Unit 2 Answers to Review for Haemophilus and other fastidious Gram-negative rods
  1. This is a Gram stain from a spinal fluid.  How would you report this out? ANSWER:Many PMN's  and Gram negative coccobacilli
  2. What would likely be the organism if it was from a 3-year-old, unvaccinated child? ANSWER: Haemophilus influenzae
  3. What other types of infections might also be positive for this organism? ANSWER: septicemia, septic arthritis, otitis media, cellulitis, epiglottitis, acute pharyngitis, bronchitis, sinusitis, pneumonia
  4. What is the likely capsular type if it is invasive? ANSWER:b

 
  1. These are pictures of the culture from the specimen whose Gram stain is shown above.  What media would support its growth? ANSWER: chocolate agar and Haemophilus isolation agar
  2. How would you describe the smell of this organism? ANSWER: mousy
  3. If you were setting up a sensitivity on this organism, what modifications would you follow? ANSWER: Would use Haemophilus Test Medium, incubate in increased carbon dioxide, the inoculum would be the direct method, use the Haemophilus chart for interpretation of zone sizes.

 

  • Starting at the top left quadrant:  X only
  • Top right: V only
  • Bottom right: XV combined
  • Bottom left:  Horse Blood agar
  1. What organism is this? ANSWER: H.parahaemolyticus
  2. What would be the expected reactions for Haemophilus influenzae? ANSWER: Growth in the XV quadrant and no hemolysis on Horse Blood agar
  3. What would be the expected reactions for Haemophilus aegyptius? ANSWER: Same as for Haemophilus influenzae
  4. What other test would be positive for H.parainfluenzae & H.parahaemolyticus? ANSWER: ALA (Porphyrin) test

 

  1. What is the term used to describe colonies growing around other colonies that provide V factor? ANSWER: Satelliting
  2. What organisms can provide V factor? ANSWER: S.aureus, Neisseria, Streptococcus pneumoniae are at least some that can produce V factor
  3. What organisms will only grow on sheep blood agar if V factor is provided by another organism? ANSWER: Haemophilus spp.
  4. How is sheep blood different from horse or rabbit blood when growing this organism? ANSWER: Sheep blood contains NADase that breaks down V factor
  1. If this was identified as "mercury drop" colonies on Bordet' Gengou, what organism is it likely to be? ANSWER: Bordetella pertussis
  2. What type of specimen is collected for this organism? ANSWER: nasopharygeal
  3. Besides the culture, what other test is routinely done to detect this organism from a specimen? ANSWER: Direct fluorescent antibody stain for Bordetella pertussis

 

  1. The picture at the right is a heart at autopsy.  The arrow is pointing to infected heart valves.  What is the term used for this type of infection? ANSWER: Endocarditis
  2. The HACEK group all cause this type of infection.  What organisms belong to the HACEK group? ANSWER: Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium homins, Eikenella corrodens, Kingella spp.
  3. What are the common characteristics of the HACEK group? ANSWER: Need CO2 , important cause of endocarditis, normal flora of the oral cavity, 
  4. Which one of these organisms line up on Gram stain as rosette, stick-like forms? ANSWER: Cardiobacterium hominis 
  1. If the organism is from a dog bite or a cat-licking a wound, what is the likely organism? ANSWER: Pasteurella multocida
  2. Does the organism grow on MacConkey? ANSWER: NO
  3. What is the Gram stain morphology of the organism? ANSWER: Gram-negative coccobacilli, bipolar staining is common
  4. What are the catalase and oxidase reactions? ANSWER: catalase + and usually oxidase + 
  5. What is the appearance of a TSI with this organism? ANSWER: SICK TSI reaction
  6. Can you use an API-20E to identify this organism? ANSWER: Yes

 

  1. If this is blood culture from an individual who ate unpasteurized goat cheese, what Brucella organism is it likely to be? ANSWER:  Brucella melitensis
  2. If this is blood culture from an individual who raised beefalos, what Brucella organism is it likely to be? ANSWER: Brucella abortus
  3. What is the name of the Brucella organism associated with pigs? ANSWER: Brucella suis
  4. What is the biosafety levels for positive cultures? ANSWER: Biosafety Level III
  5. What is another name for brucellosis in cattle? ANSWER: Bang's Disease
  6. What is another name for bruecellosis in humans? ANSWER: Undulant Fever
  1. This is a culture on Selective Buffered Charcoal Yeast Extract agar.  What organism is likely to be isolated? ANSWER:  Legionella pneumophilia
  2. What other methods can be used to diagnose this disease besides culture? ANSWER:  Urine antigen testing, Direct Fluorescent Antigen testing in sputum, Indirect Fluorescent Antibody test for Legionella pneumophilia
  3. What types of stains and modifications are useful for identifying this organism? ANSWER: Direct Fluorescent Antibody Stain and Modified Gram Stain using carbofuschin for counterstain instead of safarinin.
  4. How can health care institutions control the growth of this organism in their water lines? ANSWER: Increase hot water temperature and level of chlorine
  5. What are the names of two diseases caused by this organism? ANSWER: Legionnaires' Disease and Ponitac Fever.

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Clinical Microbiology Syllabus