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Module 8b unusual bacterial pathogens


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Module 8b unusual bacterial pathogens

  1. 1. Not normally isolateable Usually gram variable
  2. 2.  L. pneumophila is the prototype bacterium of this group Fastidious, aerobic and stains poorly with gram stain Basic fuchsin must be used as a counterstain Can be grown in buffered charcoal-yeast extract (BCYE), pH 6.9, 35 degrees & 90% humidity Catalase positive & oxidase positive
  3. 3.  Ubiquitous in warm and moist environment Can multiply in free living amoebas and coexist with them in biofilms Contamination from inhalation from airconditioning systems, shower heads Causes pneumonia and lesions within phagocytic cells Susceptible to erythromycin and other drugs such as Rifampin
  4. 4.  B. bacilliformis – causes Oroya fever B. quintana – causes trench fever B. henselae – Cat scratch fever Pleaomorphic and slow growing, difficult to isolate in the laboratory Can be seen in infected tissues stained with Warthin-Starry silver impregnation stain
  5. 5.  Caused by Bartonella, is a disease predominantly of immunosuppressed individuals, particularly AIDS patients Present as an enlarging red ( cranberry like ) papule, often with surrounding scale and erythma Clinical appearance similar with Kaposi’s sarcoma, form of the disease is called peliosis hepatis
  6. 6.  Serologically distinct organism isolated in the female genitourinary tract and associated with vaginosis ( no inflammatory cells ) In wet smears, the bacterial vaginosis yields clue cells ( vaginal epithelial cells covered with many gram variable bacilli Vaginal discharge often have a strange fishy odor with pH over 4.5 Drug of choice is oral metronidazole
  7. 7.  Motile, curved, gram variable, anaerobic rods isolated from “bacterial vaginosis” Possibly part of the vaginal normal anaerobic flora The organisms are most commonly detected but grow with difficulty in aerobic cultures
  8. 8.  Aerobic, highly pleomorphic organism that forms irregular chains of bacilli interspersed with fusiform enlargements and large round bodies Mesophilic, in media with serum, protein, egg yolk, starch & ceases to grow at 22 C Normal inhabitants of rat throats, and humans can be infected with rat bites characterized by septic fever, petechial rashes, and a very painful polyarthritis
  9. 9.  C. granulomatis, related to Klebsiella and causes granuloma inguinale, an uncommon STD characterized by genital ulcers. Hard to culture even with media enriched with egg yolk Effective treatment with ampicillin and tetracycline CausesWhipples disease, stain with Periodic Acid Schiff Stain ( PAS )