Identification of Virulence Factors Produced by Candida Isolates from HIV Seropositive and HIV Seronegative Pregnant Women

Abstract

Background: Candida infection has been shown to be a source of morbidity in pregnancy and in immunocompromised individuals due to elaboration of virulence factors. Study Design: The study was designed to identify various Candida species that were isolated from the vaginal and oropharyngeal cultures of HIV seropositive and HIV seronegative pregnant women in their third trimester of pregnancy as well as the virulence factors of the Candida isolates.   Methodology: A total of 240 pregnant women were enrolled in the study. They were screened for HIV seropositivity with HIV-1/2 strip and confirmed by Abbott  enzyme-linked immunosorbent assay (ELISA). One hundred and fourteen (114) of the women were found to be HIV seropositive, while 126 were seronegative. Vaginal and oropharyngeal swabs from the two cohorts of pregnant women were cultured on mycological agar that was supplemented with streptomycin. Candida isolates were identified by sugar assimilation and fermentation procedures and further speciated using Candida Ident chromogenic agar. Assays for virulence factors were conducted using standard techniques. Results: A total of 106 Candida isolates were recovered from the cultures, with 76.4% coming from vaginal cultures and the remaining 23.6% from oropharyngeal swabs. About 59.7% of the vaginal isolates and 92.3% of the 25 oropharyngeal isolates came from HIV seropositive pregnant women. Various Candida species were isolated from 28.9% of 114 seropositive women, compared to 18.3% of 126 seronegative women. Candida albicans and C. glabrata were the two predominant isolates from the two groups of pregnant women. The results show a higher degree of vaginal colonization among the HIV seropositive women. Interestingly, one of the C. albicans isolate from the vaginal cultures from the HIV seronegative women produced haemolysin. However, 55% to 91% of  C. albicans and C. glabrata from the same cultures produced coagulase, phospholipase and biofilm. Bile hydrolysis was the most predominant virulent factor expressed by the Candida isolates recovered from all sites in our study. Conclusion: C. albicans and C. glabrata were the two most predominant isolates that were recovered from both HIV seropositive and HIV seronegative women in our study. The degree of colonization of Candida isolates recovered from the two anatomical sites was higher in HIV seropositive women (59.7%), compared to 40.3% in HIV seronegative controls. The significant higher rate among HIV seropositive women underscores the potential burden of immunosuppression by HIV infection.