Enteric Bac 3 Flashcards
What is the gram stain for Vibrio cholera?
Curved, comma-shaped, gram negative rod with polar flagellum
What is present in pathogenic V. cholera that allows it to infect humans?
CTX–O1 and O139 groups causes epidemic disease
O cell wall antigen
Who are more susceptible to developing a vibrio cholera infection?
Pt on antacids or with gastrectomy
What is secreted by the cholera to allow them to clear a path to the brush border in the small intestine?
Mucinase
How does the cholera attach to the small intestine?
Toxin coregulated pilus (TCP)
What is the cholera toxin secreted by the growing bacteria?
Choleragen
A-B subunit–A causes persistent activation of adenylate cyclase, leads to loss of water and ions from attached cell
What is seen on PE of pts with cholera?
Rice water stool
No pain, blood or neutrophils in stool
Acidosis and hypokalemia from loss of HCO3 and K
What type of agar does V. cholera grow on?
Bile salts agar–Halophile
What is the gram stain for V. parahaemolyticus?
Gram neg curved motile rod
What does V. parahaemolyticus usually cause?
Gasteroenteritis
What does V. vulnificus cause in the immunocompromised who eat raw shellfish?
Rapidly fatal septicemia
What does V. vulnificus usually cause?
Cellulitis–hx of handling raw shellfish
Septicemia with hemorrhagic bull and hx of immunocompromised
What is the gram stain for campylobacter?
Gram neg rod–Comma or S-shaped
What env. does campylobacter prefer?
Microaerophilic–lower O2 level and grows well at 42c
C. jejuni infection strongly predisposes pt to?
Guillain-Barre syndrome
–Serotype O:19 antigenic cross-reactivity with neural glycosphingolipids
What is the presentation of Campylobacter?
Common in children
Initially watery foul-smelling diarrhea–progresses to bloody stools with fever and abd pain
Toxic megacolon can occur
What is the appearance of campylobacter in culture?
Seagull appearance under microscopy
What is the gram stain of H. pylori?
Curved Gram neg rods–LPS
Strongly urease +
What is H. pylori associated with?
Peptic ulcer disease and mucosa-associated lymphoid tissue (MALT) lymphomas, gastric lymphoma and adenocarcinoma of the stomach
What allows bacterial growth of H. pylori in the stomach lining?
Urease virulence factor causes urea breakdown to ammonia–which neutralizes stomach acid and allows growth
What is the urea breath test?
Patient ingests radiolabeled urea, if infected, exhales radio labeled CO2
What does a biopsy of a pt with H. pylori show?
H. pylori organisms
Decreased mucus film
Large inflammatory infiltrate
