FB pathogens 2 Flashcards
What is teh primary source of Yersinia and primary source of VIBRIO species
Yersinia - PIG GUTS, pig intestines.
As it is an
Vibrio - primary sourse is HUMANS as it is harboured in our intestines, we introdcue to human food chain by faecal contaminated water (marine water, esturies)
BOTH ARE Enterobacteriaceae, primary source is where bacteria harboured = INTESTINE
Growth characteristics Vibrio cholerae
• Facultatively anaerobic
• halophilics (0.5-10% NaCl) – grow in high salt conditions
• alkaliphilic (pH 7.8-8.6) – v alkali
• straight or curved, motile rods
NaCl is required for survival and growth
• Primary source is faecally contaminated water
Enterobacteriaceae
include • Salmonella spp. • Yersinia enterocolitica • E. coli O157 (and other VTEC) • Shigella spp. vibrio cholerae
What does Vibrio cholerae cause?
Incubation and what type of infection?
CHOLERA
• profuse watery diarrhoea with ‘rice water’ stools , very intensive (up to 10 litres per day)
• Severe abdominal pain, vomiting
• Fluid loss can lead to severe dehydration, acidosis, shock and circulatory collapse
• Death in few hours if not rehydrated
• Incubation 6 h -5 days
Infection: toxico-infection: enterotoxin
Symptoms of Vibrio cholerae
- profuse watery diarrhoea with ‘rice water’ stools , very intensive (up to 10 litres per day)
- Severe abdominal pain, vomiting
- Fluid loss can lead to severe dehydration, acidosis, shock and circulatory collapse
- Death in few hours if not rehydrated
Sources cholera
- Poor sanitation, using faecal contaminated water for food preparation or drinking
- Shellfish– filtrate sear water and concentrate V. cholerae
- Seafood, including raw, lightly cooked or recontaminated shellfish or fish
CONTROL MEASURES: Vibrio cholerae
- Consume only potable water.
- Dispose of sewage correctly.
- Use only potable water in seafood harvesting and preparation.
- Do not harvest seafood from waters containing V. cholerae.
- Avoid raw seafoods
- Chill seafood to <4°C at harvest and after.
- Exclude infected individuals from handling food.
Other species of Vibrio?
other than V. cholerae
2. Vibrio parahaemolyticus:
3. Vibrio vulnificus:
Theres are less common and both simialr to V cholerae but less severe those with lvier disease shoudln’t eat raw shellfish (oysters)
Listeriosis caused by what bacteria
Gram what?
and morphology
Listeria monocytogenes
Gram positive
Rods with slightly curved shape
Primary source of listeriosis
ENVIRONMENT, widespread, everywhere, on computer, desk etc. We ingest daily base but usually low dose. Not enough to lead to disease.
Main sources of Listeriamonocytogenes?
– Animal intestines (asymptomatic carriers) and human
– ubiquitous in the environment: soil, water, plants, silage
– Working surfaces in the food industry (can form persistent biofilms which are source for contamination)
– Main disease when listeria gets into food, multiples and we ingest
Characteristics of listeria monocytogenes
• Motile rod at 20-25°C, non-motile at 37°C
Gram positive
• Facultative anaerobe, but prefers a microaerophilic atmosphere if O2 is present
• Very resistant to drying
• 4°C (can grow at 0°C, even -1.5°C) to 45°C psychrophilic
• tolerate 10% NaCl – halophilic to some extent
• tolerate low aw (water activity) – can grow on v dru food stuff
• pH: 4.1 to 9.6
• Easily killed at 72 degs as don’t ahve spores
Incubation of Listeria monocytogenes
How does invasive listeria it cause listeriosis?
- Incubation 1-21 days
- Invade GI mucosa macrophages – bloodstream to CNS, or fetus
- bad for Immuno Compromised individuals (pregnant women, AIDS patients, cancer patients, young, elderly)
- In pregnant women is the main cause od abortion and miscarriage along with toxoplasmosis
- It leads to Septicaemia, meningitis, encephalitis and spontaneous abortion
Non-invasive listeriosis
When ingest lot of listeria but able to recover
• Symptoms mostly local enteric diarrhoea, mild fever, headache and myalgia
• The disease has a short incubation period (1 to 3 days).
• Healthy individuals are at risk for non-invasive listeriosis
Control measures: listeriosis
- Use GHP and HACCP in food production.
- Immunocompromised individuals and other target populations should avoid high-risk foods.
- Pasteurize milk and dairy products; don’t consume unpasteurized products.
- Prevent cross-contamination and recontamination of heat-treated foods.
- Completely separate raw and cooked products during meat product manufacture.
- Re-heat ready-to-eat foods adequately.
Which bacteria is the main source humans?
Staphylococcus aureus and Vibrio cholerae
Which bacteria primary source is the environment?
Clostridium botulinum, C. perfringens, bacillus cereus
Soil, water, veg
What are toxigenic foodborne bacteria?
Bacteria that lead to intoxication due to toxin produced in the food depending on pathogenesis
Examples of toxigenic foodborne bacteria
- B. cereus
- Clostrium. botulinum
- SStaphylococcus aureus
Important to know about onset of toxin mediated poisoning
Has a more rapid onset generally