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Photodynamic coatings kill bacteria on near-patient surfaces in intensive care units with low light intensities
B Kieninger1, R Fechter1, W Bäumler2
1Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany.
Background:
Surfaces in close proximity to patients within hospitals may cause healthcare-associated infections. These surfaces are repositories for pathogens facilitating their transmission among staff and patients. Regular cleaning and disinfection of these surfaces provides only a temporary elimination of pathogens with inevitable recontamination. Antimicrobial coatings (AMCs) of such surfaces may additionally reduce the risk of pathogen transmissions.
Aim:
To evaluate the efficacy of a standard and a novel photodynamic AMC, even at very low light intensities, in a field study conducted in two ICUs at our university hospital.
Methods:
The microbial burden was determined on three coatings: standard photodynamic AMC (A), a novel photodynamic AMC (B), and an inactive AMC as control (C). The control coating C was identical to standard coating A, but it contained no photosensitizer. During a three-month period, 699 samples were collected from identical surfaces using eSwab and were analysed (cfu/cm2).
Findings:
Mean values of all surfaces covered with control coating (C) showed a microbial burden of 5.5 ± 14.8 cfu/cm2. Photodynamic AMC showed significantly lower mean value of 1.6 ± 4.6 cfu/cm2 (coating A; P < 0.001) and 2.7 ± 9.6 (coating B; P < 0.001). When considering a benchmark of 2.5 cfu/cm2, the relative risk for higher microbial counts was reduced by 52% (coating A) or 40% (coating B), respectively.
Conclusion:
Both photodynamic AMCs offer a substantial, permanent risk reduction of microbial counts on near-patient surfaces in ICUs with low light intensities.
Insights
Antimicrobial coatings (AMCs) significantly reduced microbial counts on hospital surfaces. Both standard and novel photodynamic AMCs proved effective in reducing pathogen transmission risks in intensive care units.
Area of Science:
- Infection control
- Materials science
- Microbiology
Background:
- Hospital surfaces are reservoirs for pathogens, contributing to healthcare-associated infections.
- Routine cleaning offers only temporary pathogen reduction, with inevitable recontamination.
- Antimicrobial coatings (AMCs) present a strategy to mitigate pathogen transmission risks.
Purpose of the Study:
- To assess the efficacy of standard and novel photodynamic AMCs in reducing microbial burden.
- To evaluate AMC performance under low light conditions in a real-world hospital setting.
- To compare the effectiveness of two different photodynamic AMCs against a control.
Main Methods:
- A field study was conducted in two intensive care units (ICUs) over three months.
- Microbial burden was quantified on three types of coatings: standard photodynamic AMC (A), novel photodynamic AMC (B), and an inactive control (C).
- 699 surface samples were collected using eSwab and analyzed for colony-forming units per square centimeter (cfu/cm²).
Main Results:
- Control surfaces (C) exhibited a mean microbial burden of 5.5 ± 14.8 cfu/cm².
- Photodynamic AMCs demonstrated significantly lower microbial burdens: 1.6 ± 4.6 cfu/cm² (A) and 2.7 ± 9.6 cfu/cm² (B) (P < 0.001).
- Relative risk for microbial counts exceeding 2.5 cfu/cm² was reduced by 52% for coating A and 40% for coating B.
Conclusions:
- Both photodynamic AMCs provide significant and lasting reductions in microbial counts on near-patient surfaces.
- These findings highlight the potential of photodynamic AMCs for infection control in ICUs, even with low light.
- Antimicrobial coatings offer a promising approach to enhance patient safety by reducing pathogen transmission.
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