[Effect of promethazine hydrochloride (pipolphen) on the stability of R plasmid resistance in Escherichia coli].

The influence of promethazin hydrochloride (pipolphen) on stability of R plasmid inheritance in Escherichia coli strains of various serogroups was studied. The strains were isolated from patients with acute intestinal infection and from healthy persons. It was shown that in subbacteriostatic concentrations (100 to 450 micrograms/ml) pipolphen promoted elimination of the R plasmids. Decreased stability of the R plasmid inheritance was not associated with the pipolphen concentration. No influence of the drug on the biochemical characteristics, antigenic properties and nutritional requirements of the plasmid-free derivatives was detected. The eliminating action of pipolphen and ethidium bromide in some strans of Escherichia coli was shown to be different.