Validation of the Decontamination of a Specialist Transport System for Patients with High Consequence Infectious Diseases

Abstract

When transferring highly infective patients to specialist hospitals, safe systems of work minimise the risk to healthcare staff. The EpiShuttle is a patient transport system that was developed to fit into an air ambulance. A validated decontamination procedure is required before the system can be adopted in the UK. Hydrogen peroxide (H2O2) vapour fumigation may offer better penetration of the inaccessible parts than the liquid disinfectant wiping that is currently suggested. To validate this, an EpiShuttle was fumigated in a sealed test chamber. Commercial bacterial spore indicators (BIs), alongside organic liquid suspensions and dried surface samples of MS2 bacteriophage (a safe virus surrogate), were placed in and around the EpiShuttle, for the purpose of evaluation. The complete kill of all of the BIs in the five test runs demonstrated the efficacy of the fumigation cycle. The log reduction of the MS2 that was dried on the coupons ranged from 2.66 to 4.50, but the log reduction of the MS2 that was in the organic liquids only ranged from 0.07 to 1.90, confirming the results of previous work. Fumigation with H2O2 alone may offer insufficient inactivation of viruses in liquid droplets, therefore a combination of fumigation and disinfectant surface wiping was proposed. Initial fumigation reducing contamination with minimal intervention allows disinfectant wipe cleaning to be completed more safely, with a second fumigation step inactivating the residual pathogens.

Use of Hydrogen Peroxide Vapour for Microbiological Disinfection in Hospital Environments: A Review

“…These studies have demonstrated both antimicrobial efficacy and repeatability, which provides confidence in the use of HPV for decontamination. Furthermore, commercially available automated HPV disinfection systems can deliver concentrations of the fumigant required to achieve the criteria stated in the EN17272 standard [ 64 ]. The EN17272 is a European standard for determining the disinfectant activity of airborne room disinfection by automated processes and covers vegetative bacteria, mycobacteria, bacterial spores, yeasts, fungal spores, viruses and bacteriophages [ 65 ].…”

“…In addition, it must be noted that the entire processing workflow from collection to post-processing, as demonstrated by Grossman et al [ 111 ], which allowed healthcare workers to keep their own N95 respirators in a large academic metropolitan healthcare system, was accomplished in less than 24 h. Bailey et al [ 64 ] validated the decontamination of a specialist transport system for patients with high-consequence infectious diseases, “EpiShuttle” (a patient transport system designed to fit into air ambulance), using HPV fumigation. The authors [ 64 ], upon decontamination with HPV, achieved a complete kill of all pathogens with the use of a commercially available Bioquell HPV system, achieving a 6 log 10 reduction in Geobacillus stearothermophilus ATCC 12980 endospores, alongside organic liquid suspensions and dried surface samples of MS2 bacteriophage. However, it is important to note that HPV fumigation can be less efficient if larger amounts of biological fluids are present on the surface due to its limited penetration.…”

“…Hence, a follow-up cleaning with surface disinfectant wiping is recommended in such cases. The advantages of using HPV fumigation in comparison with manual disinfection methods include better penetration into hard-to-reach areas, no risk of cross-infection due to exposure of operators, and a reduction in deviation from the manufacturer’s instructions [ 64 ]. Such advantages suggest that an HPV system could be ideal to investigate for use in medical emergencies involving new bacteria and viruses.…”