Oestrogen binding by and effect of oestrogen on trichomonads and bacteria

It has been shown previously that Trichomonas vaginalis, a common protozoan pathogen of the female genito-urinary tract, has binding sites for oestrogen and that its growth, adherence and chemotaxis are altered after exposure to physiological concentrations of oestrogens. Two other species of trichomonad showed no physiological response to oestrogens but did have high affinity oestrogen binding with low binding capacity. To determine whether oestrogen binding sites occur in other pathogenic micro-organisms, these studies with eukaryotic pathogens were extended to prokaryotic bacteria. Numerous bacteria previously considered to be oestrogen responsive, other species of the same genera, and control bacteria (not considered oestrogen responsive) were examined. High affinity protein-containing oestrogen binding sites were demonstrated in several bacterial genera. Direct oestrogenic effects on micro-organisms, as well as the traditional oestrogenic effects on host cells, may explain why certain infections are more common or more severe after exposure to oestrogen.