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Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Chapter 25 Microbial Diseases of the Digestive System.

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Presentation on theme: "Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Chapter 25 Microbial Diseases of the Digestive System."— Presentation transcript:

1 Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Chapter 25 Microbial Diseases of the Digestive System

2 Copyright © 2010 Pearson Education, Inc. Q&A  The United States frequently imports cheese and wine from France. In return, the United States exports horses to France. What does this have to do with the disease of trichinellosis?

3 Copyright © 2010 Pearson Education, Inc. The Digestive System 25-1Name the structures of the digestive system that contact food. Learning Objective

4 Copyright © 2010 Pearson Education, Inc. The Human Digestive System Figure 25.1

5 Copyright © 2010 Pearson Education, Inc. Normal Microbiota of the Digestive System 25-2Identify parts of the gastrointestinal tract that normally have microbiota. Learning Objective

6 Copyright © 2010 Pearson Education, Inc. Normal Microbiota  Millions of bacteria per ml of saliva  Large numbers in large intestine  100 billion bacteria per gram of feces

7 Copyright © 2010 Pearson Education, Inc. Defenses  Stomach: Acidic  Small intestine: Paneth cells

8 Copyright © 2010 Pearson Education, Inc. Check Your Understanding There have been instances in which a surgeon was using spark producing instruments to remove intestinal polyps and a small explosion occurred. What ignited? 25-1 How are normal microbiota confined to the mouth and large intestine? 25-2

9 Copyright © 2010 Pearson Education, Inc. Bacterial Diseases of the Mouth 25-3Describe the events that lead to dental caries and periodontal disease. Learning Objective

10 Copyright © 2010 Pearson Education, Inc. A Healthy Human Tooth Figure 25.2

11 Copyright © 2010 Pearson Education, Inc. Dental Caries (Tooth Decay) Figure 25.3a

12 Copyright © 2010 Pearson Education, Inc. Dental Caries (Tooth Decay) Figure 25.3b

13 Copyright © 2010 Pearson Education, Inc. The Stages of Tooth Decay Figure 25.4

14 Copyright © 2010 Pearson Education, Inc. The Stages of Periodontal Disease Figure 25.5

15 Copyright © 2010 Pearson Education, Inc. Bacterial Diseases of the Mouth DiseasePathogen Dental cariesStreptococcus mutans Periodontal diseasePorphyromonas spp. Acute necrotizing gingivitis Prevotella intermedia

16 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Bacterial Diseases of the Mouth  Can you identify infections that could cause persistent sore, swollen, red, or bleeding gums, as well as tooth pain or sensitivity and bad breath?

17 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Why are “sugarless” candies and gum, which actually contain sugar alcohols, not considered cariogenic (causing caries)? 25-3

18 Copyright © 2010 Pearson Education, Inc. Diseases of Lower Digestive System 25-4List the causative agents, suspect foods, signs and symptoms, and treatments for staphylococcal food poisoning, shigellosis, salmonellosis, typhoid fever, cholera, gastroenteritis, and peptic ulcer disease. Learning Objective

19 Copyright © 2010 Pearson Education, Inc.  Infection: Growth of a pathogen  Incubation is from 12 hours to 2 weeks  Fever  Intoxication: Ingestion of toxin  Symptoms appear 1 to 48 hours after ingestion  Gastroenteritis: Diarrhea, dysentery  Treatment: Oral rehydration therapy Diseases of Lower Digestive System

20 Copyright © 2010 Pearson Education, Inc. Staphylococcal Food Poisoning PathogenStaphylococcus aureus SymptomsNausea, vomiting, and diarrhea Intoxication/InfectionIntoxication Enterotoxin (superantigen) DiagnosisPhage typing TreatmentNone

21 Copyright © 2010 Pearson Education, Inc. Events in Staphylococcal Food Poisoning Figure 25.6

22 Copyright © 2010 Pearson Education, Inc. Shigellosis (Bacillary Dysentery) PathogenShigella spp. SymptomsTissue damage and dysentery Intoxication/InfectionInfection Endotoxin and Shiga exotoxin DiagnosisIsolation of bacteria TreatmentQuinolones

23 Copyright © 2010 Pearson Education, Inc. Invasion of Intestinal Wall by Shigella Figure 25.7

24 Copyright © 2010 Pearson Education, Inc. Shigellosis Figure 25.8

25 Copyright © 2010 Pearson Education, Inc. Salmonellosis and Typhoid Fever Figure 25.10

26 Copyright © 2010 Pearson Education, Inc. Typhoid Fever  Caused by Salmonella typhi  Bacteria spread throughout body in phagocytes  1–3% of recovered patients become chronic carriers

27 Copyright © 2010 Pearson Education, Inc. DiseaseSalmonellosisTyphoid Fever PathogenSalmonella enterica S. typhi SymptomsNausea and diarrhea High fever, significant mortality Intoxication/ Infection Infection Endotoxin Infection Endotoxin DiagnosisIsolation of bacteria; serotyping TreatmentOral rehydrationQuinolones; cephalosporins

28 Copyright © 2010 Pearson Education, Inc. Salmonellosis Figure 25.9

29 Copyright © 2010 Pearson Education, Inc. FoodExposedNot Exposed Ill (a)Not ill (b)Ill (c)Not ill (d) Chicken salad Cole slaw Fruit salad Potato salad Tomato salad Determine the Salmonella Source

30 Copyright © 2010 Pearson Education, Inc. FoodRelative Risk Chicken salad1.71 Cole slaw1.58 Fruit salad1.17 Potato salad1.18 Tomato salad3.86 Determine the Salmonella Source

31 Copyright © 2010 Pearson Education, Inc. Vibrios  Cholera  Vibrio cholerae serotypes that produce cholera toxin  Toxin causes host cells to secrete Cl –, HCO –, and water  Noncholera vibrios  Usually from contaminated crustaceans or mollusks  V. cholerae serotypes other than O:1, O:139, eltor  V. parahaemolyticus  V. vulnificus

32 Copyright © 2010 Pearson Education, Inc. Vibrio cholerae Figure 25.11

33 Copyright © 2010 Pearson Education, Inc. DiseaseCholeraNoncholera vibrios PathogenVibrio cholerae O:1 and O:139 V. parahaemolyticus V. vulnificus SymptomsDiarrhea with large water loss Cholera-like diarrhea, but generally milder Rapidly spreading tissue destruction Intoxication/ Infection Cholera toxin (exotoxin) Infection, enterotoxin Infection, siderophores DiagnosisIsolation of bacteria TreatmentRehydration; doxycycline Rehydration; antibiotics Antibiotics

34 Copyright © 2010 Pearson Education, Inc. Escherichia coli Gastroenteritis  Pathogenic E. coli  Attach to intestinal cells with fimbriae  Produce toxins  May aggregate

35 Copyright © 2010 Pearson Education, Inc. DiseaseTraveler’s DiarrheaSTEC PathogenEnterotoxigenic, enteroinvasive, enteraggregative E. coli Shiga-toxin-producing E. coli SymptomsWatery diarrheaShigella-like dysentery; hemorrhagic colitis and hemolytic uremic syndrome Escherichia coli Gastroenteritis

36 Copyright © 2010 Pearson Education, Inc. DiseaseTraveler’s DiarrheaSTEC Intoxication/ Infection Infection Endotoxin Infection Shiga exotoxin DiagnosisIsolation of bacteria TreatmentOral rehydrationQuinolones; cephalosporins Escherichia coli Gastroenteritis

37 Copyright © 2010 Pearson Education, Inc. Campylobacter Gastroenteritis PathogenCampylobacter jejuni SymptomsFever, abdominal pain, diarrhea Intoxication/InfectionInfection DiagnosisIsolate bacteria ReservoirChickens, cow’s milk

38 Copyright © 2010 Pearson Education, Inc. Helicobacter Peptic Ulcer Disease Figure 25.13

39 Copyright © 2010 Pearson Education, Inc. Helicobacter Peptic Ulcer Disease PathogenHelicobacter pylori SymptomsPeptic ulcers Intoxication/InfectionInfection DiagnosisUrea breath, bacterial culture TreatmentAntimicrobial drugs

40 Copyright © 2010 Pearson Education, Inc. Yersinia Gastroenteritis PathogenY. enterocolitica, Y. pseudotuberculosis SymptomsAbdominal pain and diarrhea, usually mild; may be confused with appendicitis Intoxication/InfectionInfection Endotoxin DiagnosisBacterial culture; serotyping TransmittedMeat, milk

41 Copyright © 2010 Pearson Education, Inc. Clostridium and Bacillus Gastroenteritis PathogenC. perfringens C. difficileB. cereus SymptomsDiarrheaDiarrhea to colitis Nausea and vomiting; diarrhea Intoxication/ Infection Infection Exotoxin Infection Exotoxin Intoxication DiagnosisIsolation of bacteria Cytotoxin assay Isolation of bacteria

42 Copyright © 2010 Pearson Education, Inc. PathogenC. perfringens C. difficileB. cereus TransmittedMetronidazole; discontinue other antibiotic therapy Source of Infection MeatsElimination of normal microbiota Rice dishes Clostridium and Bacillus Gastroenteritis

43 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Salmonellosis and typhoid fever are caused by closely related organisms. Why was typhoid fever almost entirely eliminated in developed countries by modern sewage treatment whereas salmonellosis has not been? 25-4

44 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Bacterial Diseases of the Lower Digestive System  An 8-year-old boy had diarrhea, chills, fever (39.3º C), abdominal cramps, and vomiting for 3 days. The next month, his 12-year-old brother experienced the same symptoms. Two weeks before the first patient became ill, the family had purchased a small (10 cm) red-eared slider turtle at a flea market.  Can you identify infections that could cause these symptoms?

45 Copyright © 2010 Pearson Education, Inc. Viral Diseases of the Digestive System 25-5List the causative agents, modes of transmission, sites of infection, and symptoms for mumps. 25-6Differentiate hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E. 25-7List the causative agents, mode of transmission, and symptoms of viral gastroenteritis. Learning Objectives

46 Copyright © 2010 Pearson Education, Inc. Viral Diseases of the Digestive System DiseaseMumpsViral Gastroenteritis PathogenMumps virusRotavirusNorovirus SymptomsSwollen parotid glands Vomiting, diarrhea, 1 wk Vomiting, diarrhea, 2–3 days Incubation16–18 days1–3 days14–48 hr DiagnosisSymptomsEIAPCR TreatmentPreventive vaccine Oral rehydration

47 Copyright © 2010 Pearson Education, Inc. A Case of Mumps Figure 25.14

48 Copyright © 2010 Pearson Education, Inc. Hepatitis  An inflammation of the liver  May result from drug or chemical toxicity, EB virus, CMV, or the hepatitis viruses

49 Copyright © 2010 Pearson Education, Inc. DiseaseTransmissionPathogen Chronic Liver Disease? Vaccine? Hepatitis A Fecal-oralPicornaviridaeNoInactivated virus Hepatitis B Parenteral, STIHepadnaviridaeYesRecombinant Hepatitis C ParenteralFiloviridaeYesNone Hepatitis D Pareteral, HBV coinfection DeltaviridaeYesHBV vaccine Hepatitis E Fecal-oralCaliciviridaeNoHAV vaccine Hepatitis Viruses

50 Copyright © 2010 Pearson Education, Inc. Hepatitis B Virus (HBV) Figure 25.15

51 Copyright © 2010 Pearson Education, Inc. Applications of Microbiology: A Safe Blood Supply  Nucleic acid testing (NAT) is used to test donated blood and plasma:  HCV  HIV  West Nile virus  Virus-inactivation is used on plasma

52 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Viral Hepatitis  After eating at one restaurant, 355 people were diagnosed with the same hepatitis virus.  Can you identify infections that could cause these symptoms?

53 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Viral Diseases of the Digestive System  An outbreak of diarrhea began in mid-June, peaked in mid-August, and tapered off in September. A clinical case was defined as diarrhea (three loose stools during a 24-hour period).  Can you identify infections that could cause these symptoms?

54 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Why is mumps included with the diseases of the digestive system? 25-5 Of the several hepatitis diseases, HAV, HBV, HCV, HDV, and HEV, which two now have effective vaccines to prevent them? 25-6 Two very common causes of viral gastroenteritis are caused by rotaviruses and noroviruses. Which of these now can be prevented by a vaccine? 25-7

55 Copyright © 2010 Pearson Education, Inc. Fungal Diseases of the Digestive System 25-8Identify the causes of ergot poisoning and aflatoxin poisoning. Learning Objective

56 Copyright © 2010 Pearson Education, Inc. Mycotoxin Intoxications DiseaseErgot Poisoning Aflatoxin Poisoning PathogenClaviceps purpurea Aspergillus flavus SymptomsReduced blood to limbs Liver cirrhosis; liver cancer Intoxication/ Infection Mycotoxin in grainMycotoxin in food DiagnosisSclerotia in foodImmunoassay for toxin in food TreatmentNone

57 Copyright © 2010 Pearson Education, Inc. Check Your Understanding What is the connection between the occasional hallucinogenic symptoms produced by ergot poisoning and a modern illicit drug? 25-8

58 Copyright © 2010 Pearson Education, Inc. Protozoan Diseases of the Digestive System 25-9List the causative agents, modes of transmission, symptoms, and treatments for giardiasis, cryptosporidiosis, Cyclospora diarrheal infection, and amoebic dysentery. Learning Objective

59 Copyright © 2010 Pearson Education, Inc. Giardia lamblia Figure 25.17

60 Copyright © 2010 Pearson Education, Inc. Giardiasis PathogenGiardia lamblia Symptoms Protozoan adheres to intestinal wall, diarrhea ReservoirWater or mammals DiagnosisFA test TreatmentMetronidazole; quinacrine

61 Copyright © 2010 Pearson Education, Inc. Cryptosporidium hominis Figure 25.18

62 Copyright © 2010 Pearson Education, Inc. Cryptosporidium hominis in the U. S. Clinical Focus, p. 355

63 Copyright © 2010 Pearson Education, Inc. Cryptosporidiosis PathogenCryptosporidium hominis Symptoms Self-limiting diarrhea; may be life-threatening in immunosuppressed people ReservoirCattle; water DiagnosisAcid-fast stain; FA; ELISA TreatmentOral rehydration

64 Copyright © 2010 Pearson Education, Inc. Cyclospora Diarrheal Infection PathogenCyclospora cayetanensis SymptomsWatery diarrhea ReservoirHumans; birds DiagnosisMicroscopy Treatment Trimethoprim and sulfamethoxazole

65 Copyright © 2010 Pearson Education, Inc. Entamoeba histolytica Figures 12.17b, 25.19

66 Copyright © 2010 Pearson Education, Inc. Amoebic Dysentery PathogenEntamoeba histolytica Symptoms Abscesses; significant mortality rate ReservoirHumans DiagnosisMicroscopy; serology TreatmentMetronidazole

67 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Is giardiasis caused by ingestion of a cyst or an oocyst? 25-9

68 Copyright © 2010 Pearson Education, Inc. Helminthic Diseases of Digestive System 25-10List the causative agents, modes of transmission, symptoms, and treatments for tapeworms, hydatid disease, pinworms, hookworms, ascariasis, and trichinellosis. Learning Objective

69 Copyright © 2010 Pearson Education, Inc. Worldwide Prevalence of Helminthic Diseases Figure 25.20

70 Copyright © 2010 Pearson Education, Inc. Tapeworms Figure 12.26

71 Copyright © 2010 Pearson Education, Inc. Ophthalmic Cysticercosis Figure 25.21

72 Copyright © 2010 Pearson Education, Inc. Echinococcus granulosus Figure 12.27

73 Copyright © 2010 Pearson Education, Inc. Hydatid Disease Figure 25.22

74 Copyright © 2010 Pearson Education, Inc. Tapeworms and Hydatid Disease DiseaseTapewormHydatid Disease PathogenTaenia saginata T. solium Diphyllobothrium latum Echinococcus granulosus SymptomsNeurocysticercosisTissue damage Intermediate Host Cattle, pigs, fishHumans Definitive HostHumansDogs

75 Copyright © 2010 Pearson Education, Inc. Tapeworms and Hydatid Disease DiseaseTapewormHydatid Disease Diagnosis Microscopic exam of feces Praziquantel; albendazole Treatment Serology; X-ray exam Surgical removal; albendazole

76 Copyright © 2010 Pearson Education, Inc. Pinworms Figure 12.28

77 Copyright © 2010 Pearson Education, Inc. Pinworms PathogenEnterobius vermicularis SymptomsItching around anus Intermediate hostHumans Definitive hostHumans DiagnosisMicroscopy TreatmentPyrantel pamoate

78 Copyright © 2010 Pearson Education, Inc. Hookworms Figure 25.23

79 Copyright © 2010 Pearson Education, Inc. Ascariasis lumbricoides Figure 25.24

80 Copyright © 2010 Pearson Education, Inc. Heartworm Figure 12.29

81 Copyright © 2010 Pearson Education, Inc. Life Cycle of Trichinella spiralis Figure 25.25

82 Copyright © 2010 Pearson Education, Inc. Roundworms DiseaseHookwormsAscariasisTrichinellosis PathogenNecator americanus, Ancyclostoma duodenale Ascaris lumbricoides Trichinella spiralis SymptomsAnemiaFew Intermediate Host Larva in soilHumanMammals Definitive Host Human

83 Copyright © 2010 Pearson Education, Inc. Roundworms DiseaseHookwormsAscariasisTrichinellosis DiagnosisMicroscopy Biopsy; ELISA TreatmentMebendazole Mebendazole; corticosteroids

84 Copyright © 2010 Pearson Education, Inc. Q&A  The United States frequently imports cheese and wine from France. In return, the United States exports horses to France. What does this have to do with the disease of trichinellosis?

85 Copyright © 2010 Pearson Education, Inc. Check Your Understanding What species of tapeworm is the cause of cysticercosis? 25-10

86 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Fungal, Protozoan, and Helminthic Diseases  Public health officials in Pennsylvania were notified of cases of watery diarrhea with frequent, sometimes explosive, bowel movements among persons associated with a residential facility. The disease was associated with eating snow peas.  Can you identify infections that could cause these symptoms?


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