Spirochetes and Neisseria (Gram negative) Lecture 36

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Spirochetes and Neisseria (Gram
negative)Lecture 36
Faculty Dr. Alvin Fox
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Key Words

• 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

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SPIROCHETES

• Treponema, Borrelia and Leptospira

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Spirochetes

• Gram negative
• long, thin, helical, motile

• axial filaments
• locomotion
• between peptidoglycan layer/outer membrane
• runs parallel

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www.orl.cz/choroby/ustni/jazyk/zanet/1
Histology Treponema pallidum - testis infected
rabbit
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Treponema pallidum

• transmission
• genital/genital
• in utero or during birth

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Syphilis

• chronic
• slowly progressive

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• Secondary (2-10 weeks later)
• - systemic spread
• - flu-like symptoms
• - skin, particularly
• - many organisms
• - Highly infectious

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• Tertiary
• several years later
• rare
• skin
• central nervous system
• delayed hypersensitivity
• few organisms
• control by immune response

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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

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• fluorescence microscopy
• antibody staining

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Secondary and Tertiary Syphilis- serology

• screening method
• antibodies to cardiolipin
• specific diagnosis
• antibodies to treponemal antigen

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Autoimminty

• cardiolipin
• self antigen

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• no vaccine
• antibiotics (e.g. penicillin)
• effective

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Other treponemal diseases

• bejel, yaws and pinta
• extremely rare in US

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Borrelia burgdorferi and Lyme disease
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Ixodes scapularis, tick vector for Lyme disease.
Also known as Ixodes dammini. CDC
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• Lyme disease - symptoms

• bacteremia
• acute
• arthritis
• cardiac
• neurologic
• chronic
• weeks, months later

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Therapy

• early antibiotic therapy
• curable
• penicillin
• tetracycline
• late antibiotic administration
• ineffective

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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

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A physicians dilemma

• acute
• responds to antibiotic
• antibodies not detectable
• late diagnosis
• not curable
• antibodies detectable

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Lyme Disease -etiology

• reactive arthritis similar to
• Reiter's syndrome
• rheumatic fever
• resembles rheumatoid arthritis

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Relapsing fever

• lt100/ per year in US
• transmission
• tick-B. hermsii
• rodent, primary host
• lice-B. recurrentis
• human, primary host

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• Relapsing fever

• immune response develops
• disease relapses
• new antigens expressed
• no immunity
• disease reappears

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Diagnosis

• no culture
• no serological test
• detected - blood smear

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Leptospirosis
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Leptospirosis

• lt100 cases per year in US
• symptoms
• flu-like
• severe systemic disease
• kidney
• brain
• eye

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Transmission

• infected urine
• rodents
• farm animals
• water
• through broken skin.

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Laboratory Diagnosis

• serology
• most readily culturable of spirochetes
• culture still extremely difficult

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NEISSERIA
Neisseria gonorrhoeae
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• Neisseria

• Gram negative
• diplococci (pairs of cocci)
• oxidase positive
• culture
• Thayer Martin.
• selective
• chocolate agar
• heated blood (brown)

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N. gonorrhoeae the Gonococcus"

• found only in man
• gonorrhea
• second most common venereal disease

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Smear

• polymorphonuclear cell
• Gram negative cocci
• many in cells

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Dissemination -gonococci

• gonoccocal arthritis
• septic arthritis
• dermatitis

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Antibiotic therapy

• ß lactamase-resistant cephalosporin
• e.g. ceftriaxone
• resistant strains
• common
• produce ß lactamases
• destroy penicillin

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Pathogensis

• adhesion to genital epithelium
• outer membrane
• pili
• Antigenicity
• highly variable among strains
• no vaccine

• IgA protease
• also N. meningitidis

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N. gonorrhoeae

• Tissue injury
• lipopolysaccharide
• peptidoglycan

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N. meningitidis (the Meningococcus")
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N. meningitidis

• resides in man only
• usually sporadic cases
• mostly young children
• outbreaks
• adults
• crowded conditions
• e.g. army barracks, dorms

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Neisseria meningitidis

• upper respiratory tract infection
• adhesion pili

• bloodstream

brain
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Meningococcal meninigitis

• second most common meningitis
• pneumococcus, most common
• fatal if untreated
• responds well to antibiotic therapy
• penicillin

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• Laboratory Diagnosis

• spinal fluid
• Gram negative diplococci
• within polymorphonuclear cells
• meningococcal antigens
• Culture
• Thayer Martin agar

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Capsule

• capsule
• inhibit phagocytosis
• anti-capsular antibodies
• stop infection
• antigenic variation
• sero-groups
• vaccine
• multiple sero-groups