Microbial transmission in an outpatient clinic and impact of an intervention with an ethanol-based disinfectant

Abstract

Background: Halting the spread of harmful microbes requires an understanding of their transmission via hands and fomites. Previous studies explored acute and long-term care environments but not outpatient clinics. Objectives of this study were to track microbial movement throughout an outpatient clinic and evaluate the impact of a disinfectant spray intervention targeting high-touch point surfaces.

Methods: At the start of the clinic day, a harmless viral tracer was placed onto 2 fomites: a patient room door handle and front desk pen. Patient care, cleaning, and hand hygiene practices continued as usual. Facility fomites (n = 19), staff hands (n = 4), and patient hands (n = 3-4) were sampled after 2, 3.5, and 6 hours. Tracer concentrations at baseline (before intervention) were evaluated 6 hours after seeding. For the intervention trials, high-touch surfaces were cleaned 4 hours after seeding with an ethanol-based disinfectant and sampled 2 hours after cleaning.

Results: At 2, 3.5, and 6 hours after seeding, virus was detected on all surfaces and hands sampled, with examination room door handles and nurses' station chair arms yielding the highest concentrations. Virus concentrations decreased by 94.1% after the disinfectant spray intervention (P = .001).

Conclusions: Microbes spread quickly in an outpatient clinic, reaching maximum contamination levels 2 hours after inoculation, with the highest contamination on examination room door handles and nurses' station chairs. This study emphasizes the importance of targeted disinfection of high-touch surfaces.

Keywords: Disinfection; Fomites; Infection control; MS2; Outpatient clinic; Phage tracer.

Fig 1

Outpatient clinic tracer concentration before and after disinfectant spray intervention. Vertical lines represent 95% confidence intervals for the geometric means. Phase 2 refers to the baseline current cleaning practices by site staff, phase 3a refers to the first replicate of the spray disinfectant intervention. Phase 3b refers to the second replicate of the same intervention. Outliers are represented by a single point on the chart.