3/4/99

Microbiology II

· One of the most frequently used microbes for biotechnology

· Easily manipulated b/c can conjugate

· Used as a vector to introduce new genes to the organism

· Normal flora of colon

· Produce vit B and K

· Handout

Shigella

· Bacillary dysentery

· Close relative of E. coli

· Non-motile organism; while E. coli is a motile organism

· Gram negative

· 4 species

S. flexneri—south
S. sonnei—north, most common
S. boydii
S. dysenteriae

· one of the major water borne organisms,

· transmitted through food

· GI tract associated

· Food, flies, fingers, feces are routes of transmission

· Symptoms appear suddenly and include abdominal pain, diarrhea, high fever, general discomfort, stools containing mucus, blood, and pus "red currant jelly" appearance), rectal burning, and dehydration ; complications include massive bleeding and perforation of the large intestine

· Seen in very young and old

· About 10 days to 2 wks to death

· Pathogenicity—hemorrhagic, paralytic neurotoxin has been isolated form the organism

· Heat stable--90°C

· MW of 82,000 D

· Endotoxin, Gram (+)

· No CNS symptoms

· Only seen in lab animals

· 5:4:1 solution for dehydration

· antibiotic therapy shows multiple drug resistance

· ability to transfer drug resistance back and forth b/w E. coli

· grown on chocolate agar

· Tx: ampicillin, rifampin, chloramphenicol (only in life threatening situations)

Salmonella

· Many species

· 2 locations on handout

· Salmonellosis—gastroenteritis; most common food poisoning

· S. enteritdis

· S. typhimurium

· Even sterile eggs have Salmonella

· Last for 3-4 days and does not demand Tx

· Need rehydration w/5:4:1

· Symptoms appear suddenly and include abdominal pain, diarrhea, dizziness, fever, headache, nausea, vomiting and poor appetite

· Salmonella typhi

· Typhoid fever

· Successfully controlled in the US

· In other areas it is rampant

· Most deadly of Enteric fevers (GI tract related fevers)

· Can be found in water and can survive their for wks

· Step rising fever

· Petchial rash

· About 1-2wks incubation

· Gradual onset of symptoms and include abdominal distention, constipation, rising fever, headache, loss of appetite, nausea, vomiting, diarrhea, and appearance of rash (rose spots) on abdomen; complications include inflammation of gall bladder, perforation of small intestine, intestinal bleeding, and pneumonia

· Thrombophlebitis

· Meningitis

· Alopeua—abortion

· Haven't had outbreak in about 27 yrs

· Permanent carrier who stores organism in gall bladder, which becomes water borne due to fecal water contamination

· Typhoid Mary—responsible for large number of outbreaks (p619)

· Needs to be treated

· Rehydration

· Tx: ampicillin (w/no threat to life), chloremphenicol, 3^rd generation cephalosporin (only recently)

· Even w/Tx people die, should try to prevent

· Vaccine: TAB (Typhoid, paratyphoid A & B), only if traveling to areas where might be exposed is one vaccinated

· Immunity for about 1 yr

· Incapacitates one for 3-4 days after vaccination making it hard to move your arm

Vibrio cholerae

· Short, curved rod

· Not a member of Enterobaceae

· Ricewater stools

· Gram (-)

· Transmission by 4 F's

· Which disease is most aggressive dehydrating? Cholera

· If can rehydrate at same rate of dehydration; difficult to do

· Outbreaks occur, not just isolated incidents which makes it difficult

· In about 3 days of attack, the person loses 20pints of fluid and salts

· Toxin: choleragen—initiate reversal of absorption process, very rapid lose of fluid

· Die of cardiovascular collapse

· Antibiotic therapy does not work

· Rehydration of fluid and salts w/intravenous methods is the only way to save them

· Will not accept things orally