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 16-40 C,PH :6.4-9.6• 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 water2.Enrichment media:- a.Alkaline peptone water b.Monsur’s taurocholate tellurite

peptone water3.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