A Clinical Study on Clotrimazole Resistance in Candida albicans Isolated from Women with Vulvovaginal Candidiasis in Port Harcourt, Nigeria

Abstract

Background: Vulvovaginal candidiasis is a common fungal infection in women of reproductive age, with Candida albicans as the primary causative agent. Although Clotrimazole is widely used as a first-line treatment, increasing treatment failures indicate emerging antifungal resistance. Aim: This study was to evaluate the in vitro susceptibility and minimum inhibitory concentration of Clotrimazole against Candida albicans isolated from women with vulvovaginal candidiasis. Methods: This cross-sectional study involved fifty (50) women clinically diagnosed with vulvovaginal candidiasis who attended a selected medical centre in Port Harcourt. Following informed consent, high vaginal swabs were collected aseptically and transported promptly to the laboratory for microbiological analysis. The HVS samples were cultured on Sabouraud dextrose agar and incubated at 37 °C for 24-48 hours. Fungal growth was identified based on colony morphology, Gram staining, and the germ tube test for confirmation of Candida albicans. Pure colonies of confirmed Candida albicans isolates were subcultured and subsequently used for antifungal susceptibility testing with Clotrimazole at graded concentrations of 32 µg/mL, 16 µg/mL, 8 µg/mL, and 4 µg/mL. Results: Clotrimazole demonstrated a clear concentration-dependent antifungal effect against Candida albicans isolates. At 4 µg/mL and 8 µg/mL, only 12.5% of isolates were sensitive, while 87.5% exhibited resistance. Sensitivity increased markedly at 16 µg/mL, with 75% of isolates susceptible and 25% resistant. At the highest concentration tested (32 µg/mL), all isolates were sensitive, indicating 100% susceptibility and no detectable resistance. In addition, minimum inhibitory concentration (MIC) analysis showed that Clotrimazole inhibited Candida albicans isolates at varying concentrations. The majority of isolates 31 (62.0 %) exhibited an MIC of 16 µg/mL, while 13 isolates (26.0 %) had an MIC of 32 µg/mL. A smaller proportion of isolates 6 (12.0 %) demonstrated an MIC of 4 µg/mL, indicating variability in susceptibility among the isolates. Conclusion: Clotrimazole remains highly effective against Candida albicans at higher concentrations; however, reduced susceptibility at lower concentrations highlights the risk of resistance associated with sub-therapeutic dosing. These findings emphasize the importance of appropriate antifungal use and support the need for routine susceptibility testing to guide effective management of vulvovaginal candidiasis.