Miscellaneous Gram-Negative Bacilli Pt 2 Flashcards
All Haemophilus sp are catalse (+) except:
H. ducreyi & A. aprophilus
Appearance on BAP of Haemophilus species with a requirement for V factor
Satellitism
Common name of H. influenzae
Pfeiffer’s bacillus
S. ____, S. ____ & Neisseria produce V factor ad by-product of metabolism.
aureus, pneumoniae
TRUE or FALSE: Encapsulated H. influenzae species may be recovered as part of the NF of the upper RT and oral cavity/
False
Non-encapsulated
H. influenzae serotype that is most virulent and most common cause of meningitis.
Serotype B
Capsular constituent of Hib
Polyribosyl ribitol phosphate (PRP)
Non-encapsulated strains of H. influenzae; localized infections
Non-typable H. influenzae
NTHi
TRUE or FALSE: Encapsulated strains cause more invasive disease.
True
H. influenzae biogroup causing pediatric conjunctivitis & Brazilian purpuric fever (BPF)
H. influenzae biogroup aegyptius
What is the common name of H. ducreyi?
Ducrey’s bacillus
Haemophilus sp causing chancroid/soft chancre (genital ulcer disease)
H. ducreyi
Common name - Koch-Weeks bacillus
H. aegyptius
What is the causative agent of native and prosthetic valve endocarditis?
H. parainfluenzae
TRUE or FALSE: Haemophilus sp are very very fastidious.
True
What is the preferred isolation medium of Haemophilus?
CAP (37C, 5-10% CO2)
In identifying Haemophilus, CAP is supplemented with ____ to reduce overgrowth of normal RT flora.
Bacitracin
What is the preferred isolation medium of H. ducreyi?
Nairobi biplate (33C)
Clear medium with X and V factors; showing iridescent colonies of encapsulated H. influenzae
Levinthal agar
Odor of H. inluenzae
Mousy/bleach-like
Small, flat, non-mucoid, transparent to opaque or tan/yellow on CAP
H. ducreyi
What is the appearance of H. ducreyi under the microscope?
Schools of fish/railroad track/finger print
What is the smallest pathogenic bacillus?
H. ducreyi
Test based on the ability of the organism to covert D-ALA into porphyrins and porphobilinogen
Porphyrin test (D-aminolevulinic acid)
In the porphyrin test, porphobilinogen is detected by the addition of Kovac’s reagent or ____ (scientific name).
p-dimethylaminobenzaldehyde
Positive result in the porphyrin test
Brick red fluorescence
TRUE or FALSE: Results are positive in the porphyrin test if they are organisms that do not require exogenous X factor (able to synthesize X factor endogenously).
True
Negative result in the porphyrin test
Bluish
What is the UV light used to detect fluorescence in the porphyrin test?
Wood’s lamp
