Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

High prevalence of genotypic resistance to nucleoside reverse transcriptase inhibitors among therapy-naive individuals from the Warsaw cohort

BACKGROUND

The purpose of this study was to recognize nucleoside reverse transcriptase inhibitor (NRTI)-resistant HIV-1 strains among a group of therapy-naive patients, and subsequently to guide the choice of antiretroviral therapy.

PATIENTS AND METHODS

HIV strains present in sera of 128 antiretroviral therapy-naive patients were tested for NRTI resistance-associated mutations. The RT-PCR amplified HIV rt regions were analyzed with an INNI-LiPA-HIV-1 RT assay. The number and pattern of resistance-associated mutated codons were determined and interpreted as resistance to particular drugs.

RESULTS

Mutated codons were detected in 66 (51.5%) out of 128 tested samples. In 54 (81.8%) out of 66 samples, a K70R mutation was identified, which was followed by an M184V mutation in 22 cases (33.3%). For a majority of these samples, mixed wild/mutant populations were recognized in 44 (66.6%) cases. The interpretation of hybridization data revealed drug-resistant strains in 37 (28.9%) out of all samples tested. The determined resistance to particular drugs was as follows: 20 strains were resistant to zidovudine (ZDV), ten to lamivudine (3TC) and six to didanosine (ddI)/zalcitabine (ddC)/abacavir (ABC). In one case, a ZDV/3TC-resistant HIV strain was found.

CONCLUSION

The prevalence of mutations associated with NRTI resistance was high in the tested cohort. The key reasons for that were most probably needle and drug sharing within the group of intravenous drug users (IVDUs) and the use of ZDV in monotherapeutic regimes in the early 1990s.

Chromosomal localization of the human gene for palmitoyl-CoA ligase (FACL1)

We have localized the gene (FACL1) encoding human long chain fatty acid-coenzyme A ligase, E.C.6.2.1.3, also known as palmitoyl-CoA ligase. Using in-situ hybridization, we have mapped this gene to chromosome region 3q13 in the human karyotype.