Antimicrobial therapy for shigellosis.

In controlled clinical trials, which were first performed with use of the sulfonamides, antimicrobial agents have been shown to shorten the duration of symptoms and lessen the excretion of pathogens during episodes of shigellosis. Not all antimicrobial agents that are active in vitro against Shigella are effective in vivo, and efficacy of an agent can only be assessed by properly conducted clinical trials. Resistance to both ampicillin and trimethoprim-sulfamethoxazole, the drugs of choice for the treatment of shigellosis, is now common among Shigella dysenteriae type I isolates in Africa and Asia and is increasing among isolates of other Shigella species, including Shigella sonnei in the United States. Nalidixic acid, the newer quinolones, and amnidocillin pivoxil are additional agents that have been found to be effective in controlled clinical trials. There is a need, however, for more data on the safety of the quinolones before they can be routinely administered to children. Newer agents that deserve evaluation include the orally administered to children. Newer agents that deserve evaluation include the orally administered second- and third-generation cephalosporins, which are highly active in vitro against most strains of Shigella.