Bio 205 Ch 25 - Microbial Diseases of the Digestive System

Flashcards about Microbial Diseases of the Digestive System

Fecal/oral route

The typical route of transmission for microbial diseases of the digestive system.

Dental Plaque

A biofilm on the surface of teeth where organisms ferment carbohydrates, creating lactic acid.

Lactic acid

Weakens enamel, leading to dental caries.

Streptococcus ‘ mutans

The most common cause of cavities because it produces dextran.

Tartar

Calcified deposits of plaque.

Periodontal Disease

Inflammation and degeneration of structures that support the teeth.

Gingivitis

Infection of the gingiva (gums). Bleeding at brushing

Periodontitis

Chronic gingivitis where gums are inflamed and bleed easily, pus forms in tooth socket deteriotating the periodontal ligament loosing a teeth

Acute Necrotizing Gingivitis

Chewing is painful, extreme halitosis

Staphylococcal Food Poisoning

Caused by ingestion of S. aureus enterotoxins. Organism resistant to heat (everything) common in nasal passages , . proper refrigeration makes organism static

Shigellosis (bacterial dysentery)

Causative agent is a G- facultative anaerobe rod of the genus Shigella. Symptoms: diarrhea, internal hemorrhage

Salmonellosis (Gastroenteritis)

G-rod, facultative anaerobe, non-spore former; normal in the intestinal tracts of animals.

Divided in typhoid and non typhoid strains

Typhoid Fever

Causative agent is Salmonella typhi; found only in human feces, chronic carrier liver in gall bladder • symptoms like fever, headache, diarrhea. quinoles are used to treat it

Cholera

Causative agent is Vibrio cholera, a G-, flagellated curved rod that produces exotoxin. Secrete huge amounts of water and electrolytes → ↓bp = shock

Organism is destroyed by stomach acids

Traveler's Diarrhea

E. coli is most common cause

best treatment is rehydration therapy

Peptic Ulcers

Causative agent is Helicobacter pylori, can develop a ulcers or stomach cancer, there is a decrease in stomach mucus-produce high amounts of urease

C-dif

Causative agent is Clostridium difficile, a G+, spore forming obligate anaerobe rod that produces exotoxins. Antibiotics that disrupt normal flora, have symptoms like diarrhea, colitis, ulcerations of intestine. Fecal transplants

Mumps

Targets the parotid glands; saliva or respiratory transmission.

orchitis

Inflammation of testes can lead to sterility, MMR vaccine is a trivalent attenuated vaccine

HAV (Hepatitis A Virus)

Single stranded (SS) RNA virus without an envelope; food borne transmission; no chronic form.

HBV (Hepatitis B Virus)

Double stranded (DS) DNA virus with an envelope; not found in urine or feces but found in other body fluids.

HCV (Hepatitis C Virus)

SS RNA virus with envelope; often undetectable until chronic, then leads to liver cancer or cirrhosis.

HDV (Hepatitis D Virus)

SS RNA virus only found in those that already have HBV; increases the mortality rate of HBV patients.

HEV (Hepatitis E Virus)

SS RNA virus with an envelope; fecal/oral transmission; does not cause chronic liver disease.

Mycotoxins

Fungal toxins that cause blood diseases, nervous system disorders, kidney and liver damage, and cancer.

Giardiasis

Caused by a flagellated protozoan called Giardia intestinalis; attaches to the intestinal wall.

Amoebic Dysentery

Entamoeba histolytica is the causative agent; causes severe diarrhea containing RBCs. Abscesses the small intestine

Treated with metronidazole