Genotypic investigation of drug resistance in pre-treatment HIV-1 adults initiating first-line antiretroviral therapy in Mbingo baptist hospital Kom.

Médecine interne et spécialités, University of Yaounde I
July, 2017


Background: In 2015 the World Health Organization (WHO) and United Nation AIDs (UNAIDs) estimated that 36.7million people were living with AIDS globally with sub-Saharan Africa the most severely affected zone. The introduction and widespread usage of HAART has led to a reduction in morbidity and mortality but nevertheless the emergence of resistant mutations to the antiretroviral drugs has developed.
Objectives: The general objective was to ascertain the profile of pre-treatment HIV-1 genotypic drug resistance among adult patients initiating first-line ART in rural areas of the North West Region.
Methodology: A cross sectional analytic study was carried out from December 2016 to May 2017. The choice of patients was recently diagnosed patients naïve to ART, who had given their consent. Patient’s samples were collected in the HIV/AIDS care and treatment center of the Mbingo Baptist Hospital-Kom. A minimum sample size of 54 patients was needed. Laboratory tests were carried out at the Molecular and Microbiology unit of CIRCB (Centre International de Référence Chantal BIYA pour la Recherche sur la Prévention et la Prise en Charge du VIH/SIDA). A total of 10 ml of venous whole blood was sampled into two EDTA tubes, centrifuged and the plasma stored at -80 oC. The viral extraction was effected with Purelink™ Viral RNA/DNA kit protocol, then RT / PCR testing and sequencing encompassing the pol region of HIV achieved using a HOME MADE protocol. The final analysis was done using a genetic sequencer or the Abbott Applied Biosystem ABI Prism 3130 Genetic Analyzer. The sequence analysis was performed with the help of the software SeqScape version 2.5. The mutations associated to resistance were determined using the Stanford University HIV drug resistance database. Phylogenetic analysis was performed using automated subtyping tools (Stanford HIVdb version 8.1, COMET and REGA version 3.0) and the phylogenetic tree constructed using MEGA software version 5.0
Results: A total of 60 participants were enrolled in the study among which 35 patients samples were successfully analyzed with 30 sequences obtained, the mean age of the participants was 37 ± 9.98 years with a sex ratio of 3 women to 1 man. The median CD4 count was 268cell/mm3 with an interquartile value of 260cells/ul. Phylogenetic analysis of the sequenced samples encompassing the HIV-1 pol protease and reverse transcriptase regions in these patients showed a broad genetic diversity of HIV-1 with three non-recombinants sub types (A, G and F2), and five circulating recombinant forms (CRF02_AG, CRF18_cpx, CRF11_cpx, CRF06_cpx and A1/F2 recombinant). Overall, the circulating recombinant forms were the most prevalent representing 70% of patients infected. Of the 30 patients samples sequenced, 2 were infected with viruses carrying drug resistances mutations, giving a prevalence of 6.67%. Resistance mutations to non-nucleoside reverse transcriptase inhibitors (Y188YH and E138A) the only represented. No resistance mutation was found in the nucleoside reverse transcriptase inhibitors and protease inhibitors.
Conclusion: In total, this study showed that HIV-1 exhibits a great genetic diversity and presented drug-resistant mutations in patients who have never been exposed to antiretroviral treatment with a prevalence classified as moderate according to WHO and with mutations affecting only the non-nucleoside reverse transcriptase inhibitors but with no association between drug resistance and CD4 staging or viral subtyping. Hence, the implementation of HIV genotypic resistance test is indispensable for the naïve patients to prevent therapy failure and substitute of regimen upon initiating antiretroviral drugs. These resistance tests will guide clinicians on the best regimens to prescribe to the patients and this could help better the management of people living with HIV/AIDS.
Key words: HIV Drug resistance; genetic diversity; prevalence; mutation; MBH-Cameroon.