Effect of peracetic acid cleaning agents on biofilms by <i>Methylobacterium</i> spp. derived from hemodialysis equipment

We evaluated the efficacy of peracetic acid (PAA) products in disinfecting Methylobacterium radiotolerans biofilms within hemodialysis systems, using a Centers for Disease Control and Prevention (CDC) biofilm reactor. Twelve PAA products were tested with an appropriate neutralization. All products completely eradicated planktonic bacteria within 10 minutes. In contrast, the effectiveness against biofilms varied, with log reduction values (LRVs) ranging from 2.47 to 9.40, depending on PAA concentration. Products with higher hydrogen peroxide concentrations achieved greater LRVs at the same PAA concentrations, although its effect was secondary. Similar to sodium hypochlorite, extended reaction times further improved LRVs, even at higher dilutions. These findings suggest that PAA products are promising alternatives for the routine biofilm control in dialysis systems.