Aerobic Gram Negative Bacteria

  1. What bacteria:
    Associated with Tularemia, Potential bioterrorism agent, Skin ulcers at the site of inoculation, Lymph node infections, Eye infections, Lung infections, GI system infections, Intracellular bacteria resist phagocytosis
    Faintly staining coccobacilli
    Medium choice is glucose-cystine blood agar
    Agglutination and directs fluorescent antibody tests are used to confirm
  2. What biosafety level is required when handling specimens containing Francisella?
    Biosafety level 3
  3. What 4 species infect humans?
    • B. melitenis
    • B. abortus
    • B. suis
    • B. canis
  4. What biosafety level is required when handling specimens with Brucella?
    Biosafety level 3
  5. What bacteria:
    Associated with Brucellosis (also known as undulant fever), Potential bioterrorism agent, Facultative intracellular parasite
    Isolated from Blood and Bone marrow
    Incubation period is 1-3 Weeks
    Grows on buffered charcoal yeast extract (BCYE) and modified Thayer-Martin agars
    Requires 10% CO2 and 3 weeks to grow
    Oxidase POS
    Catalase POS
    Confirmation tests are usually done serologically
    Phage and dye sensitivity tests are used for ID to the species level
  6. What bacteria:
    Gram stain - poorly stained coccobacilli, single or in pairs
    Will NOT grow on MAC
    Urease NEG
    Media used: Bordet-Gengou (potato infusion), Regan-Lowe (charcoal-horse blood agar), Media are often made selective by adding cephalexin
    Bordetella pertussis
  7. What are the 3 stages of pertussis (whooping cough)?
    • 1) Catarrhal - general flu-like symptoms
    • 2) Paroxysmal - Repetitive coughing episodes
    • 3) Convalescent - Recovery phase
  8. What media is used to grow Bordetella pertussis?
    • Bordet-Gengou (potato infusion)
    • Regan-Lowe (charcoal-horse blood agar)
    • Media are often made selective by adding cephalexin
  9. What clinical conditions are associated with Bordetella parapertussis?
    Mild respiratory infections
  10. What clinical conditions are associated with Bordetella bronchiseptica?
    Respiratory infections
  11. What are the tests and results used to ID Bordetella and it's sub-species?
    • Gram stain - poorly stained coccobacilli, single or in pairs
    • Most will grow on MAC - except B. pertussis
    • Urease POS
    • B. pertussis - Urease NEG
  12. What bacteria:
    Associated with Cellulitis, Endocarditis, Gum disease
    Grows well on SBA and Chocolate but not on MAC that show starlike centers
    Catalase POS
    Glucose POS
  13. What subspecies of Pasteurella causes the most human infections?
    Pasteurella multocida
  14. What bacteria:
    Associated with Cellulitis, Osteomyelitis, Meningitis, Joint infections, Pneumonia
    Grows on nonselective media but not MAC
    Oxidase POS
    Catalase POS
    Indole POS
    Nitrate POS
    Pleomorphic - Gram Negative Coccobacilli that may show bipolar staining
    Very susceptible to penicillin
  15. What bacteria:
    Associated with Abcesses of the oral cavity and Human bite wound infections
    Approx. 50% of strains corrode or pit the agar
    Requires hemin (Factor X) for growth unless 5-10% CO2 is present
    Bleachlike odor
    Eikenella corrodens
  16. When was Legionella found?
    1st discovered in 1976 as the cause of pneumonia in people attending the American Legion convention in Philadelphia
  17. What is the most common Legionella subspecies to cause human infections?
    Legionella pneumophilia serogroup 1
  18. What bacteria:
    Associated with Legionellosis (asymptomatic), Pneumonia (mild to severe), Legionnaires disease (primary pneumonia), Pontiac fever (mild with flulike symptoms)
    Most common lab assay: Urine antigen test
    Poorly staining gram negative bacilli but it is better to use 0.1% basic fuchsin as the counter stain instead of safranin
    Most biochemical tests are NEG
    Most species will autofluroesce when exposed to UV light
    Direct fluorescent antibody test
    Urine antigen
    Nucleic acid probes
  19. What media is used to grow Legionella?
    • BCYE
    • Some will grow on Brucella blood agar (more nutritious than SBA
    • Require L-cysteine for growth
  20. What nutrient is needed for growth of Legionella?
  21. What clinical conditions are associated with Chromobacterium?
    Wound infections acquired from contaminated water or soil
  22. What does Chromobacterium look like on a plate?
    Purple or violet pigment on nutrient agar
  23. What bacteria:
    Bacterial vaginosis (BV), UTIs, PID, Postpartum sepsis, May infect the newborn
    Has Clue cells (epithelial cells with numerous bacteria attached)
    Catalase NEG
    Amsel and Nugent scoring systems are used to diagnose BV (because cultures alone are too sensitive)
    Gardnerella vaginalis
  24. What is the Amsel and Nugent scoring system?
    • Used to diagnose Gardnerella vaginalis
    • Approximately 50-60% of women who do NOT meet the criteria for BV are POS for G. vaginalis
  25. What bacteria:
    Associated with Trench fever, Causes growth of neoplastic blood vessels in various parts of the body (bacillary angiomatosis), Endocarditis
    Oxidase NEG
    Gram Neg curved bacilli
    Spread by human lice
  26. What bacteria is associated with the clinical conditions:
    Cat-scratch disease
    Bacillary peliosis hepatitis
    Bacillary angiomatosis
    Bartonella henselae
  27. What bacteria:
    Associated with endocarditis
    Gram Stain: Short chains or pairs, or rosettes of irregularly staining bacilli with bulbous ends
    Requires CO2 for initial isolation
    Growth is enhanced in media containing yeast extract
    Oxidase POS
    Catalase NEG
    Weakly Indole POS
    Cardiobacterium hominis
  28. What bacteria:
    Associated with Rat-bite fever (animal bites), Haverhill fever (ingestion of contaminated food and water), Blood infections, Synovial fluid infections, Abcess infections
    Gram-negative pleomorphic bacillus
    Grows on BAP (15% is optimal) incubated in CO2
    Streptobacillus moniliformis
  29. Where are the spores located on Bacillus species and there characteristics?
    • Centrally or Terminally located
    • Bacterial spores can survive adverse conditions for prolonged periods of time
  30. What are the pathogenic species of Bacillus?
    • B. anthracis (anthrax)
    • B. cereus (food poisoning and wounds)
  31. What bacteria:
    Large, non-hemolytic colonies with filamentous projections - referred to as "Medusa-head" colonies
    Straight bacilli with square ends (boxcar morphology) appearing in chains and singly with spores
    Does not grow on PEA (phenylethylalcohol) at 24 hours
    Catalase positive
    Bacillus anthracis
  32. What are the clinical conditions associated with bacillus anthracis?
    • Cutaneous anthrax - most common, characterized by necrotic skin lesions called black eschars
    • Pulmonary anthrax - "Wool-sorter's disease", spread by the inhalation of spores from sheep's wool
    • Gastrointestinal anthrax - Rarest form, spread by ingestion of spores
    • Potential bioterrorism agent
  33. What bacteria:
    Associated with Food poisoning, Wound infections, Opportunisitic eye, bone, and brain infections
    Resistant to 10 microgram of penicillin
    Bacillus cereus
Card Set
Aerobic Gram Negative Bacteria
Gram-Negative Bacilli