Methods for the recovery of a model virus from healthcare personal protective equipment

Abstract

Aims: To develop methods for recovering a model virus (bacteriophage MS2) from healthcare personal protective equipment (PPE).

Methods and results: Nine eluents were evaluated for recovery of infectious MS2 from PPE: 1.5% beef extract (BE) pH 7.5 with and without 0.1% Tween 80, 1.5% BE pH 9.0 with and without 0.1% Tween 80, 3% BE pH 7.5 with and without 0.1% Tween 80, 3% BE pH 9.0 with and without 0.1% Tween 80 and PBS with 0.1% Tween 80. Methods were applied to experimentally contaminated PPE. Elution followed by two-step enrichment assay could recover virus inputs as low as 1.5 log(10), and could recover >90% of inoculated virus from used items of experimentally contaminated PPE worn by human volunteers.

Conclusions: BE was effective for recovering infectious viruses from a range of PPE materials.

Significance and impact of the study: PPE plays a crucial role in interrupting transmission of infectious agents from patients to healthcare workers (HCWs). The fate of micro-organisms when PPE is removed and disposed of has important consequences for infection control. Methods described here can be used to conduct rigorous studies of viral survival and transfer on PPE for risk assessments in infection control and HCW protection.

Figure 1

Evaluation of beef extract and PBS+Tween 80 eluents for recovery of MS2 from swatches of contact isolation gown material (average of four trials). (Original inoculum on each swatch (indicated by dashed line) = 1·8 log₁₀ PFU; error bars represent 95% CI.).

Figure 2

Recovery of MS2 from PPE items using 1·5% beef extract pH 7·5 (Original inoculum on each swatch (indicated by dashed line) = 1·5 log₁₀ PFU; error bars represent 95% CI.).

Figure 3

(a) Recovery of monodispersed MS2 from contact isolation gowns using 1·5% beef extract pH 7·5 (three trials). (b) Recovery of monodispersed MS2 from multiple PPE types using 1·5% beef extract pH 7·5 (two trials). (a) error bars represent 95% CI. (b) Original inoculum on each swatch (indicated by dashed line) 4·6 log₁₀ PFU.

Figure 4

Recovery of MS2 from PPE worn by human volunteers during healthcare tasks (10 trials). (Original inoculum (indicated by dashed line) 4·3 log₁₀ PFU; error bars represent 95% CI.).