Use of a Germicidal Ultraviolet (UVC) Light on Porous and Non-porous Textiles to Reduce Staphylococcus aureus and Escherichia coli Contamination in Emergency Medical Service (EMS) Vehicles

Abstract

Introduction: Pathogens rapidly spread throughout small, enclosed areas such as emergency medical service (EMS) vehicles; posing a higher infection risk for paramedics and increasing hospital-acquired infections (HAIs) among patients. New technology has been under development utilizing ultraviolet C (UVC) light on medical equipment for disinfection proposes. Aim: Evaluate a UVC light microbial log reduction efficacy using porous and non-porous textiles commonly found in EMS vehicles. Methods: Six 5.08x5.08 cm textiles (stainless steel, cloth, vinyl, seatbelt, textured plastic, and acrylic materials) were inoculated with tryptic soy broth containing either vegetative Staphylococcus aureus or Escherichia coli and dried for 30 minutes. Each textile was positioned at a 45 angle facing the UVC light. The aim of the study was to evaluate time (30 seconds, 5 minutes, 10 minutes) and distance (12.7 cm, 50.0 cm, 100 cm) for UVC light disinfection efficacy on the six textile materials commonly found on EMS vehicles. Baseline samples were not exposed to UVC light for this study. Porous textiles were collected using digestive method and non-porous textiles were collected using swabbing method. Two separate one-way ANOVA with Bonferroni Correction tests were utilized to compare the significance of duration and distance on log reduction for both microorganisms to identify which duration and distance combinations had more efficacy on log reduction. A two-way ANOVA test was performed to analyze the significant difference of varying duration (30 seconds, 5 minutes, and 10 minutes) and distance (12.7 cm, 50.0 cm, and 100 cm) among the 5 varying textiles. A paired t-test was used to compare the mean log reductions among textile types to determine which textile material had larger log reductions. Results: The greatest log reductions were at 12.7 cm (0.9-6.1) and 50.0 cm (0.7-5.6) distance. At time intervals of 5 and 10 minutes there was no significant log reduction (p-value= 1.00) for all textile types. Greater log reductions were seen within the acrylic (S. aureus: 1.4-4.5; E. coli: 1.1-5.6) and stainless-steel (S. aureus: 2.0-4.5; E. coli: 1.5-5.2) textile materials compared to the other non-porous textiles. When comparing acrylic and stainless steel textiles, they had similar log reductions (p-value: S. aureus = 0.39; E. coli = 0.63) for both microorganisms. Porous textile log reduction varied based on the textile material. Cloth (100% cotton; S. aureus: 0.8-6.1; E. coli: 1.1-5.8) had higher log reduction compared to seatbelt (polyester; S. aureus: 0.9-2.3; E. coli: 0.6-2.6) within the porous textiles. Discussion and Conclusions: This research demonstrates that UVC light's impact on bacteria is affected by time, distance, and textile material. Shorter distances and time can significantly reduce bacterial log reductions. UVC light systems can be utilized to supplement traditional disinfection methods to minimize infection risk within EMS personnel and patients during the emergency call ride. More research should be conducted on the effects of UVC light exposure on porous textiles to capture the properties that contribute to greater log reduction and their role on causing infection risk on EMS personnel and patients in real-world use scenarios.