Multispectral fluorescence imaging to detect and ultraviolet C to disinfect single and dual-species bacterial biofilm on abiotic surfaces

Biofilms, because of their persistence on various surfaces such as medical devices or industrial piping, are associated with approximately 65% of all microbial infections. Thus, their detection and inactivation are of great importance to public health. Many detection methods, such as swabbing, require sampling by rubbing, which can be expensive, time-consuming, and require highly trained personnel. This study proposes the use of previously developed, handheld multispectral fluorescence imaging systems to detect and disinfect biofilm in situ and in real-time. We utilized the contamination and sanitization inspection (CSI) and disinfection (CSI-D+), both of which feature various cameras and UV-emitting LEDs to image and disinfect contamination. Biofilms were grown on polyvinyl chloride (PVC) and stainless steel (SS) coupons using an industrial bioreactor, including dual-species biofilms of <i>Listeria monocytogenes/Pseudomonas aeruginosa</i> or Shiga toxin-producing <i>Escherichia coli</i> (STEC)/<i>Pseudomonas aeruginosa</i>, as well as single-species biofilms of <i>Listeria monocytogenes</i> and STEC. Using 275, 365, or 405 nm illumination with combinations of cameras detected biofilm formation visually. Color data image analysis comparing sterile broth and different types of biofilm yielded accuracies of 91% on SS and 89% on PVC coupons. The UVC light significantly reduced these pathogens in single- and dual-species biofilms from surface coupons.