Spotlight on avian pathology: Salmonella - new wine and old bottles.

Salmonella enterica remains an important avian and human pathogen. Control has been effective in some countries but the hygiene and biosecurity required may not be possible everywhere. Antibiotic resistance is an increasing problem for both veterinary and human medicine. This short review commentary highlights existing and potential new control measures including legislation, hygiene and biosecurity, use of live and inactivated vaccines, and bacteriophages to tackle intestinal colonization, reduce the prevalence of antibiotic resistance and improve carcass decontamination.

Deciphering the role of ttrA and pduA genes for Salmonella enterica serovars in a chicken infection model.

Salmonella enterica serovars use self-induced intestinal inflammation to increase electron acceptor availability and to obtain a growth advantage in the host gut. There is evidence suggesting that the ability of Salmonella to use tetrathionate and 1,2-propanediol provides an advantage in murine infection. Thus, we present here the first study to evaluate both systemic infection and faecal excretion in commercial poultry challenged by Salmonella Enteritidis (SE) and S. Typhimurium (STM) harbouring deletions in ttrA and pduA genes, which are crucial to the metabolism of tetrathionate and 1,2-propanediol, respectively. Mutant strains were excreted at higher rates when compared to the wild-type strains. The highest rates were observed with white egg-layer and brown egg-layer chicks (67.5%), and broiler chicks (56.7%) challenged by SEΔttrAΔpduA, and brown egg-layer chicks (64.8%) challenged by STMΔttrAΔpduA. SEΔttrAΔpduA presented higher bacterial counts in the liver and spleen of the three chicken lineages and caecal contents from the broiler chickens, whereas STMΔttrAΔpduA presented higher counts in the liver and spleen of the broiler and brown-egg chickens for 28 days post-infection (P < 0.05). The ttrA and pduA genes do not appear to be major virulence determinants in faecal excretion or invasiveness for SE and STM in chickens. RESEARCH HIGHLIGHTSttrA and pudA do not impair gut colonization or systemic infection in chicks.Mutant strains were present in higher numbers in broilers than in laying chicks.Mutants of SE and STM showed greater pathogenicity in broiler chicks than layers.

Concordance of 3 alternative teratogenicity assays with results from corresponding in vivo embryo-fetal development studies: Final report from the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) DruSafe working group 2.

An IQ DruSafe working group evaluated the concordance of 3 alternative teratogenicity assays (rat whole embryo culture, rWEC; zebrafish embryo culture, ZEC; and murine embryonic stem cells, mESC) with findings from rat or rabbit embryo-fetal development (EFD) studies. Data for 90 individual compounds from 9 companies were entered into a database. In vivo findings were deemed positive if malformations or embryo-fetal lethality were reported in either species. Each company used their own criteria for deciding whether the alternative assay predicted the in vivo findings. Standard concordance parameters were calculated, positive and negative predictive values (PPV and NPV) were adjusted for the aggregate portfolio prevalence of positive compounds (established by a survey of participating companies), and positive and negative likelihood ratios (LR+ and iLR-) were calculated. Of the 3 assays, only rWEC data were robustly predictive, particularly for negative predictions (NPVadj = 92%). However, both LR+ (4.92) and iLR- (4.72) were statistically significant for the rWEC assay. When analyzed separately for rats, the NPVadj and iLR-values for the rWEC assay increased to 96% and 9.75, respectively. These data suggest that a negative rWEC outcome could defer or replace a rat EFD study in certain regulatory settings.

The Gordon Memorial Lecture: novel approaches to controlling bacterial infections.

1. There is huge emphasis in veterinary and agricultural science in understanding the basics of processes and exploiting them for benefits to the economy and human and animal welfare. It is always valuable to be able to step back from existing or favourite hypotheses and paradigms to look at an area of work or problem and see whether a different approach might be productive particularly by drawing parallels with other sometimes unrelated problems. 2. This approach has been used to explore (i) the use of live, attenuated Salmonella vaccines to generate a new form of competitive exclusion, (ii) gene expression technology for the design of improved inactivated vaccines (iii) use of cytokine therapy to reduce persistent carriage by Salmonella, (iv) using bacteriophages to reduce carcass contamination by food-borne pathogens and reduce carriage of antibiotic resistance plasmids. 3. The potential for extending virus therapy to parasite infections is also discussed.

Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data.

We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431_{-14}^{+16} day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9σ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8σ, from a previous analysis of a subset of this data, to 1.8σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7σ.

First Dark Matter Search Results from the XENON1T Experiment.

We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12)-kg fiducial mass and in the [5,40] keV_{nr} energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93±0.25)×10^{-4} events/(kg×day×keV_{ee}), the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10 GeV/c^{2}, with a minimum of 7.7×10^{-47} cm^{2} for 35-GeV/c^{2} WIMPs at 90% C.L.

Multicentre observational study of outcomes after drainage of acute perianal abscess.

INTRODUCTION: Management of perianal abscesses has remained largely unchanged for over 50 years. The evidence for postoperative wound packing is limited and may expose patients to painful procedures with no clinical benefit and at considerable increased cost. METHODS: Patients were recruited in 15 UK centres between December 2013 and October 2014. Outcome measures included number of dressing (pack) changes, healing, recurrence, return to work/normal function, postoperative fistula in ano and health utility scores (EQ-5D™). Pain was measured before, during and after dressing change on a visual analogue scale. RESULTS: Some 141 patients were recruited (median age 39 (range 18-86) years). The mean number of dressing changes in the first 3 weeks was 13 (range 0-21), equating to an annual cost to the National Health Service of €6 453 360 in England alone per annum. Some 43·8 per cent of wounds were healed by 8 weeks after surgery and 86 per cent of patients had returned to normal function. Some 7·6 per cent of abscesses had recurred and 26·7 per cent of patients developed a fistula in ano by 6 months following surgery. Patients reported a twofold to threefold increase in pain scores during and after dressing changes. CONCLUSION: Recurrent abscess is rare and fistula occurs in one-quarter of the patients. Packing is painful and costly.

Improving the uptake of predictive testing and colorectal screening in Lynch syndrome: a regional primary care survey.

Lynch syndrome (LS) is an autosomal dominant cancer predisposition syndrome with a 60-80% lifetime risk of colorectal cancer. We assessed the uptake of predictive testing and colorectal screening among first-degree relatives (FDRs) in LS families and explored novel methods for informing and engaging at-risk relatives. Uptake of predictive testing was explored using Kaplan-Meier analysis and engagement with colorectal screening was ascertained. A questionnaire was distributed to 216 general practitioners (GPs) of registered LS family members to determine their prior experience and opinion of an enhanced role. Of 591, 329 (55.7%) FDRs had undergone predictive testing. Uptake was significantly lower in males (p = 0.012) and individuals <25 years (p < 0.001). Mutation carriers were more likely to undergo colorectal screening than untested FDRs (97.2% vs 34.9%; P ≤ 0.0001). Of 216, 63 (29.2%) questionnaires were returned. Most GPs (55/63; 87.3%) were not confident to discuss the details of LS with patients and relatives. The main barriers were lack of knowledge and concerns about confidentiality. Compliance with colorectal screening is excellent following a mutation positive predictive test. Uptake of predictive testing could be substantially improved, particularly among males and younger age groups. GPs are unlikely to actively participate in communication with at-risk relatives without considerable support.

Search for Event Rate Modulation in XENON100 Electronic Recoil Data.

We have searched for periodic variations of the electronic recoil event rate in the (2-6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its background contributions during this run, we performed an unbinned profile likelihood analysis to identify any periodicity up to 500 days. We find a global significance of less than 1σ for all periods, suggesting no statistically significant modulation in the data. While the local significance for an annual modulation is 2.8σ, the analysis of a multiple-scatter control sample and the phase of the modulation disfavor a dark matter interpretation. The DAMA/LIBRA annual modulation interpreted as a dark matter signature with axial-vector coupling of weakly interacting massive particles to electrons is excluded at 4.8σ.

Systematic review of the impact of registration and screening on colorectal cancer incidence and mortality in familial adenomatous polyposis and Lynch syndrome.

BACKGROUND: The British Society of Gastroenterology recommends that all familial adenomatous polyposis (FAP) and Lynch syndrome (LS) families are screened in the context of a registry. This systematic review was performed to appraise the published evidence for registration and screening in relation to colorectal cancer (CRC) incidence and mortality. METHODS: Five electronic databases were searched using a combination of medical subject heading terms and free-text keywords. Titles and abstracts were scrutinized by two independent reviewers. Inclusion criteria were English-language studies describing CRC incidence and/or mortality in patients with FAP or LS, with comparison of either: screened and unscreened patients, or time periods before and after establishment of the registry. RESULTS: Of 4668 abstracts identified, 185 full-text articles were selected; 43 studies fulfilled the inclusion criteria. No randomized clinical trial evidence was identified. For FAP, 33 of 33 studies described a significant reduction of CRC incidence and mortality with registration and screening. For LS, nine of ten studies described a reduction of CRC incidence and mortality with registration and screening. Five studies (FAP, 2; LS, 3) provided evidence for complete prevention of CRC-related deaths during surveillance. Clinical and statistical heterogeneity prevented pooling of data for meta-analysis. CONCLUSION: Studies consistently report that registration and screening result in a reduction of CRC incidence and mortality in patients with FAP and LS (level 2a evidence, grade B recommendation). Funding and managerial support for hereditary CRC registries should be made available.

The long view: Salmonella--the last forty years.

As a part of the 40th anniversary celebrations of Avian Pathology we review the last four decades of Salmonella research which has led to major progress in our understanding of the bacteriology and infection biology of the organism through the huge advances in molecular biology and immunology that have accompanied technical advances in biology generally. In many countries combinations of improvements in management, sometimes under legislative pressure and supported by a number of basic biological interventions, have resulted in reductions in incidence in the Salmonella serovars that are commonly associated with food-poisoning to unprecedented low levels in parent flocks, broilers and layers. Utilisation of the information generated during the past few decades should improve the efficacy of surveillance and biological interventions both for the intestinal carriage that is associated most frequently with human infection and also for systemic diseases, including fowl typhoid and pullorum disease. These two diseases continue to be major economic problems in many countries where the possibilities for improvements in hygiene may be limited but which, nevertheless, are increasingly a significant part of the global economy in poultry meat.

Endotoxin transiently inhibits protein synthesis through Akt and MAPK mediating pathways in C2C12 myotubes.

In this study, the effect of lipopolysaccharide (LPS) on protein synthesis (PS) and intracellular signaling factors that regulate it have been investigated in C2C12 murine-derived myotubes. In particular, the role of Akt/mammalian target of rapamycin (mTOR) and the mitogen-activated protein kinases (MAPKs) [p38 and extracelluar regulated protein kinase (ERK1/2)] have been examined. The direct effect of LPS on PS was measured at 3 and 18 h. LPS significantly decreased PS at 3 h but not at the 18-h time point. This effect was preceded by decreased Akt phosphorylation at 5 and 30 min after LPS administration. The mTOR phosphorylation exhibited a long time dose-dependent increase at all the time points. Similarly, the activity-related phosphorylation of p38 and ERK1/2 significantly increased in a time- and dose-dependent manner at all the time points. Polymyxin B abolished the LPS-induced decrease in PS rate. The phosphatidylinositol 3-kinase inhibitor LY-0294002 in combination with LPS significantly decreased the rate of PS by 81% and alone by 66%, respectively, for the 3- and 18-h time points, whereas p38 and ERK inhibitors in combination with LPS significantly decreased the rate PS rate at the 18-h time point by 41% and 59%, respectively, compared with control cells. In conclusion, LPS alone transiently decreased the rate of PS by 50% at 3 h; this effect is most likely mediated via the Toll-like receptor 4 (TLR4)-Akt/mTOR pathway, and both p38 and ERK when inhibited in the presence of LPS at 3 h have a similar effect in preventing the LPS-induced reduction in PS.

Salmonella enterica serovar typhimurium colonizing the lumen of the chicken intestine grows slowly and upregulates a unique set of virulence and metabolism genes.

The pattern of global gene expression in Salmonella enterica serovar Typhimurium bacteria harvested from the chicken intestinal lumen (cecum) was compared with that of a late-log-phase LB broth culture using a whole-genome microarray. Levels of transcription, translation, and cell division in vivo were lower than those in vitro. S. Typhimurium appeared to be using carbon sources, such as propionate, 1,2-propanediol, and ethanolamine, in addition to melibiose and ascorbate, the latter possibly transformed to d-xylulose. Amino acid starvation appeared to be a factor during colonization. Bacteria in the lumen were non- or weakly motile and nonchemotactic but showed upregulation of a number of fimbrial and Salmonella pathogenicity island 3 (SPI-3) and 5 genes, suggesting a close physical association with the host during colonization. S. Typhimurium bacteria harvested from the cecal mucosa showed an expression profile similar to that of bacteria from the intestinal lumen, except that levels of transcription, translation, and cell division were higher and glucose may also have been used as a carbon source.

Pullorum disease and fowl typhoid--new thoughts on old diseases: a review.

Fowl typhoid and pullorum disease are two distinct septicaemic diseases largely specific to avian species and caused by Salmonella Gallinarum and Salmonella Pullorum, respectively. They were first described more than one century ago. Since their discovery, many efforts have been made to control and prevent their occurrence in commercial farming of birds. However, they remain a serious economic problem to livestock in countries where measures of control are not efficient or in those where the climatic conditions favour the environmental spread of these microorganisms. During the past 15 to 20 years there has been an explosion of genetic and immunological information on the biology of these two organisms, which is beginning to contribute to a better understanding of the organisms and their interaction with the host. However, it is not enough simply to understand the pathology in greater and greater detail. What is needed, in addition to this increase in basic knowledge, is creative thinking to challenge existing paradigms and to develop really novel approaches to infection control.

The prevalence of coeliac disease-associated human leukocyte antigens in South African transplant donors and recipients.

BACKGROUND: Coeliac disease (CD) is an autoimmune condition occurring in genetically predisposed individuals exposed to an environmental trigger. The human leukocyte antigen (HLA) haplotypes HLA-DQ2.5 and HLA-DQ8 have the strongest association with CD, and 90 - 95% of CD patients bear these haplotypes. The susceptibility of the South African (SA) population to CD has not been studied previously. OBJECTIVES: To describe the genetic propensity of the SA population to CD. METHODS: The South African National Blood Service database was used to analyse the prevalence of HLA-DQ2.5 and HLA-DQ8 in potential donors and recipients of organ transplants. Self-reported ethnic group was used to estimate the prevalence among different population groups. RESULTS: The overall prevalence of HLA-DQ2.5 and HLA-DQ8 was 19.8%. The prevalence was lower in black participants (15.9%) than in whites (28.6%). Coloured (22.0%) and Indian (17.4%) participants had an intermediate prevalence. There was no significant difference between potential transplant donors and recipients. CONCLUSIONS: The prevalence of HLA-DQ2.5 and HLA-DQ8 differed among SA study participants of different ethnicities. However, the notion that CD does not occur in black South Africans owing to lack of a genetic predisposition is incorrect.

Bacteriophage applications: where are we now?

Bacteriophages are bacterial viruses and have been used for almost a century as antimicrobial agents. In the West, their use diminished when chemical antibiotics were introduced, but they remain a common therapeutic approach in parts of eastern Europe. Increasing antibiotic resistance in bacteria has driven the demand for novel therapies to control infections and led to the replacement of antibiotics in animal husbandry. Alongside this, increased pressure to improve food safety has created a need for faster detection of pathogenic bacteria. Hence, there has been a resurgence of interest in bacteriophage applications, and this has encouraged the emergence of a large number of biotech companies hoping to commercialize their use. Research in Europe and the United States has increased steadily, leading to the development of a range of applications for bacteriophage agents for the healthcare, veterinary and agricultural sectors. This article will attempt to answer the question of whether bacteriophages are now delivering on their potential.

Predicting the safety of medicines in pregnancy: A workshop report.

The framework for developmental toxicity testing has remained largely unchanged for over 50 years and although it remains invaluable in assessing potential risks in pregnancy, knowledge gaps exist, and some outcomes do not necessarily correlate with clinical experience. Advances in omics, in silico approaches and alternative assays are providing opportunities to enhance our understanding of embryo-fetal development and the prediction of potential risks associated with the use of medicines in pregnancy. A workshop organised by the Medicines and Healthcare products Regulatory Agency (MHRA), "Predicting the Safety of Medicines in Pregnancy - a New Era?", was attended by delegates representing regulatory authorities, academia, industry, patients, funding bodies and software developers to consider how to improve the quality of and access to nonclinical developmental toxicity data and how to use this data to better predict the safety of medicines in human pregnancy. The workshop delegates concluded that based on comparative data to date alternative methodologies are currently no more predictive than conventional methods and not qualified for use in regulatory submissions. To advance the development and qualification of alternative methodologies, there is a requirement for better coordinated multidisciplinary cross-sector interactions coupled with data sharing. Furthermore, a better understanding of human developmental biology and the incorporation of this knowledge into the development of alternative methodologies is essential to enhance the prediction of adverse outcomes for human development. The output of the workshop was a series of recommendations aimed at supporting multidisciplinary efforts to develop and validate these alternative methodologies.

The 'ins and outs' of colonoscopy at Wits Donald Gordon Medical Centre, South Africa: A practice audit of the outpatient endoscopy unit.

BACKGROUND: In South Africa, there are no national guidelines for the conduct or quality assessment of colonoscopy, the gold standard for investigation and diagnosis of bowel pathology. OBJECTIVES: To describe the clinical profile of patients and evaluate the practice of colonoscopy using procedural quality indicators at the Wits Donald Gordon Medical Centre (WDGMC) outpatient endoscopy unit (OEU). METHODS: We conducted a prospective, clinical practice audit of colonoscopies performed on adults (≥18 years of age). A total of 1 643 patients were included in the study and variables that were collected enabled the assessment of adequacy of bowel preparation, length of withdrawal time and calculation of caecal intubation rate (CIR), polyp detection rate (PDR) and adenoma detection rate (ADR). We stratified PDR and ADR by sex, age, population group, withdrawal time and bowel preparation. CIR, PDR and ADR estimates were compared between patient groups by the χ2 test; Fisher's exact test was used for 2 × 2 tables. A p-value <0.05 was used. Benchmark recommendations by the American Society for Gastrointestinal Endoscopy (ASGE)/American College of Gastroenterology (ACG) Task Force on Colorectal Cancer (CRC) were used in this audit to assess individual endoscopist performance and that of the endoscopy unit as a whole. RESULTS: The mean age of patients was 55.7 (standard deviation (SD) 14.4; range 18 - 91) years, ~60% were female, and the majority (75.5%) were white. Of the outpatients, 77.6% had adequate bowel preparation (ASGE/ACG benchmark ≥85%). The CIR was 97.0% overall, and screening colonoscopy was 96.3% (ASGE/ACG benchmark ≥90% overall and ≥95% for screening colonoscopies). The median withdrawal time for negative-result screening colonoscopies was 5.7 minutes (interquartile range (IQR) 4.2 - 9.3; range 1.1 - 20.6) (ASGE/ACG benchmark ≥ 6minutes), and PDR and ADR were 27.6% and 15.6%, respectively (ASGE/ACG benchmark ADR ≥25%). We demonstrated a 23.7% increase in PDR and 14.1% increase in ADR between scopes that had mean withdrawal times of ≥6 minutes and <6 minutes, respectively. Although the number of black Africans in the study was relatively small, our results showed that they have similar ADRs and PDRs to the white population group, contradicting popular belief. CONCLUSIONS: The WDGMC OEU performed reasonably well against the international guidelines, despite some inadequacy in bowel preparation and lower than recommended median withdrawal times on negative-result colonoscopy. Annual auditing of clinical practice and availability of these data in the public domain will become standard of care, making this audit a baseline for longitudinal observation, assessing the impact of interventions, and contributing to the development of local guidelines.

Immunomodulation of innate immune responses by vasoactive intestinal peptide (VIP): its therapeutic potential in inflammatory disease.

Since the late 1970s a number of laboratories have studied the role of vasoactive intestinal peptide (VIP) in inflammation and immunity. These studies have highlighted the dramatic effect of VIP on immune cell activation and function, and studies using animal models of disease have indicated that VIP has significant therapeutic and prophylactic potential. This review will focus on the effects of VIP on innate immune cell function and discuss the therapeutic potential for VIP in inflammatory diseases of humans.

The contribution of genes required for anaerobic respiration to the virulence of Salmonella enterica serovar Gallinarum for chickens.

Salmonella enterica serovar Gallinarum (SG) is an intracellular pathogen of chickens. To survive, to invade and to multiply in the intestinal tract and intracellularly it depends on its ability to produce energy in anaerobic conditions. The fumarate reductase (frdABCD), dimethyl sulfoxide (DMSO)-trimethylamine N-oxide (TMAO) reductase (dmsABC), and nitrate reductase (narGHIJ) operons in Salmonella Typhimurium (STM) encode enzymes involved in anaerobic respiration to the electron acceptors fumarate, DMSO, TMAO, and nitrate, respectively. They are regulated in response to nitrate and oxygen availability and changes in cell growth rate. In this study mortality rates of chickens challenged with mutants of Salmonella Gallinarum, which were defective in utilising anaerobic electron acceptors, were assessed in comparison to group of bird challenged with wild strain. The greatest degree of attenuation was observed with mutations affecting nitrate reductase (napA, narG) with additional attenuations induced by a mutation affecting fumarate reductase (frdA) and a double mutant (dmsA torC) affecting DMSO and TMAO reductase.