Antifungal drug susceptibility of fungal isolates in patients with human immunodeficiency virus receiving highly active antiretroviral therapy

Abstract

<h3>Objectives</h3> Given the evolving drug therapy options and consequent opportunistic infections, antifungal drug resistance is a major concern in patients with human immunodeficiency virus (HIV) undergoing highly active antiretroviral therapy (HAART), prompting the need for clinically relevant antifungal susceptibility testing. The goals of the present study were to determine the asymptomatic oral fungal carriage and species distribution in patients with HIV infection receiving HAART in Kerala State, India, and to evaluate the antifungal susceptibility/resistance profile of these oral fungal isolates. We also sought to identify any correlation between antifungal susceptibility/resistance with respect to the duration of HAART therapy and if there was an association between oral fungal colonization, CD4 counts, and risk factors. <h3>Methods</h3> Thirty HIV-positive patients receiving HAART were divided into 2 groups based on duration of HAART (group 1, <2 years; group 2, >2 years). A detailed history, including demographic characteristics, treatment details, and presence of any risk factors for candidiasis, was taken before saliva sample collection by the oral rinse method. Candidal growth and colonies were evaluated on the Sabouraud slope. Germ tube, sugar assimilation, and fermentation tests were used for identification of species. When conventional methods failed to identify any fungal isolates, they were verified using the automated VITEK-2 YST system (bioMérieux, Marcy l'Etoile, France). The Wilcoxon signed-rank test was used to compare the CD4⁺ lymphocyte count before and after initiation of HAART. The association of risk factors with candidiasis was analyzed using the chi-square test. <h3>Results</h3> Overall culture positivity was 83.3%. <i>Candida albicans</i> was the most prevalent species (57.7%), followed by <i>Candida tropicalis</i> (26.9%). All except for 1 patient had a single fungal isolate. In vitro antifungal susceptibility testing of the isolates revealed that all candidal species were sensitive to amphotericin B. <i>Candida krusei</i> showed 100% resistance to fluconazole. All candidal species except <i>Geotrichum klebahnii</i> showed increased resistance to itraconazole. Comparison between initial and recent CD4⁺ counts revealed improvement in the CD4⁺ count after HAART, but no change in fungal population. Of the study sample, 63.3% had risk factors for candidiasis other than being immunocompromised, and colonization was increased in those with risk factors compared with those without risk factors. <h3>Conclusions</h3> The present study showed the distribution of yeast species and the antifungal drug susceptibility of fungal isolates in patients with receiving HAART.