Failure of norfloxacin to eradicate intestinal colonization of non-typhoidal salmonella in infants.

Infant colonization with non-typhoidal Salmonella (NTS) is common and eradication is problematic. Oral norfloxacin has promising properties for solving this problem, though it has potential toxicity to infants. The drug has been available in Thailand since 1987. Since then, some infants who had diarrhea or NTS colonization were treated with oral norfloxacin 15-20 mg/kg/day for 3-5 days on individual physician's judgement. This observational study was performed in infants and children who had NTS in stool, seen at Ramathibodi hospital from September 1987 to February 1988, in order to give preliminary information. Sixteen of 48 infants received oral norfloxacin treatment. Nine infants had established failure of NTS eradication from follow-up rectal swab cultures. Five infants did not have follow-up rectal swab culture, and two had negative culture once on day 7 after treatment. Considering that 7 infants who did not have evidence of bacteriologic failure were free from colonization, the excretion rate during the first two weeks could be estimated as 56 per cent which is not less than the natural history of this disease. This observation suggests failure of oral norfloxacin, 15 mg/kg/day given in 2 divided doses for 3 days, in eradication NTS colonization in infants.