Hidden in plain sight - Multiple resistant species within a strongyle community

Ovine parasitic gastroenteritis is a complex disease routinely treated using anthelmintics. Although many different strongyle species may contribute to parasitic gastroenteritis, not all are equally pathogenic: in temperate regions, the primary pathogen is Teladorsagia circumcincta. In this study we investigated benzimidazole and ivermectin resistance on a commercial sheep farm in southeast Scotland. We assessed the impact of species diversity on the diagnosis of resistance using the faecal egg count reduction test and in vitro bioassays, and correlated the results with the frequency of benzimidazole resistance-associated genotypes measured in the T. circumcincta population by pyrosequencing of the β-tubulin isotype-1 gene. Faecal egg count reduction test results showed efficacies of 65% for albendazole and 77% for ivermectin, indicating moderate resistance levels on the farm. However, PCR speciation of the same populations pre- and post-treatment revealed that removal of susceptible species had masked the presence of a highly resistant population of T. circumcincta. Less than 25% of individuals in the pre-treatment populations were T. circumcincta, the remainder consisting of Cooperia curticei, Chabertia ovina, Oesophagostomum venulosum and Trichostrongylus spp. In contrast, post-treatment with albendazole or ivermectin, the majority (88% and 100% respectively) of the populations consisted of T. circumcincta. The egg hatch test for benzimidazole resistance and the larval development test for ivermectin resistance were carried out using eggs obtained from the same populations and the results were broadly consistent with the faecal egg count reduction test. Thirty individual T. circumcincta from each sampling time point were assessed for benzimidazole resistance by pyrosequencing, revealing a high frequency and diversity of resistance-associated mutations, including within the population sampled post-ivermectin treatment. These results highlight the potential diversity of parasite species present on UK farms, and their importance in the diagnosis of anthelmintic resistance. On this particular farm, we demonstrate the presence of a highly dual-resistant population of T. circumcincta, which was strongly selected by treatment with either benzimidazoles or ivermectin, while other potentially less pathogenic species were removed

Increased expression of a microRNA correlates with anthelmintic resistance in parasitic nematodes

Resistance to anthelmintic drugs is a major problem in the global fight against parasitic nematodes infecting humans and animals. While previous studies have identified mutations in drug target genes in resistant parasites, changes in the expression levels of both targets and transporters have also been reported. The mechanisms underlying these changes in gene expression are unresolved. Here, we take a novel approach to this problem by investigating the role of small regulatory RNAs in drug resistant strains of the important parasite Haemonchus contortus. microRNAs (miRNAs) are small (22 nt) non-coding RNAs that regulate gene expression by binding predominantly to the 3′ UTR of mRNAs. Changes in miRNA expression have been implicated in drug resistance in a variety of tumor cells. In this study, we focused on two geographically distinct ivermectin resistant strains of H. contortus and two lines generated by multiple rounds of backcrossing between susceptible and resistant parents, with ivermectin selection. All four resistant strains showed significantly increased expression of a single miRNA, hco-miR-9551, compared to the susceptible strain. This same miRNA is also upregulated in a multi-drug-resistant strain of the related nematode Teladorsagia circumcincta. hco-miR-9551 is enriched in female worms, is likely to be located on the X chromosome and is restricted to clade V parasitic nematodes. Genes containing predicted binding sites for hco-miR-9551 were identified computationally and refined based on differential expression in a transcriptomic dataset prepared from the same drug resistant and susceptible strains. This analysis identified three putative target mRNAs, one of which, a CHAC domain containing protein, is located in a region of the H. contortus genome introgressed from the resistant parent. hco-miR-9551 was shown to interact with the 3′ UTR of this gene by dual luciferase assay. This study is the first to suggest a role for miRNAs and the genes they regulate in drug resistant parasitic nematodes. miR-9551 also has potential as a biomarker of resistance in different nematode species

The environmental stress sensitivities of pathogenic Candida species, including Candida auris, and implications for their spread in the hospital setting

We are grateful to Dr. David Stead, Evelyn Argo and Craig Pattison (Aberdeen Proteomics Core Facility) for their expert identification of Candida isolates by MALDI ToF MS, and to Dr Jill King and our colleagues in the Aberdeen Fungal Group for their helpful advice. AJPB and NARG were supported by a programme grant from the Medical Research Council [www.mrc.ac.uk] (grant number MR/M026663/1) and by the Medical Research Council Centre for Medical Mycology and the University of Aberdeen (grant number MR/N006364/1). AJPB was also supported by the UK Biotechnology and Biological Research Council [www.bbsrc.ac.uk] (grant numbers BB/F00513X/1, BB/P020119/1), and AWW by the Scottish Government’s Rural and Environment Science and Analytical Services (RESAS) division. NARG was also supported by grants from the Wellcome Trust [www.wellcome.ac.uk] (grant numbers 075470, 086827, 093378, 097377, 099197, 101873, 102705, 200208). DMM was supported by National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) [www.nc3rs.org.uk] (grant numbers NC/S001557/1 and NC/N002482/1) and the UK Biotechnology and Biological Research Council [www.bbsrc.ac.uk] (grant number BB/P02050X/1). HH was supported by the John Duthie Scholarship from the University of Aberdeen’s Development Trust. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Advancing One Health: Updated core competencies

One Health recognises the interdependence between the health of humans, animals, plants and the environment. With the increasing inclusion of One Health in multiple global health strategies, the One Health workforce must be prepared to protect and sustain the health and well-being of life on the planet. In this paper, a review of past and currently accepted One Health core competencies was conducted, with competence gaps identified. Here, the Network for Ecohealth and One Health (NEOH) propose updated core competencies designed to simplify what can be a complex area, grouping competencies into three main areas of: Skills; Values and Attitudes; and Knowledge and Awareness; with several layers underlying each. These are intentionally applicable to stakeholders from various sectors and across all levels to support capacity-building efforts within the One Health workforce. The updated competencies from NEOH can be used to evaluate and enhance current curricula, create new ones, or inform professional training programs at all levels, including students, university teaching staff, or government officials as well as continual professional development for frontline health practitioners and policy makers. The competencies are aligned with the new definition of One Health developed by the One Health High-Level Expert Panel (OHHLEP), and when supported by subjectspecific expertise, will deliver the transformation needed to prevent and respond to complex global challenges

A novel nanozyme assay utilising the catalytic activity of silver nanoparticles and SERRS

Artificial enzymes have become an increasingly interesting area of research due to their many advantages over natural protein enzymes which are expensive, difficult to isolate and unable to stand harsh environments. An important area of this research involves using metal nanoparticles as artificial enzymes, known as nanozymes, which exhibit peroxidase-like activity enabling them to catalyse the oxidation of substrates such as 3,3’,5,5’-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2), giving a colorimetric response. Here we exploit the catalytic activity of silver nanoparticles (Ag NPs) in a surface based silver-linked immunosorbent assay (SLISA) to detect human C-reactive protein (CRP), an inflammatory marker. Ag NPs were conjugated to antibodies with specific recognition for the corresponding target antigenic molecule, CRP, and used to catalyse the oxidation of TMB by H2O2. The resulting coloured oxidation product was detected using SERRS. We demonstrate that Ag NPs can replace the enzymes used in a conventional ELISA and a detection limit of 1.09 ng/mL of CRP can be achieved. It indicates the promise for SLISAs for biomarker detection and opens the way for further assays of this nature to be created. This novel assay has the potential to be optimised to detect lower levels of CRP and can be further extended for the sensitive and specific detection of other relevant biomarkers