Vibrio, Aeromonas, Campylobacter, and Helicobacter Flashcards
Module 2 (30 cards)
What are the characteristics of Vibrio cholerae?
curved, gram-negative bacilli; require salt (halophiles); waterborne and foodborne transmission
How does Vibrio cholera present?
most people are asymptomatic or have self-limiting diarrhea, but can be the source for contaminating food and water
What can Vibrio cholera produce and what does it do?
certain strains produce exotoxins that increase secretions of electrolytes and water into small intestine; acute = watery diarrhea lasting 3-5 days; severe = fluid loss of more than 1 litre per hour
Vibrio cholerae Case Study
A 40-year-old man from Texas drove to Tampico, Mexico to visit his father. He ate shrimp and boiled crab at a restaurant. The following day he developed severe diarrhea and vomiting. He was hospitalized and received 13 liters the first day; he went home the second day. Vibrio cholerae O1, biotype El Tor was isolated from his stool specimen.
What are the serotypes of Vibrio cholerae?
serotype O1, serotype O139, and serotype non-O1 and non-O139
What biotypes does V. cholerae serotype O1 have?
classical, and El Tor (currently highest number of cases, slightly milder disease)
What is V. cholerae serotype O139?
emerged in 1992 and spread rapidly through Asia; clinical disease similar to O1 cholera; restricted to South and Southeast Asia currently
What is V. cholerae serotype non-O1 and non-139?
a strain that causes mild diarrheal disease, and does not generate epidemics
How do we treat cholera?
oral rehydration; IV replacement of fluids; antibiotics decrease duration of disease and shedding or organism
What are other Vibrio species?
Vibrio parahaemolyticus and Vibrio vulnificus
What is V. parahaemolyticus?
a strain that causes acute gastroenteritis following ingestion of fish, oysters, shrimp, and crab; cause 50-70% of foodborne diarrhea in Japan; most frequent Vibrio spp. isolated in the US
What is Vibrio vulnificus?
a HIGHLY virulent strain associated with oysters; very invasive and causes wound infections and septicemia; predisposing conditions = liver disease and high serum iron
How do we test for Vibrio?
culture or molecular detection; methods include using TCBS media (contains salt); oxidase positive test; shows up as CURVED gram-negative rods (bacilli); require NaCl for growth
What is the biology of Aeromonas spp.?
1) gram-negative bacilli
2) predominantly in fresh water; can be in brackish water or water with low saline
3) isolated from cold blooded animals
What disease does Aeromonas cause?
found in fresh produce, beef, poultry, pork and dairy products; associated with diarrhea (self-limiting) and wounds acquired in or near water
How do we test for Aeromonas?
we take a specimen and use a culture or molecular detection method
How do we identify Aeromonas?
TCBS agar = no growth; oxidase = positive, NaCl is not required
What is the biology of Campylobacter spp.?
1) curved (gull wing) gram-negative bacilli
2) primarily a zoonotic disease as it inhabits GI tracts of animals
3) transmission occurs through contaminated water, poorly cooked meat or dairy products
What disease does Campylobacter cause?
most common agent of bacterial gastroenteritis; diarrhea (frequently bloody); fever; severe abdominal pain; usually self-limiting
How do we test for Campylobacter?
take a specimen and use culture, molecular detection, or antigen detection
What additional information do we need to test for campylobacter?
selective, enriched media incubated at 42 C in 10% CO2, curved gram-negative bacilli, microaerophilic conditions, and it must be oxidase positive
What is Helicobacter pylori?
a causative agent of peptic ulcer disease and a major risk factor for gastric cancer
How do we identify Helicobacter pylori?
we use gastric biopsy specimens; curved gram-negative bacilli; produces potent urease enzyme that increases the local pH
What disease does H. pylori cause?
gastritis, peptic ulcer disease, and major risk for gastric cancer
