LAB 6 - Fastidious Gram Negative Bacilli and Candida Flashcards
TSI sick yellow
Listeria
Pasteurella multocida
Yersinia
B. pertussis media
Regan Lowe (mercury drop or split pearl)
DFA + PCR +
Besides C. albicans, what other Candida is germ tube pos?
C. dublinensis
T or F. H. influenzae is part of the normal flora of the upper respiratory tract
T
What is H. influenzae associated?
meningitis
epiglottitis
pneumonia
respiratory tract infections
cellulitis
conjunctivitis
H. parainfluenzae
- endocarditis
- normal bacterial flora in resp tract
H. ducreyi
- sexually transmitted disease
- chancroid
- prevalent in more tropical areas
H. haemolyticus and parahaemolyticus
usually nonpathogenic
appropriate specimens for Haemophilus
- blood
- sputum
- CSF
- conjunctival and genital ulcer swabs
Haemophilus sp. air requirements
facultative capnophilic; mousy odor
X factor vs V factor
X = hemin
V = NAD
T or F. sheep blood does not support Haemophilus sp.
T, rabbit and horse blood do
- sheep blood has NADase; heating sheep blood destroys this, releases hemin (which Haemophilus also needs)
ALA test
- porphyrin or delta-aminolevulinic acid (ALA) test
- determines X factor requirement (ability of organism to synthesize its own hemin from supplied delta-aminolevulinic acid)
- organisms capable of synthesizing their own porphyrins have no hemin requirement (ALA positive)
when we isolate H. influenzae, what screening test do we always do?
B lactamase production by chromogenic cephalosporin method
- rapidly indicates ampicillin resistance
T or F. Bordetella pertussis won’t grow on BAP but will grow on CAP
F!
- charcoal containing media for transportation (Jones-Kendrick, Regan-Lowe, Amies)
- highly susceptible to toxic effects of unsaturated fatty acids, peroxide, and sulfides
- primary isolation media requires charcoal or starch and high concentrations of blood = Bordet-Gengou
specimens for whooping cough
tiny calcium alginate swab - nasopharyngeal
characteristics of B. pertussis
- strict aerobe
- split-pearl or drops of mercury
- ox pos
- biochemically non-reactive
- agglutination, DFA, PCR for ID
This shows bipolar staining in direct smears particularly when stained with Giemsa
Pasteurella multocida
T or F. P. multocida grows on BAP
T, BAP CO2 = non-hem trans colonies w a musty odor (due to indole production)
does not grow on MAC; but ferments glucose (weak TSI rxn)
Pasteurella biochemical tests rxn
TSI sick yellow
ox and cat +
nitrate and ornithine decarb +
nonmotile
urease neg
susceptible to penicillin
spot indole +
what will clue us that we need to work in the BSC
sterile sites direct smear = gnb or gncb and BAPss does not show sats
BSC to rule out risk group III
what can if germ tube test is incubated longer than 2.5 hrs
pseudohyphae will start to develop
needs to be straight and no constricture
gram neg cb that is high risk of lab-acquired infection
Brucella sp
Brucella sp. biochemical tests
grows on BAP and CAP but requires 4-6 wks incubation in CO2
ox, cat +
urease and nitrate +
doesn’t grow on MAC
