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Despite intensive prophylactic and pre-emptive measures, infections remain an important cause of morbidity and mortality in pediatric recipients of allogeneic hematopoietic cell transplantation (allo-HCT). Disruption of the gut microbiota has been linked to clinical outcomes after adult allo-HCT. The objective was to evaluate whether these or differing microbiota disruptions or signatures were associated with risk of infection in pediatric allo-HCT.In a prospective observational study, fecal samples from 74 children were collected prior to conditioning and at the time of neutrophil recovery and profiled by means of 16S ribosomal rRNA sequencing. The associations between microbiome signatures and infections or acute graft-versus-host disease (aGVHD) were examined using Cox proportional-hazards analysis.Previously associated indices of microbiome disruption in adults, including diversity and butyrate producer frequency, did not predict infection risk in pediatric allo-HCT. Unique microbiota signatures were associated with different infections or aGVHD. A ratio of strict and facultative anaerobes (e.g.Lachnoclostridium, Parabacteroides, Clostridium spp.) prior to conditioning predicted likelihood of bacteremia (cox hazards ratio 3.89) in first year post HCT. A distinct ratio of oral (e.g.Rothia, Veillonellaspp.) to colonic anaerobes (e.g.Anaerobutyricum, Dorea, Romboutsiaspp.) at neutrophil recovery predicted likelihood of bacterial infections (cox hazards ratio 1.81) and viral enterocolitis (cox hazards ratio 1.96) through first year post transplant.Interactions between medical interventions, pediatric hosts and microbial communities may be responsible for these consistent microbiota signatures that predict infections. A future multi-center investigation will be needed to demonstrate whether these ratios can be generalized to other pediatric cohorts.Key Points(1 or 2

Immunocompromised patients can have life-threatening adenoviral infection. Viral load in blood and stool is commonly used to guide antiviral therapy. We developed and evaluated a digital polymerase chain reaction assay to quantify human adenovirus in the respiratory tract and showed that higher peak load correlates with disseminated infection, mechanical ventilation, and death.

Through the SEA-PHAGES program at Tufts University, a bacteriophage infecting Gordonia rubripertincta NRRL B-16540 was isolated and characterized. Hexbug is a lytic phage and is currently one of 44 phages belonging to cluster CT. The Hexbug genome shares >96% nucleotide identity with cluster CT phage Orla.

Context: While randomized, double-blind, placebo-controlled trials are the gold standard for investigating the effects of dietary interventions, the complexity of designing such trials has limited their use. Study Design: Single centre, randomized, double-blind, controlled trial. Objective: Primary objectives included the assessment of the impact of a sham anti-inflammatory diet on inflammation and participant blinding. Methods: This dietary advice trial involved participants with spinal cord injury (SCI), randomized to either a sham-diet condition (n=8) or non-dieting control condition (n=8). Participants in the sham-diet group were told they would be randomized to either an anti-inflammatory diet condition, or a sham diet designed to be inflammation-neutral. Participants randomized to the sham-condition completed a diet consultation prior to beginning the diet for a period of 4-weeks. Primary outcomes of interest included the change in inflammation as assessed by plasma concentrations of C-reactive protein (CRP), and participant blinding assessed upon completion of the trial. Results: All members of the control group and 6 of 8 members of the sham-diet group completed the intervention. Blinding was successful as all 6 members who completed the sham-diet believed they were on the true anti-inflammatory diet. Further, the sham diet was shown to have no significant effect on inflammation over the 4-week intervention period as demonstrated by plasma CRP concentrations. Conclusion: This pilot study provides preliminary evidence for the utility of a sham-anti-inflammatory diet and could be used to strengthen the design of future dietary interventions utilizing anti-inflammatory diets.

The endangered beluga (Delphinapterus leucas) population in the St. Lawrence Estuary (SLE) in eastern Canada, the largest estuary in the world, is declining. Elevated tissue concentrations of a wide range of environmental contaminants, for example, halogenated flame retardants (HFRs) including polybrominated diphenyl ethers (PBDEs), might play a role in the non-recovery of this population. In mammals, HFRs have been reported to impair the metabolic regulation, including amino acid and fatty acid pathways. In the present study, we collected both blubber and skin swab samples from tissue biopsies from 56 adult SLE belugas and analyzed their blubber for the concentrations of a comprehensive suite of PBDEs and other HFRs. Using 16S rRNA marker and shotgun metagenomic approaches using skin swabs, we investigated, for the first time, the SLE beluga skin microbiome and the SLE water microbiome, providing valuable comparative taxonomic and functional microbiome information. We found that belugas have a unique skin microbiome that is distinct from surrounding SLE water, regardless of the beluga sex or location in the SLE. We further characterized the core microbiome of SLE beluga skin and surrounding SLE water, and identified bacterial taxa and gene functional pathways associated with the skin microbiome that correlated with beluga blubber HFR concentrations. Namely, we identified the phylum Nitrospinae and candidate phylum PAUC34f as potential taxa of interest that are associated with blubber HFR concentrations. We hypothesize that the biodegradation of HFRs within the beluga blubber and skin results in an increase in local metabolite concentrations that leads to the proliferation of Nitrospinae and PAUC32f. This work demonstrates the utility of studying the core microbiome of the SLE beluga skin using a swab method that could be adapted to field sampling. Further studies of the temporal effects of contaminant exposure on SLE beluga skin and SLE water microbiomes is warranted for potentially better monitoring and protecting this marine mammal which is at risk.

Background The number of cancer patients with CIED receiving radiotherapy has increased dramatically with improving life expectancy in both patients with cardiovascular disease and cancer. The advent of proton therapy adds new concern for potential malfunction in CIED devices, both due to significant neutron scatter and its use of strong magnets to focus radiation beams. Therefore, we aimed to assess the incidence of CIED malfunction secondary to proton therapy in this patient cohort. Methods We retrospectively analyzed patients with CIED undergoing proton therapy at our institute between 2011–2021. Each device was programmed pre-treatment and monitored post-treatment according to a special protocol developed in our centre. Treatments were prescribed to doses up to 70 Gy (RBE) and delivered using either passive-scattering or pencil beam techniques. Distances between the CIED and treated volumes ranged from 10–50 cm. We analyzed baseline patient demographics, CIED demographics, CIED outcomes pre-proton therapy as well as post-proton therapy including device reset and requirement for replacement, analyzing up to most recent check. Results Fifty-one patients with CIED underwent proton therapy during the study period. Estimated neutron dose ranged from 0.05–2.0 mSv/GyRBE for this patient cohort. Baseline demographics outlines in table 1. Of note 26/51 patients underwent proton therapy for ophthalmic malignancies, 6/51 for brain/skull malignancies. CIED comprised of 39 pacemakers and 12 implantable cardioverter defibrillators. Fourteen patients were pacemaker-dependent. Using 95% Confidence Interval, ventricular threshold, impedance, and amplitude, as well as atrial threshold and amplitude were unchanged, whereas atrial impedance measurements had a change pre- and post-proton therapy (Table 2). No patients had a device reset. One patient had a premature battery depletion three months post-radiotherapy for pancreatic cancer. Conclusions Our findings suggest that proton therapy does not significantly impact CIED function. Whilst caution remains as further data is accrued, close monitoring, particularly with the advent of remote monitoring, of these patients should be recommended. Funding Acknowledgement Type of funding sources: None.

Background Motivational messaging is a frequently used digital intervention to promote positive health behavior changes, including smoking cessation. Typically, motivational messaging systems have not actively sought feedback on each message, preventing a closer examination of the user-system engagement. This study assessed the granular user-system engagement around a recommender system (a new system that actively sought user feedback on each message to improve message selection) for promoting smoking cessation and the impact of engagement on cessation outcome. Methods We prospectively followed a cohort of current smokers enrolled to use the recommender system for 6 months. The system sent participants motivational messages to support smoking cessation every 3 days and used machine learning to incorporate user feedback (i.e., user’s rating on the perceived influence of each message, collected on a 5-point Likert scale with 1 indicating strong disagreement and 5 indicating strong agreement on perceiving the influence on quitting smoking) to improve the selection of the following message. We assessed user-system engagement by various metrics, including user response rate (i.e., the percent of times a user rated the messages) and the perceived influence of messages. We compared retention rates across different levels of user-system engagement and assessed the association between engagement and the 7-day point prevalence abstinence (missing outcome = smoking) by using multiple logistic regression. Results We analyzed data from 731 participants (13% Black; 73% women). The user response rate was 0.24 (SD = 0.34) and user-perceived influence was 3.76 (SD = 0.84). The retention rate positively increased with the user response rate (trend test P Conclusions High user-system engagement was positively associated with both high retention rate and smoking cessation, suggesting that investigation of methods to increase engagement may be crucial to increase the impact of the recommender system for smoking cessation. Trial registration Registration Identifier: NCT03224520. Registration date: July 21, 2017.

OBJECTIVE Nitrous oxide (Entonox®) and methoxyflurane (Penthrox®) are inhaled analgesics administered in paramedicine. Occupational exposure to nitrous oxide has been associated with negative health effects, and may inhibit professional capability. The effect of occupational exposure to methoxyflurane has not yet been clearly determined. This study identifies the frequency and duration of ambulance officer (AO) occupational exposure to nitrous oxide and methoxyflurane to provide a foundation for future assessments of occupational toxicity risk. METHODS A retrospective database review of Patient Report Forms (PRFs) in 11 months between February 2016 and February 2018 was conducted. Nitrous oxide was available for the first 5 months studied, followed by 6 months methoxyflurane availability. AO-specific measures of attendance, rate of inhaled analgesic use, and duration of analgesic use were determined. Subgroup analysis by AO qualification and rostered work hours was undertaken. RESULTS A total of 46,759 PRFs were examined, identifying 1,033 cases of nitrous oxide administration and 1456 cases of methoxyflurane was administration. There was a significant increase in the proportion of cases where inhaled analgesia was administered following the replacement of nitrous oxide with methoxyflurane. Relative risk of exposure to methoxyflurane compared with nitrous oxide was 1.22, while median duration of each exposure remained unchanged (32 vs. 33 min). CONCLUSIONS Methoxyflurane via the Penthrox® inhaler was more likely to be administered than nitrous oxide. Most AOs are infrequently exposed to inhaled analgesics and are exposed for durations slightly greater than previously reported. Relative risk of exposure was greatest for lower-qualified AOs. Peak number of exposures and duration values suggest a subset of AOs with higher occupational health risk.

Background Six million Americans suffer from atrial fibrillation (AF), a heart rhythm abnormality that significantly increases the risk of stroke. AF is responsible for 15% of ischemic strokes, which lead to permanent disability in 60% of cases and death in up to 20%. Anticoagulation (AC) is the mainstay for stroke prevention in patients with AF. Despite guidelines recommending AC for patients, up to half of eligible patients are not on AC. Clinical decision support tools in the electronic health record (EHR) can help bridge the disparity in AC prescription for patients with AF. Objective To enhance and assess the effectiveness of our previous rule-based alert on AC initiation and persistence in a diverse patient population from UMass-Memorial Medical Center and University of Florida at Jacksonville. Methods/Results Using the EHR, we will track AC initiation and persistence. We will interview both patients and providers to determine a measure of satisfaction with AC management. We will track digital crumbs to better understand the alert's mechanism of effect and further add enhancements. These enhancements will be used to refine the alert and aid in developing an implementation toolkit to facilitate use of the alert at other health systems. Conclusion If the number of AC starts, the likelihood of persisting on AC, and the frequency alert use are found to be higher among intervention vs control providers, we believe such findings will confirm our hypothesis on the effectiveness of our alert.

Bladder cancer is the 10th most common cancer worldwide. For muscle‐invasive bladder cancer (MIBC), treatment includes radical cystectomy, radiotherapy, and chemotherapy; however, the outcome is generally poor. For non–muscle‐invasive bladder cancer (NMIBC), tumor recurrence is common. There is an urgent need for more effective and less harmful therapeutic approaches. Here, bladder cancer cell metabolic reprogramming to rely on aerobic glycolysis (the Warburg effect) and expression of associated molecular therapeutic targets by bladder cancer cells of different stages and grades, and in freshly resected clinical tissue, is investigated. Importantly, analyses indicate that the Warburg effect is a feature of both NMIBCs and MIBCs. In two in vitro inducible epithelial‐mesenchymal transition (EMT) bladder cancer models, EMT stimulation correlated with increased lactate production, the end product of aerobic glycolysis. Protein levels of lactate dehydrogenase A (LDH‐A), which promotes pyruvate enzymatic reduction to lactate, were higher in most bladder cancer cell lines (compared with LDH‐B, which catalyzes the reverse reaction), but the levels did not closely correlate with aerobic glycolysis rates. Although LDH‐A is expressed in normal urothelial cells, LDH‐A knockdown by RNAi selectively induced urothelial cancer cell apoptotic death, whereas normal cells were unaffected—identifying LDH‐A as a cancer‐selective therapeutic target for bladder cancers. LDH‐A and other potential therapeutic targets (MCT4 and GLUT1) were expressed in patient clinical specimens; however, positive staining varied in different areas of sections and with distance from a blood vessel. This intratumoral heterogeneity has important therapeutic implications and indicates the possibility of tumor cell metabolic coupling., This work identifies aerobic glycolysis (the Warburg effect) as a general feature of both non–muscle‐invasive and muscle‐invasive bladder cancers. We further show that the glycolytic enzyme lactate dehydrogenase A is a cancer‐selective therapeutic target for bladder cancers, but that there is intratumoral heterogeneity in expression of metabolic targets. This raises the possibility of intratumoral metabolic coupling that could be therapeutically targeted.

Although numerous studies have evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using cycle threshold (Ct) values as a surrogate of viral ribonucleic acid (RNA) load, few studies have used standardized, quantitative methods. We validated a quantitative SARS-CoV-2 digital polymerase chain reaction assay normalized to World Health Organization International Units and correlated viral RNA load with symptoms and disease severity.

BACKGROUND: The prevalence of atrial fibrillation(AF) and diabetes mellitus is rising to epidemic proportions. We aimed to assess the impact of diabetes on the management and outcomes of patients with AF.METHODS: The EORP-AF General Long-Term Registry is a prospective, observational registry from 250 centres across 27 European countries. Outcomes of interest were as follows: i)rhythm control interventions; ii)quality of life; iii)healthcare resource utilisation; and iv)major adverse events.RESULTS: Of 11,028 patients with AF, the median age was 71 (63-77) years and 2537 (23.0%) had diabetes. Median follow-up was 24 months. Diabetes was related to increased use of anticoagulation but less rhythm control interventions. Using multivariable analysis, at 2-year follow-up, patients with diabetes were associated with greater levels of anxiety (p = 0.038) compared to those without diabetes. Overall, diabetes was associated with worse health during follow-up, as indicated by Health Utility Score and Visual Analogue Scale. Healthcare resource utilisation was greater with diabetes in terms of length of hospital stay (8.1 (±8.2) vs. 6.1 (±6.7) days); cardiology and internal medicine/general practitioner visits; and emergency room admissions. Diabetes was an independent risk factor of major adverse cardiovascular event (MACE; HR 1.26 [95% CI, 1.04-1.52]), all-cause mortality (HR 1.28 [95% CI, 1.08-1.52]), and cardiovascular mortality (HR 1.41 [95% CI, 1.09-1.83]).CONCLUSION: In this contemporary AF cohort, diabetes was present in 1 in 4 patients and it served as an independent risk factor for reduced quality of life, greater healthcare resource utilisation and excess MACE, all-cause mortality and cardiovascular mortality. There was increased use of anticoagulation therapy in diabetes but with less rhythm control interventions.

Seizures are more common in the neonatal period than at any other stage of life. Phenobarbital is the first-line treatment for neonatal seizures and is at best effective in approximately 50% of babies, but may contribute to neuronal injury. Here, we assessed the efficacy of phenobarbital versus the synthetic neurosteroid, ganaxolone, to moderate seizure activity and neuropathology in neonatal lambs exposed to perinatal asphyxia.Asphyxia was induced via umbilical cord occlusion in term lambs at birth. Lambs were treated with ganaxolone (5mg/kg/bolus then 5mg/kg/day for 2 days) or phenobarbital (20mg/kg/bolus then 5mg/kg/day for 2 days) at 6 hours. Abnormal brain activity was classified as stereotypic evolving (SE) seizures, epileptiform discharges (EDs), and epileptiform transients (ETs) using continuous amplitude-integrated electroencephalographic recordings. At 48 hours, lambs were euthanized for brain pathology.Asphyxia caused abnormal brain activity, including SE seizures that peaked at 18 to 20 hours, EDs, and ETs, and induced neuronal degeneration and neuroinflammation. Ganaxolone treatment was associated with an 86.4% reduction in the number of seizures compared to the asphyxia group. The total seizure duration in the asphyxia+ganaxolone group was less than the untreated asphyxia group. There was no difference in the number of SE seizures between the asphyxia and asphyxia+phenobarbital groups or duration of SE seizures. Ganaxolone treatment, but not phenobarbital, reduced neuronal degeneration within hippocampal CA1 and CA3 regions, and cortical neurons, and ganaxolone reduced neuroinflammation within the thalamus.Ganaxolone provided better seizure control than phenobarbital in this perinatal asphyxia model and was neuroprotective for the newborn brain, affording a new therapeutic opportunity for treatment of neonatal seizures. ANN NEUROL 2022;92:1066-1079.

Background: Breastfeeding and Kangaroo Mother Care (KMC) are interventions to reduce neonatal mortality and undernutrition. We investigated the knowledge of allopathic and Ayurvedic, Yoga-naturopathy, Siddha, and Homeopathic (AYUSH) general practitioners in rural western India and identified attributes associated with awareness and knowledge on these topics. Methods: This cross-sectional study of general practitioners in the Anand district of Gujarat, India, used an anonymous self-reported survey. Multivariable regression models were used to identify practitioner attributes associated with awareness and knowledge. Results: Among the 158 respondents, a quarter (26.0%) were trained in allopathic medicine and 63.0% had practiced for 5 years or more. The average score of breastfeeding knowledge was 8.0 of 13. Most (79.1%) did not have any awareness of KMC. After adjusting for potential confounders, knowledge of breastfeeding practices among AYUSH practitioners was 4-fold greater than that of allopathic practitioners (incidence rate ratio: 3.9; 95% CI: 3.2-4.6). By contrast, AYUSH practitioners had 80% decreased odds of awareness about KMC compared with allopathic practitioners (odds ratio: 0.2; 95% CI: 0.1-0.3). Discussion: This study demonstrates distinct knowledge gaps among allopathic and AYUSH general practitioners regarding breastfeeding and KMC. There is a need for tailored continuing medical education among general practitioners to enhance their clinical knowledge of newborn care practices to achieve improvements in neonatal health.

Environmental DNA (eDNA) has been increasingly utilized by academic, industry, and government groups for environmental monitoring due to its efficiency in regards to both time and cost, as well as non‐invasiveness to target organisms, and reduced dependency on trained biologists for sample collection. The methods typically employ quantitative real‐time polymerase chain reaction (qPCR) to detect the presence of a given organism's DNA in a sample. Currently, there is a drive to use qPCR data to infer biomass or abundance by quantitating the copy number or concentration of a given target gene fragment in a sample, which is often very dilute. Before eDNA can be fully accepted as an environmental decision‐making tool, however, certain aspects of the methods require standardization, including the quantification of target DNA in low copy number samples. Models that are not able to properly make use of data from highly dilute samples are severely hampered in their definitions of the limits of detection and quantification at the lower end of the detection curve. We propose a statistical model for a standard curve that relates the number of qPCR‐detected technical replicates to the copy number in the case of low copy number samples. Likelihood methods are used to estimate the parameters of the model and we derive inverse regression estimates together with their standard errors. Limits of copy number detection and quantification, and their confidence intervals are derived using a well‐accepted statistical approach thus providing a more broadly applicable and robust method for reporting eDNA abundance into the low copy number range. The method is illustrated using experimental results from multiple laboratories.

One topical area of supramolecular chemistry is the binding of anionic species but despite the importance of anions in diverse cellular processes and for cancer development, anion receptors or ‘binders’ have received little attention as potential anti-cancer therapeutics. Here we report self-assembling trimetallic cryptands (e.g. [L2(Metal)3]6+ where Metal = Cu2+, Zn2+ or Mn2+) which can encapsulate a range of anions and which show metal-dependent differences in chemical and biological reactivities. In cell studies, both [L2Cu3]6+ and [L2Zn3]6+ complexes are highly toxic to a range of human cancer cell lines and they show significant metal-dependent selective activity towards cancer cells compared to healthy, non-cancerous cells (by up to 2000-fold). The addition of different anions to the complexes (e.g. PO43ˉ, SO42ˉ or PhOPO32ˉ) further alters activity and selectivity allowing the activity to be modulated via a self-assembly process. The activity is attributed to the ability to either bind or hydrolyse phosphate esters and mechanistic studies show differential and selective inhibition of multiple kinases by both [L2Cu3]6+ and [L2Zn3]6+ complexes but via different mechanisms., Artificial self-assembling systems such as anion receptors or ‘binders’ are largely unexplored for therapeutic applications. Here, the authors report self-assembling trimetallic cryptands containing copper, zinc or manganese that encapsulate a range of anions, are highly toxic to human cancer cell lines and show metal-dependent selectivity towards cancer vs. healthy cells linked to the selective inhibition of multiple kinases.

This research tests the independent contribution of social capital and the use of the internet to obtain health information to support maternal-child communication about peer pressure to have sex among Puerto Rican families. A sample of 413 Puerto Rican households in Springfield, MA provides the data to independently test these hypotheses. The results of a logistic regression model suggest that Puerto Rican mothers with increased social capital and who accessed the internet for health information are more likely to communicate with their adolescent children about peer pressure to have sex. The combination of these two mechanisms provide opportunities to convey culturally generated resources to Puerto Rican mothers to assist them in helping their children develop healthy sexual behaviors.

The common fern, bracken (Pteridium aquilinum), is well known for its toxic effects on livestock due principally to the carcinogenic constituent ptaquiloside ( 1), although other toxins are present including the cyanogenic glycoside, prunasin ( 2). Here, we report an improved and relatively “green” process for the isolation of 1 and 2 from fresh bracken fronds and the evaluation of 1 for cytotoxicity against several cancer cell lines. The results indicate that 1 displays selective toxicity against cancer cells relative to noncancer retinal epithelial cells, and the improved method for the isolation of 1 is expected to facilitate further exploration of its pharmacological properties.

Blood flow restriction may augment the skeletal response to whole-body vibration. This study used a randomised, crossover design to investigate the acute response of serum sclerostin and bone turnover biomarkers to whole-body vibration with blood flow restriction. Ten healthy males (mean±standard deviation; age: 27±8 years) completed two experimental conditions separated by 7 days: (i) whole-body vibration (10 1-minute bouts of whole-body vibration with 30 s recovery) or (ii) whole-body vibration with lower-body blood flow restriction (10 cycles of 110 mmHg inflation with 30 s deflation during recovery). Fasting blood samples were obtained immediately before and immediately after exercise, then 1 hour, and 24 hours after exercise. Serum samples were analysed for sclerostin, cross-linked C-terminal telopeptide of type I collagen, and bone-specific alkaline phosphatase. There was a significant time × condition interaction for bone-specific alkaline phosphatase (p=0.003); bone-specific alkaline phosphatase values at 24 hours post-exercise were significantly higher following whole-body vibration compared to combined whole-body vibration and blood flow restriction (p=0.028). No significant time × condition interaction occurred for any other outcome measure (p0.05). These findings suggest that a single session of whole-body vibration combined with blood flow restriction does not significantly affect serum sclerostin or bone turnover biomarkers.Blood flow restriction may augment the skeletal response to whole-body vibration. This study used a randomised, crossover design to investigate the acute response of serum sclerostin and bone turnover biomarkers to whole-body vibration with blood flow restriction. Ten healthy males (mean±standard deviation; age: 27±8 years) completed two experimental conditions separated by 7 days: (i) whole-body vibration (10 1-minute bouts of whole-body vibration with 30 s recovery) or (ii) whole-body vibration with lower-body blood flow restriction (10 cycles of 110 mmHg inflation with 30 s deflation during recovery). Fasting blood samples were obtained immediately before and immediately after exercise, then 1 hour, and 24 hours after exercise. Serum samples were analysed for sclerostin, cross-linked C-terminal telopeptide of type I collagen, and bone-specific alkaline phosphatase. There was a significant time × condition interaction for bone-specific alkaline phosphatase (p=0.003); bone-specific alkaline phosphatase values at 24 hours post-exercise were significantly higher following whole-body vibration compared to combined whole-body vibration and blood flow restriction (p=0.028). No significant time × condition interaction occurred for any other outcome measure (p0.05). These findings suggest that a single session of whole-body vibration combined with blood flow restriction does not significantly affect serum sclerostin or bone turnover biomarkers.

Objective Silica gel beads have promise as a non-toxic, cost-effective, portable method for storing environmental DNA (eDNA) immobilized on filter membranes. Consequently, many ecological surveys are turning to silica bead filter desiccation rather than ethanol preservation. However, no systematic evaluation of silica bead storage conditions or duration past 1 week has been published. The present study evaluates the quality of filter-immobilized eDNA desiccated with silica gel under different storage conditions for over a year using targeted quantitative real-time polymerase chain reaction (qPCR)-based assays. Results While the detection of relatively abundant eDNA target was stable over 15 months from either ethanol- or silica gel-preserved filters at − 20 and 4 °C, silica gel out-performed ethanol preservation at 23 °C by preventing a progressive decrease in eDNA sample quality. Silica gel filter desiccation preserved low abundance eDNA equally well up to 1 month regardless of storage temperature (18, 4, or − 20 °C). However only storage at − 20 °C prevented a noticeable decrease in detectability at 5 and 12 months. The results indicate that brief storage of eDNA filters with silica gel beads up to 1 month can be successfully accomplished at a range of temperatures. However, longer-term storage should be at − 20 °C to maximize sample integrity.

Summary Background Although antibiotic prophylaxis with levofloxacin can reduce the risk of serious infection in immunocompromised patients, the potential contribution of prophylaxis to antibiotic resistance is a major drawback. We aimed to identify the effects of levofloxacin prophylaxis, given to paediatric patients with acute lymphoblastic leukaemia to prevent infections during induction chemotherapy, on antibiotic resistance in gastrointestinal microbiota after completion of induction and consolidation therapy. Methods This prospective, single-centre (St Jude Children’s Research Hospital, Memphis, TN, USA) cohort study included children (≤18 years) receiving therapy for newly diagnosed acute lymphoblastic leukaemia and who received either primary levofloxacin prophylaxis or no antibacterial prophylaxis (aside from Pneumocystis jirovecii prophylaxis with trimethoprim-sulfamethoxazole) and provided at least two stool samples, including one after completion of induction therapy. We used metagenomic sequencing to identify bacterial genes that confer resistance to fluoroquinolones, trimethoprim-sulfamethoxazole, or other antibiotics, and to identify point mutations in bacterial topoisomerases (gyrA, parC) that confer resistance to fluoroquinolones. We then used generalised linear mixed models to compare the prevalence and relative abundance of antibiotic resistance gene groups after completion of induction and consolidation therapy between participants who had received levofloxacin and those who received no prophylaxis. Findings Between Feb 1, 2012, and April 30, 2016, 118 stool samples (32 baseline, 49 after induction, and 37 after consolidation) were collected from 49 evaluable participants; of these participants, 31 (63%) received levofloxacin prophylaxis during induction therapy and 18 (37%) received no antibacterial prophylaxis. Over the course of induction therapy, there was an overall increase in the relative abundance of trimethoprim-sulfamethoxazole resistance genes (estimated mean fold change 5·9, 95% CI 3·6–9·6; p