[The effect of zinc and cobalt ions on the chromogenesis of Pseudomonas aeruginosa in the presence of methylphosphonic acid].

Adding zinc or cobalt sulphate into synthetic culture media of Pseudomonas aeruginosa was followed by partial or total inhibition of pyocyanine production, varying with the nature of the chemical source of phosphorus. An antagonism between Zn2+ and Co2+ ions was shown.