Browsing by Author "Carmona, Sergio"
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- ItemCollaborative update of a rule-based expert system for HIV-1 genotypic resistance test interpretation(Public Library of Science, 2017-07-28) Paredes, Roger; Tzou, Philip L.; Van Zyl, Gert; Barrow, Geoff; Camacho, Ricardo; Carmona, Sergio; Grant, Philip M.; Gupta, Ravindra K.; Hamers, Raph L.; Harrigan, P. Richard; Jordan, Michael R.; Kantor, Rami; Katzenstein, David A.; Kuritzkes, Daniel R.; Maldarelli, Frank; Otelea, Dan; Wallis, Carole L.; Schapiro, Jonathan M.; Shafer, Robert W.Introduction: HIV-1 genotypic resistance test (GRT) interpretation systems (IS) require updates as new studies on HIV-1 drug resistance are published and as treatment guidelines evolve. Methods: An expert panel was created to provide recommendations for the update of the Stanford HIV Drug Resistance Database (HIVDB) GRT-IS. The panel was polled on the ARVs to be included in a GRT report, and the drug-resistance interpretations associated with 160 drug-resistance mutation (DRM) pattern-ARV combinations. The DRM pattern-ARV combinations included 52 nucleoside RT inhibitor (NRTI) DRM pattern-ARV combinations (13 patterns x 4 NRTIs), 27 nonnucleoside RT inhibitor (NNRTI) DRM pattern-ARV combinations (9 patterns x 3 NNRTIs), 39 protease inhibitor (PI) DRM pattern-ARV combinations (13 patterns x 3 PIs) and 42 integrase strand transfer inhibitor (INSTI) DRM pattern-ARV combinations (14 patterns x 3 INSTIs). Results: There was universal agreement that a GRT report should include the NRTIs lamivudine, abacavir, zidovudine, emtricitabine, and tenofovir disoproxil fumarate; the NNRTIs efavirenz, etravirine, nevirapine, and rilpivirine; the PIs atazanavir/r, darunavir/r, and lopinavir/r (with “/r” indicating pharmacological boosting with ritonavir or cobicistat); and the INSTIs dolutegravir, elvitegravir, and raltegravir. There was a range of opinion as to whether the NRTIs stavudine and didanosine and the PIs nelfinavir, indinavir/r, saquinavir/r, fosamprenavir/r, and tipranavir/r should be included. The expert panel members provided highly concordant DRM pattern-ARV interpretations with only 6% of NRTI, 6% of NNRTI, 5% of PI, and 3% of INSTI individual expert interpretations differing from the expert panel median by more than one resistance level. The expert panel median differed from the HIVDB 7.0 GRT-IS for 20 (12.5%) of the 160 DRM pattern-ARV combinations including 12 NRTI, two NNRTI, and six INSTI pattern-ARV combinations. Eighteen of these differences were updated in HIVDB 8.1 GRT-IS to reflect the expert panel median. Additionally, HIVDB users are now provided with the option to exclude those ARVs not considered to be universally required. Conclusions: The HIVDB GRT-IS was updated through a collaborative process to reflect changes in HIV drug resistance knowledge, treatment guidelines, and expert opinion. Such a process broadens consensus among experts and identifies areas requiring further study.
- ItemModerate levels of pre-treatment HIV-1 antiretroviral drug resistance detected in the first South African national survey(Public Library of Science, 2016) Steegen, Kim; Carmona, Sergio; Bronze, Michelle; Papathanasopoulos, Maria A.; Van Zyl, Gert; Goedhals, Dominique; MacLeod, William; Sanne, Ian; Stevens, Wendy S.Background: In order to assess the level of transmitted and/or pre-treatment antiretroviral drug resistance to HIV-1, the World Health Organization (WHO) recommends that regular surveys are conducted. This study’s objective was to assess the frequency of HIV-1 antiretroviral drug resistance in patients initiating antiretroviral treatment (ART) in the public sector throughout South Africa. Methods: A prospective cross-sectional survey was conducted using probability proportional to size sampling. This method ensured that samples from each province were proportionally collected, based on the number of patients receiving ART in each region. Samples were collected between March 2013 and October 2014. Pol sequences were obtained using RT-PCR and Sanger sequencing and submitted to the Stanford Calibrated Population Resistance tool v6.0. Results: A total of 277 sequences were available for analysis. Most participants were female (58.8%) and the median age was 34 years (IQR: 29–42). The median baseline CD4-count was 149 cells/mm3 (IQR: 62–249) and, based on self-reporting, participants had been diagnosed as HIV-positive approximately 44 days prior to sample collection (IQR: 23–179). Subtyping revealed that 98.2% were infected with HIV-1 subtype C. Overall, 25 out of 277 patients presented with ≥1 surveillance drug resistance mutation (SDRM, 9.0%, 95% CI: 6.1–13.0%). Non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations were the most numerous mutations detected (n = 23). Only two patients presented with a protease inhibitor (PI) mutation. In four patients ≥4 SDRMs were detected, which might indicate that these patients were not truly ART-naïve or were infected with a multi-resistant virus. Conclusions: These results show that the level of antiretroviral drug resistance in ART-naïve South Africans has reached moderate levels, as per the WHO classification. Therefore, regular surveys of pre-treatment drug resistance levels in all regions of South Africa is highly recommended to monitor the changing levels of pre-treatment antiretroviral drug resistance.
- ItemMutational correlates of virological failure in individuals receiving a WHO-recommended tenofovir-containing first-line regimen : an international collaboration(Elsevier, 2017) Rhee, Soo-Yon; Varghese, Vici; Holmes, Susan P.; Van Zyl, Gert U.; Steegen, Kim; Boyd, Mark A.; Cooper, David A.; Nsanzimana, Sabin; Saravanan, Shanmugam; Charpentier, Charlotte; De Oliveira, Tulio; Etiebet, Mary-Ann A.; Garcia, Federico; Goedhals, Dominique; Gomes, Perpetua; Gunthard, Huldrych F.; Hamers, Raph L.; Hoffmann, Christopher J.; Hunt, Gillian; Jiamsakul, Awachana; Kaleebu, Pontiano; Kanki, Phyllis; Kantor, Rami; Kerschberger, Bernhard; Marconi, Vincent C.; Ndahimana, Jean D'amour; Ndembi, Nicaise; Ngo-Giang-Huong, Nicole; Rokx, Casper; Santoro, Maria M.; Schapiro, Jonathan M.; Schmidt, Daniel; Seu, Lillian; Sigaloff, Kim C. E.; Sirivichayakul, Sunee; Skhosana, Lindiwe; Sunpath, Henry; Tang, Michele; Yang, Chunfu; Carmona, Sergio; Gupta, Ravindra K.; Shafer, Robert W.Tenofovir disoproxil fumarate (TDF) genotypic resistance defined by K65R/N and/or K70E/Q/G occurs in 20% to 60% of individuals with virological failure (VF) on a WHO-recommended TDF-containing first-line regimen. However, the full spectrum of reverse transcriptase (RT) mutations selected in individuals with VF on such a regimen is not known. To identify TDF regimen-associated mutations (TRAMs), we compared the proportion of each RT mutation in 2873 individuals with VF on a WHO-recommended first-line TDF-containing regimen to its proportion in a cohort of 50,803 antiretroviral-naïve individuals. To identify TRAMs specifically associated with TDF-selection pressure, we compared the proportion of each TRAM to its proportion in a cohort of 5805 individuals with VF on a first-line thymidine analog-containing regimen. We identified 83 TRAMs including 33 NRTI-associated, 40 NNRTI-associated, and 10 uncommon mutations of uncertain provenance. Of the 33 NRTI-associated TRAMs, 12 – A62V, K65R/N, S68G/N/D, K70E/Q/T, L74I, V75L, and Y115F – were more common among individuals receiving a first-line TDF-containing compared to a first-line thymidine analog-containing regimen. These 12 TDF-selected TRAMs will be important for monitoring TDF-associated transmitted drug-resistance and for determining the extent of reduced TDF susceptibility in individuals with VF on a TDF-containing regimen.
- ItemRecommendations for the management of indeterminate HIV PCR results within South Africa’s early infant diagnosis programme(AOSIS Publishing, 2016-05-13) Mazanderani, Ahmad Haeri; Technau, Karl-Gunter; Hsiao, Nei-yuan; Maritz, Jean; Carmona, Sergio; Sherman, Gayle G.ENGLISH ABSTRACT: Indeterminate HIV PCR results represent missed diagnostic opportunities within South Africa's early infant diagnosis (EID) programme. These results not only delay diagnosis and appropriate management but are also a source of confusion and apprehension amongst clinicians and caregivers. We describe the extent of indeterminate HIV PCR results within South Africa's EID programme and provide recommendations for the management of these cases, both in terms of laboratory practice and the clinical care of the infants.