Detection and antifungal susceptibility testing of oral Candida dubliniensis from human immunodeficiency virus-infected patients

Abstract

Candida dubliniensis, an opportunistic yeast that has been implicated in oropharyngeal candidiasis (OPC) in patients infected with Human Immunodeficiency Virus (HIV) may be under-reported due to its similarity with Candida albicans. Resistance to Fluconazole is often seen in C. dubliniensis isolates from clinical specimens. To know the prevalence of C. dubliniensis in OPC in patients infected with HIV and their antifungal susceptibility pattern. One hundred and thirty-two HIV seropositive individuals and 50 healthy controls were included in the study. Two oral swabs were collected from the site of the lesion from 132 HIV-infected patients. Oral rinse was obtained from 50 healthy controls. Samples were inoculated on Sabouraud's dextrose agar (SDA) medium and on HiCrome Candida Differential Agar (CHROM agar) medium. Isolates were speciated by standard tests. Dark green-colored, germ tube positive isolates, which failed to grow at 420C and negative for xylose assimilation were identified as C. dubliniensis. Antifungal susceptibility test was performed by Macro broth dilution technique (National Committee for Clinical Laboratory Standards guidelines). From 132 patients, 22 (16.3%) C. dubliniensis were isolated; samples from healthy controls did not reveal their presence. Antifungal susceptibility test showed higher resistance among C. dubliniensis isolates to azoles compared to C. albicans. Five (22.7%) isolates of C. dubliniensis were resistant to Fluconazole followed by four (18.2%) to Ketoconazole. This study emphasizes the importance of identification and antifungal susceptibility testing of C. dubliniensis in HIV-infected patients.