Antifungal activity of germicide combinations against arthroconidia of Microsporum gallinae

Abstract

Microsporum gallinae is the fungus responsible for avian dermatophytosis. Arthroconidia are the infective spores that transmit the disease in endemic areas through direct contact. This study investigated germicide combinations for enhanced antifungal activity against M. gallinae arthroconidia. The checkerboard method revealed that benzalkonium chloride with chlorhexidine, benzalkonium chloride with glutaraldehyde, chlorhexidine with glutaraldehyde, and formaldehyde with glutaraldehyde combinations showed partial synergistic effects against M. gallinae arthroconidia with fractional inhibitory concentration indices (FICI) in the range of 0.625-0.750. In contrast, the benzalkonium chloride with formaldehyde and the chlorhexidine with formaldehyde combinations showed an indifferent effect. Time-kill assays of the synergistic combinations showed that concentrations from 50 to 500 × MIC eradicated fungal arthroconidia within 1 min. Environmental scanning electron microscopy demonstrated destruction of the cell membrane and cell wall of arthroconidia. The results of this study show the enhanced potential of germicide combinations for controlling avian dermatophytosis caused by M. gallinae.

Keywords

• arthroconidia
• avian dermatophytosis
• germicide combinations
• microsporum gallinae