Vulvovaginal candidiasis among Yemeni women: prevalence of Candida species, biofilm formation rates, antifungal susceptibility patterns, and biofilm-associated genes ALS1 and HWP1
摘要
Vulvovaginal candidiasis (VVC) is a common fungal infection in women, primarily caused by Candida species. Biofilm formation is a key virulence factor contributing to pathogenicity and antifungal resistance. This study aimed to identify Candida species, evaluate antifungal susceptibility, quantify biofilm formation, and detect virulence gene markers (ALS1 and HWP1) in vaginal isolates from women with VVC.
MethodsA cross-sectional study was conducted from December 2021 to June 2024 among 400 women attending obstetrics and gynecology clinics in Sana’a City. Vaginal swabs were collected and cultured in a microbiology laboratory. Antifungal susceptibility of isolates to nystatin, voriconazole, fluconazole, ketoconazole, clotrimazole, miconazole, itraconazole, and amphotericin B was assessed using the disk diffusion method. Biofilm formation was measured using the microtiter plate assay. The presence of ALS1 and HWP1 genes was determined by PCR. Data were analyzed using SPSS version 20, and associations were evaluated with the Chi-square test; P < .05 was considered statistically significant.
ResultsC. albicans was identified in 367 (91.8%) isolates, while non-albicans species accounted for 33 (8.2%). Of the 367 C. albicans isolates, 174 (47.4%) formed biofilms: 32 (8%) strong, 72 (18%) moderate, and 70 (17.5%) weak. Biofilm- forming isolates were associated with higher antifungal resistance, with amphotericin B (113; 64.9%) and itraconazole (108; 62.1%) showing the highest resistance, and nystatin the lowest (23; 13.2%). The ALS1 gene was detected in all biofilm- forming C. albicans isolates (174; 100%), while HWP1 was present in 82 (47.1%). Non-biofilm-forming isolates demonstrated lower resistance rates across all drugs.
ConclusionsVVC remains highly prevalent in Sana’a, Yemen, with C. albicans as the dominant pathogen. These findings suggest a potential association between biofilm formation and increased antifungal resistance also the presence of key virulence genes—particularly ALS1 and HWP1. However, due to the study’s cross-sectional design, a definitive causal relationship cannot be inferred.
This study emphasizes the importance of integrating phenotypic and molecular characterization into routine diagnostics and surveillance to improve the management of resistant Candida infections. Continuous monitoring of species distribution is also warranted to detect emerging non-albicans species.