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.

Automated image analysis of Euglena gracilis Klebs (Euglenophyta) for measuring sublethal effects of three model contaminants

The short-term impacts of atrazine (herbicide), tributyltin (organometal) and copper on the behaviour of Euglena gracilis Klebs (Euglenophyta) were assessed. First, the ECOTOX automated image analysis system was used, which measured swimming velocity, cell shape, percentage of cells swimming upwards, and randomness of swimming. Next, visual observation by microscopy was used to measure percentage of cell motility and cell shape. Behavioural changes can be used as an indicator of stress in less than 24 h, potentially making them suitable for inclusion in early-warning systems for water quality. Findings indicate that E. gracilis is a very sensitive organism to copper, showing inhibition of motility with visual observation at 0.8 μmol/L within 1 h. The image analysis system was in general less sensitive than visual observation for detecting behavioural changes after incubation in copper. In contrast, after exposure to organic contaminants atrazine and tributyltin, the ECOTOX system detected small changes in the number of cells swimming upwards (antigravitactic behaviour) at higher concentrations.

Dynamics of 103K/N and 184M/V HIV-1 drug resistant populations: Relative comparison in plasma virus RNA versus CD45RO+T cell proviral DNA

BACKGROUND

Viral populations defined by 103K/N and 184M/V as linked or single mutations in the HIV-1 reverse transcriptase gene were investigated in plasma samples and compared with previous findings in the CD45RO(+)T cell compartment.

OBJECTIVE

To develop an ARMS assay for plasma virions and to investigate the expression of resistance mutations (103N and 184V) and dynamic interactions between proviral DNA and plasma virions.

STUDY DESIGN

A clinical cross-sectional study, including 11 patients on lamivudine efavirenz and/or nevirapine therapy. The viral populations were determined by an assay based on real-time PCR and amplification refractory mutation system (ARMS).

RESULTS

The 103N and 184V mutations were not detected in patients with stable low viremia. Patients previously exposed to mono or dual therapy often carried minor viral populations of either one or both mutations in plasma. The viral population with linked mutations (103N and 184V) was detected in two patients after more than 2 years of non-NNRTI HAART.

CONCLUSION

The ARMS assay is useful for detecting viral quasi-species containing efavirenz and lamivudine resistant mutations in plasma virions and in proviral DNA. Data suggest an unequal distribution of linked-mutation populations in plasma and CD45RO(+)T cells. Furthermore, the linked 103N-184V mutation may be more fit than the single 184V mutation and this linked population emerges rapidly under inadequate drug pressure.

Fluoropolymer-coated Dacron Versus PTFE Grafts for Femorofemoral Crossover Bypass: Randomised Trial

OBJECTIVES

To investigate whether patency of a thin walled 8 mm fluoropassivated Dacron graft was similar to that of a standard 8mm PTFE graft for femorofemoral crossover bypass surgery.

DESIGN

A randomised multicentre clinical trial comparing two vascular grafts with participation of 10 departments of vascular surgery in Denmark, Sweden and Norway.

PATIENTS AND METHODS

198 patients were randomised to PTFE (n=107) or fluoropolymer-coated Dacron grafts (n=91), 63% underwent surgery for claudication, 27% for ischaemic rest pain and 10% for tissue loss. The median follow-up time was 24 months (IQR 19-26 months).

RESULTS

The primary patency rate of the two grafts was similar (log rank test: p=0.35). The primary patency rates (95% CI) for coated Dacron and PTFE grafts were 92% (86-98) and 94% (89-99) at 12 months and 87% (74-95) and 93% (87-99) at 24 months, respectively.

CONCLUSION

In patients with unilateral iliac artery disease not amenable to angioplasty, the femoral-femoral bypass is durable and effective. No difference in patency was found between the two graft materials (fluoropolymer coated Dacron and PTFE).

Two dose regimens of recombinant interferon-alpha-2b in chronic hepatitis C virus infection. Biochemistry, hepatitis C virus RNA, and liver histology as response indices

BACKGROUND

Recombinant interferon remains the cornerstone of treatment of chronic hepatitis C virus (HCV) infection. Still, evaluation of treatment on the basis of response indicators and long-term effect of the treatment raises several questions.

METHODS

Seventy-four patients with chronic HCV infection were randomized to a high (3 MIU, 3/7 days) or low (1 MIU, 3/7 days) dose of recombinant interferon-alpha-2b for 48 weeks after a 4-week course of 3 MIU, 3/7 days. Response to treatment was assessed by means of liver enzymes (transaminases), HCV RNA, and liver histology.

RESULTS

The higher maintenance dose was associated with a significantly higher rate of sustained alanine aminotransferase (ALAT) response (45% versus 19%) and with a significantly better chance of becoming HCV RNA-negative during therapy (47% versus 23%). In the high maintenance dose group 14 of the 29 (48%) patients with available HCV RNA data were negative at the 3-month follow-up, compared with 4 of 27 (15%) in the low maintenance dose group. Significantly more patients had improved liver biopsy findings after interferon in the high maintenance dose group (79%) than in the low maintenance dose group (36%). There was a close correlation between ALAT response and HCV RNA response. Of 17 patients who were HCV RNA-negative 3 months after the end of treatment, 10 remained HCV RNA-negative 2-4 years later.

CONCLUSION

The study demonstrates a higher response rate as assessed by biochemistry, HCV RNA, and liver histology in the higher dose group.