The Effect of a Novel Biomedical Technique on the Reprocessing of Biofilm-Contaminated Duodenoscopes Using Copper Sulfate and Methylene Blue Irradiated with Red Light

Overview

Endoscopy-related infections are becoming increasingly prevalent and harder to prevent in the era of increasing multidrug-resistant bacteria. Bacteria are developing resistance to bactericides at an unprecedented rate which is a growing problem in the medical field, especially in remote areas with limited resources such as military zones and field hospitals. Duodenoscopes, notably difficult to sterilize due to their intricate elevator component known to harbor bacteria that often form biofilms, frequently resulting in post-operative infections. This experiment contained 7 groups where model duodenoscopes were contaminated with P . fluorescens biofilms (modeling P . aeruginosa) and were exposed to a novel treatment consisting of varying concentrations of copper sulfate and methylene blue solutions irradiated with red light to determine the bactericidal effects. There was a positive and negative control group as well as three experimental groups that each had varying concentrations of the combination solution. Additionally, there were two groups using each chemical alone. It was hypothesized that the combination of copper sulfate and methylene blue would produce the greatest bactericidal effect. Biofilms were formed on the model duodenoscopes and the copper sulfate and methylene blue solutions were applied and irradiated with red light. The models were then swabbed and absorbances were tested using a spectrophotometer at 600 nm to compare the amounts of live bacteria. This novel treatment has potential to be a bactericide and effectively eliminate a significant amount of bacteria within biofilms and that there is a possible synergy exhibited when the chemicals are combined. All five experimental groups demonstrated bactericidal.