Isolation and identification of Candida spp. isolated from patients with oral candidiasis in Kerbala, Iraq.

Abstract

83 oral swabs were collected from patients clinically diagnosed with oral candidiasis and Who attended the Children’s Teaching Hospital in Kerbala City. Samples were cultured directly on Sabouraud Dextrose Agar medium(SDA) supplemented with amoxicillin, and it was found that there was growth in 63 samples (76%) classified according to the type of pathogen 58 samples (92%) yeast and 5 samples (8%) bacteria. Most isolated yeasts belonged to the genus Candida, which amounted to 93.1% (54 samples), while the non-Candida yeasts recorded 6.9% (4 samples). Candida albicans was recorded as the dominant among the Candida species at 53.7% (29 isolates), followed by C. dubliniesis (18.5%) (10 isolates), C.lusitaniae 12.9% (7 isolates), C.tropicalis 7.4% (4 isolates), C.parapsilosis 5.6%, and C.kefyr 1.9% (1 isolate). The results of the physiological examinations showed the ability of all C.albicans, and C.dubliniesis isolates to produce germ tubes and chlamydo spores on cornmeal agar medium compared to the other species. All species showed the ability to produce pseudohyphae, but C.albicans isolates are the only ones that can grow under a temperature of 45 m. The growth results on HiCrome™ Candida Differential Agar (M1297A) confirmed the physiological tests, where all C. albicans isolates appeared in light green and C. difficiensis in dark green. In contrast, C.lusitaniae isolates appeared in purple, C.tropicalis in metallic blue, C.parapsilosis in white to pale pink, and C.kefyr in pink to purple. The diagnosis of the isolated species was confirmed using the Vitek device by the Vitek 2 YST card, and the results were interpreted by comparing the results of biochemical reactions and information available in the system database. The Vitek system was also used to examine the sensitivity of the isolated species to six antifungals, which are Fluconazole, Flucytosine, Capsufungin, Amphotericin B, Micafungin, and Voriconazole, using the Vitek 2AST-YS08 card. All species isolates are sensitive to Capsufungin, except one isolate of C.tropicalis and one of C.parapsilosis showed moderate sensitivity to this antibiotic. As for Amphotericin B, two isolates of C. albicans showed resistance (6.9%), and one isolate of C. lusitaniae showed resistance to Amphotericin B by 14% compared to the other species that showed sensitivity to this antibiotic by 100%. In comparison, all species were sensitive to Flucytosine at 100%, except 3 isolates of C. albicans were resistant to this antibiotic (10.3%) and 1 C. dubliniesis (10%). Keywords: Candida sp., Oral candidiasis, Fungal pathogens