Chlamydia, Rickettsia, and Mycoplasma

  1. What are the smallest free-living organisms - about the size of a large virus and beyond the resolution of light microscopes?
    • Mycoplasma
    • Ureaplasma
  2. Describe Mycoplasma and Ureaplasma
    • Lack cell wall - making them pleomorphic
    • Resistant to all antibiotics that inhibit cell wall synthesis (beta-lactams)
    • Contain both RNA and DNA
    • Can self-replicate
  3. How are infections of Mycoplasma and Ureaplasma diagnosed?
  4. What media is used to grow Mycoplasma and Ureaplasma and what do they sometimes look like on the media?
    • SP4 agar
    • A8 agar
    • Shepard's 10 B broth
    • Some species will grow on chocolate agar
  5. What does U. urealyticum produce?
    Strong alkaline pH because of the activity of urease
  6. What organism is associated with:
    Community-acquired primary atypical (walking) pneumonia (dry, nonproductive cough)
    Spread by Direct repiratory contact
    Produces hydrogen peroxide - which causes a lysis of RBCs in vitro
    Mycoplasma pneumoniae
  7. What are the clinical conditions associated with Mycoplasma hominis?
    • Opportunistic pathogen linked to PID (pelvic inflammatory disease) in sexually active partners
    • Infant meningitis
    • Postpartum fever
  8. What organism is associated with:
    Nongonococcal urethritis
    May cause other genital tract infections
    Requires Urea
    Ureaplasma urealyticum
  9. What organisms are:
    Obligate intracellular parasites
    Require nucleotides and other metabolic building blocks from the host cells
    Spread by insect vectors (ticks, mites, and lice)
    Rickettsia and Ehrlichia
  10. How is diagnosis made for Rickettsia and Similar Genera?
    • Clinical symptoms
    • Patient history
    • Serology
    • Immunohistology and PCR assays are also available
  11. How are Rickettsia and similar genera cultured?
    • Bacteria can be grown in embryonated eggs and tissue cells
    • Cultures require biosafety level 3
    • Cutures are not recommended because of safety concerns
  12. Name some of the clinically important species of Rickettsia and similar genera
    • R. rickettsii
    • R. prowazekii
    • R. typhi
    • Coxiella burnetii
    • Ehrlichia chaffeensis
    • Anaplasma phagocytophilum
  13. What clinical condition is associated with R. rickettsii?
    • Rocky Mountain spotted fever (RMSF)
    • Death rates are approx. 25%
  14. What is R. rickettsii a member of?
    Member of spotted fever group
  15. How is R. rickettsii transmitted?
  16. What organism is associated with:
    Typhus (also called epidemic or louse-borne typhus)
    Brill-Zinsser disease is a reactivation of the original infections
    Transmitted by Human lice
    R. prowazekii
  17. What clinical conditions are associated with R. typhi?
    Endemic or murine typhus
  18. How is R. typhi transmitted?
  19. What organism is associated with:
    Q fever
    Transmitted by: Inhalation, Contact with fomites, Ingestion of contaminated milk
    Coxiella burnetii
  20. What organism is associated with:
    Ehrlichiosis or human monocytic ehrlichiosis
    Spread by Ticks
    Ehrlichia chaffeensis
  21. What clinical condition is associated with Anaplasma phagocytophilum?
    Human granulocytic anaplasmosis
  22. What are general characteristics of Chlamydia and Chlamydophila?
    • Obligate intracellular parasites
    • Cannot produce ATP - require it from the host cell
    • Contain both DNA and RNA
    • Susceptible to antimicrobial agents
  23. How is chlamydia and chlamydophila diagnosed?
    • Cytological methods - detect chlamydia inclusions in epithelial cells
    • Cell cultures are required to grow the bacteria
    • Nucleic acid amplification tests (NAATs) are the most common diagnositic method
    • Serology - antibody to lipopolysaccharide and outer membrane protein antigens
  24. What organism is associated with:
    Mild respiratory tract infections (flu-like symptoms)
    May cause Guillain-Barre syndrome
    Diagnosed with Fluorescence-labeled C. pneumoniae antibodies
    Chlamydophila pneumoniae
  25. What organism is associated with:
    Psittacosis (ornithosis) or parrot fever - disease of birds
    Humans get infections by inhaling bird fecal dust
    Chills, fever, malaise
    Can progress to pneumonia, which can be fatal
    Incubation period of 1-2 weeks
    Diagnosed with serology
    Chlamydiophila psittaci
Card Set
Chlamydia, Rickettsia, and Mycoplasma
Mycoplasma, Ureaplasma, Rickettsia, Chlamydia