VIBRIO CHOLERAE

Awang Ismawi Bin Awang IsmailWan Muhammad Hakimi Bin Wan Zakaria

WHAT IS VIBRIO CHOLERAE? Gram negative bacteria Three members pathogenic to human,

other species are pathogenic for animal and insects

Lead a commensal existance in numerous hosts or occur as saprophytes, particularly in water

WHERE DO THEY LIVE? Found in fresh and brackish (slighly salt)

water, shellfish and other seafood Man is the major reservoir for V.cholerae Factor of transmission – inadequate

sanitation, lack of person and food hygiene, use a polluted water to prepare food, inadequate cooked shellfish etc

HOW DOES IT’S LOOKS LIKE?

Curved rods with rounded ends 3 x 0.5µm Gram negative – pink stained Actively motile with single polar

flagellum. To- and fro- movement (dark-field micsroscopy)

Non-capsulated, Non-sporing Some strain is lateral flagellum

MICROSCOPY

COULD THEY HARM US?

Produce enterotoxin (exotoxin) that activates enzyme adenylcyclase

Causing watery diarrhoea producing ‘rice water’ stool containing vibrios, epithelial cells and mucus

Adherence factor – motility and extracellular enzymes such as proteases

Acute cholera – rapid loss of fluid and electrolytes in stool, vomit leads to muscular cramps and severe dehydration (fatal), acidosis, blood urea increase, urine increase in albumin

AerobicWide temperature. Optimum 37oCGrow in ordinary media but sensitive to acid

pH (alkaline; 8.2)2-3 mm in size after 18 – 24 hr incubation in

optimum temp.Low convex with an entire edge, whitish and

translucentOlder colonies develop a light ochre tinta tube

of peptone water with a flake of mucus from stool and incubating for only 6 – 8 hrs

CULTURATION

Ferment glucose, sucrose, mannitol and maltose without gas production

Does not utilise lactose or dulcitol Positive in indole and nitrites test Non-hemolytic in sheep blood agar

(Greig test) Can be tested in H2SO4

BIOCHEMICAL TESTS

THE END