HAEMOPHILUS AND OTHER FASTIDIOUS GRAM-NEG BACILLI

Encapsulated gram-negative coccobacillus causing meningitis, epiglottitis, and pneumonia

H. influenzae

Only Haemophilus species that produces IgA protease

H. influenzae

Nonencapsulated Haemophilus causing otitis media, sinusitis, and conjunctivitis

H. influenzae (nonencapsulated)

"Koch-Weeks bacillus" associated with acute conjunctivitis

H. aegyptius

Severe pediatric disease linked to a biogroup of H. aegyptius

Brazilian Purpuric Fever

Gram-negative bacillus causing chancroid or soft chancre

H. ducreyi

Painful sexually transmitted genital ulcer with buboes

H. ducreyi

Haemophilus species that does not require V factor and does not show satellitism

H. ducreyi

Growth of small colonies around S. aureus due to NAD production

Satellitism

Growth factor required by Haemophilus that is NAD

V factor

Growth factor required by Haemophilus that is hemin

X factor

Enriched medium used for growing Haemophilus spp.

Chocolate agar

Gram-negative pleomorphic rods or coccobacilli characteristic of this genus

Haemophilus

Characteristic bleach-like or mousy odor colonies of this organism

H. influenzae

Arrangement described as "school of fish" or "railroad tracks"

H. ducreyi

Test used to determine ability to synthesize X factor from ALA

Porphyrin test

Positive porphyrin test showing red fluorescence under UV light

Porphyrin production

Haemophilus species associated with endocarditis of the mitral valve

H. parainfluenzae

Haemophilus species implicated in some cases of pharyngitis

H. parahaemolyticus

Group of fastidious gram-negative bacilli associated with endocarditis

HACEK group

Oral flora organism with star-shaped colonies in the center

Aggregatibacter actinomycetemcomitans

Organism producing collagenase and leukotoxin causing periodontitis

Aggregatibacter actinomycetemcomitans

Pleomorphic gram-negative bacillus causing aortic valve endocarditis and agar pitting

Cardiobacterium hominis

Organism associated with human bites and agar pitting

Eikenella corrodens

Gram-negative bacillus causing infections in children <3 years affecting bones and joints

Kingella kingae

Group of organisms requiring increased CO₂ for growth

Capnophilic organisms

Common disease caused by HACEK organisms

Endocarditis

Fastidious gram-negative bacillus with gliding motility and fusiform shape

Capnocytophaga

Organism producing yellow-orange pigmented colonies resembling Eikenella

Capnocytophaga

Most common isolate of Capnocytophaga from blood cultures

C. ochracea

Zoonotic infection from animal bites, especially cats

Pasteurella multocida

Gram-negative coccobacillus showing bipolar "safety pin" staining

Pasteurella multocida

Organism growing on SBA and CHOC but not MAC with gray colonies

Pasteurella multocida

Zoonotic disease characterized by undulating fever

Brucellosis

Most virulent species causing brucellosis

B. melitensis

Transmission of brucellosis via aerosol, ingestion, or contact

Brucella spp.

Gram-negative intracellular pathogen causing tularemia

Francisella tularensis

Most common clinical form of tularemia with ulcer and lymphadenopathy

Ulceroglandular tularemia

Bioterrorism Category A agent causing tularemia

Francisella tularensis

Organism requiring cysteine for growth

Francisella tularensis

Waterborne gram-negative bacillus causing atypical pneumonia

Legionella pneumophila

Febrile pneumonia associated with contaminated water systems

Legionnaire's disease

Flu-like illness without pneumonia caused by Legionella

Pontiac fever

Special medium containing L-cysteine for isolation of Legionella

BCYE agar

Most rapid diagnostic method for Legionella infection

Urine antigen test

Environmental reservoir including cooling towers and water systems

Legionella

Intracellular pathogen surviving in macrophages

Legionella pneumophila

Small gram-negative coccobacillus causing whooping cough

Bordetella pertussis

Highly communicable childhood disease with paroxysmal coughing

Pertussis

Toxin responsible for systemic effects of pertussis

Pertussis toxin

Adhesion factors facilitating attachment to ciliated epithelium

FHA and pertactin

Specimen of choice collected from nasopharynx for diagnosis

Bordetella pertussis

Culture medium containing potato infusion, blood, and glycerol

Bordet-Gengou agar

Alternative charcoal-containing medium for Bordetella

Regan-Lowe medium

Colony morphology described as shiny "mercury droplets"

Bordetella pertussis

Three stages of whooping cough disease progression

Catarrhal, paroxysmal, convalescent stages

Human-only reservoir of this respiratory pathogen

Bordetella pertussis

Haemophilus species that require only V factor for growth

Para species

Reason Haemophilus cannot grow on SBA due to NAD breakdown

Presence of NADase

Characteristic agar pitting seen in certain oral flora organisms

Eikenella corrodens

Smooth, translucent colonies of a zoonotic gram-negative bacillus

Brucella spp.

Gray-white smooth colonies of a cysteine-requiring pathogen

Francisella tularensis

Glistening colonies with ground-glass center on BCYE agar

Legionella pneumophila

Non-fermenting gram-negative organism causing respiratory disease

Bordetella pertussis

Oxidase and catalase positive fastidious gram-negative rods

Haemophilus spp.

Gram-negative organism from animal bites with oxidase positivity

Pasteurella multocida

Gram-negative zoonotic bacteria positive for urease

Brucella spp.

Biochemically inactive gram-negative bacilli with gliding motility

Capnocytophaga