Final Exam: Gastrointestinal Infections Flashcards
Most common residents in the mouth
Streptococcus species
Feces are rich in
Bacteriodes species
live in the digestive tract
Fungi (e.g., Candida) and some protozoa
Though outnumbered by bacteria
Normal gut microbiota have essential roles
Limit available surfaces for colonization
Compete for nutrients
Excrete antimicrobial products
Assist in digestion
Provide nutrients for the body, Escherichia coli produces vitamin K
Diarrhea
frequent passing of loose or watery stool
Enteritis
inflammation of the intestines
Gastritis
inflammation of the stomach
Gastroenteritis
inflammation of the stomach and intestines
Dysentery
diarrhea accompanied by pain, blood, and/or mucus
Hypovolemic shock
organ failure
Milder signs and symptoms of GI tract infections
Abdominal pain
Diarrhea: loose or watery stools (may contain blood or mucus)
Fever and/or vomiting
Diagnosis of GI tract infections
Collecting fecal samples for:
Culturing on selective and differential media (e.g., MacConkey agar)
Molecular diagnostic analysis
Microscopic examination to identify parasites or their eggs
Common Human Pathogens: Viral
Rotavirus: attributed for children under 5 years
Norovirus: Attributed for adults in health facilities (Long term care)
Common Human Pathogens: bacterial
E. coli (most important to know)
Campylobacter species
Shigella species
Salmonella
Listeria monocytogenes
Norovirus: Etiological agent and characteristics
RNA virus
Leading cause of acute viral gastroenteritis in the U.S.
Norovirus: Signs/symptoms and transmission
Infectious dose of 20 viral particles
Feces and vomit spread the virus via the fecal–oral route
Develop within 12–48 hours
Acute diarrhea and projectile vomiting(common) lasting 36–72 hours
Norovirus: Treatment, complications and Diagnosis
Most healthy individuals recover without medical intervention
Some require fluid replacement treatment
Dehydration
Detection of norovirus RNA in patient stool samples
Foodborne Infection versus Food Poisoning: Description
Infection: after ingestion, pathogen begins to infect
Poisoning: no infection, toxins cause illness
Foodborne Infection versus Food Poisoning: Common bacterial agents
Infection: E. coli, Salmonella species, Listeria species, Shigella species, Campylobacter jejuni
Poisoning: Toxins from S. aureus, B. cereus, and Clostridium perfringens
Foodborne Infection versus Food Poisoning: Symptoms onset
Infection: 1-5 days after exposure
Poisoning: 30 min - 6 hours after exposure
Foodborne Infection versus Food Poisoning: Signs and symptoms
Infection: Fever, headache, muscle aches, nausea, Abdominal pain, diarrhea
Poisoning: Nausea, vomiting, and occasionally diarrhea and abdominal pain
Foodborne Infection versus Food Poisoning: Recovery:
Infection: days
Poisoning: ~24 hours, several days sometimes
Food poisoning
Bacteria don’t actively grow in the host
Symptoms are triggered by ingested enterotoxins (a type of exotoxin)
They may be emetic (trigger vomiting)
Causes inflammation of intestinal cells ->Prevents water absorption -> to diarrhea and abdominal pain
Food poisoning is often associated with
Prepared foods that require a lot of handling
Leaving foods at room temperature for extended periods
Will cooking food handle food poisoning toxins?
No, cooking or reheating may kill the bacteria, but won’t affect the enterotoxin
S. aureus food poisoning
Linked to creamy salads (e.g., tuna, chicken), dairy-based foods, poultry and meat products
Transmission is easy if hands are not washed before preparing food
C. perfringens food poisoning
Spore-forming organism
Commonly found in animal intestines and found on raw meat
Most cases linked to gravy and meat products that are left too long at room temperature
B. cereus food poisoning
Spore-forming organism
Present in soil and can contaminate produce
Cooking does not always kill its spores
Food is left at room temperature: Allows spores to germinate, Bacteria actively grow, Produce toxin
Botulism: Etiological agent and mechanism
Spore-forming Clostridium botulinum
Exotoxin enters the blood and targets nerves
Foodborne Infections: Prevention
Thoroughly cook meats/poultry
Use safe food-handling practices: Handwashing, Minimal meat rinsing, Separate utensils
Use a different cutting board for meat and vegetables
Discard any questionable meat/poultry products
Do not eat any questionable meat/products products
