Table 2.
Recommended information to be reported in studies on microbial/virucidal (SARS-CoV-2) inactivation by UV technologies for harmonization of PPE reuse and for scalability.
| Main factors | Recommended information for reporting |
|---|---|
| Microorganism, recovery and enumeration | Genus, species and strain of microorganism *Provide appropriate culture collection reference number and/or include type strain for test microorganism(s) in studies *Include Bacillus atrophaeus and/or Geobacillus stearothermophilus endospore along with test organisms *Confirmation of identify of test microorganisms by biochemical, physiological, morphological, immunological and/or molecular means (provide name of supplier for rapid test kits) *Method of storing cultures (cryoprotectant) and frequency of sub-culturing (using fresh microbial slope every month kept at 4 °C where bacterial indicators used) Initial inoculum * Description of procedures for microbial cultivation including name of supplier company for media (to include in vitro analysis) * Growth medium composition, growth temperature, pH, incubation time, and growth phase (exponential or stationary) * Growth achieved under static or orbital cultivation (rpm) * Confirm purity by identifying 3 randomly selected isolates Recovery conditions and enumeration methods for test strains * Composition of media used for recovery to include basal media or physiological saline as diluent * Time and storage conditions between treatment and microbiological analysis * Description of procedure for enumerating viral test strains post treatments, such as use of in vitro tissue culture procedures |
| UV treatment medium properties and conditions | For commercial: description of power unit used for generating pulses to include equipment name of the supplier company and model For prototype: adequate description of components including treatment chamber, electrical configurations and specifications Auxiliary devices – ∗ Temperature probe ∗ Thermophile power detector and software for total broad-spectrum dose received by sample ∗ Transmissivity sensor to monitor %UV transmittance Ensure microbial population density is ≤5-log orders to mitigate against influence of protective shading effects Include description of media composition, pH, aw Composition of menstruum used as diluent for treated samples Sufficient number of treatment trials and replications to provide statistical confidence of findings at 95% level; description of statistic test and version of software package (such as Minitab or SPSS) Description of method used to generate bacterial endospores (natural aged for 7 days or incorporation of manganese sulphate to expedite conversion of vegetative cells to spores on agar surfaces) Include native microflora along with artificially seeded test microorganisms due to variability in resistance profile to PL Consider occurrence of cavities in plant surface microstructures that may protect microorganisms from incident light due to shading |
| As part of EUA, the FDA (2020) reviews the totality of scientific evidence for PPE reprocessing including specialist testing | *testing submitted within previous applications supporting device clearance for other uses that considers different types of polymer materials, such as materials consistent with those found in compatible N95 respirators. *performance data such as sporicidal test, residual analysis, bioburden reduction validation demonstrating >3 log reduction of a non-enveloped virus challenge; testing regarding material compatibility, functionality and filtration performance of compatible N95 respirators after multiple decontamination cycles *testing regarding residuals after decontamination of compatible N95 respirators. *Typically, reprocessed PPE are discarded after 10 treatments as per respective factsheet for facilities and personnel furnished to FDA |