Reality Check: Harmful Microbes Flashcards
Outbreak
When two or more people become ill with similar symptoms from consuming the same food from the same source, and the epidemiological investigation implicates, either directly or indirectly, the same food from the same source as the cause of the illness
Outside of unknown agents, what is responsible for the most foodborne disease outbreaks?
Bacterial agents
What is the difference between E. coli K-12 and E. coli O157:H7?
K-12 is a “lab rat” and O157:H7
Intoxication
Ingest, pre-formed toxin
Toxicoinfection
Ingest large number of viable cells, which release toxins as they sporulate or die
Infection
Ingest viable cells, which grow causing sickness
In foodborne pathogens organism presence is ______________
suggestive; toxin presence is definitive
How is salmonella transmitted?
Food, animals, processed food, unhygienic handling and processing of food products
O antigen
Inhibits phagocyte killing
Vi capsule antigen
Inhibits complement binding
Flagellum
Motility
H antigen
Adherence; inhibits phagocyte killing
Entrotoxin
-Causes increase chloride permeability resulting in watery stool
- Attach to intestinal mucosa and invade M cells
- Multiplies intracellularly within membrane-bound vacuoles
- Host lyses and bacteria spreads
Salmonella can infect:
- only humans
- some animals and humans
- no host preference
What are the symptoms of salmonella?
Abdominal cramps, diarrhea, nausea, vomiting, chills, fever
When does salmonella develop?
12-14 hours, persists 5 days
Do microbes survive longer in wet or dry feces?
Up to 3 months in wet, up to 13 months in dry
What is the best way to kill salmonella
Heat
Where is salmonella an issue?
Globally
Entroinvasive E. coli (EIEC)
Bloody diarrhae (dysentery), headache, fever, chills
Entropathogenic E. coli (EPEC)
Colonize intestinal mucosa, forms attachment-effacing lesions which destorys microvilli
- mild to servere watery diarrhea
Enterotoxigenic E. coli (ETEC)
Heat labile and/or heat stable entrotoxins
- watery diarrhea, no fever
Entrohemorrhagic E. coli (EHEC)
Most common strain
- ingestion of <100 cells may produce disease
- Produces Shiga toxins and attachment-effacing lesions
- Onset abdominal cramps, watery diarrhea (often bloody), vomitting
- O157:H7 is atypical E. coli that is acid tolerant
Camplobacter coli (C. coli)
Interactions with certain animals, which are reservoirs or the fecal-oral route
- Large number are asymptomatic, but can cause vomiting, abdominal pain, bloody diarrhea
Campylobacteria coli can cause
Muscle weakness
- immune cells target myelin on axon
- neurons have a hard time sending signals
