Abstract
<title>Abstract</title> <p>The physicochemical properties of pipe materials influence bacterial adhesion and biofilm development, yet their impact on biofilm susceptibility to disinfection remains poorly understood. This study evaluated the antibacterial performance of a sustained-action disinfectant formulation against single- and multispecies biofilms formed on stainless steel, rigid polyvinyl chloride (r-PVC) and flexible polyvinyl chloride (f-PVC), materials commonly used in hospital greywater systems. The persistence of the disinfectant following repeated simulated water passages and its activity against preformed 48 h biofilms were assessed by viable cell enumeration, scanning electron microscopy (SEM), Live/Dead fluorescence microscopy and surface wettability measurements. The disinfectant significantly reduced bacterial viability on all tested materials under both experimental conditions. However, antibacterial performance varied according to the pipe material, with r-PVC consistently exhibiting the greatest reductions in viable cell counts and f-PVC showing greater bacterial persistence. While culture-based enumeration and fluorescence microscopy confirmed substantial bacterial inactivation, SEM revealed that residual biofilm structures remained detectable after treatment, particularly on f-PVC. These findings demonstrate that pipe material influences biofilm susceptibility to disinfection and highlight the importance of considering material-dependent responses when developing effective biofilm control strategies for hospital greywater systems.</p>