Publications by authors named "Jonathan Betts"

The development of alternatives to antibiotics is essential for the treatment of animal infections and as a measure to reduce the selective pressure on antibiotics that are critical for human medicine. Metal complexes have been highlighted for their antimicrobial activity against several bacterial pathogens. In particular, manganese carbonyl complexes have shown efficacy against multidrug-resistant Gram-negative pathogens, and relatively low cytotoxicity against avian macrophages and in wax moth larval models.

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Gastrointestinal parasites are among the most economically important pathogens of small ruminants causing serious economic losses and animal welfare problems for the livestock industry worldwide. The emergence of anthelmintic resistant H. contortus in small ruminants is a serious problem because it undermines effective helminth control and results in reduced productivity.

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The need for maintaining cell-spheroid viability and function within high-density cultures is unmet for various clinical and experimental applications, including cell therapies. One immediate application is for transplantation of pancreatic islets, a clinically recognized treatment option to cure type 1 diabetes; islets are isolated from a donor for subsequent culture prior to transplantation. However, high seeding conditions cause unsolicited fusion of multiple spheroids, thereby limiting oxygen diffusion to induce hypoxic cell death.

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Multidrug-resistant (MDR) Enterobacterales are a priority health issue with few treatment options. Recently, fosfomycin has been reconsidered for MDR bacterial infections. Zidovudine, licensed for the treatment of human immunodeficiency virus (HIV), has unexploited antibacterial properties and has been considered for drug repurposing.

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Extreme pressures and high magnetic fields can affect materials in profound and fascinating ways. However, large pressures and fields are often mutually incompatible; the rapidly changing fields provided by pulsed magnets induce eddy currents in the metallic components used in conventional pressure cells, causing serious heating, forces, and vibration. Here, we report a diamond-anvil-cell made mainly out of insulating composites that minimizes inductive heating while retaining sufficient strength to apply pressures of up to 8 GPa.

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This review summarizes the mechanisms of antibacterial action of green tea catechins, discussing the structure-activity relationship (SAR) studies for each mechanism. The antibacterial activity of green tea catechins results from a variety of mechanisms that can be broadly classified into the following groups: (1) inhibition of virulence factors (toxins and extracellular matrix); (2) cell wall and cell membrane disruption; (3) inhibition of intracellular enzymes; (4) oxidative stress; (5) DNA damage; and (6) iron chelation. These mechanisms operate simultaneously with relative importance differing among bacterial strains.

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CeRhIn provides a textbook example of quantum criticality in a heavy fermion system: Pressure suppresses local-moment antiferromagnetic (AFM) order and induces superconductivity in a dome around the associated quantum critical point (QCP) near p ≈ 23 kbar. Strong magnetic fields also suppress the AFM order at a field-induced QCP at B ≈ 50 T. In its vicinity, a nematic phase at B ≈ 28 T characterized by a large in-plane resistivity anisotropy emerges.

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Objectives: The emergence of multidrug-resistance (MDR) in Streptococcus pneumoniae clones and non-vaccine serotypes necessitate the development of novel treatment strategies. This work aimed to determine the efficacy of the Mn complex [Mn(CO)(tpa-κN)]Br against clinically important MDR strains of S. pneumoniae.

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This study aimed to investigate the mechanisms of colistin resistance in 64 Acinetobacter baumannii isolates obtained from patients with ventilator-associated pneumonia hospitalised in Greece, Italy and Spain. In total, 31 A. baumannii isolates were colistin-resistant.

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. is an important Gram-negative pathogen that is intrinsically multidrug-resistant (MDR) and frequently associated with healthcare-associated outbreaks. With increasing resistance to antibiotics and with very few novel drugs under development, clinicians often use combinations to treat critically ill patients.

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The discovery of superconductivity at 260 K in hydrogen-rich compounds like LaH re-invigorated the quest for room temperature superconductivity. Here, we report the temperature dependence of the upper critical fields μH(T) of superconducting HS under a record-high combination of applied pressures up to 160 GPa and fields up to 65 T. We find that H(T) displays a linear dependence on temperature over an extended range as found in multigap or in strongly-coupled superconductors, thus deviating from conventional Werthamer, Helfand, and Hohenberg (WHH) formalism.

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Colistin resistance in is of great concern and is a threat to human health. In this study, we investigate the mechanisms of colistin resistance in four isogenic pairs of isolates displaying an increase in colistin MICs. A mutation in was detected in each colistin-resistant isolate, three of which were novel (A28V, I232T, and ΔL9-G12).

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In recent years, several plasmids harbouring genes encoding phosphoethanolamine transferases conferring colistin resistance have been described in multiple Enterobacteriaceae species. Avian Pathogenic E. coli (APEC) causes colibacillosis and is responsible for a considerable proportion of the disease burden in commercial poultry flocks, and may be linked to zoonotic infections in humans.

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With the advent of the global antimicrobial resistance (AMR) crisis, our arsenal of effective antibiotics is diminishing. The widespread use and misuse of antibiotics in human and veterinary medicine, compounded by the lack of novel classes of antibiotic in the pharmaceutical pipeline, has left a hole in our antibiotic armamentarium. Thus, alternatives to traditional antibiotics are being investigated, including two major groups of antibacterial agents, which have been extensively studied, phytochemicals and metals.

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Extended-spectrum cephalosporin- and/or carbapenem-resistant (ESC and/or Carb) Enterobacteriaceae constitute a public health hazard because of limited treatment options and are endemic among humans in Greece. Recently, ESC and CarbEnterobacteriaceae have been increasingly isolated from companion animals, stressing their potential role as a reservoir for humans. However, the presence of ESC bacteria in companion animals within Greek households has not been determined yet.

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The bla β-lactamase gene is one of the most prevalent genes conferring resistance to extended-spectrum β-lactams in Enterobacteriaceae disseminating within and between reservoirs, mostly via plasmid-mediated horizontal gene transfer. Yet, studies regarding the biology of plasmids encoding bla are very limited. In this study, we revealed the emergence of IncX3 plasmids alongside IncI1α/γ in bla in animal-related Escherichia coli isolates.

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In this work, we review single mode SiO₂ fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity () as low as a few parts in one hundred million (≈10).

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Antimicrobial resistance is a growing global concern in human and veterinary medicine, with an ever-increasing void in the arsenal of clinicians. Novel classes of compounds including carbon monoxoide-releasing molecules (CORMs), for example the light-activated metal complex [Mn(CO)3(tpa-κ3N)]Br, could be used as alternatives/to supplement traditional antibacterials. Avian pathogenic Escherichia coli (APEC) represent a large reservoir of antibiotic resistance and can cause serious clinical disease in poultry, with potential as zoonotic pathogens, due to shared serotypes and virulence factors with human pathogenic E.

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AcrAB-TolC is the paradigm resistance-nodulation-division (RND) multidrug resistance efflux system in Gram-negative bacteria, with AcrB being the pump protein in this complex. We constructed a nonfunctional AcrB mutant by replacing D408, a highly conserved residue essential for proton translocation. Western blotting confirmed that the AcrB D408A mutant had the same native level of expression of AcrB as the parental strain.

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Introduction: Acinetobacter baumannii is an important human nosocomial pathogen; most clinical isolates are multidrug-resistant (MDR). Infections caused by A. baumannii often lead to high morbidity and mortality, with limited treatment options.

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Providencia stuartii has emerged as an important nosocomial pathogen. We describe an outbreak due to a multidrug-resistant strain over a 4-month period in a critical care unit in Athens. Molecular typing revealed each of the isolates to be clonally related with coresistance to cephalosporins, carbapenems, aminoglycosides, and quinolones.

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Bacterial infections resulting from nonsurgical traumatic wounds can be life threatening, especially those caused by multidrug-resistant (MDR) bacteria with limited therapeutic options. The antimicrobial activity of polymyxin B (1) and curcumin (2) alone and in combination was determined versus MDR bacterial isolates associated with traumatic wound infections. Cytotoxicity assays for 1 and 2 were undertaken in keratinocyte cell lines.

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We evaluated an immunochromatographic lateral flow assay to detect OXA-48-like carbapenemases (OXA-48 K-SeT) in Enterobacteriaceae (n = 82). One hundred percent sensitivity and specificity were observed using bacteria recovered from both solid medium and spiked blood culture bottles, and the results were obtained in <10 min.

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Topical infections can become life threatening in immunocompromised patients. However, fewer treatments are available as multi-drug-resistant bacteria become more common. The natural compounds epigallocatechin gallate (1) and quercetin (2) alone and in combination were tested as potential antimicrobial clinical therapies.

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The spread of multidrug-resistant Acinetobacter baumannii (MDRAB) has led to the renaissance of colistin (COL), often the only agent to which MDRAB remains susceptible. Effective therapy with COL is beset with problems due to unpredictable pharmacokinetics, toxicity, and the rapid selection of resistance. Here, we describe a potent synergistic interaction when COL was combined with fusidic acid (FD) against A.

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