Characterization of drug resistance mutations in naïve and ART-treated patients infected with HIV-1 in Yaounde, Cameroon

Currently the prevalence of HIV‐1 infection in Cameroon is 5.1%, CRF02_AG subtype is responsible for about 50% of infections. Since an HIV‐1 drug resistance test is not yet available widely, accurate data on the prevalence of resistant viral strains are missing. The objective of this study was to determine HIV‐1 genetic diversity and to characterize HIV‐1 mutations conferring drug resistance among antiretroviral therapy (ART)‐naïve and ART‐treated patients. A cohort of 239 patients infected with HIV were followed‐up between January 2007 and July 2010 in Cameroon. Two hundred and sixteen plasma samples were sequenced for phylogenetic analysis and identification of drug resistance mutations in the HIV‐1 pol region. A significant genetic diversity was found: Seven pure subtypes (A1, A3, D, F1, F2, G, H), nine circulating recombinant forms (CRFs: 01_AE, 02_AG, 06cpx, 09cpx, 11cpx, 13cpx, 16cpx, 18cpx, 37cpx) and one new unique recombinant form (URF) (G/F2). The rate of transmitted drug resistance (TDR) in naïve patients was 8.2% (4/49). Around 80% of patients failing a first‐line ART harbored a virus with at least one resistance mutation to two antiretroviral (ARV) classes, and 36% of those failing a second‐line regimen carried a virus with at least one resistant mutation to three ARV classes. The high level of drug resistance observed in the cohort is alarming because this occurred as a result of only few years of treatment. Adherence to therapy, adequate education of physicians, and the appropriate use of genotypic resistance assay are critical points of intervention for the improvement of patient care. J. Med. Virol. 84:721–727, 2012. © 2012 Wiley Periodicals, Inc.     

Molecular epidemiology of HIV-1 subtypes and drug resistant strains in Taiwan

The Taiwanese government has provided free highly active antiretroviral therapy since April 1997. Previously, we have reported on the molecular epidemiology of HIV‐1 in Taiwan from 1988 to 1998. In addition, an outbreak of circulating recombinant form (CRF) 07_BC among intravenous drug users was noted in 2004. Therefore, the purposes of this study were to elucidate the distribution of HIV‐1 subtypes among different high‐risk groups in Taiwan from 1999 to 2000 and to conduct surveillance on drug resistance among treatment naïve patients from 1997 to 2000. Blood samples from 239 HIV‐1/AIDS patients and their subtypes were examined using DNA sequencing and phylogenetic analysis. The results showed that among 226 male patients, 213 (94.2%) had subtype B, 11 (4.9%) had CRF01_AE, 1 had unique recombinant strain related to both CRF07_BC and CRF08_BC (strain T12‐99TW) and 1 had CRF08_BC (strain L9312‐00TW). The patients infected with T12‐99TW and L9312‐00TW were intravenous drug users and had needle‐sharing experiences in Yunnan Province, China. Of the 13 HIV‐1‐infected females, 7 (53.8%) had subtype B, 5 (38.5%) had CRF01_AE, and 1 (7.7%) had subtype C. Phylogenetic analysis demonstrated that the neither strain T12‐99TW nor L9312‐00TW clustered with CRF07_BC strains isolated from Taiwanese intravenous drug users in 2004. In addition, 126 treatment naïve patients were selected for genotypic DR analysis and the results showed that 4.3% (2/47) homosexual males had M184V mutations. This is the first report on the identification of CRF08_BC and a unique recombinant strain related to both CRF07_BC and CRF08_BC in Taiwan. J. Med. Virol. 80:183–191, 2008. © 2007 Wiley‐Liss, Inc.     

Prevalence of key resistance mutations K65R,K103N,and M184V as minority HIV-1 variants in chronically HIV-1 infected,treatment-naïve patients

Background and objectivesMinority drug-resistant HIV-1 variants, undetected by conventional genotyping, may impair the outcome of antiretroviral therapy (ART). Thus, we retrospectively analyzed the prevalence of minority drug-resistant HIV-1 variants before ART in chronically HIV-1 infected patients initiating first-line therapy and assessed the impact on clinical outcome in the prospective German Truvada cohort.Study designSamples from 146 antiretroviral treatment-naïve patients were collected between April 2005 and August 2006. K65R, K103N, and M184V variants at low frequencies were detected by allele-specific real-time PCR.ResultsMinority drug-resistant HIV-1 variants were detected in 20/146 patients (13.7%): the M184V mutation in 12/146 patients (8.2%), the K103N mutation in 8/146 patients (5.5%), and the K65R mutation in 4/146 patients (2.7%). Four patients with the M184V mutation also harbored the K65R or the K103N mutation. The 12- and 24 months virological efficacy data revealed that the rate of treatment failure was not increased in the group of patients harboring minority drug-resistant HIV-1 variants prior to ART.ConclusionsMinority drug-resistant HIV-1 variants can be frequently detected in treatment-naïve, chronically HIV-1 infected patients. Despite the presence of those mutations as minority variants before initiating ART, most of the patients were successfully treated.     

体外无药物选择压力条件下HIV-1耐药基因突变的演变

目的 分离培养体外稳定传代的原代HIV-1耐药毒株,观察失去药物压力下,耐药毒株的体外生长以及主要耐药突变的演化趋势.方法 采集15例服用拉米夫定+司他夫定+萘韦拉平(3TC+D4T+NVP)的HIV-1感染者的外周血单个核细胞(PBMC),用体外共培养的方法从中分离原代HIV-1毒株;RT-PCR扩增耐药毒株历代培养上清的HIV-1 pol区基因并测序,在Stanford HIV Drug Resistance Database数据库进行耐药性分析.结果 15例患者中病毒载量>1000拷贝/ml的有8例,均成功分离出稳定传代的原代毒株,其中2株为耐药毒株,所携带的主要耐药突变分别是K103N/K238T和M184V/K103N/Y181C/H221Y,分别对NVP和3TC/NVP高度耐药;无药物压力的体外培养过程中,M184V、K103N、Y181C和H221Y等耐药突变可以稳定传代,但是K238T发生了回复突变.结论 分离出2株稳定传代的HIV-1耐药毒株,无药物压力情况下,携带K103N突变的毒株具有较好的复制适应性,可稳定传代;携带M184V和K103N/Y181C/H221Y的毒株也能够稳定复制;本研究中发现K238T耐药突变在失去药物的条件下稳定性差,提示该位点易发生回复突变.     

Diverse pattern of protease inhibitor resistance mutations in HIV-1 infected patients failing nelfinavir

The aim of the study was to describe the pattern of resistance mutations in human immunodeficiency virus type 1 (HIV‐1) infected patients experiencing their first protease inhibitor (PI) failure on nelfinavir (NFV)‐containing therapy. Earlier PI‐naïve patients (n = 172) with NFV‐containing therapy were therefore retrospectively studied. Plasma HIV RNA from 43 failing patients was sequenced. In addition, virus from the baseline was sequenced in 29 patients. Failure was defined as two consecutive measurements of viral load of >50 copies/ml after 6 months treatment. Subtyping was done in most patients (n = 118). At baseline, the V82A mutation was found in four PI‐naïve patients of whom two failed therapy exhibiting this mutation. At therapy failure, 17 of the 43 (40%) patients had primary PI mutations. In nine subjects, RTI‐mutations only were found and 17 patients had a wild‐type virus. Patients with primary PI and/or RTI mutations had a higher viral load at failure than those who failed with wild‐type virus. A surprisingly diverse pattern of primary PI mutations was seen: M46I (n = 7), D30N (n = 6), L90M (n = 5), and V82A (n = 4). Four patients exhibited more than one primary PI mutation. PI‐naïve patients in Sweden may harbor PI‐resistant virus and resistance testing should be considered before treatment. Patients who fail NFV may develop the M46I mutation, which has been related earlier to mainly other PI. The diverse pattern of the evolved PI‐mutations and the relative low occurrence of the D30N mutation in the material was unexpected and did not seem to be related to the viral subtype. J. Med. Virol. 76:447–451, 2005. © 2005 Wiley‐Liss, Inc.