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Food/water borne infections (Campylobacter jejuni (food+ water) (gram…
Food/water borne infections
Campylobacter jejuni (food+ water)
gram negative
micro-aerophilic
dose only 500
cause diarrhea (+ - blood)
developed countries = water
due to contamination of water by bird dropping or cattle run offs
C. Jejuni still alive in composted animal feces
C. jejuni not well detected by water quality control
cause long term neuro-muscular paralysis = gullian barre syndrome
developing countries = food
present in intestine of poultry and cattle as commensal
contamination of meat during processing
strains from chicken to human or cross contamination
pet associated transmission
Treatments:
antibiotics = BUT RESISTANCE
walkerton 2000
Listeria monocytogens (food)
minor illness, bacteremia, fatal meningitidis, abortions
gram positive coocabacilli
that live in soil and water
L. monocytogens present in most ready to eat food or ready to eat processed meats
it is acid-, salt- and colt-tolerant (grows 4 degrees)
exposure frequent. Listeriosis is rare)
T-cell mediated immunity eliminates infected cells (except in elderly, pregnant woment, AIDS..etc)
Treatments of antibiotics emerged
Salmonella typhi and typhimurium (food+ water)
Facultative
, intracellular,
gram negative
pathogen
ingest live salmonella --> intestinal colonization --> intercollitis
S. Typhimurium --> salmonellosis (self limiting entercolitis 2-3 days)
S. Typhi --> typhoid fever (systemic infection blood - high fever for several weeks, fatal in 15% of cases)
patients can be carriers for months - typhoid mary
comes from colonization of guts of animals (cattle and chicken) - found in run offs/seqafe --> water. or passed into products like eggs and milk.
Pathogenic E. coli (food + water)
most e. coli are non-pathogenic and are commensals
short gram negative rods = enteric
about 200 strains known
pathogenic strains affect intestine and several of them produce potent enterotoxin
Divisions made based on toxin and disease produced
Enterotoxicgenic (ETEC)
present on fresh vegetables and in water
cause travellers disease. local population immune.
heat liable (similar to cholera tozxin)
controls activity of adeylate cyclase of host
increased lvels of cAMP
release of ions and water into epithelium lumen
watery diarrhea
no damage to the cells
Enterohemorrhagic EHEC
most widely distributed O157:H7: O antigen of LPS and H antigen = flagella
source: cattle
water borne = walkerton 2000
food borne: undercooked meat - ground beef (hamburger disease) :
water borne: since present in feces.
toxin = vertoxin similar to shigella
Has affinity for:
colonic epithelium --> entry damage in cells --> diarrhea
erythrocytes --> hemolytic --> blood loss
endotehlial cells of kidney --> damage to kidney (uremic)
bloody dirrhea + kidney failure =
hemolytic uremic syndrome
(most survivers = blood pressure_
(50% renal impairment)
(10% death)
(5-10% EHEC patient)
symptoms: diarrhea, dystentry (blood/mucous), septicaemia, UTI)
Vibrio Cholera (water)
gram negative
, curved rod
chlorination in developed = efficient against cholera
8 major epidemics
Two main strains involved (well adapted)
dukarol against one strain: cholera Tor
pathogenesis
resides in small intestine attaches to epithelial cells, grows
large inoculum needed (Acid sensitivity)
releases enterotoxin that causes severe diarrhea = dehydration and death
mortality = 25-50% and more