LAB 11 – HAEMOPHILUS, BORDETELLA, PASTEURELLA, BRUCELLA Flashcards
How does a staph streak allow Haemophilus to grow on a BAP?
- S. aureus lyse RBCs to produce hemin (x factor) and NAD (v factor)
- Haemophilus sp. will satellite
NAD - nicotinamide adenine dinucleotide
Why does H. influenzae only grow around the disc with both X and V factor?
- requires both exogenous x and v
(ie. hemin and NAD, respectively)
NAD - nicotinamide adenine dinucleotide
Where would you incubate a plate with Bordetella pertussis?
O2; strict aerobe
Why does sheep blood not support the growth of Haemophilus sp.? Why can they grow
on CAP using sheep’s blood?
- Haemophilus sp. require both x and v factors
- NADase in BAP breaks down NAD (v factor) needed
- CAP has been heated; RBCs release hemin (x factor) and NADase is inactivated
What is special about the staining of Pasteurella multocida?
a. What stain is this most commonly seen with?
bipolar g-cb on Giemsa stain
What are X and V factors?
X factor = hemin; an iron porphyrin
V factor = NAD
NAD - nicotinamide adenine dinucleotide
What does the ALA test determine? What is it testing for?
delta-AminoLevulinic Acid test:
- determines whether organism requires exogenous x factor
- tests organism’s ability to produce its own hemin
Results: Red fluorescence under UV = (+) porphyrin
No fluorescence = (-) porphyrin
NOTE: also called Porphyrin test
Appropriate specimens for Haemophilus sp.?
- blood
- sputum
- CSF
- conjunctival and genital ulcer swabs
What cautions have to be taken with Brucella spp.?
- Biosafety level 3 protocols
How is brucellosis usually diagnosed?
- based on detection of serum antibodies (1:160 titre), rather than isolation of organism
What antibiotic does H. influenzae have a high resistance to? Why?
a. Which specimens are screened for this antibiotic resistance?
- High ampicillin resistance (β-lactamase)
a. primary cultures from blood and CSF are screened via chromogenic cephalosporin method
Specimen type for Bordetella and any special collection instructions?
- nasopharyngeal swabs collected using a tiny calcium alginate swab
What effects are B. pertussis highly susceptible to?
a. What media is required to isolate?
- fragile specimens susceptible to toxic unsaturated fatty acids, peroxides and sulfides
a. requires charcoal or starch and high concentrations (10-20%) of blood for primary isolation
What are the following results for Pasteurella multocida?
a. Gram
b. Colonial morph
c. Catalase
d. Oxidase
e. Spot indole
f. Nitrate
g. Ornithine decarboxylase
h. Urease
i. Motility
j. TSI
a. Gram = g-cb, bipolar
b. Colonial morph = muc, gy sm, translucent
c. Catalase = (+)
d. Oxidase = (+)
e. Spot indole = (+)
f. Nitrate = (+)
g. Ornithine decarboxylase = (+)
h. Urease = (-)
i. Motility = (-)
j. TSI = wk A/A
NOTE: no growth on MAC
What are the results for the following tests for Brucella abortus?
a. Gram
b. Colonial morphology
c. Urease
d. Oxidase
e. Catalase
f. Nitrate
a. Gram = g-cb
b. Colonial morphology = sm gy, translucent
c. Urease = (+)
d. Oxidase = (+)
e. Catalase = (+)
f. Nitrate = (+)