Normal Microbiota of the Digestive System
- The Mouth = millions per ml of saliva
- The Stomach = sterile
- The Small Intestine = just a few!
- The Large Intestine = billions and billions
- Symbionic Relationship
Normal Microbiota in Large Intestine
- Anaerobes: Lactobacillus and Bacteroides
- Facultative anaerobes: Enterics
Bacterial Diseases of the Mouth
- Dental Carries
- Periodontal Disease
Dental Carries
- cavities
- Dental plaque = calcified bacteria and their waste products
- bacteria = Streptococcus mutans
Periodontal Disease
- Disease of supporting structures of teeth
2 kinds:
- Gingivitis = gum inflammation
- Periodontitis = structures that hold teeth get inflamed. (Acute narcotizing ulcerative gingivitis also called Vincent's Disease or trench mouth)
Types of Diseases of Lower Digestive System
- Infection
- Intoxication
- Gastroenteritis
Infection
- Growth of a pathogen
- Incubation is from 12 hrs to 2 weeks
- Fever
- Causes gastroenteritis
- Treatment: oral rehydration therapy
Intoxication
- Ingestion of toxin
- Symptoms appear 1 to 48 hrs after ingestion
- Causes gastroenteritis
- Treatment: oral rehydration therapy
Gastroenteritis
diarrhea, dysentery
- dysentery = very severe form of diarrhea with huge amount of fluid loss.
Staphylococcal Food Poisoning
- Also called Staphylococcal enterotoxicosis
- Caused by Staphylococcus aureus
- Incubation of Staph aureus on food is called temperature abuse
- Staph aureus also produces toxins which are not destroyed by cooking.
- Symptoms: Nausea, vomiting, diarrhea
Process of Staphylococcal Food Poisoning
1. Food containing protein is cooked (bacteria usually killed).
2. Then food is contaminated by worker with staphylococci on hands (competing bacteria have been eliminated).
- temperature room holding -
3. Organisms incubate in food (temperature abuse) lo
Shigellosis (Bacillary Dysentery)
- Shigella sonei - traveler's diarrhea (few days)
- Shigella dysentaria - more serious
- Symptoms - Tissue damage and dysentery
- Infection, Endotoxin, Shiga exotoxin
Typhoid Fever
- Caused by Salmonella typhi
- Only found in human and their feces
- High fever, and severe diarrhea (significant mortality)
- Associated with poor sanitation and sewage treatment
- A substantial number of recovered patients become carriers
- Infection, E
Salmonellosis
- Salmonella enterica
- Symptoms: Nausea and diarrhea
- Symptoms 12-36 hrs after incubation
- Associated with chicken, eggs, and reptiles
- In bloodstream - end up with gram negative sepsis
- Infection, Endotoxin
Cholera
- Vibrio cholerae serotypes that produce cholera toxin (0:1 & 0:139), eltor
- Toxin causes host cels to secrete Cl-, HCO-, and water
- Causes very severe dysentery
- Cholera toxin (exotoxin)
Noncholera vibrios
- Usually from contaminates crustaceans and mollusks (bad oysters)
- get diarrhea
2 types:
- V. parahaemolyticus = Cholera-Like diarrhea but gently milder, Infection, enterotoxin
- V. vulnificus = Rapidly spreading tissue destruction, Infection, sideropho
Escherichia coli Gastroenteritis
- E.coli that attaches to intestinal cells with fimbriae
- Produce toxins
2 types:
- Traveler's diarrhea (E.coli 0157:H7): Enterotoxigenic, Enteroinvasive (inflammation and fever), Infections, Watery diarrhea
- STEC: Shiga-toxin-producing-E.coli, Shigella
Campylobacter Gastroenteritis
- Campylobacter jejuni
- Symptoms: Fever, abd. pain, diarrhea
- Infection
- Reservoir: Chickens, cow's milk
Helicobacter Peptic Ulcer Disease
- H.Pylori Disease
- Helicobacter pylori
- Symptoms: Peptic Ulcers
- Infection
- It doesn't cause peptic ulcers. It takes advantage of people who already have them. (It secretes ammonia to survive stomach acid).
Yersinia Gastroenteritis
- Y. enterocolitica, Y. pseudotuberculosis
- Symptoms: abd. pain, mild diarrhea, may be confused with appendicitis
- Infection, Endotoxin
- Transmitted: meat, milk
Clostridium and Bacillus Gastroenteritis
1. C. perfringens
-Symptoms: diarrhea
- Infection, Exotoxin
2. C. difficile
- Symptoms: diarrhea to colitis
- Infection, Exotoxin
3. B. cereus
- Symptoms: Nausea, vomiting, diarrhea
- Intoxication
Viral Diseases of the Digestive System
1. Mumps
2. Viral Gastroenteritis
3. Hepatits
Mumps
- Mumps virus
- Symptoms: Swollen parotid glands, Orchitis
Viral Gastroenteritis
stomach flu"
1. Rotavirus
- Symptoms: Vomiting, diarrhea, 1 wk
2. Norovirus
- cruise ships
- Symptoms: Vomiting, diarrhea, 2-3 days1
Hepatitis
- inflammation of the liver
- 2nd most frequently reported infectious disease in the US
- At least 5 different viruses: HAV, HBV, HCV, HDV, HEV
Hepatitis A Virus (HAV)
- 50% sub-clinical
- Transmission: fecal-oral
- Chronic Liver Disease? No.
- Vaccine? Inactivated virus
Hepatitis B Virus (HBV)
- Transmission: Parenteral, STI
- Chronic Liver Disease? Yes.
- Vaccine? Recombinant
Hepatitis C Virus (HCV)
- Transmission: Parenteral
- Chronic Liver Disease? Yes.
- Vaccine? No.
- deadliest of them all
Hepatitis D Virus (HDV)
- Transmission: Parenteral, HBV coinfection
- Chronic Liver Disease? Yes.
- Vaccine? HBV vaccine
Hepatitis E Virus (HEV)
- Mostly sub-clinical
- Transmission: fecal-oral
- Chronic Liver Disease? No.
- Vaccine? HAV vaccine
Protozoan Diseases of the Digestive System
there are several pathogenic protozoa that can cause human digestive diseases"
1. Giardiasis
2. Amoebic Dysentery
3. Cryptosporidiosis
Giardiasis
- Giardia lamblia
- Symptoms: Protozoan adheres to intestinal wall, diarrhea, upset stomach
- Reservoir: Water or mammals
- Most common water-borne
Amoebic Dysentery
- Entamoeba histolytica
- Symptoms: Abscess, significant mortality rate
- Reservoir: Humans
- Very serious infection
Cryptosporidiosis
- Cryptosporidium hominis
- Symptoms: Self-limiting diarrhea, may be life-threatening in immunosuppressed people
- Reservoir: Cattle, water
Helminthic Diseases of the Digestive System
- Tapeworms
- Nematodes
Tapeworms
(flatworms)
- Ingestion of cysticerci (eggs) from under-cooked pork, beef, or fish.
1. Tapeworms
- Taenia saginata (beef)
- Taenia solium (pork)
- Diphyllobothrium latum (fish)
- Symptoms: Neurocysticercosis
2. Hydatid Disease
- Echinococcus granulosus
-
Nematodes
(roundworms)
1. Pinworms
2. Hookworms
3. Ascariasis
4. Trichinellosis
Pinworms
- Enterobius vermicularis
- Symptoms: itching around the anus
Hookworms
- Necator americanus
- Ancyclostoma duodenale
Ascariasis
- Ascaris lumbricoides
- from undercooked meat also
Trichinellosis
- Trichinella spiralis
- from undercooked meat also