An outbreak occurs in a community where the water supply is contaminated. Multiple patients experience nausea and vomiting as well as profuse diarrhea with abdominal cramps; stools are described as "rice water." Curved, gram-negative rods are isolated on a sulfate-citrate-bile- sucrose agar. In the treatment of patients who have cholera, the use of a drug that inhibits adenyl cyclase would be expected to have which of the following characteristics?

Cholera is a toxicosis. The mode of action of cholera toxin is to stimulate the activity of adenyl cyclase, an enzyme that converts ATP to cyclic AMP. Cyclic AMP stimulates the secretion of chloride ion, and affected patients lose copious amounts of fluid. A drug that inhibits adenyl cyclase thus might block the effect of cholera toxin. Water and electrolyte replacement are primary management mechanisms, while oral tetracycline may help reduce stool output. Many antimicrobial agents are effective against V. cholerae, notably oral tetracycline. A sensitivity test would be needed for choosing the best drug to kill the bacteria. Fluid secretion would be lessened if adenyl cyclase was inhibited. Our patient would not die with the described medical treatment but be helped to overcome the infection. Reduction of bacterial motility has no association with bacterial virulence.