Aerobic Gram Negative Bacteria

  1. What are the general tests and results of Vibrio species?
    • Most Indole POS
    • All are Oxidase POS - except V. metschnikovii
    • Halophilic (salt loving) - except V. cholerae and V. mimicus
    • Most labs use biochemical testing to presumptively ID then confirm with serology based on somatic O antigens
  2. What agar is used for its' selective properties and for differential for Vibrio species?
    TCBS (Thiosulfate citrate salt sucrose agar)
  3. What bacteria:
    Sucrose POS
    Yellow colonies with TCBS (Thiosulfate citrate bile salt) sucrose agar?
    V. cholerae
  4. What bacteria is Sucrose NEG with TCBS (Thiosulfate citrate bile salt) sucrose agar?
    V. parahaemolyticus
  5. What bacteria is associated with:
    Cholera (Severe watery diarrhea with flecks of mucus sometimes referred to as "rice-water" stool)
    Wound infections
    Otitis media
    Vibrio cholerae O1 serological group
  6. What clinical conditions are associated with Vibrio cholera Serogroups Non-O1?
    Mild choleralike illness
  7. What clinical conditions are associated with Vibrio cholera Serogroup O139?
    Severe disease similar to V. cholerae O1
  8. What are the 3 serotypes and 2 biotypes of Vibrio cholerae O1?
    • Serotypes: Inaba, Ogawa, Hikojima
    • Biotypes: Classical El Tor
  9. How are cholera infections acquired?
    Ingestion of undercooked seafood or contaminated drinking water
  10. Where is Cholera usually seen?
    • Southeast Asia
    • Africa
    • South America
  11. What are the important virulence mechanisms of Vibrio cholera?
    • Cholera toxin (choleragen, an enterotoxin)
    • Motility
    • Pili (hairlike appendage on bacteria)
    • Mucinase
  12. What clinical conditions are associated with Vibrio parahaemolyticus?
    • Mild to moderate choleralike diarrhea disease
    • Food poisoning (mostly in Asia because of eating raw shellfish)
  13. What clinical conditions are associated with Vibrio vulnificus?
    • Septicemia
    • (after ingestion of undercooked seafood, notably raw oysters)
    • Rapidly progressive wound infections
  14. What clinical conditions are associated with Vibrio alginolyticus
    • Otitis media
    • Wound infections
  15. What clinical conditions are associated with Aeromonas?
    • Cellulitis
    • Diarrhea
  16. What are the clinically important species of Aeromonas?
    • A. hydrophilia
    • A. caviae
    • A. veronii biovar sobria
    • A. veronia biovar veronii
  17. What bacteria:
    Beta hemolytic
    Oxidase POS
    Citrate POS
    Indole POS
    VP POS
    Aeromonas hydrophilia
  18. What bacteria:
    Eating undercooked seafood
    Oxidase POS
    Associated with Self-limiting gastroenteritis (treatment only in immunosuppressed or severe cases)
    Plesiomonas shigelloides
  19. What species of Campylobacter causes most of the infections?
    Campylobacter jejuni
  20. What bacteria:
    Associated with Food poisoning, Gastroenteritis, Diarrhea, Septic arthritis
    Gram stain: curved bacilli that appear S-shaped or spiral
    Need selective media for isolation (charcoal cefoperzone deoxycholate agar and Campy-colistin vancomycin amphotericin B)
    Grows at 42 degrees celcius (will grow at 37 degrees but slowly)Catalase POS
    Oxidase POS
    Darting motility
  21. What bacteria:
    Associated with Peptic ulcers, Duodenal ulcers, Stomach cancer
    Oxidase POS
    Rapid Urease POS
    Catalase POS
    Other labs: fecal antigen detection, urea breath test, demonstration of urease activity in stomach biopsy material
    Use the media: BAP, Brucella, Skirrow's agar Incubated microaerophilically
    Helicobacter pylori
  22. What specimen is helicobacter mostly isolated from?
    Gastric biopsy
  23. What are the general characteristics of Nonfermentative Bacilli (NFB)?
    • Most are obligate aerobes
    • Do NOT form spores
    • Do NOT metabolize carbohydrates under anaerobic conditions (fermentation)
    • Most are Oxidase POS
    • TSI K/no (alkaline over nothing)
  24. What is the most important Nonfermentative Bacilli (NFB)?
    Pseudomonas aeruginosa
  25. Name the members of Psudomonas fluorescent group
    • P. aeruginosa
    • P. fluoresceins
    • P. putida
  26. What do all of the members of Pseudomonas fluorescent group produce?
    Fluorescein (pyoverdin) - a yellow pigment that fluoresces
  27. What agar enhances fluorescein production?
    Cetrimide agar
  28. What bacteria: 
    Associated with Eye infections (for those who wear contact lenses), Ear infections, Swimmer's ear (external otitis), Lower respiratory tract infections (for those with cystic fibrosis (CF)Burn wound infections, Important in immunocompromised individuals, Nosocomial infections
    Oxidase POS
    Lactose NEG
    Beta hemolytic with grapelike odor and metallic sheen on SBA
    Produces a blue (blue-green) pigment because of the production of pyocyanin
    Very resistant to antimicrobial agents
    Pseudomonas aeruginosa
  29. What bacteria:
    Associated with Pneumonia, UTIs, Wound infections
    Oxidase NEG
    Maltose POS
    Lysine decarboxylase POS
    Resistant to most antimicrobials
    Stenotrophomonas maltophilia
  30. What bacteria:
    Nosocomial infections, Repiratory tract pathogen (in patient's with CF), Potential bioterrorism agent
    Oxidase POS
    Lactose POS
    Lysine decarboxylase POS
    Enhanced growth on PC (P. cepacia) agar that inhibits P. aeruginosa
    Burkholderia cepacia
  31. What are the two clinically encountered Nonfermentative Bacilli (NFB) that are lysine decarboxylase POS?
    • Stenotrophomonas maltophilia
    • Burkholderia cepacia
  32. What bacteria:
    Associated with Glanders (highly contagious disease of livestock, like horses, mules, and donkeys), Potential bioterrorism agent
    Oxidase VARIABLE
    Reduces nitrate to nitrite without gas
    Oxidizes glucose
    Burkholderia mallei
  33. What bacteria:
    Associated with Meliodosis - disease of humans and animals to endemic to Southeast Asia and northern Australia
    Oxidase POS
    Reduces nitrate to nitrite with gas
    Oxidizes several sugars (including glucose and lactose)
    Burkholderia pseudomallei
  34. What bacteria:
    Associated with Nosocomial infections (usually A. baumanii), UTIs
    Multidrug resistant
    Some produce acid from glucose (saccharolytic group)
    Others are asacchrolytic (can't breakdown carbs)
    Oxidase NEG
    Nitrate NEG
    Catalase POS
    Multidrug resistant
  35. What bacteria:
    Associated with Variety of infections in neonates, pregnant women, and immunosuppressed patients, Meningitis is the common outcome of infection
    End-over-end (tumbling) motility on wet mount
    Hippurate hydrolysis - POS
    CAMP test - POS
    Esculin - POS
    Catalase - POS
    Listeria monocytogenes
  36. What bacteria causes diphtheria?
    Corynebacterium diphtheriae
  37. Describe diphtheria
    Pseudomembrane formed by dead cells and exudate at the back of the throat
  38. What bacteria:
    Associated with Bacterial toxins damage major organs, resulting in a high death rate, Toxigenic strains are infected with a bacteriophage that contains the gene for the diphtheria toxin
    Gram stain - can be pleomorphic, "picket fence", or "Chinese letters"
    Staining with methylene blue will reveal metachromatic granules, which are red to purple intracellular granules
    Urease - NEG
    Pyrazidamidase - NEG
    Nitrate - POS
    Catalase - POS
    Elek test (uses anti-toxin to detect the toxin)
    Corynebacterium diphtheriae
  39. What media is used for the detection of Corynebacterium and what will it look like on the media?
    • Tinsdale agar - form brown to black colonies with halos from hydrolysis of tellurite
    • Cystine-tellurite - form black colonies from hydrolysis of tellurite
    • Loeffler agar - nonselective medium that supports growth and enhances pleomorphism and the formation of metachromatic granules; form small white to gray colonies
  40. What bacteria:
    Associated with Nosocomial infections, Infections after prosthetic device implants, Infections in immunocompromised patients
    Pyrazidamidase - POS
    Resistant to most antimicrobial agents
    Corynebacterium jeikeium
  41. What bacteria:
    Associated with UTIs
    Rapid Urease - POS
    Grows very slowly
    Corynebacterium urealyticum
  42. What bacteria:
    Associated with Abcess formations, Wound, Soft tissue infections
    Small beta-hemolytic colonies on SBA
    Catalase - NEG
    Arcanobacterium pyogenes
  43. What bacteria:
    Associated with Pharyngitis, Wound infections, Tissue infections
    CAMP inhibition test: Produces phopholipase D, which inhibits the activity of the Staphylococcus aureus beta-lysine
    Small beta-hemolytic colonies on SBA
    Catalase - NEG
    Arcanobacterium haemolyticum
  44. What bacteria:
    Associated with Cellulitis (erysipelois lesions that can resemble erysipelas cause by Streptococcus pyogenes), Bacteremia, Endocarditis
    Pleomorphic gram positive bacilli
    Catalase - NEG
    Hydrogen sulfide - POS
    Erysipelothrix rhusiopathiea
  45. Name the other clinical relevant species of Nocardia
    • Nocardia asteroides (most significant)
    • N. brasiliensis
    • N. otitidiscaviarum
  46. What bacteria:
    Pleomorphic, branching gram-positve bacilli in chains that produce a beading arrangement, appear fungal-like
    Partially acid fast
    Catalase - POS
    Requires 6 weeks for growth
    Exudate contains masses of filamentous organisms with pus that resemble sulfur granules
    Nocardia asteroides
Card Set
Aerobic Gram Negative Bacteria
Vibrio, GNB