Chapter 16 Vibrio

section 1 Vibrio cholera

Biological characterization A. Morphology and identification  Comma shaped, curved rod  G-  Single polar flagellum  Highly motile

B. Culture and growth  Grow at a very high pH 8.5—9.5  Rapidly killed by acid

C. Antigenic structure and biological classification  Serogroup O1 and O139 cause classic cholera in humans  Non-O1/non-O139: either cause sporadic disease or nonpathogens

 The O1 organisms  Two biotypes: El Tor and cholerae  Three serotypes: Ogawa, Inaba and Hikojima

Pathogenesis and symptomatology A. pathogenesis  do not reach the bloodstream  require large number of B.----sensitive to stomach acid  Colonization of the small intestine  Attach to the micronilli of the brush border of epithelial cells

A. pathogenesis  Cholera toxin  Mucinase: dissolve the protective glycoprotein coating over the intestinal cells----enhances attachment  endotoxin

Enterotoxin (choleragen):  produce the symptoms of cholera  A-B type ADP-ribosylating toxin subunit A: ADP-ribosylating activity subunit A: ADP-ribosylating activity subunit B: bind to a GM1ganglioside receptor subunit B: bind to a GM1ganglioside receptor  Catalyze the ADP ribosylation of the G protein

 cAMP  Secretion of chloride ions and water  Massive watery diarrhea without inflammation(20-30L/d)  Dehydration and electrolyte imbalance, shock, acidosis, death

Clinical findings  Nausea and vomiting  Massive watery diarrhea  No red or white blood cells in the stool  “rice-water” stool containing mucus, epithelial cells and large numbers of vibrios  dehydration  cardiac and renal failure

Section 2 vibrio parahaemolyticus vibrio parahaemolyticus

 Cause acute gastroenteritis  By ingestion of contaminated seafood  Halophilic, require NaCl to growth  optimal NaCl concentration contained in culture media is 3.5%;  Nausea and vomiting, abdominal cramps, fever, watery to bloody diarrhea  hemolysin related to its pathogenicity, can be detected by human or rabbit RBC test (Kanagawa test);

ENTEROBACTERIACEA E Rod-Shaped Bacterium, E. coli (division) (SEM x22,245) E. coli (0157:H7) a rod prokaryote. Hemorrhagic type © Dr Dennis Kunkel, University of Hawaii. Used with permission

4) Enterohemorrhagic E. coli (EHEC). These are usually serotype O157:H7. Transmission electron micrograph of Escherichia coli O157:H7 CDC/Peggy S. Hayes

Shigella (ii) Shigella Shigella sonnei - rod prokaryote; causes shigellosis (bacterial dysentery) (x 22,400) © Dr Dennis Kunkel, University of Hawaii. Used with permission

Salmonella (iii) Salmonella Salmonella typhimurium - rod prokaryote (dividing); note the flagella. Causes salmonellosis (food poisoning). (x 20,800) © Dr Dennis Kunkel, University of Hawaii. Used with permission