Novel Photodynamic Coating Reduces the Bioburden on Near-Patient Surfaces Thereby Reducing the Risk for Onward Pathogen Transmission: A Field Study in Two Hospitals

J Hosp Infect. 2020 Jan;104(1):85-91. doi: 10.1016/j.jhin.2019.07.016. Epub 2019 Jul 29.

Abstract

Background: Near-patient surfaces are recognized as a source for hospital-acquired infections. Such surfaces act as reservoirs for microbial contamination by which pathogens can be transmitted from colonized or infected patients to susceptible patients. Routine disinfection of surfaces only results in a temporal elimination of pathogens, and recontamination inevitably occurs shortly between disinfections.

Aim: A novel antimicrobial coating based on photodynamics was tested under laboratory conditions and subsequently in a field study in two hospitals under real-life conditions.

Methods: Identical surfaces received a photodynamic or control coating. Bacterial counts [colony-forming units (cfu)/cm2) were assessed regularly for up to 6 months.

Findings: The laboratory study revealed a mean reduction of several human pathogens of up to 4.0 ± 0.3 log10. The field study in near-patient environments demonstrated mean bacterial values of 6.1 ± 24.7 cfu/cm2 on all control coatings. Photodynamic coatings showed a significantly lower mean value of 1.9 ± 2.8 cfu/cm2 (P<0.001). When considering benchmarks of 2.5 cfu/cm2 or 5 cfu/cm2, the relative risk for high bacterial counts on surfaces was reduced by 48% (odds ratio 0.38, P<0.001) or 67% (odds ratio 0.27, P<0.001), respectively.

Conclusion: Photodynamic coatings provide a significant and lasting reduction of bacterial counts on near-patient surfaces, particularly for high bacterial loads, in addition to routine hygiene. The promising results of this proof-of-concept study highlight the need for further studies to determine how this novel technology is correlated with the frequency of hospital-acquired infections.

Keywords: Antimicrobial surface; Decontamination; Hospital-acquired infections; Pathogen transmission; Photodynamic coating.