All of the following statements about El-Tor vibrios are true, except:
Enterotoxin can have direct effects on other tissues besides intestinal epithelial cells is not true. Option 1 - Reservoir: Humans are the only reservoir. Option 2 - Vibrios are resistant to high alkalinity. Option 3 - Cholera toxin: exotoxin, heat-labile protein- destroyed by heating at 56degC for 15 minutes. Option 4 - V. cholera enterotoxin do not have any affects on extra-intestinal tissues (lack of receptors of toxin).