Download Chapter 25a

TORTORA • FUNKE
• CASE
Microbiology
AN INTRODUCTION
EIGHTH EDITION
B.E Pruitt & Jane J. Stein
Chapter 25, part A
Microbial Diseases of the Digestive System
PowerPoint® Lecture Slide Presentation prepared by Christine L. Case
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Microbial Diseases of the Digestive
System
• Transmitted in food and water
• Fecal-oral cycle can be broken by:
• Proper sewage disposal
• Disinfection of drinking water
• Proper food preparation and storage
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The Digestive System
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Figure 25.1
Normal Microbiota
• >300 species in mouth
• Large numbers in large intestine, including:
• Bacteroides
• E. coli
• Enterobacter
• Klebsiella
• Lactobacillus
• Proteus
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Dental Caries
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Figure 25.3a, b
Tooth Decay
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Figure 25.4
Periodontal Disease
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Figure 25.5
Bacterial Diseases of the Lower Digestive System
• Symptoms usually include diarrhea, gastroenteritis,
dysentery
• Treated with fluid and electrolyte replacement
• Infection caused by growth of pathogen
• Incubation from 12 hr to 2 wk
• Intoxication caused by ingestion of toxin
• Symptoms appear 1-48 hr after ingestion
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Staphylococcal Food Poisoning
• Staphylococcus
aureus
enterotoxin is a
superantigen
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Figure 25.6
Shigellosis
• Shigella spp.
producing Shiga
toxin
• Shiga toxin causes
inflammation and
bleeding
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Figure 25.8
Salmonellosis
• Salmonella enterica
serovars such as S.
enterica Typhimurium
• Mortality (<1%) due to
septic shock caused by
endotoxin
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Figure 25.9
Salmonellosis and Typhoid Fever Incidence
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Figure 25.10
Typhoid Fever
• Salmonella enterica Typhi
• Bacteria spread throughout body in phagocytes
• 1-3% recovered patients become carriers, harboring
Salmonella in their gallbladder
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Cholera
• Vibrio cholerae serotypes that produce cholera toxin
• Toxin causes host cells to secrete Cl–, HCO–, and
water
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Figure 25.12
Noncholera Vibrios
• Usually from contaminated crustaceans or mollusks
• V. cholerae serotypes other than O:1, O:139, and
eltor
• V. parahaemolyticus
• V. vulnificus
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