Awang Ismawi Bin Awang Ismail Wan Muhammad Hakimi Bin Wan Zakaria

 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

 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

 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

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

Aerobic Wide temperature. Optimum 37 o C Grow 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 translucent Older colonies develop a light ochre tinta tube of peptone water with a flake of mucus from stool and incubating for only 6 – 8 hrs

 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 H 2 SO 4