Transcript Infection
The Human Digestive System Figure 25.1 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 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 Bacterial Diseases of the Mouth Disease Dental caries Pathogen Streptococcus mutans Periodontal disease Porphyromonas spp. Acute necrotizing gingivitis Prevotella intermedia 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 Symptoms Staphylococcus aureus Nausea, vomiting, and diarrhea Intoxication/Infection Intoxication Enterotoxin (superantigen) Phage typing None Diagnosis Treatment Shigellosis (Bacillary Dysentery) Pathogen Symptoms Shigella spp. Tissue damage and dysentery Intoxication/Infection Infection Endotoxin and Shiga exotoxin Isolation of bacteria Quinolones Diagnosis Treatment 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 Intoxication/ Infection Infection Endotoxin High fever, significant mortality Infection Endotoxin Diagnosis Isolation of bacteria; serotyping Isolation of bacteria; serotyping Treatment Oral rehydration Quinolones; cephalosporins 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 Vibrio cholerae Figure 25.11 Disease Pathogen Symptoms Cholera Vibrio cholerae O:1 and O:139 Diarrhea with large water loss Noncholera vibrios V. parahaemolyticus V. vulnificus Cholera-like diarrhea, but generally milder Intoxication/ Cholera Infection toxin (exotoxin) Infection, enterotoxin Rapidly spreading tissue destruction Infection, siderophores Diagnosis Isolation of bacteria Isolation of bacteria Isolation of bacteria Treatment Rehydration; Rehydration; doxycycline antibiotics Antibiotics Escherichia coli Gastroenteritis Pathogenic E. coli Attach to intestinal cells with fimbriae Produce toxins May aggregate Escherichia coli Gastroenteritis Disease Pathogen Symptoms Traveler’s Diarrhea Enterotoxigenic, enteroinvasive, enteraggregative E. coli Watery diarrhea STEC Shiga-toxin-producing E. coli Shigella-like dysentery; hemorrhagic colitis and hemolytic uremic syndrome Escherichia coli Gastroenteritis Disease Traveler’s Diarrhea Intoxication/ Infection Infection Endotoxin STEC Infection Shiga exotoxin Diagnosis Isolation of bacteria Isolation of bacteria Treatment Oral rehydration Quinolones; cephalosporins Helicobacter Peptic Ulcer Disease Figure 25.13 Helicobacter Peptic Ulcer Disease Pathogen Symptoms Helicobacter pylori Peptic ulcers Intoxication/Infection Diagnosis Infection Urea breath, bacterial culture Antimicrobial drugs Treatment Clostridium and Bacillus Gastroenteritis Pathogen C. difficile B. cereus Diarrhea to colitis Nausea and vomiting; diarrhea Intoxication/ Infection Infection Exotoxin Infection Exotoxin Intoxication Diagnosis Cytotoxin assay Isolation of bacteria Symptoms C. perfringens Diarrhea Isolation of bacteria Clostridium and Bacillus Gastroenteritis Pathogen Transmitted Source of Infection C. C. difficile B. cereus perfringens Metronidazole; discontinue other antibiotic therapy Meats Elimination of normal microbiota Rice dishes Viral Diseases of the Digestive System Disease 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 Symptoms EIA PCR Treatment Preventive vaccine Oral rehydration 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 Vaccine? Disease? Hepatitis A Fecal-oral Picornaviridae No Hepatitis B Parenteral, STI Hepadnaviridae Yes Recombinant Hepatitis C Parenteral Yes None Hepatitis D Pareteral, HBV Deltaviridae coinfection Yes HBV vaccine Hepatitis E Fecal-oral No HAV vaccine Filoviridae Caliciviridae Inactivated virus Hepatitis B Virus (HBV) Figure 25.15