A SIMPLIFIED RAPID METHOD FOR THE REMOVAL OF IRON AND OTHER CATIONS FROM COMPLEX MEDIA

Chelex 100 resin when added to tryptone soy and brain heart infusion broths (TSB, BHI) and stirred under controlled conditions, removed iron and other cations from complex media rapidly and efficiently. Dose-response kinetics were obtained for iron removal when broths were treated with differeing amounts of resin. Satisfactory cation depletion resulted when TSB was extracted for between 0.75 to 1 h, and when BHI was extracted for 1 h, respectively. Iron depletion was assessed by growth characterisation, and alos gel electrophoresis of Pseudomonas aeruginosa and Pasteurella haemolytica and immunoblotting of Staphylococcus aureus cultures. Atomic absorption spectroscopy programmes were modified to ensure accuray. The method is usedful and economical as large batches of depleted media could be prepared in a day and repeated regeneration of the resin did not appear to affect its chelating capacity. © 1990.