Spirochaetes

Presentation Outline

• Morphology

• Organisms

• Diseases
  • Leptospirosis
  • Lyme disease
  • Syphilis

• Tests

Spirochete Morphology

• Gram negative cell wall
  • often too small to see by light microscopy
  • special stains

• Spiral morphology

• distinctive tight coils

• Motile
  • Periplasmic flagella

Spiral

Spiral bacterium

Spirillum volutans

Spirochete

Axial Filament

• Between cell wall and cytoplasmic membrane

• Attached at either end of cell

• Overlap in the centre
  • constrict at overlap
  • pulls ends together

Spirochetes:Features

• Chemoorganotropic

• Range of oxygen requirements

• Life style
  • Free living
  • host associated

Spirochaete Motility

Click on image

Spirochetes: genera

• Borrelia (lyme disease)

• Brachyspira

• Cristispira

• Leptonema

• Leptospira (Leptospirosis)

• Serpulina

• Spirochaeta

• Treponema (Syphilis)

Leptospirosis

Leptospira biflexa

• free living saprophyte in moist environments

• motile, flagella

• aerobic

• can be grown in 2 weeks

Leptospirosis

• Leptospira interrogans

• Zoonosis of wild & domestic animals
  • acquired from urine of infected animals
  • Dogs, rodents

• Portal of entry
  • broken skin or mucosa

• Bacteremia

L. interrogans

• Carried by wild and domestic animals

• source of human infection

• Streams, rivers, moist soil

• contaminated by animal urine

• Person to person very rare.

Occupational exposure

• farmers, slaughter house

• workers, veterinarians.

L. interrogans

• mild flu like febrile illness

• Weil’s disease
  • renal and hepatic failure
  • vasculitis
  • meningitis
  • myocarditis
  • death

• Penetrate all organs including CNS

• Enter through small cuts

Leptospirosis

• Febrile illness not clinically distinctive

• Acute phase
  • Leptospiremic phase
  • incubation 7 -14 days
  • fever, headache, muscle pain nausea

• Immune phase
  • found in urine
  • meningitis

Borrelia

Relapsing Fevers

Lyme Disease

Relapsing Fever

• Borrelia recurrentis

• Tick borne Relapsing fever
  • rodents are reservoir
  • soft shelled ticks

• Louse borne Relapsing fever
  • humans are reservoir
  • body louse

Borrelia

• Easily seen in blood smear

• Also confirmed by injecting mouse
  • blood stream teaming with Borrelia

B.recurrentis

• Tick borne relapsing fever is a zoonotic

• Clinical evolution: relapsing fever

• Serological tests not useful

• treatment
  • tetracycline

Lyme Disease

• Lyme, Conneticut USA - spring/fall

• Borrelia burgdorfii

• reservoir rodents, pets, deer

• vector hard shelled ticks

• Bite: incubation 3-30 days

Lyme Disease: Early Signs

• Erythema chronicum migrans

• Erythematous skin lesion
  • small macule or papule - enlarges to 68 mm.

• Malaise, severe fatigue, headache, fever, chills,

• chronic neurologic, cardiac rheumatic manifestations.

Lyme Disease: Complications

• 1 month or more
  • myalgia, lymphadenopathy

• Up to 2 years
  • meningitis, encephalitis, peripheral nerve neuropathy.

• Cardiac disfunction, myopericarditis.

Lyme Disease: Serology

• Immunofluorescence assay

• Enzyme-linked immunoabsorbent assay (ELISA)

• False positives
  • other spirochaetes
  • infectious mononucleosis
  • autoimmune disease

Lyme Disease:Treatment

• tetracycline or penicillin

Syphilis

Stages of Syphilis

• Primary

• Secondary

• Tertiary

Primary syphilis

Chancre: painless blister at the site of contact

Heals spontaneously even if untreated

Syphilitic lesions of vulva

Secondary Syphilis

• Lesions of secondary syphilis are dispersed over the body

• Lesions appear on the cooler parts of the body

Secondary syphilis

Syphilitic lesion on the cooler parts of the body

Neuronal Syphilis

• Treponemes have invaded the nerve and set up a lesion

Syphilic lesions on bones

Cardio Syphilis

Tests for Syphilis

• Break down products of infected cells
  • cardiolipin
  • VDRL, Wasserman
  • Simple, well documented
  • cross reactive eg TB
  • presumtive test

• Treponemal antigens
  • more expensive
  • more specific
  • confirmatory test

Performance Objectives

Key terms, concepts

short answers

Key Terms

Key Terms

Key Organisms

Key Concepts

Epidemiology of ???

• Disease/bacterial factors

• Transmission

• Who is at risk

• Geography/ season

• Incidence

• Modes of control

Short Answers

• Construct a table of the virulence factors associated with ??? and the biological activity of each

• Use a series of no more than four diagrams to describe the mechanism of ??? activity

• Describe the clinical manifestions ???

• Construct a table listing the common ??? species and the associated human diseases.

The End

Icteric leptospirosis

• first stage: 3-7 days - septicemic

• 10-30 days - immune

• Cultures positive: blood, then CSF, then urine

Icteric leptospirosis

• Jaundice, hemorrhage, renal failure, myocarditis

• Anicteric described

• Best in CSF, blood, and urine culture -- 1st week

• Lab test -- slide agglutination

• Doxycycline - treatment

• Prevention: rodent control

So What

• Know importance
  • #1 communicable disease growing fast

• Know how it is spread
  • Sexual intercourse
  • skin-skin contact

• Know the symptoms

• Syphilis can be identified and cured