Enterobacteriaceae/Salmonella Flashcards
(46 cards)
Gram-negative bacillus
Member of the family Enterobacteriaceae
Over 2500 serotypes / strains characterized by “O” and “H” antigens (most common strains have been given what appear to be “species” names)
Salmonella spp.
Most common human Salmonella spp.
Salmonella enterica, serovar Typhi
S. enterica, serovar. Enteritidis
ingestion of contaminated food and water
Frequent normal flora of poultry (turkeys, chickens), livestock, rodents, reptile (turtle)
Many bacteria are destroyed by stomach acids, so ingestion of large quantity are needed to initiate infection
salmonella
Transmitted by contaminated food and water, especially
(a) Meat products not properly cleaned or cooked
(b) Eggs and dairy products
(c) Other foods prepared on contaminated surfaces (e.g. cutting boards)
salmonella
(enterocolitis syndrome) (Salmonella food poisoning) – caused by Salmonella enteritidis (and numerous other serotypes)
Acute gastroenteritis
Bacteria invade the intestinal mucous membranes causing an acute inflammatory reaction in the subepithelial tissue
ii. Symptoms include sudden onset of diarrhea (rarely bloody) and vomiting along with fever about 6 to 48 hours after consumption of contaminated food or water;
Salmonella enteritidis
symptoms persist 2 to 7 days (just a framework)
Typhoid fever
enteric fever (salmonella typhi & paratyphi)
Bacteria invade epithelial cells of terminal portion of small intestine and then into the lymphoid follicles where they multiply
(salmonella typhi, paratyphi)
Enteric Fever (Typhoid fever)
Localizes in gallbladder, spleen, liver, bones (occasionally)
Bacteria invade epithelial cells of terminal portion of small intestine and then into the lymphoid follicles where they multiply
Bacteria migrate to the blood stream, the fever period begins, and rose spots appear on the skin. Local necrosis can lead to hemorrhage and lesions
Enteric Fever (Typhoid fever)
Fever begins 10-14 days after ingestion of bacteria
• Headache, myalgia, malaise persist for about 5-10 days
• Gastrointestinal symptoms begin about 15-20 days after ingestion of bacteria
Enteric Fever (Typhoid fever) — Salmonella Typhi & Paratyphi
Gram-negative bacillus; member of the family Enterobacteriaceae
shigella and salmonella
Gram-negative bacillus; member of the family Enterobacteriaceae
shigella
salmonella
E. Coli
Pathogenicity – Shigellosis or Bacillary Dysentery –enterocolitis syndrome
shigella
Pathogenicity – Shigellosis or Bacillary Dysentery –enterocolitis syndrome
shigella
Endotoxin - potent and is present in all strains
Produce Shiga Toxin (AB-type) – disrupts protein synthesis – damages the intestinal epithelium
Neurotoxin and enterotoxin produced by S. dysenteriae type I
Some strains of S. flexneri produce enterotoxins
Shigella spp.
Incubation: 12-48 hours depending on dose of microbes (10-100 bacteria) with symptoms lasting 1-3 days
Symptoms: Diarrhea (liquid stools), lesions in the colon producing pus and blood in feces (dysentery), and fever
Shigella spp.
Attach/penetrate muscosal epithelium of intestine
Bacterial multiplying cause host cell death and bleeding
Bacteria release endotoxin, causing fever, inflammation & local damage (ulcerations/pus/bleeding)
Exotoxin causes fluid loss (diarrhea)
shigellosis dz progression
Big need with tx for gastroenteritis?
rehydration
Escherichia coli
Gram-negative bacillus; member of family Enterobacteriaceae
A predominant normal flora of intestinal tract; a ____ refers to those members that are normal flora of the intestinal tract; primarily Escherichia, Klebsiella, Enterobacter
coliform
causes 75% to 85% of all UTIs; mostly in outpatient females
E. Coli
(a) Symptoms: Flank pain, dysuria (painful urination), fever
(b) Route of infection: Bacteria attach to epithelial cells of the urinary tract by means of fimbrae
(c) Source: Fecal contamination – poor personal hygiene or nosocomial (e.g. catheterization)
E. Coli UTI/cystitis:
(a) Symptoms: Flank pain, dysuria (painful urination), fever
(b) Route of infection: Bacteria attach to epithelial cells of the urinary tract by means of ____
fimbrae
Causes “Traveler’s Diarrhea” due to cholera-like toxin – several antigenic types involved
Enterotoxic E. coli (ETEC)
(a) Bacteria enter small intestines and release heat-labile (LT) and/or heat-stable (ST) enterotoxins (genes on plasmids)
(b) Causes hypersecretion of water and chlorides into the lumen. Also inhibits absorption of sodium
(c) Symptoms: Cramps fever, dehydration and mild (to occasionally profusely) watery stools without mucus and blood (8-12 unformed stools per day and may last 4-5 days)
Enterotoxic E. coli (ETEC)
similar to cholera toxin
