Defining Operational UV-C Dose Requirements for Autonomous Disinfection of Clinically Relevant Pathogens Across Healthcare and High-Touch Surfaces
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Background
Autonomous ultraviolet-C (UV-C) disinfection systems are increasingly used to supplement manual environmental cleaning, yet evidence-based guidance defining pathogen- specific UV-C dose requirements across representative surfaces remains limited.
Aim
To characterize operational UV-C dose requirements for clinically relevant pathogens across diverse high-touch and healthcare surfaces and determine how experimentally derived microbial inactivation can inform operational exposure parameters.
Methods
SARS-CoV-2, adenovirus, Pseudomonas aeruginosa , Staphylococcus aureus , Klebsiella pneumoniae , Enterococcus faecalis , Candida auris , and Clostridioides difficile spores were exposed to defined UV-C doses on representative high-touch materials or stainless steel under standardized conditions, including a 10% fetal bovine serum organic soil challenge. Microbial inactivation was quantified by viable recovery. Dose-response analysis and operational modelling were used where supported by the experimental data.
Findings
UV-C exposure significantly reduced viable recovery of all pathogens, with substantial differences in the exposure conditions associated with microbial inactivation. SARS- CoV-2 exhibited substantial inactivation at doses as low as 2.6 mJ/cm 2 , whereas the highest evaluated doses were 1,800 mJ/cm 2 for C. difficile spores and 3600 mJ/cm 2 for C. auris . For C. auris , multi-dose data estimated that approximately 1,410 mJ/cm 2 was associated with a 2-log 10 reference reduction, enabling distance-dependent exposure-time predictions.
Conclusion
Experimentally quantified UV-C exposures produced substantial microbial inactivation across diverse pathogen classes and surfaces. Integrating delivered dose with microbial reduction provides a quantitative framework for translating laboratory efficacy into operational parameters for autonomous UV-C disinfection.
