Abstract
Oral candidiasis is a frequent opportunistic fungal infection among cancer patients due to therapy-induced immunosuppression. This study aimed to determine the prevalence of oral Candida spp. in cancer patients in Erbil, Kurdistan Region, Iraq, and to characterize the isolates using phenotypic and molecular methods. In addition, antifungal susceptibility patterns and the antifungal potential of selected medicinal plant extracts were evaluated.
A total of 100 oral swab samples were collected from cancer patients undergoing chemotherapy, radiotherapy, or biological therapy. Candida isolates were identified using conventional phenotypic methods, including culture characteristics, microscopic examination, germ tube test, and CHROMagar Candida, followed by molecular identification through PCR amplification and sequencing of the internal transcribed spacer (ITS) region. Biofilm formation was assessed using the Congo red agar method. Antifungal susceptibility testing was performed against commonly used antifungal drugs, discs, and the inhibitory activity of ethanolic and aqueous extracts of Golden berry(Physalis peruviana), Chamomile(Matricaria chamomilla), and Broadleaf(Plantago major) was examined using the agar well diffusion method.
Out of the 100 samples, 76 (76)% yielded positive cultures, with an overall oral candidiasis prevalence of 73 (73)%. The age of participants was between 4 to 85 years, comprised males 42 (42%) and females 58 (58%). A total of seven Candida species Phenotypes were identified among the isolates. Candida albicans was the most frequently isolated species, accounting for 43 (58.90%), followed by C. dubliniensis with 10 (13.69%), C. kefyr with 7 (9.58%), and C. tropicalis with 6 (8.21%). Lower frequencies were observed for C. parapsilosis with 3 (4.10%), while C. lusitaniae and C. glabrata were each represented by 2 isolates (2.73%). The most prevalent cancer types associated with oral candidiasis were breast cancer 27 (36.99 %). Biofilm formation was detected in a limited number of isolates, mainly among C. albicans. In general, Ketoconazole was susceptible to C. albicans and C. parapsilosis, and C. dubliniensis was moderately sensitive to Ketoconazole and Nystatin.
Antifungal susceptibility by the Agar Well diffusion method revealed high resistance to Fluconazole, Griseofulvin, Itraconazole, and Ketoconazole, whereas Nystatin demonstrated the highest antifungal activity. Ethanolic plant extracts showed weak antifungal effects, while aqueous extracts exhibited no inhibitory activity. Molecular characterization, conducted via sequencing of the ITS1(forward primer Fw) and ITS4 (reverse primer Rv) region, identified all isolates as Candida albicans according to the NCBI database. These isolates exhibited sequence similarities ranging from 97% to 100%. Other identified species included C.dubliniensis (99%), Kluyveromyces maraxianus (100%), Clavispora Lusitaniae (95%), and C. tropicalis (100%).
In conclusion, Candida albicans remains the most prevalent species causing oral candidiasis in cancer patients, with notable antifungal resistance, highlighting the importance of accurate molecular identification and effective therapeutic strategies
