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Phenotypic Variation in Clinical S. aureus Isolates Did Not Affect Disinfection Efficacy Using Short-Term UV-C
Birte Knobling1, Gefion Franke1, Laura Carlsen1
1Department Infection Prevention and Control, Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany.
Microorganisms
|June 15, 2023
Summary
Automatic UV-C disinfection effectively reduces Staphylococcus aureus, including clinical isolates. Virulence factors like pigmentation and biofilm formation did not impact UV-C tolerance, suggesting broad efficacy against S. aureus strains.
Area of Science:
- Microbiology
- Infection Control
- Environmental Hygiene
Background:
- Virulence factors such as pigmentation, catalase activity, and biofilm formation contribute to Staphylococcus aureus resistance against disinfectants.
- Automatic UV-C room disinfection is increasingly utilized in hospitals to enhance disinfection efficacy.
Purpose of the Study:
- To investigate the influence of naturally varying virulence factor expression in clinical S. aureus isolates on their tolerance to UV-C radiation.
- To assess the effectiveness of UV-C disinfection against diverse S. aureus strains.
Main Methods:
- Quantified staphyloxanthin expression, catalase activity, and biofilm formation in nine clinical S. aureus isolates and a reference strain.
- Determined Log10 reduction values (LRVs) after exposing contaminated ceramic tiles to 50 and 22 mJ/cm² UV-C radiation using a disinfection robot.
Main Results:
- Significant variations in virulence factor expression were observed among the S. aureus isolates.
- No direct correlation was found between the expression levels of staphyloxanthin, catalase activity, or biofilm formation and UV-C tolerance.
- All tested S. aureus isolates showed effective reduction, with LRVs ranging from 4.75 to 5.94.
Conclusions:
- UV-C disinfection is highly effective against a broad range of Staphylococcus aureus strains, irrespective of variations in key virulence factors.
- The effectiveness of UV-C suggests it is a reliable disinfection method for healthcare settings, with reference strains potentially representing clinical isolates.
