4 Food and Waterborne Diseases Flashcards
population with the highest frequency of foodborne illness
children
most common cause of foodborne disease
viruses
norovirus causes more than half of all cases a quarter of all admissions
foodborne bacteria most often resulting in fatality
nontyphoidal salmonella
listeria
most common foods associated with foodborne illness outbreaks from any pathogen reported in the uS
poultry
leafy vegetables
fruits/nuts
etiologic agents that may cause gastroenteritis in 1-6 hours
S aureus
B cereus
C botulinum
astrovirus
norovirus
Ciguatoxin (barracuda)
Tetrodotoxin (pufferfish)
Scombroid toxin (tuna)
etiologic agents that involves toxin production after ingestino
vibrio
shigella
STEC
etiologic agents that involve direct invasinoof the intestinal epithelium
salmonella
enteroinvasive E coli
campylobacter
causes bloody stools and fever
upper and lower GI symptoms last from 24 hours to weeks
obtain a stool test in those with:
watery diarrhea with signs of hypovolemia
bloody diarrhea
fever ≥38.5C
duration of illness >1 week
severe abdominal pain or tenderness
hospitalized patients or recent antibiotic use
elderly (≥70 years of age) or the immunocompromised
pregnant women or those with comorbid conditions such as inflammatory bowel disease
how to make oral rehydration solution as per WHO
8 teaspoon of sugar
1 teaspoon of salt
in 1L of water
the 2017 Infectious Diseases Sociaty of America guidlines recommend empiric treatment for patients with bloody diarrhea under the ff circumstances
infants less than 3 months of age
immunocompromised patients with severe illness
Ill immunocompetent people with documented fever, abdominal pain, bloody diarrhea, and bacillary dysentery presumptively due to shigella
recent international travelers with fever ≥38.5C or signs of sepsis
remarks on STEC
Avoid empiric antibioitics if you believe illness is from STEC O157 and other STEC that produce Shiga toxin due to increased risk of hemolytic-uremic syndrome (HUS)
Antibiotics may promote Shiga toxin release, which increases the incidence of HUS
Treatment of HUS is supportive
A common bacterial enteritis regimen is
oral ciprofloxacin 500mg BID x 3-5 days
levofloxacin 500mg BID x 3-5 days
Azithromycin 500mg OD x 3 days
most common cause of HUS in children
EHEC that produces Shiga toxin (STEC)
remarks on scombroid poisoning
culprit: tuna, macckerel
sx: flushing, headache, abdominal cramping, vomiting, diarrhea
tx: antihistamines
remarks on ciguatera poisoning
culprit: barracuda, amberjack
sx: hyperestehsias,numbness, reversal of hot/cold sensation, bradycardia, hypotension
tx: atropine, mannitol
remarks on puffer fish
toxin: tetrodotoxin
sx: paresthesias, headache, VAD, ascending paralysis
death in 4-6 hours
tx:
emergent supportive care
anticholinesterases such as neostigmine and edrophonium
remarks on GBS
associated with Campylobacter infection
symptoms typically occur 7-21 days after the GI symptoms resolve
most common bacteria associated with recreational waterborne disease outbreaks
Campylobacter
- found in virtually all surface waters due to contamination from wild bird feces
- most enteric bacteria, including E coli O157:H7 and Campylobacter, are susceptible to chlorination
most common cause of recreational waterborne GI illness [in the US]
Cryptosporidium
- an intracellular protozoan parasite
- standard doses of chlorine and zonation used in water treatment are not effective against Cryptosporidium, which explaines its association with recreational water sources
Vibrio vulnificus vs Aeromonas
Vibrio vulnificus
- seawater
- assoc’d with life- and limb-threatening necrotic wound infections
Aeromonas
- fresh and marine waters
- majority of wound infections are simple cellulitis, but necrotizing infections and septic arthritis occur
leading cause of acute gastroenteritis across all age groups
Noroviruses, including the Norwalk virus
When to use azithromycin instead of doxycyline
pregnant women
children
patients with travel to areas fluoroquinolone-resistant Campylobacter (Thailand)
first priority for Cryptosporidium treatment in patients with HIV
initiation of highly active antiretroviral threapy
a monoclonal antibody to complement factor C5 that blocks complement activation;
eculizumab
- shows promise in severe cases of STEC-related HUS
adjunct in cryptosporidium infection
nitazoxanide or paromomycin
(used for patients with prolonged infections, children, and the immunocompromised)
