The interaction between Shewanella oneidensis MR-1 and the soluble metal Pd(II) during the reductive precipitation of Pd(0) determined the size and properties of the precipitated Pd(0) nanoparticles. Assessment of cell viability indicated that the bioreduction of Pd(II) was a detoxification mechanism depending on the Pd(II) concentration and on the presence and properties of the electron donor. The addition of H(2) in the headspace allowed S. oneidensis to resist the toxic effects of Pd(II). Interestingly, 25 mM formate was a less effective electron donor for bioreductive detoxification of Pd(II), since there was a 2 log reduction of culturable cells and a 20% decrease of viable cells within 60 min, followed by a slow recovery. When the ratio of Pd:cell dry weight (CDW) was below 5:2 at a concentration of 50 mg l(-1) Pd(II), most of the cells remained viable. These viable cells precipitated Pd(0) crystals over a relatively larger bacterial surface area and had a particle area that was up to 100 times smaller when compared to Pd(0) crystals formed on non-viable biomass (Pd:CDW ratio of 5:2). The relatively large and densely covering Pd(0) crystals on non-viable biomass exhibited high catalytic reactivity towards hydrophobic molecules such as polychlorinated biphenyls, while the smaller and more dispersed nanocrystals on a viable bacterial carrier exhibited high catalytic reactivity towards the reductive degradation of the anionic pollutant perchlorate.

BackgroundGlobally, the population of adolescents living with perinatally acquired HIV (APHs) continues to expand. In this study, we pooled data from observational pediatric HIV cohorts and cohort networks, allowing comparisons of adolescents with perinatally acquired HIV in “real-life” settings across multiple regions. We describe the geographic and temporal characteristics and mortality outcomes of APHs across multiple regions, including South America and the Caribbean, North America, Europe, sub-Saharan Africa, and South and Southeast Asia.Methods and findingsThrough the Collaborative Initiative for Paediatric HIV Education and Research (CIPHER), individual retrospective longitudinal data from 12 cohort networks were pooled. All children infected with HIV who entered care before age 10 years, were not known to have horizontally acquired HIV, and were followed up beyond age 10 years were included in this analysis conducted from May 2016 to January 2017. Our primary analysis describes patient and treatment characteristics of APHs at key time points, including first HIV-associated clinic visit, antiretroviral therapy (ART) start, age 10 years, and last visit, and compares these characteristics by geographic region, country income group (CIG), and birth period. Our secondary analysis describes mortality, transfer out, and lost to follow-up (LTFU) as outcomes at age 15 years, using competing risk analysis. Among the 38,187 APHs included, 51% were female, 79% were from sub-Saharan Africa and 65% lived in low-income countries. APHs from 51 countries were included (Europe: 14 countries and 3,054 APHs; North America: 1 country and 1,032 APHs; South America and the Caribbean: 4 countries and 903 APHs; South and Southeast Asia: 7 countries and 2,902 APHs; sub-Saharan Africa, 25 countries and 30,296 APHs). Observation started as early as 1982 in Europe and 1996 in sub-Saharan Africa, and continued until at least 2014 in all regions. The median (interquartile range [IQR]) duration of adolescent follow-up was 3.1 (1.5–5.2) years for the total cohort and 6.4 (3.6–8.0) years in Europe, 3.7 (2.0–5.4) years in North America, 2.5 (1.2–4.4) years in South and Southeast Asia, 5.0 (2.7–7.5) years in South America and the Caribbean, and 2.1 (0.9–3.8) years in sub-Saharan Africa. Median (IQR) age at first visit differed substantially by region, ranging from 0.7 (0.3–2.1) years in North America to 7.1 (5.3–8.6) years in sub-Saharan Africa. The median age at ART start varied from 0.9 (0.4–2.6) years in North America to 7.9 (6.0–9.3) years in sub-Saharan Africa. The cumulative incidence estimates (95% confidence interval [CI]) at age 15 years for mortality, transfers out, and LTFU for all APHs were 2.6% (2.4%–2.8%), 15.6% (15.1%–16.0%), and 11.3% (10.9%–11.8%), respectively. Mortality was lowest in Europe (0.8% [0.5%–1.1%]) and highest in South America and the Caribbean (4.4% [3.1%–6.1%]). However, LTFU was lowest in South America and the Caribbean (4.8% [3.4%–6.7%]) and highest in sub-Saharan Africa (13.2% [12.6%–13.7%]). Study limitat...

Background

Background Estimates of incidence of switching to second-line antiretroviral therapy (ART) among children with HIV are necessary to inform the need for paediatric second-line formulations. We aimed to quantify the cumulative incidence of switching to second-line ART among children in an international cohort collaboration. Methods In this international cohort collaboration study, we pooled individual patient-level data for children younger than 18 years who initiated ART (two or more nucleoside reverse-transcriptase inhibitors [NRTI] plus a non-NRTI [NNRTI] or boosted protease inhibitor) between 1993 and 2015 from 12 observational cohort networks in the Collaborative Initiative for Paediatric HIV Education and Research (CIPHER) Global Cohort Collaboration. Patients who were reported to be horizontally infected with HIV and those who were enrolled in trials of treatment monitoring, switching, or interruption strategies were excluded. Switch to second-line ART was defined as change of one or more NRTI plus either change in drug class (NNRTI to protease inhibitor or vice versa) or protease inhibitor change, change from single to dual protease inhibitor, or addition of a new drug class. We used cumulative incidence curves to assess time to switching, and multivariable proportional hazards models to explore patient-level and cohort-level factors associated with switching, with death and loss to follow-up as competing risks. Findings At the data cutoff of Sept 16, 2015, 182 747 children with HIV were included in the CIPHER dataset, of whom 93 351 were eligible, with 83 984 (90•0%) from sub-Saharan Africa. At ART initiation, the median patient age was 3•9 years (IQR 1•6-6•9) and 82 885 (88•8%) patients initiated NNRTI-based and 10 466 (11•2%) initiated protease inhibitor-based regimens. Median duration of follow-up after ART initiation was 26 months (IQR 9-52). 3883 (4•2%) patients switched to second-line ART after a median of 35 months (IQR 20-57) of ART. The cumulative incidence of switching at 3 years was 3•1% (95% CI 3•0-3•2), but this estimate varied widely depending on the cohort monitoring strategy, from 6•8% (6•5-7•2) in settings with routine monitoring of CD4 (CD4% or CD4 count) and viral load to 0•8% (0•6-1•0) in settings with clinical only monitoring. In multivariable analyses, patient-level factors associated with an increased likelihood of switching were male sex, older age at ART initiation, and initial NNRTI-based regimen (p<0•0001). Cohort-level factors that increased the likelihood of switching were higher-income country (p=0•0017) and routine or targeted monitoring of CD4 and viral load (p<0•0001), which was associated with a 166% increase in likelihood of switching compared with CD4 only monitoring (subdistributional hazard ratio 2•66, 95% CI 2•22-3•19). Interpretation Our global paediatric analysis found wide variations in the incidence of switching to second-line ART across monitoring strategies. These findings suggest the scale-up of viral load monitoring would probably increase demand for paediatri...

One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch.