Shige∥/ a Dysentery 1. Gram-negative bacillus does not ferment lactose nonmotile 2. Induces ruffling of host cells; once internalized, escapes to the cytoplasm a)Moves through the cytoplasm and spreads from cell to cell by polymerizing actin b)Accelerates cell death, forming plaques of necrotic cells c) Induces marked inflammation and rarely invades the bloodstream
Shigella Dysentery 1. Gram-negative bacillus, does not ferment lactose, nonmotile. 2. Induces ruffling of host cells; once internalized, escapes to the cytoplasm. a) Moves through the cytoplasm and spreads from cell to cell by polymerizing actin. b) Accelerates cell death, forming plaques of necrotic cells. c) Induces marked inflammation and rarely invades the bloodstream. 16
3. Resistance to gastric acid means that a small numbers of organisms (200 bacteria)can cause disease 4. Initially grows in the small intestine, and then spreads to the colon 5. Spreads from person to person. Daycare centers, toilet seats, contaminated water are vectors can be spread by flies Less commonly foodborne
3. Resistance to gastric acid means that a small numbers of organisms (200 bacteria) can cause disease. 4. Initially grows in the small intestine, and then spreads to the colon. 5. Spreads from person to person.Daycare centers, toilet seats, contaminated water are vectors.Can be spread by flies. Less commonly foodborne. 17
ampylobacter gastroenteritis Campylobacter is a coma-shaped gram-negative rod, micro- aerophilic bowel flora overgrow. Only C fetus can grow at 25.dium or other 2. Grows best at 42C, requires Campy-BAP selective me 3. Internalized by and lives in monocytes and intestinal epithelial cells, induces cell death bowel ulceration and intense inflammation 4. C fetus is carried by monocytes to the bloodstream; it resists serum bactericidal activity and causes persistent bacteremia
Campylobacter Gastroenteritis 1. Campylobacter is a coma-shaped gram-negative rod, microaerophilic. 2. Grows best at 42C, requires Campy-BAP selective medium or other bowel flora overgrow. Only C. fetus can grow at 25C. 3. Internalized by and lives in monocytes and intestinal epithelial cells; induces cell death, bowel ulceration, and intense inflammation. 4. C. fetus is carried by monocytes to the bloodstream; it resists serum bactericidal activity and causes persistent bacteremia. 18
5. Like Salmonella, Campylobacter is sensitive to gastric acid and requires a high inoculum( more than 104 bacteria) 6. Epidemiology is similar to that of salmonella. C jejuni is primarily responsible for diarrhea a Survives well in chickens because of their high body temperature (30%of carcasses test positive) b Carried in water, raw milk, sheep, cattle, swine, and reptiles
5. Like Salmonella, Campylobacter is sensitive to gastric acid and requires a high inoculum (more than 104 bacteria). 6. Epidemiology is similar to that of Salmonella. C. jejuni is primarily responsible for diarrhea. a. Survives well in chickens because of their high body temperature (30% of carcasses test positive). b. Carried in water, raw milk, sheep, cattle, swine, and reptiles. 19
Escherichia coli gastroenteritis 1. Serotyping identifies specific o (lipopolysaccharide) and h antigens (flagellar proteins 2. Five pathogenic classes have been defined a)Enterotoxigenic(ETEC): Produce a choleralike toxin Spread by water contaminated with human sewage in developing countries. Cause of travelers' diarrhea b) Enteroaggregative(EaggEC): Adhere as large aggregates Enterotoxin produces watery diarrhea. Cause of travelers'diarrhea
Escherichia coli Gastroenteritis 1. Serotyping identifies specific O (lipopolysaccharide) and H antigens (flagellar proteins). 2. Five pathogenic classes have been defined: a) Enterotoxigenic (ETEC): Produce a choleralike toxin. Spread by water contaminated with human sewage in developing countries. Cause of travelers’ diarrhea. b) Enteroaggregative (EaggEC):Adhere as large aggregates. Enterotoxin produces watery diarrhea. Cause of travelers’ diarrhea. 20