Variations in antimicrobial resistance genes present in the rectal faeces of seals in Scottish and Liverpool Bay coastal waters.

Antibiotic resistance genes originating from human activity are considered important environmental pollutants. Wildlife species can act as sentinels for coastal environmental contamination and in this study we used qPCR array technology to investigate the variety and abundance of antimicrobial resistance genes (ARGs), mobile genetic elements (MGEs) and integrons circulating within seal populations both near to and far from large human populations located around the Scottish and northwest English coast. Rectal swabs were taken from 50 live grey seals and nine live harbour seals. Nucleic acids were stabilised upon collection, enabling extraction of sufficient quality and quantity DNA for downstream analysis. 78 ARG targets, including genes of clinical significance, four MGE targets and three integron targets were used to monitor genes within 22 sample pools. 30 ARGs were detected, as well as the integrons intl1 and intl2 and tnpA transposase. Four ß-lactam, nine tetracycline, two phenicol, one trimethoprim, three aminoglycoside and ten multidrug resistance genes were detected as well as mcr-1 which confers resistance to colistin, an important drug of last resort. No sulphonamide, vancomycin, macrolide, lincosamide or streptogramin B (MLSB) resistance genes were detected. Resistance genes were detected in all sites but the highest number of ARGs (n = 29) was detected in samples derived from grey seals on the Isle of May, Scotland during the breeding season, and these genes also had the highest average abundance in relation to the 16S rRNA gene. This pilot study demonstrates the effectiveness of a culture-independent workflow for global analysis of ARGs within the microbiota of live, free-ranging, wild animals from habitats close to and remote from human habitation, and highlights seals as a valuable indicator species for monitoring the presence, abundance and land-sea transference of resistance genes within and between ecosystems.

Tailoring follow-up endoscopy in patients with severe oesophagitis.

Objective: We aimed to investigate the clinical utility of follow-up oesophagogastroduodenoscopy (OGD2) in patients with severe oesophagitis (Los Angeles grades C or D) through evaluating the yield of Barrett's oesophagus (BO), cancer, dysplasia and strictures. Second, we aimed to determine if the Clinical Frailty Scale (CFS) may be used to identify patients to undergo OGD2s. Design/method: Patients in NHS Lothian with an index OGD (OGD1) diagnosis of severe oesophagitis between 1 January 2014 and 31 December 2015 were identified. Univariate analysis identified factors associated with grade. Patients were stratified by frailty and a diagnosis of stricture, cancer, dysplasia and BO. Results: In total 964 patients were diagnosed with severe oesophagitis, 61.7% grade C and 38.3% grade D. The diagnostic yield of new pathology at OGD2 was 13.2% (n=51), new strictures (2.3%), dysplasia (0.5%), cancer (0.3%) and BO (10.1%). A total of 140 patients had clinical frailty (CFS score ≥5), 88.6% of which were deceased at review (median of 76 months). In total 16.4% of frail patients underwent OGD2s and five new pathologies were diagnosed, none of which were significantly associated with grade. Among non-frail patients at OGD2, BO was the only pathology more common (p=0.010) in patients with grade D. Rates of cancer, dysplasia and strictures did not vary significantly between grades. Conclusion: Our data demonstrate that OGD2s in patients with severe oesophagitis may be tailored according to clinical frailty and only be offered to non-frail patients. In non-frail patients OGD2s have similar pick-up rates of sinister pathology in both grades of severe oesophagitis.

Analgesic effect of local anaesthetic in haemorrhoid banding: systematic review and meta-analysis.

PURPOSE: Rubber band ligation of haemorrhoids can be,painful and there is no consensus regarding the optimal analgesic strategy. This study aims to determine whether there is a difference in post-procedural pain in adults undergoing haemorrhoid banding who have received local anaesthetic, a pudendal nerve block or no regional or local analgesia. METHODS: MEDLINE, Embase, Google Scholar and clinical trial registries were searched for randomised trials of local anaesthetic or pudendal nerve block use in banding. Primary outcomes were patient-reported pain scores. The quality of the evidence was assessed using the GRADE approach. RESULTS: Seven studies were included in the final review. No articles were identified that studied pudendal nerve blocks. The difference in numerical pain scores between treatment groups favoured the local anaesthetic group at all timepoints. The mean difference in scores on a 10-point scale was at 1 h,-1.43 (95% CI-2.30 to-0.56, p < 0.01, n = 342 (175 in treatment group)); 6 h,-0.52 (95% CI-1.04 to 0.01, p = 0.05, n = 250 (130 in treatment group)); and 24 h,-0.31 (95% CI-0.82 to 0.19, p = 0.86, n = 247 (127 in treatment group)). Of reported safety outcomes, vasovagal symptoms proceeded to meta-analysis, with a risk ratio of 1.01 (95% CI 0.64-1.60). The quality of the evidence was rated down to 'low' due to inconsistency and imprecision. CONCLUSION: This review supports the use of LA for reducing early post-procedural pain following haemorrhoid banding. The evidence was limited by small sample sizes and substantial heterogeneity across studies. REGISTRATION: PROSPERO (ID CRD42022322234).

Use of pudendal nerve blocks in rubber band ligation of haemorrhoids: an Australia-wide cross-sectional analysis.

BACKGROUND: Surgeons vary in their approach to preventing pain post rubber band ligation (RBL) of haemorrhoids, with pudendal nerve blocks (PNB) being one analgesic strategy. No data exists on how commonly PNBs are used in RBL in Australia, and whether use varies by year and patient and hospital characteristics. METHODS: Aggregate data from the National Hospital Morbidity Database was obtained for all admissions for RBL in Australia from 2012 to 2021, with and without a PNB, overall and in relation to sex, age group, hospital remoteness, hospital sector, and year of procedure. Adjusted relative risks (adj. RR) of PNB were estimated using Poisson regression, mutually adjusting for all variables. RESULTS: Of the 346 542 admissions for RBL, 14013 (4.04%) involved a PNB. The proportion of patients receiving a PNB increased between 2012-2013 and 2020-2021, from 1.62% to 6.63% (adj. RR 3.99, CI 3.64-4.36). Patients most likely to receive a PNB were female (adj. RR 1.10; CI 1.07-1.14) aged 25-34 years (adj. RR 1.13; CI 1.01-1.26); in major-city (adj. RR 1.25 CI 1.20-1.30) and private hospitals (adj. RR 3.28 CI 3.13-3.45). CONCLUSION: This is the first published analysis of the use of PNB in RBL. Pudendal nerve block use has increased over time, with substantial variation in practice. Blocks were more than three times as likely to be used in private compared to public hospitals. If evidence supporting PNB use is established, equitable access to the procedure should be pursued.

Training primary care staff in delivering the primary care consultation remotely: a systematic review.

BACKGROUND: Remote consultation is widely used in primary care, and its use has increased greatly since the onset of the COVID-19 pandemic. Despite this, primary care clinicians lack formal training in delivering remote consultation. There is a need to understand how training might best be delivered, and what evidence there is to support this. AIM: To summarise existing published literature about training primary care staff in conducting primary care consultation remotely, to outline which models of training may be effective, and to identify unanswered questions for future research. DESIGN & SETTING: Systematic review of English language studies in primary care included in Medline (Ovid), Cochrane Database, PubMed, Embase (Ovid), Web of Science, and CINAHL from 2010-2021; and in Google results from 2010-2022. METHOD: Databases were searched using a predefined search strategy. Title, abstract, and full-text screening was conducted to identify eligible studies for inclusion in the review. The quality of included studies was assessed, and findings were synthesised to answer the research questions. RESULTS: We included 10 studies. Seven examined training on remote consultation with trainee GPs or residents, and three examined training on remote consultation with qualified primary care clinicians. Training described led to positive change overall, including increased confidence and self-efficacy in delivering remote consultations. Furthermore, trainees reported increased use of remote consultation, increased efficiency, and increased engagement from patients. Studies where training involved workshops or didactic learning alongside experiential learning resulted in more positive feelings and more confidence about how technology could aid consultations. CONCLUSION: There is limited evidence on training primary care staff in conducting remote consultation. Available evidence indicates that training has a positive impact on the ability of clinicians and staff to deliver remote consultation.

Local anaesthetic infiltration in rubber band ligation of rectal haemorrhoids: study protocol for a three-arm, double-blind randomised controlled trial (PLATIPUS trial).

INTRODUCTION: Rubber band ligation ('banding') is a common approach for the management of symptomatic haemorrhoids. However, up to 90% of patients experience postprocedural pain, and there is no consensus regarding the optimal analgesic strategy. In practice, patients may receive submucosal local anaesthetic, pudendal nerve block or routine periprocedural analgesia. The aim of this study is to compare the efficacy of submucosal local anaesthetic, pudendal nerve block and routine analgesia for postprocedural pain in patients undergoing haemorrhoid banding. METHODS AND ANALYSIS: This is a multicentre, prospective, three-arm, double-blind randomised controlled trial of adults booked for haemorrhoid banding. Participants will be randomised to one of three groups in a 1:1:1 ratio: (1)submucosal bupivacaine injection; (2) pudendal nerve ropivacaine injection and (3) no local anaesthetic. The primary outcome is patient reported postprocedural pain (scored 0-10) from 30 min to 2 weeks. Secondary outcomes include postprocedural analgesia use, time to discharge, patient satisfaction, time to return to work and complications. A sample size of 120 patients is required to achieve statistical significance. ETHICS AND DISSEMINATION: This study received Human Research Ethics Approval from the Austin Health Human Research Ethics Committee (March 2022). Trial results will be submitted to a peer-reviewed journal, and presented at academic meetings. A summary of the trial results will be made available to study participants on request. TRIAL REGISTRATION NUMBER: ACTRN12622000006741p.

Improving communication access in psychoeducational interventions for people with complex communication needs: a scoping review and stakeholder consultation.

PURPOSE: Psychoeducational interventions are commonly used to improve mental health among the general population; however, their application among people with complex communication needs is under explored. This scoping review aims to identify the psychoeducational interventions utilised with people with complex communication needs, any adaptations to improve communication access, and outcomes for this population. MATERIALS AND METHODS: The scoping review was conducted using the Arksey and O'Malley guidelines and included stakeholder consultations. A systematic search of the literature was conducted. Stakeholder consultations were conducted via semi-structured interviews with informants from three populations: people with complex communication needs, everyday communication partners and mental health workers. RESULTS: The search yielded 2112 articles. Twenty-four articles were retained for data extraction. Numerical analysis provided an overview of the existing literature. Thematic analysis highlighted the range of communication access strategies applied within psychoeducational interventions. Common aims and outcomes of interventions occurred across three interrelated themes: education, symptom reduction, and improved coping and wellbeing. Stakeholder consultations enabled contextualisation of literature. CONCLUSIONS: People with complex communication needs may benefit from psychoeducational interventions when effective, personalised communication access strategies are employed. Future research should include lived-experience perspectives to ensure the relevance of communication access strategies in mental health support.Implications for rehabilitationThis scoping review adds to the evidence base supporting equitable access to mental health support for people with complex communication needs.A range of specific strategies are presented for mental health workers to consider when working with people with complex communication needs.Positive behaviour support (PBS) practitioners must be equipped to address the psychoeducational and mental health support requirements of people with complex communication needs.

Navigating parenthood in the surgical profession: mixed-methods study.

BACKGROUND: Significant barriers exist to surgeons being good parents and parents being good surgeons, and these barriers are heightened for women. Considering the gender balance now present in postgraduate medical schools, it is critical that these barriers are overcome if surgery is to attract and retain applicants. This study aimed to investigate patterns of parenthood in surgery, explore associated attitudes and experiences, and identify barriers and solutions within an Australian and New Zealand context. METHODS: Surgeons and trainees were invited to participate in a survey and focus groups. Quantitative results were described, and textual responses and focus group transcriptions were analysed thematically. RESULTS: There were 261 survey respondents (62.8 per cent women, 37.2 per cent men) and six focus groups (34 participants). Of the survey respondents, 79.6 per cent of women and 86.5 per cent of men had children. Women were more likely to time childbirth around training or work, and most respondents without children attributed this to their career. Tensions between parenthood and surgery engendered guilt for surgeon-parents. Parenthood was often the 'elephant in the room' in training and employment discussions. Breaking the silence around parenthood and surgery made it more acceptable, normalising positive behaviour changes. The major barrier to parenthood and surgery was the lack of flexible training opportunities. Participants called for top-down establishment of mandated, stand-alone, permanent part-time training positions. CONCLUSION: Many barriers to parenthood in surgery are created by rigid workplace and professional structures that are reflective of male-dominated historical norms. A willingness to be flexible, innovative and rethink models of training and employment is central to change.

It is difficult for surgeons to be good parents and parents to be good surgeons. This is a problem because it means that fewer doctors may want to be surgeons. This study asked surgeons and trainee surgeons what it is like to do their job as a parent. They were asked about this on their own and in groups. It was found that it is more difficult for female surgeons to have children than male surgeons. Surgeons with children feel guilty that they are not able to do a good job both at work and at home. Surgeons often avoid talking about parenting at work, because it is not normal to do so and they are afraid that it will have a negative effect on their career. If surgeons can work part-time while training, it would enable them to better balance their responsibilities as surgeons and parents. At the moment, there are not many opportunities to train part-time in Australia and New Zealand. This study suggests that surgeons and hospitals should make sure that this becomes accessible and normal.

The contribution of sex chromosome conflict to disrupted spermatogenesis in hybrid house mice.

Incompatibilities on the sex chromosomes are important in the evolution of hybrid male sterility, but the evolutionary forces underlying this phenomenon are unclear. House mice (Mus musculus) lineages have provided powerful models for understanding the genetic basis of hybrid male sterility. X chromosome-autosome interactions cause strong incompatibilities in M. musculus F1 hybrids, but variation in sterility phenotypes suggests a more complex genetic basis. In addition, XY chromosome conflict has resulted in rapid expansions of ampliconic genes with dosage-dependent expression that is essential to spermatogenesis. Here, we evaluated the contribution of XY lineage mismatch to male fertility and stage-specific gene expression in hybrid mice. We performed backcrosses between two house mouse subspecies to generate reciprocal Y-introgression strains and used these strains to test the effects of XY mismatch in hybrids. Our transcriptome analyses of sorted spermatid cells revealed widespread overexpression of the X chromosome in sterile F1 hybrids independent of Y chromosome subspecies origin. Thus, postmeiotic overexpression of the X chromosome in sterile F1 mouse hybrids is likely a downstream consequence of disrupted meiotic X-inactivation rather than XY gene copy number imbalance. Y chromosome introgression did result in subfertility phenotypes and disrupted expression of several autosomal genes in mice with an otherwise nonhybrid genomic background, suggesting that Y-linked incompatibilities contribute to reproductive barriers, but likely not as a direct consequence of XY conflict. Collectively, these findings suggest that rapid sex chromosome gene family evolution driven by genomic conflict has not resulted in strong male reproductive barriers between these subspecies of house mice.

Docking and molecular dynamics studies of human ezrin protein with a modelled SARS-CoV-2 endodomain and their interaction with potential invasion inhibitors.

Human ezrin protein interacts with SARS-CoV S endodomain and restricts virus fusion, entry, and early events of infection. In general, their binding strength and their structural stability determines their successful entry into the host cells. However, the binding affinity of these two endodomains with the ezrin protein has been elusive due to a paucity of knowledge on the 3D structure. This study modelled the endodomains of both SARS-CoV-1 and SARS-CoV-2 and then docked these models with human ezrin protein. This study establishes that the modelled endodomains of both SARS-CoV-1 and SARS-Cov-2 consisted of three disulphide bridges for self-stabilization. Protein-protein docking listed four salt bridges with a higher buried surface area between ezrin-SARS-CoV-1 endodomain compared to that of ezrin-SARS-CoV-2 with six salt bridges with lower buried surface area. Molecular simulation of the ezrin-SARS-CoV-1 endodomain showed better structural stability with lower Root Mean Square Deviation score compared to that of ezrin-SARS-CoV-2 endodomain due to the substitution of alanine with cysteine residue. Protein-ligand docking studies confirmed better ezrin-drug interaction for quercetin, minocycline, calcifediol, calcitriol, selamectin, ivermectin and ergocalciferol. However, protein-ligand simulation confirmed strong drug-protein interaction during simulation for all the above-listed drugs except for ergocalciferol which could not establish its interaction with the protein during simulation. Strong drug binding within the active site pocket therefore restricts the interaction of viral endodomain and simultaneously stabilizes the ezrin protein. Furthermore, the higher stability between the ezrin after their interaction with the drug moiety could restrict the virus fusion and the infection. This study provides a basis for further development of these drug molecules to clinical trials aiming to identify potential drug molecules which can treat COVID-19 infection.

A comparative study of the fecal microbiota of gray seal pups and yearlings - a marine mammal sentinel species.

Gray seals (Halichoerus grypus) can act as sentinel species reflecting the condition of the environment they inhabit. Our previous research identified strains of pathogenic Campylobacter and Salmonella, originating from both human and agricultural animal hosts, on rectal swabs from live gray seal (H. grypus) pups and yearlings on the Isle of May, Scotland, UK. We examined rectal swabs from the same pup (n = 90) and yearling (n = 19) gray seals to gain further understanding into the effects of age-related changes (pup vs. yearling) and three different natal terrestrial habitats on seal pup fecal microbiota. DNA was extracted from a subset of rectal swabs (pups n = 23, yearlings n = 9) using an optimized procedure, and the V4 region of the 16S ribosomal RNA gene was sequenced to identify each individual's microbiota. Diversity in pup samples was lower (3.92 ± 0.19) than yearlings (4.66 ± 0.39) although not significant at the p = 0.05 level (p = 0.062) but differences in the composition of the microbiota were (p < 0.001). Similarly, differences between the composition of the microbiota from pups from three different terrestrial habitats (Pilgrim's Haven [PH], Rona Rocks [RR], and Tarbet Slope [TS]) were highly significant (p < 0.001). Pairwise tests showed significant differences between all three habitats: PH versus TS (p = 0.019), PH versus RR (p = 0.042) and TS versus RR (p = 0.020). This preliminary study suggests a general trend, that seal microbiomes are modified by both age and, in pups, different terrestrial habitats. Furthermore, knowledge of the microbiota species present has the potential to be used in determining the environmental quality index.

Risk stratifying gastric ulcers: development and validation of a scoring system.

Objective: Debate is ongoing regarding the need for universal endoscopic follow-up to ensure gastric ulcer healing. We aimed to assess the value of follow-up oesophago-gastro-duodenoscopies (OGDs) for gastric ulcer healing and stratify patients according to risk of malignancy by developing a risk score. Design/method: All patients in National Health Service (NHS) Lothian with an index OGD and a diagnosis of gastric ulcer between 1 January 2014 and 31 December 2018 were identified. Data were analysed with logistic regression to identify factors significantly associated with a diagnosis of cancer; a risk score was derived and externally validated. Results: 778 patients were identified and 60.3% (469/778) of patients had a follow-up OGD. 8.6% (66/778) of patients were diagnosed with cancer. No cases of cancer were found on follow-up OGD of a benign appearing ulcer with negative biopsies. Macroscopic suspicion of malignancy was present at index OGD in 100% (3/3) of those diagnosed with cancer on subsequent OGDs. Older age (p=0.014), increased ulcer size (p<0.001) and non-antral location (p=0.030) were significantly associated with malignancy. A risk score (area under the curve (AUC) 0.868, p<0.001, minimum score=0, maximum score=6) was derived from these variables. 78.0% of patients with malignant ulcers scored ≥3, only 15.8% with benign ulcers scored ≥3 (negative predictive value (NPV) 97.4%). External validation yielded an AUC of 0.862 (p<0.001) and NPV of 98.6%; 84.0% of those with malignant ulcers scored ≥3. Conclusion: Ulcers with a combination of macroscopically benign appearances, at least six negative biopsies and a low risk score do not necessarily need endoscopic follow-up.

A pilot randomised controlled trial of patient education to improve umbilical cleanliness prior to laparoscopic surgery.

BACKGROUND: Before laparoscopic abdominal surgery, surgeons frequently remove debris from patients' umbilici to prevent it from passing into the abdomen and optimise skin antisepsis. This task irritates the skin, takes time and contaminates sterile equipment. This pilot randomised controlled trial aimed to inform a definitive study investigating whether patient education improves umbilical cleanliness in these patients. METHODS: To generate data on effect size and sample size, adult patients undergoing elective and emergency laparoscopic abdominal surgery were randomised to an intervention group, who received an education pack to clean their umbilicus prior to surgery, or a control group, who received no pack. Umbilical cleanliness was measured using a novel scale. To assess scale validity and reliability, all umbilici were scored by nine surgeons and surgical trainees using photographs and umbilici were swabbed to estimate bacterial load. Intervention acceptability was assessed via study consent and withdrawal rates and trial feasibility was evaluated using qualitative insights documented by investigators. RESULTS: Seventy-one percent (22/31) of the intervention group had clean umbilici versus 61% (19/31) in the control group. A definitive trial would require 712 participants to show statistical significance between study groups. The umbilical cleanliness scale had excellent interrater and test-retest reliability and a moderate degree of convergent validity with respect to bacterial load. The intervention was highly acceptable to participants, and theatre nurses and surgical trainees were central to trial feasibility. CONCLUSION: A definitive trial is warranted and would contribute to an evidence-based, standardised approach to preoperative care. Trial registration no. ACTRN12620000278932.

IEEE P7001: A Proposed Standard on Transparency.

This paper describes IEEE P7001, a new draft standard on transparency of autonomous systems. In the paper, we outline the development and structure of the draft standard. We present the rationale for transparency as a measurable, testable property. We outline five stakeholder groups: users, the general public and bystanders, safety certification agencies, incident/accident investigators and lawyers/expert witnesses, and explain the thinking behind the normative definitions of "levels" of transparency for each stakeholder group in P7001. The paper illustrates the application of P7001 through worked examples of both specification and assessment of fictional autonomous systems.

Telomere Distribution in Human Sperm Heads and Its Relation to Sperm Nuclear Morphology: A New Marker for Male Factor Infertility?

Infertility is a problem affecting an increasing number of couples worldwide. Currently, marker tests for male factor infertility are complex, highly technical and relatively subjective. Up to 40% of cases of male factor infertility are currently diagnosed as idiopathic therefore, there is a clear need for further research into better ways of diagnosing it. Changes in sperm telomere length have been associated with infertility and closely linked to DNA damage and fragmentation, which are also known to be related to infertility. However, telomere distribution is a parameter thus far underexplored as an infertility marker. Here, we assessed morphological parameters of sperm nuclei in fertile control and male factor infertile cohorts. In addition, we used 2D and 3D fluorescence in situ hybridization (FISH) to compare telomere distribution between these two groups. Our findings indicate that the infertile cohort sperm nuclei were, on average, 2.9% larger in area and showed subtle differences in sperm head height and width. Telomeres were mainly distributed towards the periphery of the nuclei in the control cohort, with diminishing telomere signals towards the center of the nuclei. Sperm nuclei of infertile males, however, had more telomere signals towards the center of the nuclei, a finding supported by 3D imaging. We conclude that, with further development, both morphology and telomere distribution may prove useful investigative tools in the fertility clinic.

Mental health matters: a pilot study exploring the experiences and perspectives of individuals with complex communication needs.

Mental health and wellbeing are foundational in human interaction and life satisfaction. Persons with complex communication needs are at risk of reduced mental health and wellbeing. The aim of this project was to identify the facilitators and barriers that individuals with complex communication needs experience when attending to their mental health and wellbeing. A qualitative study design using a phenomenological approach was utilized. Data was collected through in-depth interviews with three participants with complex communication needs, observation, and reflexive journaling. An inductive process of cross-case thematic analysis identified common barriers and facilitators experienced by the participants when addressing mental health and wellbeing. The opportunity barriers described in Beukelman and Mirenda's  Participation Model were applied to classify the assistive and obstructive roles of communication partners. Barriers and facilitators to obtaining assistance for mental health and wellbeing related predominantly to communication partners' skills, attitudes, and support practices. The findings highlight a need to equip individuals with complex communication needs, carers, support workers, and mental health professionals with the knowledge, skills, and attitudes to promote mental health and wellbeing among this population.

Metagenomic sequencing of clinical samples reveals a single widespread clone of Lawsonia intracellularis responsible for porcine proliferative enteropathy.

Lawsonia intracellularis is a Gram-negative obligate intracellular bacterium that is the aetiological agent of proliferative enteropathy (PE), a common intestinal disease of major economic importance in pigs and other animal species. To date, progress in understanding the biology of L. intracellularis for improved disease control has been hampered by the inability to culture the organism in vitro. In particular, our understanding of the genomic diversity and population structure of clinical L. intercellularis is very limited. Here, we utilized a metagenomic shotgun approach to directly sequence and assemble 21 L. intracellularis genomes from faecal and ileum samples of infected pigs and horses across three continents. Phylogenetic analysis revealed a genetically monomorphic clonal lineage responsible for infections in pigs, with distinct subtypes associated with infections in horses. The genome was highly conserved, with 94 % of genes shared by all isolates and a very small accessory genome made up of only 84 genes across all sequenced strains. In part, the accessory genome was represented by regions with a high density of SNPs, indicative of recombination events importing novel gene alleles. In summary, our analysis provides the first view of the population structure for L. intracellularis, revealing a single major lineage associated with disease of pigs. The limited diversity and broad geographical distribution suggest the recent emergence and clonal expansion of an important livestock pathogen.

Characterisation of a niche-specific excretory-secretory peroxiredoxin from the parasitic nematode Teladorsagia circumcincta.

BACKGROUND: The primary cause of parasitic gastroenteritis in small ruminants in temperate regions is the brown stomach worm, Teladorsagia circumcincta. Host immunity to this parasite is slow to develop, consistent with the ability of T. circumcincta to suppress the host immune response. Previous studies have shown that infective fourth-stage T. circumcincta larvae produce excretory-secretory products that are able to modulate the host immune response. The objective of this study was to identify immune modulatory excretory-secretory proteins from populations of fourth-stage T. circumcincta larvae present in two different host-niches: those associated with the gastric glands (mucosal-dwelling larvae) and those either loosely associated with the mucosa or free-living in the lumen (lumen-dwelling larvae). RESULTS: In this study excretory-secretory proteins from mucosal-dwelling and lumen-dwelling T. circumcincta fourth stage larvae were analysed using comparative 2-dimensional gel electrophoresis. A total of 17 proteins were identified as differentially expressed, with 14 proteins unique to, or enriched in, the excretory-secretory proteins of mucosal-dwelling larvae. One of the identified proteins, unique to mucosal-dwelling larvae, was a putative peroxiredoxin (T. circumcincta peroxiredoxin 1, Tci-Prx1). Peroxiredoxin orthologs from the trematode parasites Schistosoma mansoni and Fasciola hepatica have previously been shown to alternatively activate macrophages and play a key role in promoting parasite induced Th2 type immunity. Here we demonstrate that Tci-Prx1 is expressed in all infective T. circumcincta life-stages and, when produced as a recombinant protein, has peroxidase activity, whereby hydrogen peroxide (H2O2) is reduced and detoxified. Furthermore, we use an in vitro macrophage stimulation assay to demonstrate that, unlike peroxiredoxins from trematode parasites Schistosoma mansoni and Fasciola hepatica, Tci-Prx1 is unable to alternatively activate murine macrophage cells. CONCLUSIONS: In this study, we identified differences in the excretory-secretory proteome of mucosal-dwelling and lumen-dwelling infective fourth-stage T. circumcincta larvae, and demonstrated the utility of this comparative proteomic approach to identify excretory-secretory proteins of potential importance for parasite survival and/or host immune modulation.