IRON(III)-CHELATING RESINS .9. ANTIBACTERIAL ACTIVITY OF A WATER-INSOLUBLE IRON(III)-CHELATING RESIN

Antibacterial activity of a water-insoluble iron(III)-chelating resin with covalently bonded 3-hydroxy-2-methyl-4(1H)-pyridinone (HMP) groups was evaluated in a brain heart infusion (BHI) medium. The activity of the resin against Escherichia coli was lower than that of soluble HMP iron(III) chelators, whereas against Listeria inocua, an activity approximately equal to those of the soluble chelators was found. It was observed that the growth of E. coli and L. inocua was reduced by increasing the amounts of the resin from 2 to 40 mg of resin/mL of medium. Inhibition of bacterial growth in the presence of the resin (10 mg/mL) was abolished by addition of ferric ion to the medium, indicating that the growth of E. coli and L. inocua was dependent on the available iron in the medium. Reducing the iron concentration in the medium from 14.2 to 0.16 mu M (by action of the resin) resulted in a decrease in the growth response from 100% to 19% for E. coli and from 100% to 10% for L. inocua. In addition, the influence of citrate was studied, but only small effects of citrate supplementation on the growth of bacteria and on the antibacterial activity of the resin were observed.