Ultraviolet light C prototype device against Sporothrix brasiliensis as a potential physical method for surface disinfection

Abstract

Sporothrix brasiliensis is recognized as an emergent fungal pathogen and the high amount of fungal propagules in the lesions of infected cats allows the contamination of surfaces by direct contact. Given that the environment can play a role in the transmission of this fungus, effective methods to eliminate this pathogen from contaminated surfaces are necessary. Physical methods, such as ultraviolet light C (UVC), are broad used for surfaces disinfection, however, non-data about its activity against S. brasiliensis is reported. Therefore, we aimed to evaluate an easy handled prototype of a UVC device, in the inhibition of S. brasiliensis. Three doses and times of exposure of irradiance were tested: 3.5 mJ/cm² (1 s), 5.25 mJ/cm² (1.5 s) and 329 mJ/cm² (94 s) against a standardized inoculum of yeast and mold phase of S. brasiliensis. A decrease in CFU was shown in all doses of irradiance in both phases of S. brasiliensis, the average reduction ranged from 78 to 100% among doses, being a complete fungicidal activity achieved against the yeast phase after the 94 s exposure (329 mJ/cm²). Our data shows that UVC is a potential physical method for disinfection of surfaces contaminated with S. brasiliensis, and the prototype device developed provides an easy handling, and quickly results.

Keywords: Cat disease; Physical method; Sporotrichosis; UVC; Zoonosis.

Fig. 1

Experiment design to test the activity of ultraviolet light C (UVC) in Sporothrix brasiliensis cells (mold and yeast phase)

Fig. 2

Colony Forming Units of Sporothrix brasiliensis (yeast and mold phase) after exposure to ultraviolet light C (UVC) in different doses: 0 (control); 3.5 mJ/cm² (1 s), 5.25 mJ/cm² (1.5 s), and 329 mJ/cm² (94 s). *Statistical difference (p = 0.009) was found between control growth and growth after 94 s of exposure, using Kruskall Wallis nonparametric test