Miscellaneous Gram-Negative Rods Clinical Microbiology Review 196
ORGANISM PATHOGENICITY GRAM STAIN CULTURE KEY CHARACTERISTICS
Bartonella
Bordetella
pertussis
Brucella
Francisella
Dx usually by serological or
molecular methods.
Fluorescent antibody stain.
DTaP vaccine (diphtheria,
tetanus, pertussis).
Oxidase & urease pos.
Level 3 pathogen. Potential
bioterrorism agent. Re-
portable disease. Serological
tests are primary means
of Dx.
Level 3 pathogen. Direct
fluorescent ab methods for
ID. Send to public health
lab for confirmation.
Serological tests.
Trench fever, relapsing fever,
bacteremia, endocarditis,
cat-scratch disease
Whooping cough in children
& adults
Brucellosis (undulant fever).
From unpasteurized milk or
contact with infected goats,
cows, hogs, dogs
Tularemia (rabbit fever). Man
infected by tick or handling
infected animal
Intracellular GNCB
Small GNCB
Tiny, faintly staining
GNCB
Pale-staining, small,
pleomorphic, intra-
cellular GNCB with
bipolar staining
Not practical. Takes 9–40 days
to grow.
Grows on Bordet-Gengou
& Regan-Lowe (charcoal,
horse’s blood) after 3–7 days.
Most often isolated from blood
cultures or biopsies of reticu-
loendothelial (RE) tissue. Blood
cultures incubated in ↑CO 2 for
3 wk. Culture not sensitive.
Grows on special media en-
riched with glucose & cystine
(e.g., blood cysteine glucose
agar), TM, & BCYE. Small,
transparent colonies after
3 days.
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