14 - Facultative anaerobes part 4 ( VIBRIONACEAE )

VIBRIONACEAE : 

• Curved to comma shaped

• Polarly flagellated

• Facultative anaerobes

o Aerobic & therefore catalase & oxidase +ve (similar to aerobic Pseudomonads)
o Fermenters ie anaerobic

• Widespread distribution (fresh water, sea water) & human & animal intestinal tracts); not indicators of fecal pollution.

• 3 genera (Vibrio, Aeromonas, Photobacterium)

o Vibrio Cholera (aka Asiatic cholera)
 Two biotypes of serogroup O:1 known (classic cholera & Eltor [Mecca camp]); Eltor endemic in coastal regions eg India, Bangladesh & South America; USA non-O1 serogroup due to consumption of contaminated seafood.
 Transmitted thro' sewage contaminated water & food; rice water stools
 Multiplies in intestinal epithelial cells (but not invasive to other tissues) & produces an enterotoxin (binds irreversibly to epithelial cells stimulating the production of cyclic which changes cell permeability leading to the secretion of water & electrolytes into the lumen. 12 to 20 litres of water lost-- dehydration; replacement of electrolytes & water necessary is the best treatment; Tetracycline decreases disease period; vaccines provide short immunity but natural infections provide a longer duration (against enterotoxin & cells)
 Culture in alkaline medium (high pH decreases the growth of other bacteria)
 Vibrio parahemolyticus
 Habitat is salt water and requires > 2% NaCl for growth in laboratory media (halophilic) Gastroenteritis from contaminated shell fish, crabs; USA, Japan, Hawaii Large nos. within 24 hr & recovery follows in a few days.

o Aeromonas
 Mainly pathogens of fresh water fish, turtles & frogs.
 May be encountered as causative agents of human diseases.

o Photobacterium
 Interesting due to the property of bioluminescence (aka luminescent bacteria); ATP + electron transport chain + enzyme luciferase = luminescence
 Normal flora of some fish (flash light fish); behavioral activities (mating, protection)