Frederick Lyagoba

Transmitted antiretroviral drug resistance among newly HIV-1 diagnosed young individuals in Kampala.

Objective:To assess the emergence of transmitted HIV-1 drug resistance (TDR) in Kampala, Uganda, 10 years after the scale-up of antiretroviral treatment (ART) and to compare with a previous survey among antenatal clinic attendees in 2007 (reporting 0% TDR). Design:A cross-sectional survey was conducted among newly HIV-1 diagnosed, antiretroviral-naive young adults attending two large voluntary counseling and testing centers within the geographic area of Kampala. Methods:Proxy criteria for recent HIV-1 infection were used as defined by the WHO. Population sequencing of the pol gene was performed on plasma samples with HIV-1 RNA at least 1000 copies/ml. Surveillance drug resistance mutations (SDRMs) were identified according to the 2009 WHO list for surveillance of TDR. HIV-1 subtypes were designated using maximum likelihood phylogenetic reconstruction. Results:Genotypic test results were obtained for 70 of 77 (90.9%) participants. SDRMs were identified in six samples yielding a prevalence of TDR of 8.6% (95% confidence interval 3.2–17.7%). Two had SDRMs to nucleoside reverse-transcriptase inhibitors (D67G and L210W), three had SDRMs to nonnucleoside reverse transcriptase inhibitors (G190A, G190S, and K101E), and one had SDRMs to protease inhibitors (N88D). Frequencies of HIV-1 subtypes were A (36/70, 51.4%), C ( two of 70; 2.9%), D (23/70, 32.9%), and unique recombinant forms (nine of 70, 12.9%). Conclusion:This repeated survey suggests an increase in TDR in Kampala, compared with a previous survey. This finding justifies increased vigilance with respect to surveillance of TDR in areas in Africa where ART programs are rolled-out.

Transmitted Antiretroviral Drug Resistance Surveillance among Newly HIV Type 1-Diagnosed Women Attending an Antenatal Clinic in Entebbe, Uganda

To evaluate transmitted HIV-1 drug resistance and study the natural polymorphism in pol of HIV-1 strains of newly diagnosed women attending an antenatal clinic in Uganda we sequenced the protease and reverse transcriptase genes for 46 HIV-1 strains from the threshold surveillance. Of the 46 sequences analyzed, 48.0% were subtype A1 (n 22), 39.0% subtype D (n 18), 2.0% subtype A2 (n 1), 2.0% subtype C (n 1), and 9.0% intersubtype recombinant A1/D (n 4). Overall, many minor mutations were identified in the protease sequences. None of the strains had major associated mutations to any RTI drug or drug class interest after genotyping 37 samples of our cohort. The HIV drug resistance prevalence estimate in Entebbe following the HIVDR-TS methodology is less than 5% as set out by WHO guidelines.

Inter- and intra-genic intersubtype HIV-1 recombination in rural and semi-urban Uganda.

Objective To investigate the number and variety of viruses with discrepant subtypes between env and gag and within gag in two cohorts in Uganda. Methods Sequences were generated from PCR products amplified directly (without cloning) from patient blood and compared in the v3/v4 region of env and the p17 and p24 regions of gag to reference subtype strains by phylogenetic analysis. Gag sequences with a discrepant subtype between p17 and p24 were analysed further to indicate approximate sites of recombination. Results Envelope subtypes D and A were predominant, but subtypes B, C and G were also found. From analysis of three short regions of the HIV genome we found 15 different combinations of subtype assortment, including 11 different recombinant permutations. Approximately 30% of viruses (29/104) in this part of Uganda appear to be recombinants between the env and gag genes and 10% (11/104) are recombinant within the gag gene. There was no clear pattern of crossover points within the gag gene. There seems to be no evidence of new circulating recombinant forms. Conclusion Both inter-genic and intra-genic inter-subtype recombination appear to be a relatively common occurrence in this geographical region where two subtypes of virus co-circulate. These results have implications for cross-clade vaccine design.

Multiple HIV-1 infections with evidence of recombination in heterosexual partnerships in a low risk rural clinical cohort in Uganda.

We report on the frequency of multiple infections, generation of recombinants and consequences on disease progression in 35 HIV-1 infected individuals from 7 monogamous and 6 polygamous partnerships within a Rural Clinical Cohort in Uganda. The env-C2V3, gag-p24 and pol-IN genes were sequenced. Single genome amplified half genome sequences were used to map recombination breakpoints. Three participants were dually infected with subtypes A and D, one case with subtype A and A/D recombinant and the fifth with 2 phylogenetically distinct A/D recombinants. Occurrence of A/D recombination was observed in two multiple infected individuals. Rate of late stage WHO events using Cox regression was 3 times greater amongst multiple infected compared to singly infected individuals (hazard ratio 3.35; 95% CI 1.09, 10.3; p = 0.049). We have shown that polygamous relationships involving subtype discordant partnerships was a major contributor of multiple infections with generation of inter subtype recombinants in our cohort.

Effect of HIV-1 Subtypes on Disease Progression in Rural Uganda: A Prospective Clinical Cohort Study

Objective We examined the association of HIV-1 subtypes with disease progression based on three viral gene regions. Design A prospective HIV-1 clinical cohort study in rural Uganda. Methods Partial gag, env and pol genes were sequenced. Cox proportional hazard regression modelling was used to estimate adjusted hazard ratios (aHRs) of progression to: CD4≤250, AIDS onset and death, adjusted for sex, age and CD4 count at enrolment. Results Between 1990 and 2010, 292 incident cases were subtyped: 25% had subtype A, 45% had D, 26% had A/D recombinants, 1% had C and 4% were other recombinant forms. Of the 278 incident cases included in the disease progression analysis, 62% progressed to CD4≤250, 32% to AIDS, and 34% died with a higher proportion being among subtype D cases. The proportions of individuals progressing to the three endpoints were significantly higher among individuals infected with subtype D. Throughout the study period, individuals infected with subtype D progressed faster to CD4≤250, adjusted HR (aHR), (95% CI)u200a=u200a1.72 (1.16–2.54), but this was mainly due to events in the period before antiretroviral therapy (ART) introduction, when individuals infected with subtype D significantly progressed faster to CD4≤250 than subtype A cases; aHR (95% CI)u200a=u200a1.78 (1.01–3.14). Conclusions In this population, HIV-1 subtype D was the most prevalent and was associated with faster HIV-1 disease progression than subtype A. Further studies are needed to examine the effect of HIV-1 subtypes on disease progression in the ART period and their effect on the virological and immunological ART outcomes.

Low Drug Resistance Levels Among Drug-Naive Individuals with Recent HIV Type 1 Infection in a Rural Clinical Cohort in Southwestern Uganda

To investigate the prevalence of transmitted drug resistance (TDR) among individuals with recent HIV-1 infection between February 2004 and January 2010 in a rural clinical cohort, samples from 72 participants were analyzed. Results from the 72 participants showed no protease inhibitor and nucleoside reverse transcriptase inhibitor-associated mutations. One participant (1.4%, 95% CI: 0.04-7.5%) had two nonnucleoside reverse transcriptase inhibitor mutations (G190E and P225H). HIV-1 subtype frequencies were A 22 (30.6%), D 38 (52.8%), and C 1 (1.4%); 11 (15.3%) were A/D unique recombinant forms. Seven years after the scale up of antiretroviral therapy (ART) in a rural clinical cohort in Uganda, the prevalence of TDR among recently HIV-1-infected individuals was low at 1.4%. Since our findings from an HIV study cohort may not be generalizable to the general population, routine TDR surveys in specific populations may be necessary to inform policy on the magnitude and prevention strategies of TDR.

Transmitted Antiretroviral Drug Resistance Among Drug-Naive Female Sex Workers With Recent Infection in Kampala, Uganda

During 2006-2007, transmitted human immunodeficiency virus (HIV) drug resistance (TDR) among drug-naive women with newly diagnosed HIV infection and likely to be recently infected when attending antenatal clinics in Entebbe was found to be <5% with use of the World Health Organization (WHO) survey method. Using the same method, we attempted to classify TDR among women who seroconverted during 2008-2010 and who were identified from a cohort of recently infected sex workers in Kampala, Uganda. TDR mutations were identified using the 2009 WHO TDR mutations list. The WHO survey method could not be used to classify TDR because the necessary sample size was not reached during the survey period. However, a point prevalence estimate of 2.6% (95% confidence interval, 0.07%-13.8%) nonnucleoside reverse-transcriptase inhibitor TDR was determined.