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

Context: 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. Aims: To know the prevalence of C. dubliniensis in OPC in patients infected with HIV and their antifungal susceptibility pattern. Settings and Design: One hundred and thirty-two HIV seropositive individuals and 50 healthy controls were included in the study. Materials and Methods: 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). Results and Conclusions: 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.

Significance of isolation and drug susceptibility testing of non-Candida albicans species causing oropharyngeal candidiasis in HIV patients.

Oropharyngeal candidiasis (OPC) continues to be a common opportunistic infection in patients infected with Human Immunodeficiency Virus (HIV) and is predictive of increasing immunosuppression. Though Candida albicans remains the predominant isolate, a rise in the frequency of isolation of non-albicans Candida (NAC) species is being observed. The levels of virulence and the sensitivities to available antifungal drugs vary among these species. Of 340 HIV seropositive patients in this study, 132 (38.8%) had oral lesions suggestive of candidiasis. Samples were collected from the lesion using sterile cotton swabs. Isolation and speciation were done by standard techniques. Antifungal drug susceptibility testing was done by macro broth dilution. The total number of Candida isolates was 135, of which, 45 (33.3%) were NAC species and 90 were C.albicans (66.6%). Of the NAC species, C. dubliniensis was the predominant pathogen (22,48.9%). Antifungal susceptibility testing showed that 14 (31.1%) of the NAC species and 11 (12.2%) of C. albicans were resistant to fluconazole (MIC > 8 microg/ml). A very high MIC of > 32 microg/ml was noted among the NAC species resistant to fluconazole.