Microbiology Ch 25

• -millions of bacteria per ml of saliva
• -large numbers in large intestine
• -100 billion bacteria per gram of feces 

• -Stomach; acidic 
• -small intestines; paneth cells
•         Defensins and lysozyme  

It is Tooth Decay

• -S.mutans attaches to proteins on tooth
• -Eat sucrose to produce dextran
• -Bacteria accumulate on dextran=dental plaque
• -Ferment sugar to produce lactic acid
•    = cavity  

• -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 

Pathogen: Staphyloccus aureus

Symptoms: Nausea, vomiting, and diarrhea

Intoxication/infection: intoxication, enterotoxin (superantigen)

Diagnosis: phage typing

Treatment: none 

1-Food containing protein is cooked (bacteria usually killed)

2-Then food is contaminated by worker with staphyloocci on hands (competing bacteria have been eliminated)

3-Food is left at room temperature. Organisms incubatee in food (temperature abuse) long enough to form and release toxins. (Reheating will eliminate staphylococi but not the toxins).

4-Food containing toxins is eaten

5- In one to six hours, staphylococcal intoxication occurs.  

Pathogen: Shigella spp

Symptoms: tissue damage and dysentery

Intoxication/infection: Infection endotoxin and shiga exotoxin

Diagnosis: isolation of bacteria

Treatment: Quinolones  

• Pathogen: Salmonella enterica
• Symptoms: Nausea and diarrhea
• Intoxication/infection: infection endotoxin
• Diagnosis: Isolation of bacteria; serotyping
• Treatment: oral rehydration  

• Pathogen: S.typhi
• Symptoms: High fever, significant mortality
• Intoxication/infection: Infection endotoxin
• Diagnosis: isolation of bacteria; serotyping
• Treatment: Quinolones; cepholosporins  

• -Caused by Salmonella tyhpi
• -Bacteria spread throughout body in phagocytes
• -1-3% of recovered patients become chronic carriers

 

• -Cholera
•     *Vibrio cholerae serotypes that produce choler toxin
•     * Toxin causes host cells to secret Cl-, HCO-, and water

• -Noncholera vibrios
•     -Usually from contamintd crustaceans or mollusks
•     -V.cholerae serotypes other than O:1,  O:139, eltor
•     -V.parahaemolyticus
•     -V.vulnificus 

-Pathogenic E.Coli

•     * attach to intestinal cells with fimbriae
•     *Produces toxins
•     * May aggregate  

• Pathogen: campylobacter jejuni
• Symptoms: Fever, abdominal pain, diarrhea
• Intoxication/infection: infection
• Diagnosis: Isolate Bacteria
• Reservoir: chickens, cow's milk  

• Pathogen: Helicobacter pylori
• Symptoms: peptic ulcers
• Intoxication/infection: infection
• Diagnosis: Urea breath, bacterial culture
• Treatment: antimicrobial drugs  

• -An inflammation of the liver
• -Caused by at least 5 different viruses
• -may result from drug or chemical toxicity, EB virus, CMV, or the hepatitis viruses 

• pathogen: Giardia lamblia
• symptoms: protozoan adheres to intestinal wall, diarrhea
• Reservoir: water or mammals
• Diagnosis: FA test
• treatment: metronidazole; quinacrine  

• 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

• Pathogen: Cyclospora cayetanensis
• Symptoms: Watery diarrhea
• Reservoir: humans; birds
• Diagnosis: Microscopy
• Treatment: trimethoprim and sulfamethoxazole 

• Pathogen: Entamoeba histolytica
• Symptoms: Abscesses; significant mortality rate
• Reservoir: humans
• Diagnosis: microscopy; serology
• treatment: Metronidazole