Digestive System

Digestive system

• less microbes in stomach due to HCI production (very acidic)

• small intestine (Paneth cells) with phagocytic cells, produce defensins

• - a large amount of bacteria in large intestine

• - anaerobes and facultative anaerobes

Dental Plaque

• carries (tooth decay)

• biofilms cause dental carroes

• cause: strep.

• sucrose becomes latic acid

• prod dextran and uses polysacc to form plaque

Gingivitis and Periodontitis

• inflammation and infection of gums

• destroys bone and tissue around both (bacterias toxins)

Staphy. Food Poisoning

Enterotoxin caused bty S. Aureus

• caused by TOXIN not the bacteria

• COOKING/reheating may kill bacteria, but toxin remains

Diarrheal infections: Shigellosis and Salmonellosis

Shigellosis

• Bacillary dysentery

• Shiga toxin, bloody due to destroying the intestine

Salmonellosis

• typhoid fever causes life-threatening infection, causes systemic infection

cont. Cholera and E. Coli

Cholera

• waterborne

• watery

• surface level (not fully invading GI)

• stop absorption of ions / ion uptake causing watery stool

Escherichia coli

• gastroenteritis

• bloody, Shiga-like toxin

• enterohemorrhagic e coli (EHEC)

• causes hemorrhagic colitis and hemolytic uremic syndrome

Helicobacter peptic ulcers

Cause: H Pylori

• grown in stomach acid, prod. urease (turns urea to ammonia, raising pH)

• disrupt the stomach mucosa causing inflammation

• Treat: antimicrobials, and bismuth subsalicylate

• diagnostic test: biopsy, culture, urea breath test

Closterium Diff - Diarrhea

• gram -, endospore, anerobic

• more deaths than other digestive infections

• mostly in healthcare

• life threatening colitis - ulceration and perforation of the intestinal wall

• precipitated by extended use of antibiotics (eliminates competing bacteria, may have to discont antibiotics)

HEP A VIRUS - VAX

acure infection - entry: oral

• spread to liver, kidney, spleen

• anorexia, nausea, diarrha, fever, chilles, jaundice, dark urine

HEP B VIRUS - VAX

• sexual contact

• serum Hep - entry; blood and bodily fluids

• acute: fulminant Hep - sudden massive liver damge; fatal

• could cause cirrhosis or chronic infection or liver cancer

HEP C - no vax

• IV drug use and blood transmission

• destroy liver

• cause chronic infection / cancer

• effective drugs treat and cure disease

Viral enterotritis

• Rotavirus - VAX (diarrhea/vomit, common in children)

• Norovirus - low ID50, fecal-oral trans., outbreaks in cruise ships

Gastroenteritis - Protozoa

Cyst - infectious

Trophozoite - growing form

Giardiasis - prolonged diarrhea due to outdoor activities

Cryptosporidiosis - diarrhea - municipality outbreaks

Amebiasis - blood diarrhea, may spread to other organs