Susceptibility Pattern of Candida albicans from vaginal candidiasis to azole antifungal agents and Extracts of Lannea welwitschii (Hiern) Engl. (Anacardiaceae)

Abstract

Increase in resistance of Candida species to antifungal drugs including those of azole group commonly employed to treat vaginal candidiasis is a global health challenge, necessitating the need to seek alternative therapeutic approaches from medicinal plants. This study investigated the susceptibility pattern of Candida albicans to selected azole antifungal agents and extracts from a Nigerian medicinal plant, Lannea welwitschii. Thirty-five clinical isolates of C. albicans collected from University College Hospital, Ibadan, were further identified using Sabouraud dextrose agar, CHROM-agar (Candida), catalase, germ tube and lactose fermentation tests. Susceptibility of the isolates to azole antifungal drugs (fluconazole and voriconazole) and methanol extract of L. welwitschii stem bark at 100 and 50mg/ml were determined using agar-well diffusion method. Minimum inhibitory concentrations (MICs) of the extract and Miconazole (control) were determined using agar dilution method. Using CLSI breakpoint standard; for Voriconazole (25μg), 82.85% of the isolate were resistant, 5.71% intermediate and 11.43% susceptible while for Fluconazole(1μg), 88.57% resistant, 5.71% intermediate and 2.85% susceptible. The isolates showed 83-89% susceptibility to the plant’s extract. The MIC of L. welwitschii and Miconazole on seven (7) selected isolates were 3.1-12.5mg/ml and 1.0-1.6μg/ml respectively. The study showed an increase in resistance of Candida species to azole antifungal agents when compared to previous studies. Extract of Lannea welwitschii showed good anti-candida activity comparable to Miconazole, even on isolates that were resistant to Fluconazole and Voriconazole, and as such may be investigated for treating vagina candidiasis.