Ampicillin vs. placebo for Yersinia pseudotuberculosis infection in children.

For evaluation of the efficacy of early treatment with ampicillin on the clinical course of Yersinia pseudotuberculosis infection in children, 136 patients were randomly assigned to receive either ampicillin or placebo. Subjects were those who were diagnosed as having Kawasaki syndrome and those who satisfied three of the following four criteria: fever; rash; abdominal symptoms; and a history of ingestion of untreated drinking water. Fifty-six patients had evidence of Y. pseudotuberculosis infection bacteriologically and/or serologically. Twenty-six were assigned to placebo and 28 to ampicillin. Ampicillin therapy did not show a significant benefit in shortening the duration of fever, diarrhea and abdominal pain or in preventing rash, erythema nodosum and acute renal failure. After 5 days of treatment none of the patients in the ampicillin group excreted the organism in the stool whereas 19 (90%) of 21 in the placebo group did (P less than 0.001). Ampicillin did not show a clinical benefit but reduced the fecal excretion of the organism.