Patterns of adherence to antiretroviral therapy and HIV drug resistance over time in the Stratall ANRS 12110/ESTHER trial in Cameroon.

OBJECTIVES: The emergence of HIV drug resistance is a crucial issue in Africa, where second-line antiretroviral therapy (ART) is limited, expensive and complex. We assessed the association between adherence patterns and resistance emergence over time, using an adherence measure that distinguishes low adherence from treatment interruptions, in rural Cameroon. METHODS: We performed a cohort study among patients receiving nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART in nine district hospitals, using data from the Stratall trial (2006-2010). Genotypic mutations associated with antiretroviral drug resistance were assessed when 6-monthly HIV viral loads were > 5000 HIV-1 RNA copies/mL. ART adherence data were collected using face-to-face questionnaires. Combined indicators of early (1-3 months) and late (6 months to t - 1; t is the time point when the resistance had been detected) adherence were constructed. Multivariate logistic regression and Cox models were used to assess the association between adherence patterns and early (at 6 months) and late (after 6 months) resistance emergence, respectively. RESULTS: Among 456 participants (71% women; median age 37 years), 45 developed HIV drug resistance (18 early and 27 late). Early low adherence (< 80%) and treatment interruptions (> 2 days) were associated with early resistance [adjusted odds ratio (95% confidence interval) 8.51 (1.30-55.61) and 5.25 (1.45-18.95), respectively]. Early treatment interruptions were also associated with late resistance [adjusted hazard ratio (95% confidence interval) 3.72 (1.27-10.92)]. CONCLUSIONS: The emergence of HIV drug resistance on first-line NNRTI-based regimens was associated with different patterns of adherence over time. Ensuring optimal early adherence through specific interventions, adequate management of drug stocks, and viral load monitoring is a clinical and public health priority in Africa.

Genotyping and antifungal susceptibility testing of Cryptococcus neoformans isolates from Cameroonian HIV-positive adult patients.

Cryptococcus neoformans is the most common cause of meningitis amongst adult Africans with HIV/AIDS. The widespread use of fluconazole may lead to the emergence of isolates with reduced susceptibility. We studied C. neoformans isolates from HIV-infected patients with cryptococcal meningitis. Genotyping and antifungal testing were performed to assess the genetic diversity, occurrence of mixed infections and in vitro activity of antifungal agents. Isolates were recovered from cerebrospinal fluid prior to systemic antifungal treatment. Six isolates were studied for each sample (a total of 114 isolates from 19 patients). Serotyping was performed via LAC 1 and CAP 64 gene amplification and genotyping was performed using phage M13 core, (GACA)4 and (GTG)5 primers and restriction polymorphism analysis of the URA5 gene. Susceptibilities for amphotericin B, flucytosine, fluconazole, voriconazole and posaconazole were tested by the Sensititre YeastOne® method. All strains were identified as C. neoformans var. grubii serotype A. We identified nine major genotypes. Up to two genotypes were identified in the same sample. None of the isolates were resistant to the studied drugs. However, 13 of 114 strains exhibited a reduced susceptibility to fluconazole and 13 of 114 strains exhibited a reduced susceptibility to flucytosine. No correlation was found between the genotype and susceptibility. This study confirms the prevalence of C. neoformans serotype A in Cameroon. Two genotypes may be responsible for a single episode of cryptococcosis. The possibility of mixed infection and diminished susceptibility to fluconazole or flucytosine must be considered for the management of cryptococcosis.

Genetic diversity among human immunodeficiency virus-1 non-B subtypes in viral load and drug resistance assays.

The tremendous diversity of human immunodeficiency virus (HIV)-1 strains circulating worldwide has an important impact on almost all aspects of the management of this infection, from the identification of infected persons, through treatment efficacy and monitoring, and prevention strategies such as vaccine design. The areas where HIV-1 genetic diversity is highest are those where the majority of patients in need of treatment and biological monitoring live. With increased access to treatment in these areas, it is expected that the demand for monitoring tools such as viral load assays and resistance tests will also increase, and their reliability will be critical. Regular updates of these assays during the last two decades have aimed at improving their performances in different ways that include their reliability with different HIV-1 strains. We here review to what extent HIV-1 genetic diversity still limits or not the use of currently available viral load and resistance tests.