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MICROBIAL DISEASES OF THE DIGESTIVE SYSTEM. MOUTH Over 300 types of bacteria Dental caries Periodontal disease –Gingivitis –Periodontitis.

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Presentation on theme: "MICROBIAL DISEASES OF THE DIGESTIVE SYSTEM. MOUTH Over 300 types of bacteria Dental caries Periodontal disease –Gingivitis –Periodontitis."— Presentation transcript:



3 MOUTH Over 300 types of bacteria Dental caries Periodontal disease –Gingivitis –Periodontitis

4 DENTAL CARIES Dental plaque –Accumulation of microorganisms and their products (dental plaque) –Streptococcus mutans –Actinomyces spp.

5 DENTAL CARIES (cont.) Attachment Colonization Sugar (glucose+fructose) Glucose > dextran Fructose > lactic acid

6 Enamel

7 DENTAL CARIES (cont.) Lactic acid softens enamel Initial, S. mutans Advance, Lactobacillus spp. Pulp infection

8 DENTAL CARIES (cont.) Treatment –Root canal therapy –Penicillin Prevention –Fluoride –Reduced sucrose in diet –Brushing and flossing –Professional cleaning

9 PERIODONTAL DISEASE Inflammation of teeth-supporting tissue Gingivitis –Gums inflammation (bleeding)

10 PERIODONTAL DISEASE (cont.) Streptococci, actinomyces and gram-negative bacteria Prevented by brushing & flossing

11 PERIODONTITIS Chronic gingivitis 10% of teeth loss Affects bone Surgery and cleaning

12 LOWER DIGESTIVE SYSTEM Infections –Salmonellosis Intoxications –Staphylococcus aureus

13 Practice that contributed to food- borne disease (1988-1992) 1. Improper holding temperature 2. Poor personal hygiene of food handlers 3. Food obtained from an unsafe source was the least commonly reported factor

14 Syndrome A group of symptoms that together are characteristic of a specific disease

15 Gastrointestinal Syndrome Gastroenteritis associated with nausea, vomiting and diarrhea

16 Dysentery syndrome Any infectious disease of the large intestine marked by ulceration, hemorrhagic diarrhea with mucus and often blood

17 GASTROENTERITIS Inflammation of the stomach and intestinal mucosa

18 GASTROENTERITIS (cont.) Abdominal cramps Nausea Vomiting Dehydration

19 GASTROENTERITIS (cont.) E. coli Shigella spp. Salmonella spp. Campylobacter spp. Staphylococcus aureus Rotavirus Norwalk virus (Noro virus)

20 Routes of exposure to enteric pathogens Fecal contamination (human/animal) –Food –Water –Fomites (doorknobs, telephones) –Direct contact


22 Petting zoos

23 Non-traditional pets

24 Pest animals

25 Population at risk

26 Occupational risk


28 STAPHYLOCOCCAL FOOD POISONING S. aureus survives 30 min at 60 o C (140 o F) High salt concentration Skin and nasal mucosa Facultative anaerobes -Coagulase positive

29 STAPHYLOCOCCAL FOOD POISONING (cont.) Temperature abuse –Food let to cool slowly –Organisms grow producing toxin

30 STAPHYLOCOCCAL FOOD POISONING (cont.) High risk foods –Custards –Cream pies –Ham

31 STAPHYLOCOCCAL FOOD POISONING (cont.) Toxin affects brain’s vomiting reflex Abdominal cramps Diarrhea


33 Salmonella spp. Gram negative rods Facultative anaerobe 2000 serovars

34 SALMONELLOSIS (cont.) S. dublin S. enteritidis S. typhimurium S. cholerasuis

35 SALMONELLOSIS (cont.) Domestic animals –Poultry –Swine –Cattle –Dogs and cats

36 SALMONELLOSIS (cont.) Wild animals –Rodents –reptiles –Terrapins (turtles)


38 SALMONELLOSIS (cont.) Incubation of 12 - 36 h Intestinal mucosa Lymphatic and cardiovascular systems

39 SALMONELLOSIS (cont.) Fever Nausea Abdominal pain Cramps Diarrhea

40 SALMONELLOSIS (cont.) Mortality among infants and the elderly Many shed Salmonella for 6 months Many animals are chronic carriers

41 SALMONELLOSIS (cont.) Treatment –Rehydration –Antibiotics prolong carrier state and increase resistance

42 TYPHOID FEVER Salmonella typhi –Rare in animals! Incubation –2 weeks

43 TYPHOID FEVER (cont.) High fever (104 o F) Continual headache Constipation more common than diarrhea 10% fatality rate

44 TYPHOID FEVER (cont.) Many recovered patients become carriers (Typhoid Mary) Obligatory case report in most states and countries Lifelong immunity

45 TYPHOID FEVER (cont.) Treatment –Cephalosporins –Chloramphenicol –Amoxillin

46 Shigellosis

47 SHIGELLOSIS (Bacillary dysentery) Shigella spp. Gram negative facultative anaerobic rod Only infects humans Low infectious dose –Resistant to low stomach pH

48 SHIGELLOSIS (cont.) S. sonnei – Most common in the USA – Least severe S. dysenteriae –Uncommon in the USA –Most severe

49 SHIGELLOSIS (cont.) Shiga toxin –Inhibits protein synthesis –Diarrhea with blood and mucus (dysentery)

50 SHIGELLOSIS (cont.) 20,000- 25,000 cases/year 5 to 15 deaths Treatment –Rehydration –Fluoroquinolones (severe cases)

51 Cholera

52 CHOLERA Vibrio cholerae Aquatic organism Gram-negative rod Non-invasive –toxin producing

53 Cholera epidemic South America 1991-1994 1 million cases 9,600 deaths

54 CHOLERA (cont.) Enterotoxin Rice-water stools 20 liters of liquid lost/day Occasional outbreaks in Gulf coast (seafood)



57 CHOLERA (cont.) 50% mortality if untreated 1% mortality if treated –Rehydration –Tetracycline

58 Vibrio gastroenteritis Vibrio parahaemolyticus Salt water estuaries Resembles cholera Often foodborne (seafood)

59 E. coli

60 Escherichia coli gastroenteritis Enterotoxigenic E. coli Enteroinvasive E. coli Enterohemorrhagic E. coli

61 Enterotoxigenic E. coli Specialized fimbriae –Attachment Not invasive Toxins Severe diarrhea

62 Enteroinvasive E. coli Specialized fimbriae –Attachment Toxins (cholera-like) Traveler’s diarrhea (?) Penetrate intestinal lining –Shigellosis-like dysentery


64 Enterohemorrhagic E. coli O157:H7 strain Foodborne (hamburgers, milk, apple cider) Verotoxins (colon bleeding)

65 Enterohemorrhagic E. coli (cont.) Cattle carrier Hemolytic uremic syndrome –Blood in urine –Kidney failure

66 Campylobacter jejuni gastroenteritis Gram-negative microaerophilic spirally curved rods Common in (healthy) domestic animals –May be shed in milk Small infectious dose Dysentery

67 Yersinia spp. gastroenteritis Common in domestic animals Grows at refrigeration temperature Acute pain

68 Clostridium perfringens gastroenteritis Gram-positive, spore-forming anaerobic rod Contaminated-cooked meat Temperature abuse Mild diarrhea

69 Bacillus cereus gastroenteritis Gram-positive, spore-forming anaerobic rod Common in soil and vegetation Gastroenteritis is similar to Cl. perfringens



72 ROTAVIRUS Most common viral gastroenteritis 1,000,000 cases/year (USA) 100 deaths/hour (developing countries)


74 NORWALK VIRUS Common among adults More resistant to chlorine than other viruses No animal models or cell culture available

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