Factors affecting Candida albicans exoenzyme activities in HIV-infected patients

Abstract

The mortality and morbidity of HIV-infected patients have declined with the advent of highly active antiretroviral therapy (HAART). However, its effect on Candida infections remains inconclusive. Objectives: To determine the phospholipase, proteinase and haemoltyic activities of oral C. albicans in HIV-infected patients on HAART, and the factors affecting their activities. Methods: Altogether 32 C. albicans isolates were tested in vitro for phospholipase, proteinase and haemolytic activities using three different plate assays. Control group comprised of C. albicans collected from 16 healthy individuals. Simple regression was used to study the correlation of the enzymatic activities with gender, age, education level, income, HIV stage of infection, current medications, duration on HAART, history of oral candidiasis, HIV viral load, CD4 count and salivary flow rate. Results: Phospholipase and haemolytic activities were found to be significantly higher (p < 0.05) and proteinase activities were lower in the test group (p < 0.05). There was a significant correlation of the pH value of saliva with the phospholipase activities in the test group (R Sq Linear = 0.594). Patients taking abacavir, a nucleoside reverse transcriptase inhibitor (NRTI), were found to have higher proteinase activities (p < 0.05). However, haemolysin activities were significantly lower in patients taking abacavir (p < 0.05). The use of protease inhibitors ritonavir and lopinavir was also found to be associated with decreased haemolysin activities (p < 0.05). The lower proteinase activities in HIV-infected group could be due to the direct effect of protease inhibitors in HAART while the higher phospholipase and haemolytic activity in the HIV-infected group remains elusive. Conclusion: These finding provide evidence of altered extracellular enzyme activities in C. albicans isolates obtained from HIV patients on HAART, which may affect the infectivity of the Candida isolates.