The efficiency of cross-linking methods in eradication of bacteria is influenced by the riboflavin concentration and the irradiation time of ultraviolet light

• Purpose: To determine bacterial eradication using numerous riboflavin concentrations and different ultraviolet light A (UVA) radiant and exposure time in an experimental model.Methods: Dilutions of Staphylococcus epidermidis were mixed with riboflavin at varying concentrations (0.007-0.09%). Effects on bacterial growth were evaluated after 0, 3, 6, 30 and 60min of UVA exposure (irradiance 30 and 3mW/cm(2)). Standard settings of UVA were compared with high-power UVA approach. Different fluid thicknesses of the exposed dilutions were also examined to improve the model.Results: Bacterial eradication (%) was increased after 60 compared with 30min of UVA exposure for concentrations of 0.03-0.07% but not for 0.09% riboflavin. There was a significant difference between the efficacy between 0.03 and 0.09% and eradication dropped from 80% to 50% (p=0.01). A correlation could be calculated for the amount of riboflavin at 60min of UVA and the ability to kill bacteria (p=0.01). The antibacterial effect was more pronounced when the tested bacterial suspension thickness was reduced. High-power UVA method was less potent in microbial elimination, eradicating only 60% of bacteria after 6min versus 97-99% after 60min in the low-power setting, compared with respective controls (p=0.02).Conclusions: In these in vitro experiments, a longer UVA exposure time in combination with lower riboflavin levels were found to be favourable in killing bacteria as compared to the standard cross-linking settings. Further studies are needed to evaluate the clinical relevance of these findings.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Oftalmologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Ophthalmology (hsv//eng)

Nyckelord

Bacteria

cross-linking

exposure time

riboflavin

UVA

Publikations- och innehållstyp

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