Distribution And Susceptibility Profile Of Candida Isolates From Hiv Patients With Oropharyngeal Candidiasis

ABSTRACT

Background: Oropharyngeal candidiasis (OPC) has been indicated as the most prevalent fungal opportunistic infection in individuals infected with Human Immunodeficiency Virus (HIV). Candida albicans has been the most isolated species in OPC. However, other Candida species have been implicated as potential pathogens. Majority of these species have been found to be less susceptible to commonly administered antifungal drugs.

Aim: The aim of this study was to determine the distribution and prevalence of antifungal resistance among Candida isolates from HIV-infected patients presenting with OPC. 

Methodology: The study participants were recruited from HIV-infected patients with OPC attending anti-retroviral clinics of selected health facilities, using non-probability sampling methods. Clinical data including information on ART therapy were extracted from patient’s folder. Oropharyngeal specimens were collected from participants for culture using sterile swabs. Speciation of presumptive Candida isolates recovered from Sabouraud dextrose agar (SDA) plates was done using standard identification methods. The E-TEST stable agar gradient minimum inhibitory concentration (MIC) method was used to determine the susceptibility of the Candida isolates to selected antifungals. CD4+ T-lymphocyte counts were also estimated using the BD FACS count machine. 

Results: Of the 286 samples collected, 67.8% (n=194) were culture positive for seven (7) different Candida species, whose distributions were as follows: C. albicans (69.1%, n=134), C. tropicalis (10.3%, n=20), C. glabrata (6.7%, n=13), C. parapsilosis (5.7%, n=11), C. krusei (4.1%, n=8), C. dubliniensis (2.6%, n=5) and C. lusitaniae (1.5%, n=3). C. albicans-associated OPC was significantly higher among HIV-infected patients on ART compared to ART-naïve patients [(73.9% vs. 26.1%; OR=2.16, 95% CI, 1.141-4.101) (p=0.018)]. Non-C.albicans isolates were significantly more resistant to fluconazole than C. albicans identified [Non-C. albicans =

45% (n=27) vs. C. albicans = 29.1 % (n=39); p= 0.033]. Fluconazole resistance was significantly higher among participants with previous history of fluconazole therapy compared to fluconazolenaïve patients [Fluconazole exposed patients = 70% (14/20) vs. Fluconazole naïve patients = 29.9 % (52/174); p= 0.001]. The C. albicans isolates showed a reduced susceptibility to Amphotericin B relative to the non-Candida albicans isolates (1.5% vs. 3.3%; p= 0.266). Prevalence of flucytosine resistance were 2.3% (3/134) and 8.3% (5/60) for C. albicans and non Candida albicans respectively.  

Conclusion: C. albicans accounted for majority of OPC in this cohort of HIV patients, with nonCandida albicans species showing significantly higher resistance to fluconazole. C. albicans associated OPC was significantly associated with ART, but not with duration of ART, age, gender, and prior antifungal therapy. Previous history of fluconazole therapy and ART were associated with reduced susceptibilities to fluconazole. Without any contraindication, flucytosine and Amphotericin B may be considered for OPC not responding to fluconazole therapy.