Resistance to antiretroviral drugs in newly diagnosed, young treatment-naïve HIV-positive pregnant women in the province of KwaZulu-Natal, South Africa

In 2004, KwaZulu‐Natal initiated one of the world's largest HIV/AIDS treatment programs. Studies in South Africa have shown that patients on antiretroviral therapy (ART) develop rapidly and transmit drug resistant mutations. Since resistance testing is not widely available in Kwazulu‐Natal, the Department of Health conducted the first HIV drug resistance (HIVDR) threshold survey in 2005, which did not identify any mutations associated with HIVDR. The objective of this study was to conduct a follow‐up threshold survey to update the information on HIVDR. This study was conducted in 2009 in five antenatal care sites in Kwazulu‐Natal using the HIVDR threshold survey method developed by WHO. Two hundred and thirteen newly‐diagnosed HIV positive, drug‐naïve primigravidae, less than 22 years of age were included in the survey. Of the 82 HIV positive specimens, 17 had insufficient volume for genotyping and, of the remaining 65, 47 were genotyped sequentially. Drug resistance was identified by sequencing the HIV‐1 pol gene, using the ViroSeq® HIV‐1 genotyping system v2.0. Of the 47 samples that were genotyped, only one presented with a K103N mutation, which equates to a prevalence of transmitted HIVDR of <5%. The low prevalence of transmitted HIVDR is in keeping with statistical models of the early stages of ART rollout. As ART coverage is increasing continuously, there is a need to ensure that vigilance of HIVDR continues so that the emergence and spread of HIVDR is minimized. This survey should be repeated in 2011, in accordance with WHO guidelines. J. Med. Virol. 83:1508–1513, 2011. © 2011 Wiley‐Liss, Inc.     

Absence of genotypic drug resistance and presence of several naturally occurring polymorphisms of human immunodeficiency virus‐1 CRF06_cpx in treatment‐naive patients in Estonia

All non‐B HIV‐1 subtypes and circulating recombinant forms (CRFs) are characterized by several polymorphisms in protease (PR) region. In addition, in recent years the increasing use of antiretroviral treatment (ART) has rapidly raised the spread of transmitted drug resistance. We aimed to determine the presence of naturally occurring polymorphisms and transmitted drug resistance mutations (DRMs) in ART naïve HIV‐1‐positive subjects in Estonia. A total of 115 drug‐naive HIV‐1‐infected subjects (mean age 27 years; 70% male; 65% infected via intravenous drug use and 34% by heterosexual contact) were enrolled. Viral genomic RNA from plasma was directly sequenced in PR, revertase (RT), and envelope (env) regions. Phylogenetic analysis of RT and env regions revealed that 89% and 3% of sequenced viruses belonged to CRF06_cpx and subtype A1, respectively, and 6% were described as unique recombinants (signed A1‐06) between CRF06_cpx and subtype A1 viruses. No primary DRMs were found in PR or RT regions indicating the absence of transmitted drug resistance. The most common polymorphisms in the PR region were K14R, M36I, H69K, and L89M seen in 96%, 100%, 99%, and 100%, respectively. The clinical relevance of these polymorphisms in terms of success of ART has to be monitored in future clinical studies. J. Med. Virol. 81:953–958, 2009. © 2009 Wiley‐Liss, Inc.     

Subtype CRF01_AE dominate the sexually transmitted human immunodeficiency virus type 1 epidemic in Guangxi,China

Human immunodeficiency virus type 1 (HIV‐1) infection by sexual transmission in Guangxi, China had increased dramatically. However, limited information is available on the genetic characterization of the HIV‐1 epidemic. In this study, HIV‐1 seropositive drug‐naïve patients infected by heterosexual transmission were enrolled. The full length gag and pol genes were sequenced followed by phylogenetic analysis, recombinant analysis and drug resistant analysis. Multiple subtypes were identified, including CRF01_AE (80.1%), CRF07_BC (6.4%), CRF08_BC (10.2%), subtype B (1.7%), and URFs (1.7%). In the phylogenetic tree, two large CRF01_AE clusters were identified. One cluster is originating from Vietnam strains as being reported previously in intravenous drug users. One novel cluster was identified and showed close relationship to strains from Fujian province. Inter‐subtype recombination among CRF01_AE, subtype B and C was identified. Low level drug‐resistance in drug‐naïve heterosexually transmitted infections was found. The results suggested that multiple originating CRF01_AE strains dominated the HIV‐1 epidemic in heterosexual transmission in Guangxi province. J. Med. Virol. 85:388–395, 2013. © 2013 Wiley Periodicals, Inc.     

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.     

The effects of RNase H inhibitors and nevirapine on the susceptibility of HIV-1 to AZT and 3TC

It was recently proposed that HIV RT mutations that decrease RNase H activity increase zidovudine (AZT) resistance by delaying the degradation of the RNA template, allowing more time for AZTMP excision from the 3′ end of the viral DNA. This predicts that suboptimal concentrations of an RNase H Inhibitor (RNHI), which would decrease RNaseH activity, would decrease AZT susceptibility. Conversely, a suboptimal concentration of a nonnucleoside RT inhibitor (NNRTI) would decrease polymerase activity and increase AZT susceptibility. We determined the effect of several RNHIs and an NNRTI (nevirapine) on AZT and lamivudine (3TC) susceptibility with vectors that replicate using WT or AZT resistant RTs. Susceptibility to 3TC, which is not readily excised, did not change significantly. Nevirapine, and most RNHIs tested, had only small effects on the susceptibility of either HIV vector to AZT and 3TC. One RNHI, F0444-0019, increased the IC₅₀ for AZT for either vector by ~ 5-fold, which may be a concern.