Spirochetes

Borrelia, Treponema, and Leptospira

genera

- Borrelia

- Treponema

- Leptospira

characteristics

- helically coiled

- motile

- GN cell wall characteristics

- do NOT gram stain well

- not classified as GP or GN

Borrelia characteristics (oxygen, morphology, motility, staining)

-Microaerophilic

-Helically coiled

-Corkscrew or oscillating motility

-Stain with Giemsa

-Generally require vectors such as lice and ticks to initiate infection

relapsing fever

• a bacterial infection caused by spirochetes in the Borrelia genus

• Borrelia enters the blood and lesions form in the spleen, liver, or kidneys

• symptoms

  • fever, muscle pain, bone pain, confusion, hepatosplenomegaly

• the disease can relapse due to changes in the organism’s antigenicity

how do we ID relapsing fever?

–Based on clinical symptoms

–Difficult to culture Barbour-Stoenner-Kelly media

–Thick blood films with Giemsa stain during febrile episode

Borrelia burgdorfei characteristics and infection

• spirochete carried by several tick species

• causes Lyme Disease

  • varied presentation

first stage of Lyme disease

erythema migrans (EM) "bull's eye" rash

second stage of Lyme disease

Spirochete spread through blood to

- Bones (arthritis)

- CNS (meningitis, facial palsy, other neurological signs)

- Heart

- Liver

third stage of Lyme disease

- chronic arthritis of large joints

- skin lesions

- peripheral neuropathy

how can we prevent Lyme disease?

- person protective measures

- tick check & remove ticks

- preventative antibiotics after a tick bite

how can we treat Lyme disease?

Doxycycline or amoxicillin for 3-4 weeks

diagnosing Lyme disease

- EM rash

- biopsy & silver stain

- serology

- two-tier testing (EIA/IFA and Western Blot)

- PCR

- culture

Treponema

- thin, helically shaped with tight coils

– Some are normal microbiota in oral cavity, gastrointestinal tract, and genital tract of humans and other animals

– Most are anaerobic

– Microaerophilic species are pathogenic

– Never cultured on or in artificial media

- T. pallidum subsp. pallidum

- T. pallidum subsp. pertenue

- T. pallidum subsp. endemicum

- T. carateum

T. pallidum subsp. pallidum

Venereal Syphilis

- transmitted through sexual contact or trans-placentally

- incubate 10-90 days (14-21 days)

- chancre

primary stage of syphilis

- Hallmark sign is painless chancre at portal of entry

- Regional lymphadenopathy

secondary stage of syphilis

- Occurs 3-10 weeks after chancre

- Widespread skin rash on palms and soles

- Lesions are infectious

- Lymphadenopathy; fever; involvement of liver, eye, bone, CNS

how do we diagnose syphilis?

- Dark-field for early secondary

- Serology for late secondary

tertiary stage of syphilis

- Months to years after primary syphilis

- CNS involvement with neurological disorders

- Cardiovascular abnormalities

- Gummas

- Intense cellular immune response

gummas

granulomatous inflammation

- Painless ulcers that may contain a few spirochetes

latent syphilis

- Absence of clinical symptoms

- Positive serological tests

- Relapses are possible

congenital syphilis

Trans-placental transfer from mother to fetus during primary, secondary or latent syphilis

what can congenital syphilis cause?

- Stillbirth or miscarriage

- Bone malformations, widespread rash, meningitis, hepatosplenomegaly, blindness, deafness

non-treponemal testing

- screening tests (RPR, VDRL)

- first tests to become positive & useful to monitor treatment

- detects reagin

- high sensitivity but low specificity (false pos, confirm with treponemal test)

treponemal testing

confirmatory tests are specific

- FTA-Ab (Fluorescent Treponemal Antibody Absorbed)

- TP-PA (T. pallidum Particle Agglutination)

- EIA

- become positive later & remain positive for life

- NOT useful to monitor treatment

T. pallidum subsp. pertenue

Yaws

– Chronic, non-venereal disease of skin and bones

– Found in tropical areas of Africa, South America, and Indonesia

– Direct contact with infected skin lesions

– Resembles T. pallidum subsp. pallidum genetically and morphologically

T. pallidum subsp. endemicum

Bejel

– Non-venereal, endemic syphilis

– Found in arid climates of India, Asia, Africa, Middle East

– Oral lesions that may become widespread in the skin and bones

T. pallidum subsp. carateum

Pinta

- found in South and Central America

- infected skin lesions

- Papule with red halo that later become brown to black and then de-pigmented

- Antibodies cross-react with those from T. pallidum subsp. pallidum

miscellaneous spirochetes

- several spirochetes found in gingival plaque in human oral cavity & colon

- strict anaerobes

- rarely pathogenic

- may cause gingivitis or periodontal disease

- T. socranskii

- T. denticola

- T. pecintovorum

Leptospira

– Flexible, tightly coiled spirochete

– Stain faintly with aniline dyes

– Ends of cell are pointed or bent into hook

– Obligate aerobes

– Motile

– Oxidase positive

– Catalase positive

- L. biflexa

- L. interrogans

L. biflexa

non-pathogenic

L. interrogans

- Human and animal leptospirosis

- Found in rodents, cattle, dogs, cats, and raccoons and shed in urine

- Humans acquire infection through contact with infective animal urine or contact with contaminated soil or water

How does L. interrogans cause disease?

bacteria enter the blood and can disseminate to the brain, liver, lungs, heart, and kidneys, causing hemorrhage and necrosis

L. interrogans symptoms

- fever, headache, chills, vomiting, jaundice, multi-organ involvement (liver, kidney and CNS)

- icteric form known as Weil's syndrome is severe

who is at risk for L. interrogans?

Slaughterhouse workers, farmers, veterinarians, pet owners, sewage plant workers, campers, rodent-infested areas

diagnosing L. interrogans

- paired sera: IgM and IgG

- microscopic agglutination test (MAT)

- dark-field on blood, CSF, urine

- culture

L. interrogans culture requirments

- rabbit or bovine serum albumin

- may need 6-13 weeks to grow