Medical Technology Department, Faculty of Science, Islamic University-Gaza M MICRO B BIOLOGY Dr. Abdelraouf A. Elmanama Dr. Abdelraouf A. Elmanama Ph. D Microbiology Ph. D Microbiology 2008 Chapter 25 Chapter 25 Microbial Diseases of the Microbial Diseases of the Digestive System Digestive System
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Medical Technology Department, Faculty of Science, Islamic University-Gaza MB M ICRO B IOLOGY Dr. Abdelraouf A. Elmanama Ph. D Microbiology 2008 Chapter.
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Medical Technology Department, Faculty of Science, Islamic University-Gaza
MMICROBBIOLOGY
Dr. Abdelraouf A. ElmanamaDr. Abdelraouf A. ElmanamaPh. D MicrobiologyPh. D Microbiology
2008
Chapter 25Chapter 25Microbial Diseases of the Digestive SystemMicrobial Diseases of the Digestive System
2008
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
2008
The Digestive System
Figure 25.1
2008
• >300 species in mouth
• Large numbers in large intestine, including:
• Bacteroides
• E. coli
• Enterobacter
• Klebsiella
• Lactobacillus
• Proteus
Normal Microbiota
2008
Dental Caries
Figure 25.3a, b
2008
Tooth Decay
Figure 25.4
2008
Periodontal Disease
Figure 25.5
2008
• 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
Bacterial Diseases of the Lower Digestive System
2008
Staphylococcal Food Poisoning
Figure 25.6
• Staphylococcus aureus enterotoxin is a superantigen
2008
Shigellosis
Figure 25.8
• Shigella spp. producing Shiga toxin
• Shiga toxin causes inflammation and bleeding
2008
Salmonellosis
Figure 25.9
• Salmonella enterica serovars such as S. enterica Typhimurium
• Mortality (<1%) due to septic shock caused by endotoxin
2008
Salmonellosis and Typhoid Fever Incidence
Figure 25.10
2008
• Salmonella enterica Typhi
• Bacteria spread throughout body in phagocytes
• 1-3% recovered patients become carriers, harboring Salmonella in their gallbladder
Typhoid Fever
2008
Cholera
Figure 25.12
• Vibrio cholerae serotypes that produce cholera toxin
• Toxin causes host cells to secrete Cl–, HCO–, and water
2008
• Usually from contaminated crustaceans or mollusks
• V. cholerae serotypes other than O:1, O:139, and eltor
• V. parahaemolyticus
• V. vulnificus
Noncholera Vibrios
2008
• Occurs as traveler's diarrhea and epidemic diarrhea in nurseries
• 50% of feedlot cattle may have enterohemorrhagic strains in their intestines
• Enterohemorrhagic strains such as E. coli O157:H7 produce Shiga toxin
• O = cell wall antigen
• H = flagellar antigen
Escherichia coli Gastroenteritis
2008
• Campylobacter jejuni
• Usually transmitted in cow's milk
Campylobacter Gastroenteritis
2008
Helicobacter Peptic ulcer disease
• Treated with antibiotics
• H. pylori causes stomach cancer
Figure 11.11
2008
Helicobacter Peptic ulcer disease
Figure 25.13
2008
• Y. enterocolitica and Y. pseudotuberculosis
• Can reproduce at 4°C
• Usually transmitted in meat and milk
Yersinia Gastroenteritis
2008
• Grow in intestinal tract producing exotoxin
Clostridium perfringens Gastroenteritis
2008
• Ingestion of bacterial exotoxin produces mild symptoms
Bacillus cereus Gastroenteritis
2008
Mumps
Figure 25.14
• Mumps virus
• Enters through respiratory tract
• Infects parotid glands
• Prevented with MMR vaccine
2008
• Inflammation of the liver
• Hepatitis may result from drug or chemical toxicity, EB virus, CMV, or the Hepatitis viruses