Gram (-) Zoonotic Bacteria

Question 1

Yersinia pestis

Answer 1

Key:

• bipolar bacillus
• (vf) V, W antigens and I-capsule
• rodent/flea contact
• bubo
• pneumonia death in 24 hrs

Extra:

• V,W antigens allow for intracellular growth, I-antigen capsule occurs later on and prevents phagocytosis
• flea contracts pestis from rodent -> coagulase -> regurgitates pestis into humans (aersolized pestis from rodents)
• bubonic plague- axilla/groin/neck bubo swollen lymphnode with intense pain
• pneumonic plague- human to human, hematogenous spread from bubo to lung, death in 24 hrs
• septicemic plague- no bubo -> bacteremia

Question 2

Yersinia enterocolitica

Answer 2

Key:

• bacillus, *urease posiive
• raw pork (chitlins)
• appendicitus-like in Black children
• invasin, attachment invasion locus, YadA (vf) for attachment and invasion of intestinal epithelium

Extra:

• infect Peyer’s patches, ulcerate intestines
• pYV can resist phagocytosis
• bloody mucous stool
• pseudoappendicular syndrome
• post-infectious polyarthritis due to HLA-B27 mimicry

Question 3

Pasteurella multocida

Answer 3

Key:

• cat > dog bite, wound lick
• cellulitis
• coccobacillus with capsules, toxins, transferrin

Extra:

• normal oral flora of cats/dogs
• humoral immunity is protective
• 24 hrs inflammation, erythema, tenderness, purulence at site with regional lymphadenopathy

Question 4

Fracisella tularensis (Tularemia)

Answer 4

Key:

• intracellular, coccobacillus, chocolate agar/Thayer-martin only, *cysteine needed
• outdoorsmen, trappers - rodent aerosoles or arthropods
• ulcerated papule -> lymphohematogenous spread -> necrosis
• ulceroglandular, glandular, oculoglandular, typhoidal, pneumonic

Extra:

• beta lactamase
• required cell-mediated immunity, humoral insufficientlc
• ulceroglandular*- lymphadenopathy, infection site ulcer
• glandular- lymhadenopathy with no/healed ulcer
• oculoglandular- conjunctival invasion and unilateral papules/ulcers
• typhoidal- febrile + bradycardia
• pneumonic- pulmonary infection presentation

Question 5

Legionella pneumophila

Answer 5

Key:

• non-capsulated bacillus requiring amoeba for growth, chlorine tolerant
• Mip protein for MN phagocytosis->T cells for IFN gamma lysosomal fusion
• severe pneumonia, hyponatremia, diarrhea
• Pontiac fever - endotoxin

Extra:

• aquatic body resevoirs able to survive in a ide range of temperatures that are transmitted through inhaled aerosols
• 3rd most common cause f pneumonia
• incubates in veolar macrophages using Mip proteinand multiplies until rupture
• Pontiac fever- acute fever w/o penumonia nonantibioic recovery <1 week. caused by inhalation of Legionella endotoxin