Bacterial Infections w/ Animal Reservoirs or Insect Vectors

Question 1

Brucella

Answer 1

Aerobic, Gram (-) rods
Primarily infect monocytes/macrophages
Infected via: contact w/ infected blood, ingesting contaminated meat or milk, inhaling contaminated aerosols
Multiply w/in macrophages

Question 2

Brucella melitensis

Answer 2

Animal reservoir: sheep & goats

Small aggregates of mononuclear inflammatory cells throughout the liver

Question 3

Brucella abortus

Answer 3

Animal reservoir: cattle
Conspicuous noncaseating granulomas
Lymphadenopathy & splenomegaly

Question 4

Brucells suis

Answer 4

Animal reservoir: swine

Suppurative liver abcesses

Question 5

Brucella canis

Answer 5

Animal reservoir: dogs

Question 6

Yersinia pestis

Answer 6

Gram (-)
Bubonic plague- bacteremic, accompanied by enlarged, painful regional lymph nodes (buboes).
Found in wild rodents, humans infected by bites from infected fleas
Replicate in macrophages & cause hemorrhagic necrosis. In lungs cause necrotizing Necrotic, hemorrhagic skin lesions.

Question 7

Francisella tularensis

Answer 7

Gram (-) coccobacillus
Tularemia- reservoirL: rabbits, rodents
Multiplies at site of innoculation forming a focal exudative, pyogenic ulcer, later undergoing central necrosis surrounded by granulomatous rxn.

Question 8

Ulceroglandular tularemia

Answer 8

Most common form of the diease
Begins as tender erythematous papule at site of innoculation, develops into pustule, which then ulcerates.
Lymphadenopathy is the 1st sign of infection.

Question 9

Oculoglandular tularemia

Answer 9

Rare
Characterized by primary conjunctival papule, which forms a pustule & ulcerates.
Lymphadenopathy of head and neck become prominent

Question 10

Typhoidal tularemia

Answer 10

Hepatosplenomegaly, texemia and fever

Question 11

Pneumonic tularemia

Answer 11

pneumonia is a major feature

Question 12

Bacillus antrhacis

Answer 12

Anthrax- necrotizing disease
Gram +- large spore former
Humans are infected w/ spores which germinate in the body to yield vegetative bacteria that multiply & release a potent, necrotizing toxin.
Cutaneous lesion: ulcerated
Pulmonary “woolsorter’s disease”: necrotizing hemorrhagic pneumonia. Can be followed by septicemia.

Question 13

Listeria monocytogenes

Answer 13

Gram + coccobacillus
Unpasteurized milk, cheese and dairy products
When enter phagolysosome, low pH activates listeriolysin O (exotoxin) that disrupts the vesicular membrane and allows bacteria to escape into cytplasm. bacteria usurp host cytoskeleton contractile elements to form elongated protrusions that are engulfed by adjacent cells.
*Infection during pregnancy may lead to abortion or premature delivery. neurologic sequelae is common
Meningitis in immunosuppressed.

Question 14

Bartonella henselae
Bartonella quintana (rare)

Answer 14

Cat-Scratch Disease- Self limited granulomatous lymphadenitis
Gram (-) rods
Reservoir: cats
bacteria multiply in the calls of small vessels & collagen fibers at site in inoculation. Carried to lymph nodes leading to suppurative & granulomatous lymphadentitis.
Parinaud oculoglandular syndrome

Question 15

Pseudomonas mallaei

Answer 15

Glanders- granulomatous infection acquired from horses
Gram (-), non-motile bacillus
Acute: Bacteremia, granulomatous abscesses, almost always fatal
Chronic: low grade fever, draining abscesses of skin, lymphadenopathy & splenomegaly

Question 16

Bartonella bacilliformis

Answer 16

Bartonellosis- Acute anemia and chronic skin disease
Gram (-) coccobacillus, multi-flagellated
Transmitted by sand flies- Peru, Ecuador, Colombia
Biphasic response: Acute hemolytic anemia (Oroya fever)** most severe, months later Chronic dermal phase (verruga pernuana)