Decontamination of unused, packaged consumables contaminated with vancomycin-resistant enterococci (VRE) using hydrogen peroxide vapour (HPV)

Background: An increasing body of literature has shown that VRE can survive on high touch surfaces and objects in hospitals.  Few studies, however, have investigated contamination of unused, packaged consumables. In many institutions, routine terminal cleaning of rooms of patients colonized or infected with VRE involves disposal of all unused, packaged consumables when each patient on precautions for VRE is discharged, which increases costs. HPV has been shown to decontaminate effectively the rooms of patients with VRE but no studies have investigated the potential use of HPV for the decontamination of unused, packaged consumables.

Objective: We sought to determine whether unused, packaged consumables can become contaminated with VRE; whether HPV is effective for the decontamination of these items; and the costs associated with the disposal of unused, packaged consumables. 
Methods: Twenty intensive care unit rooms that had been occupied by patients with VRE were selected for study; rooms of patients with recent positive VRE cultures were prioritized. Five pairs of unused, packaged consumables were selected from the consumables cart in each study room when the patient was discharged. One item of the pair was sampled before exposure to HPV and the other item was sampled after HPV. Items were sampled by being immersed in thioglycollate broth in a sterile bag and incubated at 35oC for 24 hours. After the incubation period, one loopful of the thioglycollate was plated onto CNA agar at 35oC for 24 hours and VRE was identified by standard methods. Contamination rates before and after HPV treatment were compared. The total cost of consumables per room was calculated on three of the intensive care units in which HPV operates in our hospital and the typical remaining proportion of consumables was noted at patient discharge to calculate the average value of disposed consumables per discharge.

Results: Seven (7%) of 100 items sampled before HPV grew VRE and none of 100 paired items cultured after HPV grew VRE (p =0.014, Fisher's Exact Test). Contaminated consumables were identified in four (20%) of the 20 rooms sampled. We did not note any damage on the consumables due to HPV exposure. The average value of disposed consumables was $92 per discharge.
Conclusions: Consumables in rooms of patients with VRE were likely contaminated by healthcare workers' hands as they selected other supplies. In our study, HPV was effective for the decontamination of unused, packaged consumables. Our findings support either disposing of or decontaminating adequately unused, packaged consumables when a patient on precautions for VRE is discharged. Routine use of HPV for the decontamination of unused, packaged consumables that would otherwise have been disposed of would save $92 per discharge, thus offsetting the cost of HPV.