Abnormalities in the Fecal Flora of Subacute Myelo-Optic Neuropathy (SMON) Patients and Effects of Clioquinols on Human Intestinal Flora

Abstract

The fecal flora of 51 SMON patients were cotpared with those of 35 healthy adult subjects. Marked abnormalities were found in the flora of SMON patients, who had received clioquinols for a long period. The total counts and the counts of anaerobic bacterial species in the feces of SMDN patients were found to be markedly reduced. Sixteen cases of the patients were reexamined on their flora one year after discontinuation of clioquinol, and nine of them shewed inprovement. These results suggested that the administration of clioquinols was closely associated with the abnormalities. When the flora of seven healthy adults were examined in the presence or absence of clioquinol in the plating media, similar changes were observed. Sensitivity test to clioquinol with 26 strains of several predominant bacterial species revealed that most anaerobes except bifidobacteria were sensitive, while aerobes were insensitive. It was shown that clioquinols did not inhibit the intracellular multiplication of virulent Shigella flexneri and enteropathogenic Escherichia coli in the in viro experimental infection model. Clioquinol proved to exhibit both growth inhibition and cytotoxicity to cultured cells at the concentrations of 8 µg per ml and higher.