Microbial Diseases of the Digestive System Chapter 25 Microbial Diseases of the Digestive System

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?

The Digestive System Learning Objective 25-1 Name the structures of the digestive system that contact food.

The Human Digestive System Figure 25.1

Normal Microbiota of the Digestive System Learning Objective 25-2 Identify parts of the gastrointestinal tract that normally have microbiota.

Normal Microbiota Millions of bacteria per ml of saliva Large numbers in large intestine 100 billion bacteria per gram of feces

Defenses Stomach: Acidic Small intestine: Paneth cells

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

Bacterial Diseases of the Mouth Learning Objective 25-3 Describe the events that lead to dental caries and periodontal disease.

A Healthy Human Tooth Figure 25.2

Dental Caries (Tooth Decay) Figure 25.3a

Dental Caries (Tooth Decay) Figure 25.3b

The Stages of Tooth Decay Figure 25.4

The Stages of Periodontal Disease Figure 25.5

Bacterial Diseases of the Mouth Pathogen Dental caries Streptococcus mutans Periodontal disease Porphyromonas spp. Acute necrotizing gingivitis Prevotella intermedia

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?

Why are “sugarless” candies and gum, which actually contain sugar alcohols, not considered cariogenic (causing caries)? 25-3

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

Diseases of Lower Digestive System 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

Staphylococcal Food Poisoning Pathogen Staphylococcus aureus Symptoms Nausea, vomiting, and diarrhea Intoxication/Infection Intoxication Enterotoxin (superantigen) Diagnosis Phage typing Treatment None

Events in Staphylococcal Food Poisoning Figure 25.6

Shigellosis (Bacillary Dysentery) Pathogen Shigella spp. Symptoms Tissue damage and dysentery Intoxication/Infection Infection Endotoxin and Shiga exotoxin Diagnosis Isolation of bacteria Treatment Quinolones

Invasion of Intestinal Wall by Shigella Figure 25.7

Shigellosis Figure 25.8

Salmonellosis and Typhoid Fever Figure 25.10

Typhoid Fever Caused by Salmonella typhi Bacteria spread throughout body in phagocytes 1–3% of recovered patients become chronic carriers

Disease Salmonellosis Typhoid Fever Pathogen Salmonella enterica S. typhi Symptoms Nausea and diarrhea High fever, significant mortality Intoxication/ Infection Infection Endotoxin Diagnosis Isolation of bacteria; serotyping Treatment Oral rehydration Quinolones; cephalosporins

Salmonellosis Figure 25.9

Determine the Salmonella Source Food Exposed Not Exposed Ill (a) Not ill (b) Ill (c) Not ill (d) Chicken salad 47 40 6 13 Cole slaw 32 20 21 33 Fruit salad 34 30 19 23 Potato salad 42 39 11 14 Tomato salad 24 29

Determine the Salmonella Source Food Relative Risk Chicken salad 1.71 Cole slaw 1.58 Fruit salad 1.17 Potato salad 1.18 Tomato salad 3.86

Vibrios Cholera Noncholera vibrios 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

Vibrio cholerae Figure 25.11

Vibrio cholerae O:1 and O:139 V. vulnificus Disease Cholera Noncholera vibrios Pathogen Vibrio cholerae O:1 and O:139 V. parahaemolyticus V. vulnificus Symptoms Diarrhea with large water loss Cholera-like diarrhea, but generally milder Rapidly spreading tissue destruction Intoxication/Infection Cholera toxin (exotoxin) Infection, enterotoxin Infection, siderophores Diagnosis Isolation of bacteria Treatment Rehydration; doxycycline Rehydration; antibiotics Antibiotics

Escherichia coli Gastroenteritis Pathogenic E. coli Attach to intestinal cells with fimbriae Produce toxins May aggregate

Escherichia coli Gastroenteritis Disease Traveler’s Diarrhea STEC Pathogen Enterotoxigenic, enteroinvasive, enteraggregative E. coli Shiga-toxin-producing E. coli Symptoms Watery diarrhea Shigella-like dysentery; hemorrhagic colitis and hemolytic uremic syndrome

Escherichia coli Gastroenteritis Disease Traveler’s Diarrhea STEC Intoxication/Infection Infection Endotoxin Infection Shiga exotoxin Diagnosis Isolation of bacteria Treatment Oral rehydration Quinolones; cephalosporins

Campylobacter Gastroenteritis Pathogen Campylobacter jejuni Symptoms Fever, abdominal pain, diarrhea Intoxication/Infection Infection Diagnosis Isolate bacteria Reservoir Chickens, cow’s milk

Helicobacter Peptic Ulcer Disease Figure 25.13

Helicobacter Peptic Ulcer Disease Pathogen Helicobacter pylori Symptoms Peptic ulcers Intoxication/Infection Infection Diagnosis Urea breath, bacterial culture Treatment Antimicrobial drugs

Yersinia Gastroenteritis Pathogen Y. enterocolitica, Y. pseudotuberculosis Symptoms Abdominal pain and diarrhea, usually mild; may be confused with appendicitis Intoxication/Infection Infection Endotoxin Diagnosis Bacterial culture; serotyping Transmitted Meat, milk

Clostridium and Bacillus Gastroenteritis Pathogen C. perfringens C. difficile B. cereus Symptoms Diarrhea Diarrhea to colitis Nausea and vomiting; diarrhea Intoxication/Infection Infection Exotoxin Intoxication Diagnosis Isolation of bacteria Cytotoxin assay

Clostridium and Bacillus Gastroenteritis Pathogen C. perfringens C. difficile B. cereus Transmitted Metronidazole; discontinue other antibiotic therapy Source of Infection Meats Elimination of normal microbiota Rice dishes

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

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?

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

Viral Diseases of the Digestive System Mumps Viral Gastroenteritis Pathogen Mumps virus Rotavirus Norovirus Symptoms Swollen parotid glands Vomiting, diarrhea, 1 wk Vomiting, diarrhea, 2–3 days Incubation 16–18 days 1–3 days 14–48 hr Diagnosis EIA PCR Treatment Preventive vaccine Oral rehydration

A Case of Mumps Figure 25.14

Hepatitis An inflammation of the liver May result from drug or chemical toxicity, EB virus, CMV, or the hepatitis viruses

Hepatitis Viruses Disease Transmission Pathogen Chronic Liver Disease? Vaccine? Hepatitis A Fecal-oral Picornaviridae No Inactivated virus Hepatitis B Parenteral, STI Hepadnaviridae Yes Recombinant Hepatitis C Parenteral Filoviridae None Hepatitis D Pareteral, HBV coinfection Deltaviridae HBV vaccine Hepatitis E Caliciviridae HAV vaccine

Hepatitis B Virus (HBV) Figure 25.15

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

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?

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?

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

Fungal Diseases of the Digestive System Learning Objective 25-8 Identify the causes of ergot poisoning and aflatoxin poisoning.

Mycotoxin Intoxications Disease Ergot Poisoning Aflatoxin Poisoning Pathogen Claviceps purpurea Aspergillus flavus Symptoms Reduced blood to limbs Liver cirrhosis; liver cancer Intoxication/ Infection Mycotoxin in grain Mycotoxin in food Diagnosis Sclerotia in food Immunoassay for toxin in food Treatment None

What is the connection between the occasional hallucinogenic symptoms produced by ergot poisoning and a modern illicit drug? 25-8

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

Giardia lamblia Figure 25.17

Giardiasis Pathogen Giardia lamblia Symptoms Protozoan adheres to intestinal wall, diarrhea Reservoir Water or mammals Diagnosis FA test Treatment Metronidazole; quinacrine

Cryptosporidium hominis Figure 25.18

Cryptosporidium hominis in the U. S. Clinical Focus, p. 355

Cryptosporidiosis Pathogen Cryptosporidium hominis Symptoms Self-limiting diarrhea; may be life-threatening in immunosuppressed people Reservoir Cattle; water Diagnosis Acid-fast stain; FA; ELISA Treatment Oral rehydration

Cyclospora Diarrheal Infection Pathogen Cyclospora cayetanensis Symptoms Watery diarrhea Reservoir Humans; birds Diagnosis Microscopy Treatment Trimethoprim and sulfamethoxazole

Entamoeba histolytica Figures 12.17b, 25.19

Amoebic Dysentery Pathogen Entamoeba histolytica Symptoms Abscesses; significant mortality rate Reservoir Humans Diagnosis Microscopy; serology Treatment Metronidazole

Is giardiasis caused by ingestion of a cyst or an oocyst? 25-9

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

Worldwide Prevalence of Helminthic Diseases Figure 25.20

Tapeworms Figure 12.26

Ophthalmic Cysticercosis Figure 25.21

Echinococcus granulosus Figure 12.27

Hydatid Disease Figure 25.22

Tapeworms and Hydatid Disease Pathogen Taenia saginata T. solium Diphyllobothrium latum Echinococcus granulosus Symptoms Neurocysticercosis Tissue damage Intermediate Host Cattle, pigs, fish Humans Definitive Host Dogs

Tapeworms and Hydatid Disease Diagnosis Microscopic exam of feces Praziquantel; albendazole Treatment Serology; X-ray exam Surgical removal; albendazole

Pinworms Figure 12.28

Pinworms Pathogen Enterobius vermicularis Symptoms Itching around anus Intermediate host Humans Definitive host Diagnosis Microscopy Treatment Pyrantel pamoate

Hookworms Figure 25.23

Ascariasis lumbricoides Figure 25.24

Heartworm Figure 12.29

Life Cycle of Trichinella spiralis Figure 25.25

Roundworms Disease Hookworms Ascariasis Trichinellosis Pathogen Necator americanus, Ancyclostoma duodenale Ascaris lumbricoides Trichinella spiralis Symptoms Anemia Few Intermediate Host Larva in soil Human Mammals Definitive Host

Roundworms Disease Hookworms Ascariasis Trichinellosis Diagnosis Microscopy Biopsy; ELISA Treatment Mebendazole Mebendazole; corticosteroids

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?

What species of tapeworm is the cause of cysticercosis? 25-10

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?