SPIROCHETES

• Spirochetes


  Helically coiled bacteria transmitted through arthropod vectors
• Borrelia spp.


  • Flexible twisted organisms resembling stretched spiral
  • Transmitted through lice & ticks
• Laboratory diagnosis of Borrelia


  1. Culture: Kelly's medium, Barbour Stoenner-Kelly's (BSK)

  2. Serological tests: ELISA, Westernblot (gold standard)

  3. DNA: WB

  4. RNA: NB
• Borrelia recurrentis


  Agent of Louse-borne relapsing fever
• Borrelia hermsii/Borrelia parkeri


  Agents of Tick-borne relapsing fever
• Borrelia burgdorferi


  Agent of Lyme disease
• Stages of Lyme disease

  1. I: Appearance of lesion; Erythema chronicum migrans (bull's eye rashes)

  2. II: Dissemination through blood; bones, CNS, heart & liver

  3. III: Neurological abnormalities, arthritis & skin lesion (chronic stage)
• Treponema spp.


  • Tightly twisted organism resembling cork screw
• Treponema pallidum subsp. pallidum

  Agent of Venereal syphilis
• Stages of syphilis


  1. Primary syphilis: hard chancre (painless & firm)

  2. Secondary syphilis: condylomata lata (wart-like lesions)

  3. Latent syphilis: absence of clinical symptoms (+ serologic tests)

  4. Tertiary syphilis: gummas, neurosyphilis
• Congenital syphilis


  Hutchinsonian Triad: notched teeth, keratitis, eczema
• Laboratory diagnosis of syphilis

  1. Direct microscopic examination using Dark field microscope

  2. Serological tests
• Treatment of syphilis


  • Heavy metals: Arsenic, Arsphenamine, Salvarsan
  • Drug of choice: Penicillin
• Jorisch-Herxheimer reaction


  Large quantities of toxins are released as the bacterium dies during treatment
• Treponema pallidum subsp. pertenue


  Agent of Yaws (chronic nonvenereal disease of skin and bones)
• Treponema pallidum subsp. endecume


  Agent of Bejel (lesion in oral cavity, oral mucosa, skin, bones & nasopharynx)
• Treponema carateum


  Agent of Pinta (ulcerative skin disease)
• Leptospira spp.


  • Tightly twisted with one or both ends bent into a hook
• Leptospira biflexa


  Non-pathogenic, found in water & soil
• Leptospira interrogans


  Agent of leptospirosis (human and animals)
• Principal leptospiral diseases


  • icterohemorrhagiae → Weil's disease
  • canicola → Infectious jaundice
  • autumnalis→ Fo'rt Bragg or Pretibial fever
  • grippotyphosa → Marsch fever
  • hebdomadis → 7-day fever
  • mitis/Pomona → Swine-herd's disease
• Culture of Leptospira


  1. Specimen: Blood (early infection); Urine (2nd week)

  2. Media: Elllinghausen-McCullough-Johnson-Harris, Fletcher's & Stuart's (6-8 weeks)
• Chlamydia spp.


  Formerly Bedsonia ("large virus"), Obligate intracellular, Gram (-) like CW, binary fission, Infectious particle: Elementary bodies
• Chlamydia psittaci


  Agent of Psittacosis/ ornithosis (disease of birds, parrots, parakeets & cockatoos)
• Chlamydia pneumoniae


  Associated with mild respiratory tract infections, TWAR (Taiwan Acute Respiratory) strain
• Chlamydia trachomatis subtypes


  • A, B, Ba, C: Endemic trachoma
  • Inclusion conjunctivitis
  • D-K: Urethritis, cervicitis, pelvic inflammatory disease, epididymitis, infant pneumonia
  • L1, L2, L3: Lymphogranuloma venereum
• Laboratory diagnosis of Chlamydia


  1. Culture: McCoy's cell

  2. FREI's test: delayed hypersensitivity skin test for LGV
• Mycoplasma spp.


  Smallest free-living organisms (gram -), Found in plants & animals, Formerly known as pleuropneumonia-like organisms (PPLOs)
• Mycoplasma pneumoniae


  Eaton's agent, Cause of community-acquired pneumonia & tracheobronchitis in children and young adults, Primary atypical pneumonia/ Walking pneumonia
• Mycoplasma hominis & Ureaplasma urealyticum

  Genital mycoplasmas, Colonize adults asymptomatically, Cause of nongonococcal urethritis in males, M. hominis: Agent of salpingitis & postpartal fever in females
• Laboratory diagnosis of Mycoplasma

  Culture: Shepard's/ A7B/ Ɛ-Agar, "Fried egg" colonies, Serologic tests: Cold agglutinin (Anti-I)
• Rickettsiae


  Genera: Rickettsia, Ehlichia, Coxiella & Rochalimea, Gram (-) obligate intracellular bacteria, Vector transmitted (lice, fleas & ticks), Coxiella: cannot survive outside animal host or insect vector EXCEPT C. burnetti
• Rickettsia species and associated infections


  • R. rickettsii: Rocky Mountain Spotted Fever
  • R. conorii: Boutonneuse fever, Mediterranean & Israeli Spotted Fever, Indian tick typhus, Kenya tick typhus
  • R. australis: Australian/ Queensland tick typhus
  • R. akari: Rickettsialpox
  • R. prowazekii: Epidemic typhus, Sporadic typhus, Brill-Zinsser disease (latent)
  • R. Typhi: Murine typhus/ Endemic typhus
  • R. tsutsugamushi: Scrub typhus
  • C. burnetti: Q fever
  • E. chaffeensis: Human monocyte ehrlichiosis
  • E. phagocytophila: Human granulocyte ehrlichiosis
  • E. owingii: Sennetsu fever
  • R. quintana: Trench fever
• Bartonella species and associated infections

  • B. quintana: Trench fever
  • B. bacilliformis: Carrion's disease, Oroya fever
  • B. henselae: Cat-scratch disease, Peliosis hepatitis
  • B. clarridgeiae: Bacteremia, Cat-scratch disease
  • B. elizabethae: Endocarditis
• Afipia felis


  Associated with cat-scratch disease (CSD), Rare isolation but may be more commonly linked to CSD than is currently appreciated due to lack of appropriate laboratory methods for detection
• The spirochete can be detected using dark-field microscopy, which allows visualization due to its motility.
• Borrelia burgdorferi is the causative agent of Lyme disease.