VIBRIONACEAE

It contains 3 genera: Vibrio Aeromonas Plesiomonas VIBRIO: GENERAL CHARACTERS : Gram negative, rigid, curved rods. vibratory motility – charecteristic feature asporogenous, non-capsulated

VIBRIO SPECIES: V.cholerae V. mimicus HALOPHILIC VIBRIOS: V.parahaemolyticus V.alginolyticus V. vulnificus

GARDNER AND VENKATRAMAN’S CLASSIFICATION: VIBRIO GROUP A GROUP B (biochemically and antigenically heterogenous ) OSUB GROUP O1 Non-01 (SERO GROUPS ) (up to 0-13) (SERO VARS) BIOTYPES : CLASSICAL El Tor SEROTYPES : Ogawa Inaba Hikojima

TEST CLASSICAL El Tor Hemolysis _ + VP test _ + Chick erythrocyte _ + agglutination polymyxinB sensitivity + _ GroupIV phage Susceptibility + _ El Tor phage V Suceptibility _ +

VIBRIO CHOLERAE MORPHOLOGY Short,curved,cylindrical rods V.comma S-shaped or spiral forms Pleomorphism Fish in stream appearance Darting motility Swarm of gnats

CULTURAL CHARACTERISTICS Strongly aerobic Temp C,PH : Requirement of Nacl Grows well on ordinary media Nutrient agar: moist,translucent,rounddiscs,1-2mm in diameter with bluish tinge in transmitted light

Mac conkeys agar :- Late lactose fermenters Blood agar:- hemodigestion Gelatin stab culture:- infundibuliform or napiform liquefaction Peptone water:- forms surface pellicle-in 6hrs

SPECIAL MEDIA:- 1.Holding or transport media:- a.Venkatraman-Ramakrishnan medium b.Cary-Blair medium c.Autoclaved sea water 2.Enrichment media:- a.Alkaline peptone water b.Monsur’s taurocholate tellurite peptone water 3.Plating media:- a.alkaline bile salt agar b.monsur’s gelatin taurocholate trypticase tellurite agar c.TCBS medium

BIOCHEMICAL REACTIONS :- catalase -positive oxidase - positive Indole - positive methyl red -negative voges-proskauer test -negative citrate test - positive nitrate test - positive

Sugar fermentation tests ferments glucose mannitol maltose mannose sucrose with the production of acid only not ferments inositol arabinose or lactose Vibrios decarboxylate lysine and ornithine but not arginine Vibrios elaborate several enzymes CHOLERA RED REACTION

RESISTANCE Susceptible to heat,drying and acids & disinfectants Resist high alkalinity Destroyed at 55 C in 15 min Affected by vibriophages Killed in the gastric juice of normal acidity with in min El Tor vibrios survive longer than classical cholera vibrio