‘Secondary biofilms’ could cause failure of peracetic acid high-level disinfection of endoscopes

Introduction The reduced susceptibility of biofilms to disinfectants presents a challenge the successful reprocessing medical equipment. This study examined effect residual biomass remaining after previous disinfection with peracetic acid (PAA) on tolerance subsequent mature Pseudomonas aeruginosa PAA. enzymatic degradation specific components extracellular polymeric substance (EPS) P. biofilm effectiveness PAA was also evaluated. Methods grown PAA-killed compared in wells 24-well plate by evaluating their viability using count assay. measured crystal violet quantification total biomass, while its polysaccharide and protein EPS quantified phenol-sulphuric assay or Bradford assay, respectively. A confocal microscope used visualize distribution living dead cells biomass. Findings presence from previously disinfected significantly enhanced biofilms. 96-h-old ‘secondary biofilm’ formed survived concentrations 4000 ppm, which exceeds practice for high-level disinfection. Conclusion These observations indicate that, under certain circumstances, recolonization can cause failure equipment such as endoscopes, emphasizes importance cleaning endoscopes prior