ABSTRACT
Parental behavior is pervasive throughout the animal kingdom and essential for species survival. However, the relative contribution of the father to offspring care differs markedly across animals, even between related species. The mechanisms that organize and control paternal behavior remain poorly understood. Using Sprague-Dawley rats and C57BL/6 mice, two species at opposite ends of the paternal spectrum, we identified that distinct electrical oscillation patterns in neuroendocrine dopamine neurons link to a chain of low dopamine release, high circulating prolactin, prolactin receptor-dependent activation of medial preoptic area galanin neurons, and paternal care behavior in male mice. In rats, the same parameters exhibit inverse profiles. Optogenetic manipulation of these rhythms in mice dramatically shifted serum prolactin and paternal behavior, whereas injecting prolactin into non-paternal rat sires triggered expression of parental care. These findings identify a frequency-tuned brain-endocrine-brain circuit that can act as a gain control system determining a species' parental strategy.
Subject(s)
Dopamine/metabolism , Hypothalamus/physiology , Neurons/physiology , Paternal Behavior/physiology , Animals , Brain/physiology , Male , Mice , Mice, Inbred C57BL , Neurons/metabolism , Optogenetics , Patch-Clamp Techniques , Prolactin/blood , Rats , Rats, Sprague-Dawley , Receptors, Prolactin/deficiency , Receptors, Prolactin/genetics , Receptors, Prolactin/metabolismABSTRACT
A novel group of biocidal compounds are the Crystal 3D (Cry) and Cytolytic (Cyt) proteins produced by Bacillus thuringiensis (Bt). Some Bt Cry proteins have a selective nematocidal activity, with Cry5B being the most studied. Cry5B kills nematode parasites by binding selectively to membrane glycosphingolipids, then forming pores in the cell membranes of the intestine leading to damage. Cry5B selectively targets multiple species of nematodes from different clades and has no effect against mammalian hosts. Levamisole is a cholinergic anthelmintic that acts by selectively opening L-subtype nicotinic acetylcholine receptor ion-channels (L-AChRs) that have been found on muscles of nematodes. A synergistic nematocidal interaction between levamisole and Cry5B at the whole-worm level has been described previously, but the location, mechanism and time-course of this synergism is not known. In this study we follow the timeline of the effects of levamisole and Cry5B on the Ca2+ levels in enterocyte cells in the intestine of Ascaris suum using fluorescence imaging. The peak Ca2+ responses to levamisole were observed after approximately 10 minutes while the peak responses to activated Cry5B were observed after approximately 80 minutes. When levamisole and Cry5B were applied simultaneously, we observed that the responses to Cry5B were bigger and occurred sooner than when it was applied by itself. It is proposed that the synergism is due to the cytoplasmic Ca2+ overload that is induced by the combination of levamisole opening Ca2+ permeable L-subtype nAChRs and the Ca2+ permeable Cry5B toxin pores produced in the enterocyte plasma membranes. The effect of levamisole potentiates and speeds the actions of Cry5B that gives rise to bigger Ca2+ overloads that accelerates cell-death of the enterocytes.
Subject(s)
Ascaris suum , Bacillus thuringiensis Toxins , Bacterial Proteins , Endotoxins , Hemolysin Proteins , Levamisole , Levamisole/pharmacology , Animals , Bacillus thuringiensis Toxins/pharmacology , Endotoxins/pharmacology , Endotoxins/metabolism , Hemolysin Proteins/pharmacology , Hemolysin Proteins/metabolism , Bacterial Proteins/metabolism , Ascaris suum/drug effects , Anthelmintics/pharmacology , Intestines/drug effects , Intestines/parasitology , Drug Synergism , Antinematodal Agents/pharmacology , Bacillus thuringiensis/drug effectsABSTRACT
The alarming rise in superbugs that are resistant to drugs of last resort, including vancomycin-resistant enterococci and staphylococci, has become a significant global health hazard. Here, we report the click chemistry synthesis of an unprecedented class of shapeshifting vancomycin dimers (SVDs) that display potent activity against bacteria that are resistant to the parent drug, including the ESKAPE pathogens, vancomycin-resistant Enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), as well as vancomycin-resistant S. aureus (VRSA). The shapeshifting modality of the dimers is powered by a triazole-linked bullvalene core, exploiting the dynamic covalent rearrangements of the fluxional carbon cage and creating ligands with the capacity to inhibit bacterial cell wall biosynthesis. The new shapeshifting antibiotics are not disadvantaged by the common mechanism of vancomycin resistance resulting from the alteration of the C-terminal dipeptide with the corresponding d-Ala-d-Lac depsipeptide. Further, evidence suggests that the shapeshifting ligands destabilize the complex formed between the flippase MurJ and lipid II, implying the potential for a new mode of action for polyvalent glycopeptides. The SVDs show little propensity for acquired resistance by enterococci, suggesting that this new class of shapeshifting antibiotic will display durable antimicrobial activity not prone to rapidly acquired clinical resistance.
Subject(s)
Methicillin-Resistant Staphylococcus aureus , Vancomycin-Resistant Enterococci , Vancomycin/pharmacology , Anti-Bacterial Agents/therapeutic use , Microbial Sensitivity TestsABSTRACT
Earth's equator-to-pole temperature gradient drives westerly mid-latitude jet streams through thermal wind balance1. In the upper atmosphere, anthropogenic climate change is strengthening this meridional temperature gradient by cooling the polar lower stratosphere2,3 and warming the tropical upper troposphere4-6, acting to strengthen the upper-level jet stream7. In contrast, in the lower atmosphere, Arctic amplification of global warming is weakening the meridional temperature gradient8-10, acting to weaken the upper-level jet stream. Therefore, trends in the speed of the upper-level jet stream11-13 represent a closely balanced tug-of-war between two competing effects at different altitudes14. It is possible to isolate one of the competing effects by analysing the vertical shear-the change in wind speed with height-instead of the wind speed, but this approach has not previously been taken. Here we show that, although the zonal wind speed in the North Atlantic polar jet stream at 250 hectopascals has not changed since the start of the observational satellite era in 1979, the vertical shear has increased by 15 per cent (with a range of 11-17 per cent) according to three different reanalysis datasets15-17. We further show that this trend is attributable to the thermal wind response to the enhanced upper-level meridional temperature gradient. Our results indicate that climate change may be having a larger impact on the North Atlantic jet stream than previously thought. The increased vertical shear is consistent with the intensification of shear-driven clear-air turbulence expected from climate change18-20, which will affect aviation in the busy transatlantic flight corridor by creating a more turbulent flying environment for aircraft. We conclude that the effects of climate change and variability on the upper-level jet stream are being partly obscured by the traditional focus on wind speed rather than wind shear.
ABSTRACT
BACKGROUND: The National Cancer Institute-Children's Oncology Group Pediatric Molecular Analysis for Therapy Choice (MATCH) precision oncology platform trial enrolled children aged 1-21 years with treatment-refractory solid tumors and predefined actionable genetic alterations. Patients with tumors harboring alterations in DNA damage repair (DDR) genes were assigned to receive olaparib. METHODS: Tumor and blood samples were submitted for centralized molecular testing. Tumor and germline sequencing were conducted in parallel. Olaparib was given twice daily for 28-day cycles starting at a dose 30% lower than the adult recommended phase 2 dose (RP2D). The primary endpoint was the objective response. RESULTS: Eighteen patients matched (1.5% of those screened) based on the presence of a deleterious gene alteration in BRCA1/2, RAD51C/D, or ATM detected by tumor sequencing without germline subtraction or analysis of loss of heterozygosity (LOH). Eleven (61%) harbored a germline mutation, with only one exhibiting LOH. Six patients enrolled and received the olaparib starting dose of 135 mg/m2/dose. Two participants were fully evaluable; 4 were inevaluable because <85% of the prescribed dose was administered during cycle 1. There were no dose-limiting toxicities or responses. Minimal hematologic toxicity was observed. CONCLUSION: Most DDR gene alterations detected in Pediatric MATCH were germline, monoallelic, and unlikely to confer homologous recombination deficiency predicting sensitivity to olaparib monotherapy. The study closed due to poor accrual. CLINICALTRIALS.GOV IDENTIFIER: NCT03233204. IRB approved: initial July 24, 2017.
Subject(s)
DNA Repair , Neoplasms , Phthalazines , Piperazines , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Young Adult , Ataxia Telangiectasia Mutated Proteins/genetics , BRCA1 Protein/genetics , BRCA2 Protein/genetics , DNA Damage/drug effects , DNA Repair/drug effects , DNA Repair/genetics , DNA-Binding Proteins/genetics , Germ-Line Mutation , Neoplasms/drug therapy , Neoplasms/genetics , Phthalazines/therapeutic use , Phthalazines/adverse effects , Phthalazines/administration & dosage , Piperazines/therapeutic use , Piperazines/administration & dosage , Piperazines/adverse effects , Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use , Poly(ADP-ribose) Polymerase Inhibitors/adverse effectsABSTRACT
Orthostatic intolerance (OI), including postural orthostatic tachycardia syndrome (PoTS) and orthostatic hypotension (OH), are often reported in long covid, but published studies are small with inconsistent results. We sought to estimate the prevalence of objective OI in patients attending long covid clinics and healthy volunteers and associations with OI symptoms and comorbidities. Participants with a diagnosis of long covid were recruited from eight UK long covid clinics, and healthy volunteers from general population. All undertook standardized National Aeronautics and Space Administration Lean Test (NLT). Participants' history of typical OI symptoms (e.g., dizziness, palpitations) before and during the NLT were recorded. Two hundred seventy-seven long covid patients and 50 frequency-matched healthy volunteers were tested. Healthy volunteers had no history of OI symptoms or symptoms during NLT or PoTS, 10% had asymptomatic OH. One hundred thirty (47%) long covid patients had previous history of OI symptoms and 144 (52%) developed symptoms during the NLT. Forty-one (15%) had an abnormal NLT, 20 (7%) met criteria for PoTS, and 21 (8%) had OH. Of patients with an abnormal NLT, 45% had no prior symptoms of OI. Relaxing the diagnostic thresholds for PoTS from two consecutive abnormal readings to one abnormal reading during the NLT, resulted in 11% of long covid participants (an additional 4%) meeting criteria for PoTS, but not in healthy volunteers. More than half of long covid patients experienced OI symptoms during NLT and more than one in 10 patients met the criteria for either PoTS or OH, half of whom did not report previous typical OI symptoms. We therefore recommend all patients attending long covid clinics are offered an NLT and appropriate management commenced.
Subject(s)
COVID-19 , Orthostatic Intolerance , Postural Orthostatic Tachycardia Syndrome , United States , Humans , Orthostatic Intolerance/epidemiology , Orthostatic Intolerance/complications , Orthostatic Intolerance/diagnosis , Post-Acute COVID-19 Syndrome , Prevalence , COVID-19/epidemiology , COVID-19/complications , Postural Orthostatic Tachycardia Syndrome/complications , Postural Orthostatic Tachycardia Syndrome/diagnosisABSTRACT
Introduction The role of balloon aortic valvuloplasty (BAV) amid the era of transcatheter aortic valve replacement (TAVR) remains a topic of debate. We sought to study the safety and feasibility of combined balloon aortic valvuloplasty and percutaneous coronary intervention (BAV-PCI). Methods Between November 2009 and July 2020, all patients undergoing BAV were identified and divided into three groups: combined BAV-PCI (group A), BAV with significant unrevascularised CAD (group B) and BAV without significant CAD (group C). Procedural outcomes, 30-day and one-year mortality were compared. Results A total of 264 patients were studied (n = 84, 93 and 87 patients in group A, B and C, respectively). The STS score was 10.2 ±8, 13.3 ±19 and 8.1 ±7, p = 0.026, in group A, B and C, respectively. VARC-3 adjudicated complications were similar among groups (11%, 13% and 5%, respectively, p = 0.168, respectively). Thirty-day and one-year mortality were 9.8% (n =26) and 32% (n = 86) of the entire cohort. The differences among groups did not reach statistical significance. Using univariate Cox regression analysis, group B were at higher risk of dying compared to group A patients (HR 1.58, 95% CI 1.11 - 2.25, p = 0.010). With multivariate Cox regression analysis, the predictors of mortality were STS score, cardiogenic shock, and mode of presentation and lack of subsequent definitive valve intervention. Conclusion In high-risk patients with aortic valve stenosis, combined BAV-PCI is safe and feasible with comparable outcomes to BAV with and without significant CAD.
ABSTRACT
Filarial nematode infections are a major health concern in several countries. Lymphatic filariasis is caused by Wuchereria bancrofti and Brugia spp. affecting over 120 million people. Heavy infections can lead to elephantiasis, which has serious effects on individuals' lives. Although current anthelmintics are effective at killing microfilariae in the bloodstream, they have little to no effect against adult parasites found in the lymphatic system. The anthelmintic diethylcarbamazine is one of the central pillars of lymphatic filariasis control. Recent studies have reported that diethylcarbamazine can open transient receptor potential (TRP) channels in the muscles of adult female Brugia malayi, leading to contraction and paralysis. Diethylcarbamazine has synergistic effects in combination with emodepside on Brugia, inhibiting motility: emodepside is an anthelmintic that has effects on filarial nematodes and is under trial for the treatment of river blindness. Here, we have studied the effects of diethylcarbamazine on single Brugia muscle cells by measuring the change in Ca2+ fluorescence in the muscle using Ca2+-imaging techniques. Diethylcarbamazine interacts with the transient receptor potential channel, C classification (TRPC) ortholog receptor TRP-2 to promote Ca2+ entry into the Brugia muscle cells, which can activate Slopoke (SLO-1) Ca2+-activated K+ channels, the putative target of emodepside. A combination of diethylcarbamazine and emodepside leads to a bigger Ca2+ signal than when either compound is applied alone. Our study shows that diethylcarbamazine targets TRP channels to promote Ca2+ entry that is increased by emodepside activation of SLO-1 K+ channels.
Subject(s)
Anthelmintics , Brugia malayi , Elephantiasis, Filarial , Transient Receptor Potential Channels , Animals , Adult , Female , Humans , Diethylcarbamazine/pharmacology , Diethylcarbamazine/therapeutic use , Brugia malayi/physiology , Elephantiasis, Filarial/drug therapy , Elephantiasis, Filarial/parasitology , Transient Receptor Potential Channels/pharmacology , Transient Receptor Potential Channels/therapeutic use , Anthelmintics/pharmacology , MusclesABSTRACT
Bacterial biofilms are structured communities consisting of cells enmeshed in a self-generated extracellular matrix usually attached to a surface. They contain diverse classes of molecules including polysaccharides, lipids, proteins, nucleic acids, and diverse small organic molecules (primary and secondary metabolites) which are organized to optimize survival and facilitate dispersal to new colonization sites. In situ characterization of the chemical composition and structure of bacterial biofilms is necessary to fully understand their development on surfaces relevant to biofouling in health, industry, and the environment. Biofilm development has been extensively studied using confocal microscopy using targeted fluorescent labels providing important insights into the architecture of biofilms. Recently, cryopreparation has been used to undertake targeted in situ chemical characterization using Orbitrap secondary ion mass spectrometry (OrbiSIMS), providing a label-free method for imaging biofilms in their native state. Although the high mass resolution of OrbiSIMS enables more confident peak assignments, it is still very challenging to assign most of the peaks in the spectra due to complexity of SIMS spectra and lack of automatic peak assignment methods. Here, we analyze the same OrbiSIMS depth profile data generated from the frozen-hydrated biofilm, but employ a new untargeted chemical filtering process utilizing mass spectral databases to assign secondary ions to decipher the large number of fragments present in the SIMS spectra. To move towards comprehensive analysis of different chemistries in the sample, we apply a molecular formula prediction approach which putatively assigns 81% of peaks in the 3D OrbiSIMS depth profile analysis. This enables us to catalog over 1000 lipids and their fragments, 3500 protein fragments, 71 quorum sensing-related molecules (2-alkyl-4-quinolones and N-acylhomoserine lactones), 150 polysaccharide fragments, and glycolipids simultaneously from one data set and map these separated molecular classes spatially through a Pseudomonas aeruginosa biofilm. Assignment of different chemistries in this sample facilitates identification of differences between biofilms grown on biofilm-promoting and biofilm-resistant polymers.
Subject(s)
Biofilms , Pseudomonas aeruginosa , Pseudomonas aeruginosa/chemistry , Quorum Sensing , Spectrometry, Mass, Secondary Ion/methods , GlycolipidsABSTRACT
In Gram-positive bacteria such as Staphylococcus aureus and the coagulase-negative staphylococci (CoNS), the accessory gene regulator (agr) is a highly conserved but polymorphic quorum-sensing system involved in colonization, virulence and biofilm development. Signalling via agr depends on the interaction of an autoinducing peptide (AIP) with AgrC, a transmembrane sensor kinase that, once phosphorylated activates the response regulator AgrA. This in turn autoinduces AIP biosynthesis and drives target gene expression directly via AgrA or via the post-transcriptional regulator, RNAIII. In this review we describe the molecular mechanisms underlying the agr-mediated generation of, and response to, AIPs and the molecular basis of AIP-dependent activation and inhibition of AgrC. How the environment impacts on agr functionality is considered and the consequences of agr dysfunction for infection explored. We also discuss the concept of AIP-driven competitive interference between S. aureus and the CoNS and its anti-infective potential.
Subject(s)
Staphylococcus aureus , Staphylococcus , Staphylococcus/genetics , Staphylococcus aureus/metabolism , Peptides, Cyclic/genetics , Peptides, Cyclic/chemistry , Peptides, Cyclic/metabolism , Protein Kinases/genetics , Peptides/metabolism , Quorum Sensing , Bacterial Proteins/metabolismABSTRACT
In Pseudomonas aeruginosa, quorum sensing (QS) depends on an interconnected regulatory hierarchy involving the Las, Rhl and Pqs systems, which are collectively responsible for the co-ordinated synthesis of a diverse repertoire of N-acylhomoserine lactones (AHLs) and 2-alkyl-4-quinolones (AQs). Apparent population density-dependent phenomena such as QS may, however, be due to growth rate and/or nutrient exhaustion in batch culture. Using continuous culture, we show that growth rate and population density independently modulate the accumulation of AHLs and AQs such that the highest concentrations are observed at a slow growth rate and high population density. Carbon source (notably succinate), nutrient limitation (C, N, Fe, Mg) or growth at 25 °C generally reduces AHL and AQ levels, except for P and S limitation, which result in substantially higher concentrations of AQs, particularly AQ N-oxides, despite the lower population densities achieved. Principal component analysis indicates that ~26â% variation is due to nutrient limitation and a further 30â% is due to growth rate. The formation of N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL) turnover products such as the ring opened form and tetramic acid varies with the limiting nutrient limitation and anaerobiosis. Differential ratios of N-butanoyl-homoserine lactone (C4-HSL), 3OC12-HSL and the AQs as a function of growth environment are clearly apparent. Inactivation of QS by mutation of three key genes required for QS signal synthesis (lasI, rhlI and pqsA) substantially increases the concentrations of key substrates from the activated methyl cycle and aromatic amino acid biosynthesis, as well as ATP levels, highlighting the energetic drain that AHL and AQ synthesis and hence QS impose on P. aeruginosa.
Subject(s)
Pseudomonas aeruginosa , Quorum Sensing , Pseudomonas aeruginosa/genetics , Lactones/chemistry , Lactones/metabolism , 4-Butyrolactone/metabolism , Acyl-Butyrolactones/metabolism , Bacterial Proteins/geneticsABSTRACT
Extracellular DNA (eDNA) is a major constituent of the extracellular matrix of Pseudomonas aeruginosa biofilms and its release is regulated via pseudomonas quinolone signal (PQS) dependent quorum sensing (QS). By screening a P. aeruginosa transposon library to identify factors required for DNA release, mutants with insertions in the twin-arginine translocation (Tat) pathway were identified as exhibiting reduced eDNA release, and defective biofilm architecture with enhanced susceptibility to tobramycin. P. aeruginosa tat mutants showed substantial reductions in pyocyanin, rhamnolipid and membrane vesicle (MV) production consistent with perturbation of PQS-dependent QS as demonstrated by changes in pqsA expression and 2-alkyl-4-quinolone (AQ) production. Provision of exogenous PQS to the tat mutants did not return pqsA, rhlA or phzA1 expression or pyocyanin production to wild type levels. However, transformation of the tat mutants with the AQ-independent pqs effector pqsE restored phzA1 expression and pyocyanin production. Since mutation or inhibition of Tat prevented PQS-driven auto-induction, we sought to identify the Tat substrate(s) responsible. A pqsA::lux fusion was introduced into each of 34 validated P. aeruginosa Tat substrate deletion mutants. Analysis of each mutant for reduced bioluminescence revealed that the primary signalling defect was associated with the Rieske iron-sulfur subunit of the cytochrome bc1 complex. In common with the parent strain, a Rieske mutant exhibited defective PQS signalling, AQ production, rhlA expression and eDNA release that could be restored by genetic complementation. This defect was also phenocopied by deletion of cytB or cytC1. Thus, either lack of the Rieske sub-unit or mutation of cytochrome bc1 genes results in the perturbation of PQS-dependent autoinduction resulting in eDNA deficient biofilms, reduced antibiotic tolerance and compromised virulence factor production.
Subject(s)
Biofilms/growth & development , Electron Transport Complex III/metabolism , Extracellular Vesicles/genetics , Pseudomonas aeruginosa/growth & development , Quinolones/metabolism , Quorum Sensing , Twin-Arginine-Translocation System/metabolism , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Biofilms/drug effects , DNA, Bacterial/genetics , Electron Transport Complex III/genetics , Gene Expression Regulation, Bacterial , Glycolipids/metabolism , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/metabolism , Pyocyanine/metabolism , Twin-Arginine-Translocation System/genetics , Virulence Factors/genetics , Virulence Factors/metabolismABSTRACT
Presented in this work is the use of a molecular descriptor, termed the α parameter, to aid in the design of a series of novel, terpene-based, and sustainable polymers that were resistant to biofilm formation by the model bacterial pathogen Pseudomonas aeruginosa. To achieve this, the potential of a range of recently reported, terpene-derived monomers to deliver biofilm resistance when polymerized was both predicted and ranked by the application of the α parameter to key features in their molecular structures. These monomers were derived from commercially available terpenes (i.e., α-pinene, ß-pinene, and carvone), and the prediction of the biofilm resistance properties of the resultant novel (meth)acrylate polymers was confirmed using a combination of high-throughput polymerization screening (in a microarray format) and in vitro testing. Furthermore, monomers, which both exhibited the highest predicted biofilm anti-biofilm behavior and required less than two synthetic stages to be generated, were scaled-up and successfully printed using an inkjet "valve-based" 3D printer. Also, these materials were used to produce polymeric surfactants that were successfully used in microfluidic processing to create microparticles that possessed bio-instructive surfaces. As part of the up-scaling process, a novel rearrangement was observed in a proposed single-step synthesis of α-terpinyl methacrylate via methacryloxylation, which resulted in isolation of an isobornyl-bornyl methacrylate monomer mixture, and the resultant copolymer was also shown to be bacterial attachment-resistant. As there has been great interest in the current literature upon the adoption of these novel terpene-based polymers as green replacements for petrochemical-derived plastics, these observations have significant potential to produce new bio-resistant coatings, packaging materials, fibers, medical devices, etc.
Subject(s)
Biofilms , Terpenes , Terpenes/pharmacology , Polymers/chemistry , Bacteria , MethacrylatesABSTRACT
Anthropogenic environments such as those created by intensive farming of livestock, have been proposed to provide ideal selection pressure for the emergence of antimicrobial-resistant Escherichia coli bacteria and antimicrobial resistance genes (ARGs) and spread to humans. Here, we performed a longitudinal study in a large-scale commercial poultry farm in China, collecting E. coli isolates from both farm and slaughterhouse; targeting animals, carcasses, workers and their households and environment. By using whole-genome phylogenetic analysis and network analysis based on single nucleotide polymorphisms (SNPs), we found highly interrelated non-pathogenic and pathogenic E. coli strains with phylogenetic intermixing, and a high prevalence of shared multidrug resistance profiles amongst livestock, human and environment. Through an original data processing pipeline which combines omics, machine learning, gene sharing network and mobile genetic elements analysis, we investigated the resistance to 26 different antimicrobials and identified 361 genes associated to antimicrobial resistance (AMR) phenotypes; 58 of these were known AMR-associated genes and 35 were associated to multidrug resistance. We uncovered an extensive network of genes, correlated to AMR phenotypes, shared among livestock, humans, farm and slaughterhouse environments. We also found several human, livestock and environmental isolates sharing closely related mobile genetic elements carrying ARGs across host species and environments. In a scenario where no consensus exists on how antibiotic use in the livestock may affect antibiotic resistance in the human population, our findings provide novel insights into the broader epidemiology of antimicrobial resistance in livestock farming. Moreover, our original data analysis method has the potential to uncover AMR transmission pathways when applied to the study of other pathogens active in other anthropogenic environments characterised by complex interconnections between host species.
Subject(s)
Escherichia coli , Livestock , Animals , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial/genetics , Drug Resistance, Multiple, Bacterial , Farms , Humans , Livestock/microbiology , Longitudinal Studies , Machine Learning , PhylogenyABSTRACT
BACKGROUND: This study aimed to compare the achievement of pharmacokinetic-pharmacodynamic (PK-PD) exposure targets for vancomycin using a newly developed dosing guideline with product-information-based dosing in the treatment of adult patients with serious infections. METHODS: In silico product-information- and guideline-based dosing simulations for vancomycin were performed across a range of doses and patient characteristics, including body weight, age, and renal function at 36-48 and 96 hours, using a pharmacokinetic model derived from a seriously ill patient population. The median simulated concentration and area under the 24-hour concentration-time curve (AUC 0-24 ) were used to measure predefined therapeutic, subtherapeutic, and toxicity PK-PD targets. RESULTS: Ninety-six dosing simulations were performed. The pooled median trough concentration target with guideline-based dosing at 36 and 96 hours was achieved in 27.1% (13/48) and 8.3% (7/48) of simulations, respectively. The pooled median AUC 0-24 /minimum inhibitory concentration ratio with guideline-based dosing at 48 and 96 hours was attained in 39.6% (19/48) and 27.1% (13/48) of simulations, respectively. Guideline-based dosing simulations yielded improved trough target attainment compared with product-information-based dosing at 36 hours and significantly less subtherapeutic drug exposure. The toxicity threshold was exceeded in 52.1% (25/48) and 0% (0/48) for guideline- and product-information-information-based dosing, respectively ( P < 0.001). CONCLUSIONS: A Critical care vancomycin dosing guideline appeared slightly more effective than standard dosing, as per product information, in achieving PK-PD exposure associated with an increased likelihood of effectiveness. In addition, this guideline significantly reduced the risk of subtherapeutic exposure. The risk of exceeding toxicity thresholds, however, was greater with the guideline, and further investigation is suggested to improve dosing accuracy and sensitivity.
Subject(s)
Anti-Bacterial Agents , Vancomycin , Humans , Adult , Vancomycin/pharmacokinetics , Anti-Bacterial Agents/pharmacokinetics , Body Weight , Area Under Curve , Microbial Sensitivity TestsABSTRACT
BACKGROUND: In recent years, numerous dosing studies have been conducted to optimize therapeutic antibiotic exposures in patients with serious infections. These studies have led to the inclusion of dose optimization recommendations in international clinical practice guidelines. The last international survey describing dosing, administration and monitoring of commonly prescribed antibiotics for critically ill patients was published in 2015 (ADMIN-ICU 2015). This study aimed to describe the evolution of practice since this time. METHODS: A cross-sectional international survey distributed through professional societies and networks was used to obtain information on practices used in the dosing, administration and monitoring of vancomycin, piperacillin/tazobactam, meropenem and aminoglycosides. RESULTS: A total of 538 respondents (71% physicians and 29% pharmacists) from 409 hospitals in 45 countries completed the survey. Vancomycin was mostly administered as an intermittent infusion, and loading doses were used by 74% of respondents with 25 mg/kg and 20 mg/kg the most favoured doses for intermittent and continuous infusions, respectively. Piperacillin/tazobactam and meropenem were most frequently administered as an extended infusion (42% and 51%, respectively). Therapeutic drug monitoring was undertaken by 90%, 82%, 43%, and 39% of respondents for vancomycin, aminoglycosides, piperacillin/tazobactam, and meropenem, respectively, and was more frequently performed in high-income countries. Respondents rarely used dosing software to guide therapy in clinical practice and was most frequently used with vancomycin (11%). CONCLUSIONS: We observed numerous changes in practice since the ADMIN-ICU 2015 survey was conducted. Beta-lactams are more commonly administered as extended infusions, and therapeutic drug monitoring use has increased, which align with emerging evidence.
Subject(s)
Anti-Bacterial Agents , Vancomycin , Humans , Adult , Vancomycin/therapeutic use , Meropenem , Cross-Sectional Studies , Piperacillin, Tazobactam Drug Combination , Surveys and Questionnaires , Intensive Care Units , Aminoglycosides , Critical Illness/therapy , PiperacillinABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted human-to-human via aerosols and air-borne droplets. Therefore, capturing and destroying viruses from indoor premises are essential to reduce the probability of human exposure and virus transmission. While the heating, ventilation, and air conditioning (HVAC) systems help in reducing the indoor viral load, a targeted approach is required to effectively remove SARS-CoV-2 from indoor air to address human exposure concerns. The present study demonstrates efficient trapping and destruction of SARS-CoV-2 via nano-enabled filter technology using the UV-A-stimulated photoelectrochemical oxidation (PECO) process. Aerosols containing SARS-CoV-2 were generated by nebulization inside an air-controlled test chamber where an air purifier (Air Mini+) was placed. The study demonstrated the efficient removal of SARS-CoV-2 (99.98 %) from the test chamber in less than two minutes and PECO-assisted destruction (over 99%) on the filtration media in 1 h. Furthermore, in a real-world scenario, the Molekule Air-Pro air purifier removed SARS-CoV-2 (a negative RT-qPCR result post-running the filter device) from the circulating air in a COVID-19 testing facility. Overall, the ability of two FDA-approved class II medical devices, Molekule Air-Mini+ and Air-Pro air purifiers, to remove and destroy SARS-CoV-2 in indoor settings was successfully demonstrated. The study indicates that as the "tripledemic" of COVID-19, influenza, and respiratory syncytial virus (RSV) overwhelm the healthcare facilities in the USA, the use of a portable air filtration device will help contain the spread of the viruses in close door facilities, such as in schools and daycare facilities.
Subject(s)
Air Filters , Air Pollution, Indoor , COVID-19 , Humans , SARS-CoV-2 , COVID-19 Testing , Respiratory Aerosols and Droplets , Air Pollution, Indoor/prevention & controlABSTRACT
The study of wearable sensors for human disease monitoring has developed into an important research area due to its potential for personalized health care. Various sensor types have been proposed for assessing the range of joint movement in patients with progressive diseases or following post-surgical treatments. Many of these methods suffer from poor accuracy, sensitivity, and linearity or are very expensive and complex to implement. To overcome some of these limitations, this paper reports on the development of a novel flexible sensor for the measurement of bending by utilizing the Matteucci effect in the amorphous wire. This paper describes a bend sensor that utilizes positive magnetostrictive amorphous wire to achieve a measurement sensitivity equal to 5.68 ± 0.02 mV/cm with a resolution of ±0.2° over a measuring range of 64 to 143°.
Subject(s)
Wearable Electronic Devices , Humans , MovementABSTRACT
South African legislation regulates the classification/labelling and compositional specifications of raw beef patties, to combat processed meat fraud and to protect the consumer. A near-infrared hyperspectral imaging (NIR-HSI) system was investigated as an alternative authentication technique to the current destructive, time-consuming, labour-intensive and expensive methods. Eight hundred beef patties (ca. 100 g) were made and analysed to assess the potential of NIR-HSI to distinguish between the four patty categories (200 patties per category): premium 'ground patty'; regular 'burger patty'; 'value-burger/patty' and the 'econo-burger'/'budget'. Hyperspectral images were acquired with a HySpex SWIR-384 (short-wave infrared) imaging system using the Breeze® acquisition software, in the wavelength range of 952-2517 nm, after which the data was analysed using image analysis, multivariate techniques and machine learning algorithms. It was possible to distinguish between the four patty categories with accuracies ≥97%, indicating that NIR-HSI offers an accurate and reliable solution for the rapid identification and authentication of processed beef patties. Furthermore, this study has the potential of providing an alternative to the current authentication methods, thus contributing to the authenticity and fair-trade of processed meat products locally and internationally.
Subject(s)
Meat Products , Meat , Animals , Cattle , AlgorithmsABSTRACT
Bacterial contamination during space missions is problematic for human health and damages filters and other vital support systems. Staphylococcus aureus is both a human commensal and an opportunistic pathogen that colonizes human tissues and causes acute and chronic infections. Virulence and colonization factors are positively and negatively regulated, respectively, by bacterial cell-to-cell communication (quorum sensing) via the agr (accessory gene regulator) system. When cultured under low-shear modelled microgravity conditions (LSMMG), S. aureus has been reported to maintain a colonization rather than a pathogenic phenotype. Here, we show that the modulation of agr expression via reduced production of autoinducing peptide (AIP) signal molecules was responsible for this behavior. In an LSMMG environment, the S. aureus strains JE2 (methicillin-resistant) and SH1000 (methicillin-sensitive) both exhibited reduced cytotoxicity towards the human leukemia monocytic cell line (THP-1) and increased fibronectin binding. Using S. aureus agrP3::lux reporter gene fusions and mass spectrometry to quantify the AIP concentrations, the activation of agr, which depends on the binding of AIP to the transcriptional regulator AgrC, was delayed in the strains with an intact autoinducible agr system. This was because AIP production was reduced under these growth conditions compared with the ground controls. Under LSMMG, S. aureus agrP3::lux reporter strains that cannot produce endogenous AIPs still responded to exogenous AIPs. Provision of exogenous AIPs to S. aureus USA300 during microgravity culture restored the cytotoxicity of culture supernatants for the THP-1 cells. These data suggest that microgravity does not affect AgrC-AIP interactions but more likely the generation of AIPs.