Pathogenic vibrios. Vibrio cholerae. Laboratory diagnostics, treatment

and prophylaxis of cholera.

Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

TAXONOMIC POSITION OF THE PATHOGENIC VIBRIOS

• Family Vibrionaceae

• Genus Vibrio

• Medical important species:

• V.cholerae

• V.parahaemolyticus

• V.vulnificus

• V.alginolyticus

Classification of the vibrios

• Biochemical classification by Heiberg (1934)

• Serological classification

VIBRIO CHOLERAE

Cultural characteristics• The cholera vibrions is strongly aerobic • Growth is better in an alkaline medium the

range of pH being 6.4-9.6 (optimum 8.2)• Special media:• Alkaline peptone water at pH 8.6;• Monsur's taurocholate tellurite peptone

water at pH 9.2.• Alkaline bile salt agar (BSA) pH 8.2.

Classification of the V. cholerae

Biovars:

•V. cholerae b/v classical

•V. cholerae b/v El-Tor

Serotypes:

•Ogawa (AB)

•Inaba (AC)

•Hikojima (ABC)

Distinguishing features of biovarsTests b/v

classicalb/v El Tor

Agglutination of fowl erythrocytes - +

Lysis of sheep erythrocytes - +

Growth in the presence of polymixin B

- +

Sensitivity to phages Mukerjee`s group IV phage (C)

Mukerjee`s group V phage (El -Tor)

Acetoin production in the Voges-Proskauer test

- +

Factors of virulence• Exotoxin (choleragen, cholera enterotoxin,

cholera toxin, CT, or CTX)• Endotoxin.

• Adherence factors (pili)

• Proteolytic enzymes (gelatinase, mucinase)

Epidemiology and pathogenesis

• Infection is acquired through fecally contaminated water or food.

• Clinical forms:

1.Enteritis

2.Gastroenteritis

3.Choleric algid

4.Choleric coma (severe dehydration)

Laboratory diagnosis

• Rapid tests

• Microscopy

• Bacteriological method

• Serology

Prophylaxis

• General measures

• Specific measures

Vibrio cholerae