Oral gentamicin is not effective treatment for persistent diarrhea.

We conducted a randomized, double-blind, placebo controlled clinical trial of oral gentamicin (10 milligrams/kilogram body weight/day for five days) in treatment of unselected cases of persistent diarrhea (duration 14-18 days at initiation of treatment) among 3-36-month-old children in a rural Guatemalan community. Following random assignment of each child to a treatment group, the appropriate dose of gentamicin or placebo was administered to the child three times daily by a study nurse; this nurse also identified the presence or absence of diarrhea on each day of treatment and for the next two days. Cure was defined as cessation of diarrhea during the five-day treatment period, sustained through at least the two days after completion of treatment. Among 92 evaluable cases who entered the clinical trial, there was essentially no difference in cure rate between gentamicin and placebo treatment groups (42% versus 43%). Enteroadherent strains of Escherichia coli were identified in 46% of children tested in this trial; no significant difference existed between treatment groups in frequency of isolation of this or any other enteropathogen. Among 40 children having successful duodenal cultures immediately prior to beginning treatment, > or = 10(4) aerobic organisms per milliliter of fluid were identified in 12 (30%); treatment groups did not differ substantially with respect to proportion of children identified with this level of duodenal microbial colonization. Failure of gentamicin treatment did not appear to be explained by emergence of resistance, although a small number of resistant enteropathogens were identified near the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)