Transcript Document

TORTORA  FUNKE  CASE
ninth edition
MICROBIOLOGY
an introduction
25
Part A
Microbial Diseases
of the Digestive
System
PowerPoint® Lecture Slide Presentation prepared by Christine L. Case
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
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
 >700 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 25.3
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, and
dysentery.
 Are treated with fluid and electrolyte replacement.
 Infection is caused by growth of a pathogen:
 Incubation is from 12 hours to 2 weeks.
 Intoxication caused by ingestion of toxin:
 Symptoms appear 1 to 48 hours 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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Figures 25.7, 25.8
Salmonellosis
 Salmonella enterica
serovars such as S.
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
Calculate the Relative Risk to Determine the
Most Likely Source of Salmonella
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
47
24
6
29
a
e=
a+b
f=
c
c+d
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Relative Risk =
e
f
What Was the Most Likely Source of This
Outbreak of Salmonella?
Food
Relative Risk
Chicken salad
1.71
Cole slaw
1.58
Fruit salad
1.17
Potato salad
1.18
Tomato salad
3.86
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Typhoid Fever
 Salmonella typhi
 Bacteria is spread throughout body in phagocytes.
 1 to 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 25.11
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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