Gram-negative curved rods

Question 1

T/F: H. pylori is a gram-negative rod that creates an alkaline environment.

Answer 1

true

Question 2

What lab findings are useful to help diagnose Helicobacter pylor (aka Camylobacter pylori)? (5)

Answer 2

urease positive; spiral gram negative rod; endoscopy; stomach tissue culture; serum anti-H. pylori IgG

Question 3

How does Vibrio cholerae toxin work?

Answer 3

permanently activates G-protein (continually stimulates cAMP) causing excessive water and electrolytes into the lumen of the intestine.

Question 4

Describe the clinical presentation of a Campylobacter jejuni enterocolitis.

Answer 4

enterocolitis- 1-7 days incubation followed by fever and acute lower right quadrant pain, foul smelling watery diarrhea with blood or pus. May last 1-2 weeks but is usually self-limiting, with systemic infections in neonates and immunocompromised only.

Question 5

How does Vibrio cholerae gram stain?

Answer 5

negative

Question 6

How is Vibrio cholerae transmitted?

Answer 6

fecal-oral, contaminated food or water. Humans can be carriers

Question 7

How is Campylobacter jejuni transmitted?

Answer 7

fecal oral route, contaminated food or water

Question 8

What is the morphology of Vibrio cholerae?

Answer 8

curved rod

Question 9

Identify the major virulence factor associated with Helicobacter pylor (aka Campylobacter pylori).

Answer 9

urease produces NH3 which can buffer stomach acid

Question 10

What is the clinical manifestation of VIbrio cholerae?

Answer 10

cholera- rapid onset of severe watery diarrhea “rice-water stool” can cause death by dehydration.

Question 11

What lab findings are useful to help diagnose Vibrio cholerae? (2)

Answer 11

comma shaped gram negative rod; oxidase positive.

Question 12

What lab findings are useful to help diagnose Campylobacter jejuni? (4)

Answer 12

microaerophillic curved gram negative rod is comma or “S” shaped; requires 42 degrees Celsius and 5% oxygen to grow; oxidase positive; sensitivity to nalidixic acid.

Question 13

How does Helicobacter pylori (aka Campylobacter pylori) gram stain?

Answer 13

negative

Question 14

What is the major resevoir for VIbrio parahemolyticus?

Answer 14

salt water

Question 15

What is the major resevoir for Vibrio cholerae?

Answer 15

feces, water

Question 16

What are the clinical manifestations of Helicobacter pylor (aka Campylobacter pylori)? (4)

Answer 16

gastritis- intermittent dyspepsia, worse eating. Peptic Ulcer- 90% infected. Gastric ulcer 75% infected. Gastric adenocarcinoma- increased risk due to presence of H pylori.

Question 17

How does Campylobacter jejuni gram stain?

Answer 17

negative

Question 18

What is the morphology of Campylobacter jejuni?

Answer 18

curved rod

Question 19

Identify relevant epidemiology and risk factors associated with Vibrio cholerae. (2)

Answer 19

major epidemics in Southeast Asia, Europe and Africa. Hypochlorhydria or antacid use lowers the infective dose required to get through stomach

Question 20

How does Vibrio parahemolyticus gram stain

Answer 20

negative

Question 21

Identify the major virulence/toxicity factors associated with Campylobacter jejuni. (3)

Answer 21

low infectious dose (500 organisms) required for infection. Cholera-like enterotoxin. Penicilin and cephalosporin resistant.

Question 22

What is the major reservoir for Campylobacter jejuni?

Answer 22

animal feces

Question 23

What is the pathognomic symptom associated with Vibrio cholerae infection?

Answer 23

rice water stool

Question 24

What is the morphology of Vibrio parahemolyticus?

Answer 24

curved rod

Question 25

What is the “most common” associated with Campylobacter jejuni?

Answer 25

one of the most common causes of infectious diarrhea

Question 26

Describe the food poisoning of Vibrio parahemolyticus.

Answer 26

food poisoning- 24-48 hours after eating contaminated seafood, self-limiting but paiful abdominal cramps and watery diarrhea. Antibiotics are not helpful.

Question 27

What is the morphology of Helicobacter pylori (aka Campylobacter pylori)?

Answer 27

curved rod

Question 28

Identify the major virulence/toxicity factors associated with Vibrio cholerae. (3)

Answer 28

01 group produces enterotoxin choleragen which permanently activates G-protein; Very large infective dose required (10^9); Mucinase allows organisms to attach to brush border in the intestine