A tight Erd\H{o}s-P\'osa function for wheel minors

Let $W_t$ denote the wheel on $t+1$ vertices. We prove that for every integer $t \geq 3$ there is a constant $c=c(t)$ such that for every integer $k\geq 1$ and every graph $G$, either $G$ has $k$ vertex-disjoint subgraphs each containing $W_t$ as minor, or there is a subset $X$ of at most $c k \log k$ vertices such that $G-X$ has no $W_t$ minor. This is best possible, up to the value of $c$. We conjecture that the result remains true more generally if we replace $W_t$ with any fixed planar graph $H$.Comment: 15 pages, 1 figur

OA04-01. Safety and immunogenicity of LIPO-5, a HIV-1 lipopeptide vaccine: results of ANRS VAC18, a phase 2, randomized, double-blind, placebo-controlled trial

International audiencen.

A Phylogenetic Analysis of Human Immunodeficiency Virus Type 1 Sequences in Kiev: Findings Among Key Populations

Background: The human immunodeficiency virus (HIV) epidemic in Ukraine has been driven by a rapid rise among people who inject drugs, but recent studies have shown an increase through sexual transmission. Methods: Protease and reverse transcriptase sequences from 876 new HIV diagnoses (April 2013–March 2015) in Kiev were linked to demographic data. We constructed phylogenetic trees for 794 subtype A1 and 64 subtype B sequences and identified factors associated with transmission clustering. Clusters were defined as ≥2 sequences, ≥80% local branch support, and maximum genetic distance of all sequence pairs in the cluster ≤2.5%. Recent infection was determined through the limiting antigen avidity enzyme immunoassay. Sequences were analyzed for transmitted drug resistance mutations. Results Thirty percent of subtype A1 and 66% of subtype B sequences clustered. Large clusters (maximum 11 sequences) contained mixed risk groups. In univariate analysis, clustering was significantly associated with subtype B compared to A1 (odds ratio [OR], 4.38 [95% confidence interval {CI}, 2.56–7.50]); risk group (OR, 5.65 [95% CI, 3.27–9.75]) for men who have sex with men compared to heterosexual males; recent, compared to long-standing, infection (OR, 2.72 [95% CI, 1.64–4.52]); reported sex work contact (OR, 1.93 [95% CI, 1.07–3.47]); and younger age groups compared with age ≥36 years (OR, 1.83 [95% CI, 1.10–3.05] for age ≤25 years). Females were associated with lower odds of clustering than heterosexual males (OR, 0.49 [95% CI, .31–.77]). In multivariate analysis, risk group, subtype, and age group were independently associated with clustering (P < .001, P = .007, and P = .033, respectively). Eighteen sequences (2.1%) indicated evidence of transmitted drug resistance. Conclusions Our findings suggest high levels of transmission and bridging between risk groups

Meropenem vs standard of care for treatment of late onset sepsis in children of less than 90 days of age: study protocol for a randomised controlled trial

Background: Late onset neonatal sepsis (LOS) with the mortality of 17 to 27% is still a serious disease. Meropenem is an antibiotic with wide antibacterial coverage. The advantage of it over standard of care could be its wider antibacterial coverage and thus the use of mono-instead of combination therapy.Methods: NeoMero-1, an open label, randomised, comparator controlled, superiority trial aims to compare the efficacy of meropenem with a predefined standard of care (ampicillin + gentamicin or cefotaxime + gentamicin) in the treatment of LOS in neonates and infants aged less than 90 days admitted to a neonatal intensive care unit. A total of 550 subjects will be recruited following a 1:1 randomisation scheme. The trial includes patients with culture confirmed (at least one positive culture from normally sterile site except coagulase negative staphylococci in addition to one clinical or laboratory criterion) or clinical sepsis (at least two laboratory and two clinical criteria suggestive of LOS in subjects with postmenstrual age = 44 weeks). Meropenem will be given at a dose of 20 mg/kg q12h or q8h depending on the gestational- and postnatal age. Comparator agents are administered as indicated in British National Formulary for Children. The primary endpoint measured at the test of cure visit (2 days after end of study therapy) is graded to success (all baseline symptoms and laboratory parameters are resolved or improved with no need to continue antibiotics and the baseline microorganisms are eradicated and no new microorganisms are identified and the patient has received allocated treatment for 11 +/- 3 days with no modification) or a failure (all remaining cases). Secondary outcome measures include comparison of survival, relapse rates or new infections by Day 28, clinical response at Day 3 and end of therapy, duration of hospitalisation, population pharmacokinetic analysis of meropenem and effect of antibiotics on mucosal colonisation and development of antibacterial resistance. The study will start recruitment in September 2011; the total duration is of 24 months

Incidence and risk factors for liver enzymes elevations in highly treatment-experienced patients switching from enfuvirtide to raltegravir: a sub-study of the ANRS-138 EASIER trial.

International audienceIn the ANRS EASIER trial where treatment-experienced patients switched from enfuvirtide (ENF) to raltegravir (RAL), a high incidence of transaminase elevation was reported in the RAL arm. We compared the incidence of emergent liver enzyme elevations (LEE) of grade 2 or more among patients randomized to the maintenance ENF arm or the switch RAL arm up to W24. We also assessed the overall incidence of LEE over the 48-week duration of the trial and baseline risk factors for grade 2 or more alanine aminotransferase (ALT) elevation using univariate and multivariate analyses. During the first 24 weeks, 6/84 (7.1 %) and 2/85 patients (2.4 %) presented with ALT elevation of grade 2 or more in the RAL and ENF arms, respectively (p = 0.21). Grade 2 or more γGT and ALP elevations were seen in 18 and 11 % (p = 0.35), and 5 and 1 % (p = 0.14) of patients in the RAL and ENF arms, respectively. The 48-week incidence of grade 2 or more LEE was 11.6 per 100-pts-years for ALT, 24.5 per 100-pts-years for γ-GT and 4.5 per 100-pts-years for ALP, respectively. In the multivariate analysis, tipranavir/ritonavir use (OR 3.66; 95 % CI [1.20-11.1], p = 0.022) and elevated ALT at baseline (OR 10.3; 95 % CI [2.67-39.6], p < 10(-3)) were significantly associated with a grade 2 or more ALT elevation during follow-up. The incidence of LEE was relatively high in these highly treatment-experienced patients switching to a RAL-based regimen. Both tipranavir/ritonavir use and high baseline ALT levels were associated with an increased risk of ALT. ClinicalTrials.gov identifier: NCT00454337

Interactions between Atazanavir-Ritonavir and Tenofovir in Heavily Pretreated Human Immunodeficiency Virus-Infected Patients

The aim of the present study was to assess the pharmacokinetic behavior of atazanavir-ritonavir when it is coadministered with tenofovir disoproxil fumarate (DF) in human immunodeficiency virus (HIV)-infected patients. Eleven patients enrolled in Agence Nationale de Recherche sur le SIDA (National Agency for AIDS Research, Paris, France) trial 107 were included in this pharmacokinetic study. They received atazanavir at 300 mg and ritonavir at 100 mg once a day (QD) from day 1 to the end of study. For the first 2 weeks, their nucleoside analog reverse transcriptase inhibitor (NRTI) treatments remained unchanged. Tenofovir DF was administered QD from day 15 to the end of the study. Ongoing NRTIs were selected according to the reverse transcriptase genotype of the HIV isolates from each patient. The values of the pharmacokinetic parameters for atazanavir and ritonavir were measured before (day 14 [week 2]) and after (day 42 [week 6]) initiation of tenofovir DF and are reported for the 10 patients who completed the study. There was a significant decrease in the area under the concentration-time curve from 0 to 24 h (AUC(0-24)) for atazanavir with the addition of tenofovir DF (AUC(0-24) ratio, 0.75; 90% confidence interval, 0.58 to 0.97; P = 0.05). There was a trend for a decrease in the minimum concentrations of atazanavir and ritonavir in plasma when they were combined with tenofovir, but none of the differences reached statistical significance. The median decreases in the HIV RNA loads at week 2 and week 6 were 0.1 and 0.2 log copies/ml, respectively. In summary, our data are consistent with the existence of a significant interaction between atazanavir and tenofovir DF

Long-term immunogenicity of two doses of 2009 A/H1N1v vaccine with and without AS03(A) adjuvant in HIV-1-infected adults.

International audienceOBJECTIVE: In immunocompromised patients, alternative schedules more immunogenic than the standard influenza vaccine regimen are necessary to enhance and prolong vaccine efficacy. We previously reported that the AS03A-adjuvanted 2009 A/H1N1v vaccine yielded a higher short-term immune response than the nonadjuvanted one in HIV-1-infected adults. This study reports the long-term persistence of the immune response. DESIGN AND METHODS: In a prospective, multicenter, randomized, patient-blinded trial, two doses of AS03A-adjuvanted H1N1v vaccine containing 3.75 μg haemagglutinin (n = 155; group A) or nonadjuvanted H1N1v vaccine containing 15 μg haemagglutinin (n = 151; group B), were administered 21 days apart. Haemagglutination inhibition and neutralizing antibodies were assessed 6 and 12 months after vaccination. RESULTS: In group A and B, the seroprotection rates were 83.7 and 59.4% at month 6, and 70.4 and 49.3 at month 12, respectively. In a multivariate analysis, persistence of seroprotection 12 months after vaccination was negatively associated with current smoking (odds ratio = 0.6, P = 0.03) and positively related with the AS03A-adjuvanted H1N1v vaccine (odds ratio = 2.7, P = 0.0002). CONCLUSION: In HIV-1-infected adults, two doses of adjuvanted influenza vaccine induce long-term persistence of immune response up to 1 year after vaccination

Minor HIV-1 variants with the K103N resistance mutation during intermittent efavirenz-containing antiretroviral therapy and virological failure.

The impact of minor drug-resistant variants of the type 1 immunodeficiency virus (HIV-1) on the failure of antiretroviral therapy remains unclear. We have evaluated the importance of detecting minor populations of viruses resistant to non-nucleoside reverse-transcriptase inhibitors (NNRTI) during intermittent antiretroviral therapy, a high-risk context for the emergence of drug-resistant HIV-1. We carried out a longitudinal study on plasma samples taken from 21 patients given efavirenz and enrolled in the intermittent arm of the ANRS 106 trial. Allele-specific real-time PCR was used to detect and quantify minor K103N mutants during off-therapy periods. The concordance with ultra-deep pyrosequencing was assessed for 11 patients. The pharmacokinetics of efavirenz was assayed to determine whether its variability could influence the emergence of K103N mutants. Allele-specific real-time PCR detected K103N mutants in 15 of the 19 analyzable patients at the end of an off-therapy period while direct sequencing detected mutants in only 6 patients. The frequency of K103N mutants was 0.1% in 8. It was 0.1%-10% in 6 of these 8 patients. The mutated virus populations of 4 of these 6 patients underwent further selection and treatment failed for 2 of them. The K103N mutant frequency was >10% in the remaining 2, treatment failed for one. The copy numbers of K103N variants quantified by allele-specific real-time PCR and ultra-deep pyrosequencing agreed closely (ρ = 0.89 P0.1%) than in the 11 patients in whom it did not (32 hours) (P = 0.04). Thus ultrasensitive methods could prove more useful than direct sequencing for predicting treatment failure in some patients. However the presence of minor NNRTI-resistant viruses need not always result in virological escape.ClinicalTrials.gov NCT00122551