Norwalk-like Organism viruses Rotavirus Astrovirus Campylobacter spp Giardia lamblia Salmonella, nontyphoidal Shigella spp Cryptosporidium parvum Clostridium perfringens Toxoplasma gondii Staphylococcus food poisoning Yersinia enterocolitica Hepatitis A E. coli enterotoxigenic E. coli other diarrheogenic E. coli O157:H7 Streptococcus, foodborne E. coli non-O157 STEC Bacillus cereus Cyclospora cayetanensis Vibrio, other Listeria monocytogenes Brucella spp Salmonella typhi V. vulnificus Botulism, foodborne Vibrio cholerae, toxigenic Trichinella spiralis Total Viral Total Bacterial Total Parasitic Grand Total
Illnesses Hospitalizations Deaths 23,000,000 50,000 310 3,900,000 50,000 30 3,900,000 12,500 10 2,453,926 13,174 124 2,000,000 5,000 10 1,412,498 16,430 582 448,240 6,231 70 300,000 1,989 66 248,520 41 7 225,000 5,000 750 185,060 1,753 2 96,368 83,391 79,420 79,420 73,480 50,920 36,740 27,360 16,264 7,880 2,518 1,554 824 94 58 54 52 30,833,391 5,204,934 2,541,316 38,629,641 1,228 10,841 21 21 2,168 358 1,084 8 17 99 2,322 122 618 86 46 18 4 3 83 0 0 61 0 30 0 0 20 504 11 3 37 4 0 0
Food-borne Pathogens in US Ranked by Illnesses Per Year
123,341 433 45,826 1,458 12,010 827 181,177 2,718
137
Cholera
Diarrheal disease
Rapid water loss Dehydration Death
Drinking water and eating food contaminated with human feces containing Vibrio cholerae
138
Cholera
Vibrio cholerae Gram negative facultative anaerobe Free living salt water (often associated with shellfish) and fresh water organism Major Virulence Factors
Pilus attaches to intestinal epithelium Cholera Toxin
Experimentally, the major disease symptom (massive diarrhea) can be induced with toxin alone
139
Vibrio cholerae
140
Vibrio cholerae pili
A B Toxins
A Portion
|
S
|
S
|
B Portion
B
B B B B
Example: Cholera
B Portion
A
Example: Diphtheria
A Portion 141
Cholera Toxin
A-B type toxin Bacteriophage encoded (CTX phage) B portion binds intestinal A epithelium portion ADP ribosylates G proteins
G proteins involved in cell signaling e.g., Hormonal regulation of cAMP levels
142
cAMP
143
FYI
Hormone
via G proteins
cAMP
activates
Protein kinase
phosphorylates
Protein (inactive)
Protein (active)
Function in cell
148
Hormonal regulation of cAMP levels via G proteins
Hormone G proteins Hormone Receptor
GDP = guanosine diphosphate
Adenylate Cyclase
1
2
Hormone binds receptor 144
3
4
GTP = guanosine triphosphate
Causes G proteins to exchange GDP for GTP and produces conformational change in G protein subunit
145
5
G protein subunit activates Adenylate Cyclase to make cAMP
6
Hydrolysis of GTP to GDP
146
7
Conformational change in G protein subunit that no longer activates Adenylate Cyclase G proteins reassociate If hormone still bound to receptor cycle repeats 147
8
Cholera Toxin (A portion) ADP ribosylates G proteins that lock it into an active state that stimulates adenylate cyclase to make cAMP
1 3
2
Cholera toxin
4
149
Water Transport: Follow the Sodium Secretory Diarrhea
H+ HCO3Apical Brush Border
Na+
H+ + HCO3-
Cl- Glu Na+
CO2 + H2O
Basolateral
Na+
Cl-
150
Rice Water Stool Rice Water Stool
151
The Cholera Cot The Cholera Cot
152
Treatment
Rehydration therapy Replace fluid, sugar and electrolytes Oral Intravenous (IV) Antibiotics may hasten clearing of bacteria
153
Water Transport: Follow the Sodium Secretory Diarrhea
H+ HCO3Apical Brush Border
Na+
H+ + HCO3-
Cl- Glu Na+
CO2 + H2O
Basolateral
Na+
Cl-
154
Treatment
Rehydration therapy Replace fluid, sugar and electrolytes Oral Intravenous (IV) Antibiotics may hasten clearing of bacteria
155
Prevention
Travel to high risk areas
Drink only boiled or treated (chlorine or iodine) water. Coffee or tea made with boiled water. Bottled beverages. No ice. Eat thoroughly cooked food. Fruit you must peel. Avoid undercooked seafood.
No vaccine (US)
156