms • control by immune response
Microbiological diagnosis • not culturable • dark field microscopy • actively motile organisms • brightly lit against dark backdrop • light shines at an angle • reflected from thin organisms • enters objective • conventional light microsrcopy • light shines through • NOT visualized
fluorescence microscopy • antibody staining
Secondary and Tertiary Syphilis- serology • screening method • antibodies to cardiolipin • specific diagnosis • antibodies to treponemal antigen
Autoimminty • cardiolipin • self antigen
no vaccine • antibiotics (e.g. penicillin) • effective
Other treponemal diseases • bejel, yaws and pinta • extremely rare in US
Ixodes scapularis, tick vector for Lyme disease. Also known as Ixodes dammini. CDC
Lyme disease - symptoms • bacteremia • acute • arthritis • cardiac • neurologic • chronic • weeks, months later
Therapy • early antibiotic therapy • curable • penicillin • tetracycline • late antibiotic administration • ineffective
Diagnosis • serum antibodies to B. burgdorferi. • laboratory strains • grow extremely slowly • tissue culture media • not bacteriological media • patient body fluids/tissue sample • almost never growth
A physicians dilemma • acute • responds to antibiotic • antibodies not detectable • late diagnosis • not curable • antibodies detectable
Lyme Disease -etiology • reactive arthritis similar to • Reiter's syndrome • rheumatic fever • resembles rheumatoid arthritis
Relapsing fever • <100/ per year in US • transmission • tick-B. hermsii • rodent, primary host • lice-B. recurrentis • human, primary host
“Relapsing” fever • immune response develops • disease relapses • new antigens expressed • no immunity • disease reappears
Diagnosis • no culture • no serological test • detected - blood smear
Leptospirosis • <100 cases per year in US • symptoms • flu-like • severe systemic disease • kidney • brain • eye
Transmission • infected urine • rodents • farm animals • water • through broken skin.
Laboratory Diagnosis • serology • most readily culturable of spirochetes • culture still extremely difficult
NEISSERIA Neisseria gonorrhoeae
Neisseria • Gram negative • diplococci (pairs of cocci) • oxidase positive • culture • Thayer Martin. • selective • chocolate agar • heated blood (brown)
N. gonorrhoeae the “Gonococcus" • found only in man • gonorrhea • second most common venereal disease
Smear • polymorphonuclear cell • Gram negative cocci • many in cells
Dissemination -gonococci • gonoccocal arthritis • “septic” arthritis • dermatitis
Antibiotic therapy • βlactamase-resistant cephalosporin • e.g. ceftriaxone • resistant strains • common • produceβ lactamases • destroy penicillin
Pathogensis • adhesion to genital epithelium • outer membrane • pili • Antigenicity • highly variable among strains • no vaccine • IgA protease • also N. meningitidis
N. gonorrhoeae • Tissue injury • lipopolysaccharide • peptidoglycan
N. meningitidis • resides in man only • usually sporadic cases • mostly young children • outbreaks • adults • crowded conditions • e.g. army barracks, dorms
Neisseriameningitidis • upper respiratory tractinfection • adhesion pili • bloodstream brain
Meningococcal meninigitis • second most common meningitis • pneumococcus, most common • fatal if untreated • responds well to antibiotic therapy • penicillin
Laboratory Diagnosis • spinal fluid • Gram negative diplococci • within polymorphonuclear cells • meningococcal antigens • Culture • Thayer Martin agar
Capsule • capsule • inhibit phagocytosis • anti-capsular antibodies • stop infection • antigenic variation • sero-groups • vaccine • multiple sero-groups