ABSTRACT
Vaccination of badgers with Mycobacterium bovis Bacille Calmette-Guérin (BCG) has been shown to protect badgers against tuberculosis in experimental trials. During the 3-year County Kilkenny BCG vaccine field study, badgers were treated orally with placebo (100% in Zone A), BCG (100% in Zone C) or randomly assigned 50%: 50% treatment with BCG or placebo (Zone B). At the end of the study, 275 badgers were removed from the trial area and subjected to detailed post-mortem examination followed by histology and culture for M. bovis. Among these badgers, 83 (30.2%) were captured for the first time across the three zones, representing a non-treated proportion of the population. Analysis of the data based on the infection status of treated animals showed a prevalence of 52% (95% CI: 40%-63%) infection in Zone A (placebo), 39% (95% CI: 17%-64%) in Zone B (placebo) and 44% (95% CI: 20%-70%) in Zone B (BCG vaccinated) and 24% (95% CI: 14%-36%) in Zone C (BCG vaccinated). There were no statistically significant differences in the proportion of animals with infection involving the lung and thoracic lymph nodes, extra-thoracic infection or in the distribution and severity scores of histological lesions. Among the 83 non-treated badgers removed at the end of the study, the infection prevalence of animals in Zone A (prevalence = 46%, 95% CI: 32%-61%) and Zone B (prevalence = 44%, 95% CI: 23%-67%) was similar to the treated animals in these zones. However, in Zone C, no evidence of infection was found in any of the untreated badgers (prevalence = 0%, 95% CI: 0%-14%). This is consistent with an indirect protective effect in the non-vaccinated badgers leading to a high level of population immunity. The results suggest that BCG vaccination of badgers could be a highly effective means of reducing the incidence of tuberculosis in badger populations.
Subject(s)
Cattle Diseases , Mustelidae , Mycobacterium bovis , Tuberculosis, Bovine , Tuberculosis , Animals , BCG Vaccine , Cattle , Mustelidae/microbiology , Tuberculosis/epidemiology , Tuberculosis/prevention & control , Tuberculosis/veterinary , Tuberculosis, Bovine/epidemiology , Tuberculosis, Bovine/prevention & control , Vaccination/veterinaryABSTRACT
For an antibody to be a successful therapeutic many competing factors require optimization, including binding affinity, biophysical characteristics, and immunogenicity risk. Additional constraints may arise from the need to formulate antibodies at high concentrations (>150 mg/ml) to enable subcutaneous dosing with reasonable volume (ideally <1.0 mL). Unfortunately, antibodies at high concentrations may exhibit high viscosities that place impractical constraints (such as multiple injections or large needle diameters) on delivery and impede efficient manufacturing. Here we describe the optimization of an anti-PDGF-BB antibody to reduce viscosity, enabling an increase in the formulated concentration from 80 mg/ml to greater than 160 mg/ml, while maintaining the binding affinity. We performed two rounds of structure guided rational design to optimize the surface electrostatic properties. Analysis of this set demonstrated that a net-positive charge change, and disruption of negative charge patches were associated with decreased viscosity, but the effect was greatly dependent on the local surface environment. Our work here provides a comprehensive study exploring a wide sampling of charge-changes in the Fv and CDR regions along with targeting multiple negative charge patches. In total, we generated viscosity measurements for 40 unique antibody variants with full sequence information which provides a significantly larger and more complete dataset than has previously been reported.
Subject(s)
Antibodies, Monoclonal/chemistry , Immunoglobulin G/chemistry , Antibodies, Monoclonal/genetics , Antibodies, Monoclonal/immunology , Becaplermin/immunology , Computer-Aided Design , Humans , Immunoglobulin G/genetics , Immunoglobulin G/immunology , Models, Molecular , Mutation , Protein Conformation , Surface Properties , ViscosityABSTRACT
Medical errors are a significant source of morbidity and mortality, and while focused efforts to prevent harm have been made, sustaining reductions across multiple categories of patient harm remains a challenge. In 2008 BJC HealthCare initiated a systemwide program to eliminate all major causes of preventable harm and mortality over a five-year period with a goal of sustaining these reductions over the subsequent five years. METHODS: Areas of focus included pressure ulcers, adverse drug events, falls with injury, health care-associated infections, and venous thromboembolism. Initial efforts involved building system-level multidisciplinary teams, utilizing standardized project management methods, and establishing standard surveillance methods. Evidence-based interventions were deployed across the system; core standards were established while allowing for flexibility in local implementation. Improvements were tracked using actual numbers of events rather than rates to increase meaning and interpretability by patients and frontline staff. RESULTS: Over the course of the five-year intervention period, total harm events were reduced by 51.6% (10,371 events in 2009 to 5,018 events in 2012). Continued improvement efforts over the subsequent five years led to additional harm reduction (2,605 events in 2017; a 74.9% reduction since 2009). CONCLUSION: A combination of project management discipline, rigorous surveillance, and focused interventions, along with system-level support of local hospital improvement efforts, led to dramatic reductions in preventable harm and long-term sustainment of progress.
Subject(s)
Iatrogenic Disease/prevention & control , Quality Improvement/organization & administration , Accidental Falls/prevention & control , Cross Infection/prevention & control , Drug-Related Side Effects and Adverse Reactions/prevention & control , Electronic Health Records/standards , Humans , Medical Errors/prevention & control , Patient Safety , Pressure Ulcer/prevention & control , Quality Improvement/standards , Venous Thromboembolism/prevention & controlABSTRACT
BACKGROUND: Studies of sheep mortality or cause-specific mortality, in Ireland or internationally, are relatively scarce but are important in presenting baseline levels and changing trends of endemic disease. This study assessed sheep mortality and cause-specific mortality in 33 sentinel sheep flocks in Ireland. METHODS: Sentinel flocks were requested to submit carcases of all sheep that died to the regional veterinary laboratories (RVLs) of the Department of Agriculture, Food and Marine during a calendar year (2016). Postmortem examinations were performed on 1247 submissions to Athlone, Kilkenny and Sligo RVLs. RESULTS: The median overall submission rate was 13.8 per cent (range 2.5 per cent-35.8 per cent) per adult female sheep in the flock in January 2016. The median fetal, perinatal, lamb and adult submissions per adult female sheep in the flock in January 2016 were 2.1 per cent (0.0 per cent-15.2 per cent), 3.5 per cent (0.0 per cent-20.0 per cent), 3.0 per cent (0.0 per cent-12.4 per cent) and 2.8 per cent (0.8 per cent-7.1 per cent), respectively. The frequency of detection of categories of postmortem diagnoses in fetuses, perinates, lambs and adults are presented. CONCLUSIONS: Comparisons with existing passive surveillance findings reflect some differences in the relative frequency of detection of certain categories of disease suggesting that sentinel flock surveillance could usefully supplement existing passive animal disease surveillance activities for ovine disease.
Subject(s)
Mortality , Sentinel Surveillance/veterinary , Sheep , Animals , Female , Ireland/epidemiologyABSTRACT
BACKGROUND: Infection Preventionists have varying levels of educational preparation. Many have no prior experience in IP. The diversity makes design of professional development programs challenging. Recent surveys suggest that only about half of practicing IPs are board certified. There is an urgent need to employ competent IP's to drive improvement in patient outcomes. METHODS: This is a project that utilized the APIC Competency Model to create a professional development program characterizing three career stages. Methods included a review of literature on professional development; a survey of IP competence; an assessment of job descriptions and performance evaluations; and a crosswalk of IP competencies. RESULTS: The professional development program includes competency - based IP job descriptions and performance evaluations for each career stage; a professional portfolio; and a toolkit for supervisors. DISCUSSION: Participants agreed that application of the model resulted in tools which are more closely aligned with current roles for IPs; and increased satisfaction and motivation with the new program. CONCLUSION: Competent and knowledgeable IP's are crucial to optimizing efficacy of IPC programs. A professional development program has the potential to guide staff orientation, improve satisfaction and retention, improve patient outcomes and promote a positive trajectory in advancing practice.
Subject(s)
Infection Control Practitioners/education , Professional Competence , Program Development/methods , Societies, Scientific/organization & administration , Humans , Infection Control/methods , Infection Control/organization & administration , Infection Control/standardsABSTRACT
Although the rumen fluke, Calicophoron daubneyi is now very common and widespread throughout Western Europe, reports of clinical cases are still rare. This study explores the epidemiological background to a severe rumen fluke outbreak in 6-month-old heifers on a dairy farm in Ireland. Sequence analysis of the cytochrome oxidase subunit 1 (Cox1) gene of the rumen fluke metacercariae on pasture failed to identify predominant, possibly pathogenic subtypes. However, estimates of metacercarial load indicated that the animals were exposed to a daily dose of about 5334 C. daubneyi metacercariae for a period of 3 weeks resulting in the build-up of very large numbers of immature worms in the small intestine. It is hypothesized that specific environmental conditions may favour this parasite over its competitor, the liver fluke, Fasciola hepatica, possibly by allowing it to emerge earlier. The possibility that C. daubneyi may be better adapted to the Irish climate than F. hepatica together with the fact that selective treatment against F. hepatica effectively frees the niche for C. daubneyi, may result in the gradual replacement of F. hepatica by C. daubneyi.
Subject(s)
Cattle Diseases/epidemiology , Disease Outbreaks/veterinary , Rumen/parasitology , Trematode Infections/veterinary , Animals , Cattle , Cattle Diseases/parasitology , DNA, Helminth/genetics , Dairying , Electron Transport Complex IV/genetics , Fasciola hepatica/physiology , Fascioliasis/epidemiology , Fascioliasis/veterinary , Feces/parasitology , Female , Ireland/epidemiology , Metacercariae/genetics , Metacercariae/isolation & purification , Snails/parasitology , Trematoda/genetics , Trematode Infections/epidemiologyABSTRACT
A 3-day-old, 2.2-kg former 34-week premature infant with imperforate anus required loop ileostomy surgery. At delivery, the child had respiratory distress. Endotracheal intubation was "confirmed" by detection of exhaled carbon dioxide with a Pedi-Cap (Covidien, Dublin, Ireland) and subsequent chest x-ray. On arrival to the operating room, the pulse oximeter reading was 100% despite a large leak around the endotracheal tube and high-airway pressures. Packing the throat reduced the leak and increased the tidal volume. Intraoperative bronchospasm occurred during the surgery. On postoperative day 1, fiberoptic examination by an otolaryngologist revealed esophageal intubation and the absence of laryngeal opening. Subsequent computed tomography scan revealed Floyd type II tracheal agenesis. To our knowledge, this is the only case of tracheal agenesis diagnosed after a non-airway related procedure. We discussed how the diagnosis was missed.
Subject(s)
Constriction, Pathologic/therapy , Esophagus , Intubation, Intratracheal/methods , Trachea/abnormalities , Constriction, Pathologic/diagnostic imaging , Constriction, Pathologic/physiopathology , Diagnostic Errors , Fatal Outcome , Fiber Optic Technology , Humans , Infant, Newborn , Predictive Value of Tests , Tomography, X-Ray Computed , Trachea/diagnostic imaging , Trachea/physiopathology , Treatment OutcomeABSTRACT
A field trial was conducted to investigate the impact of oral vaccination of free-living badgers against natural-transmitted Mycobacterium bovis infection. For a period of three years badgers were captured over seven sweeps in three zones and assigned for oral vaccination with a lipid-encapsulated BCG vaccine (Liporale-BCG) or with placebo. Badgers enrolled in Zone A were administered placebo while all badgers enrolled in Zone C were vaccinated with BCG. Badgers enrolled in the middle area, Zone B, were randomly assigned 50:50 for treatment with vaccine or placebo. Treatment in each zone remained blinded until the end of the study period. The outcome of interest was incident cases of tuberculosis measured as time to seroconversion events using the BrockTB Stat-Pak lateral flow serology test, supplemented with post-mortem examination. Among the vaccinated badgers that seroconverted, the median time to seroconversion (413 days) was significantly longer (p = 0.04) when compared with non-vaccinated animals (230 days). Survival analysis (modelling time to seroconversion) revealed that there was a significant difference in the rate of seroconversion between vaccinated and non-vaccinated badgers in Zones A and C throughout the trial period (p = 0.015). For badgers enrolled during sweeps 1-2 the Vaccine Efficacy (VE) determined from hazard rate ratios was 36% (95% CI: -62%- 75%). For badgers enrolled in these zones during sweeps 3-6, the VE was 84% (95% CI: 29%- 97%). This indicated that VE increased with the level of vaccine coverage. Post-mortem examination of badgers at the end of the trial also revealed a significant difference in the proportion of animals presenting with M. bovis culture confirmed lesions in vaccinated Zone C (9%) compared with non-vaccinated Zone A (26%). These results demonstrate that oral BCG vaccination confers protection to badgers and could be used to reduce incident rates in tuberculosis-infected populations of badgers.
Subject(s)
Animals, Wild , BCG Vaccine , Mustelidae , Mycobacterium bovis , Tuberculosis/veterinary , Vaccination/veterinary , Administration, Oral , Animals , Tuberculosis/prevention & controlABSTRACT
The scope of a healthcare institution's infection prevention and control/healthcare epidemiology program (IPC/HE) should be driven by the size and complexity of the patient population served, that population's risk for healthcare-associated infection (HAI), and local, state, and national regulatory and accreditation requirements. Essential activities of all IPC/HE programs include but are not limited to the following: â Surveillance.â Performance improvement to reduce HAI â Acute event response, including outbreak investigation â Education and training of both healthcare personnel and patients â Reporting of HAI to the Centers for Disease Control and Prevention's National Healthcare Safety Network as well as entities required by law.
Subject(s)
Cross Infection/prevention & control , Disease Outbreaks/prevention & control , Health Personnel/education , Infection Control/standards , Centers for Disease Control and Prevention, U.S. , Humans , United StatesABSTRACT
BACKGROUND: Carriage of Streptococcus pneumoniae is considered a precursor to pneumococcal diseases including pneumonia. As part of the Kalgoorlie Otitis Media Research Project, we characterised pneumococci isolated from the nasopharynx of Western Australian Aboriginal and non-Aboriginal children. METHODS: Between 1999 and 2005, 100 Aboriginal and 180 non-Aboriginal children were followed from birth to two years, with nasopharyngeal aspirates collected at ages 1-3 and 6-8 weeks, then at 4, 6, 12, 18 and 24 months. Introduction of 7-valent pneumococcal conjugate vaccine (7vPCV) in 2001 enabled evaluation of its impact on carriage in study participants according to vaccines doses received. Pneumococcal serotyping was performed by Quellung and antimicrobial susceptibility by disk diffusion and Etest®. Molecular epidemiology of pneumococcal isolates was investigated by pulse-field gel electrophoresis and multilocus sequence typing. RESULTS: Overall, the prevalence of 7vPCV serotypes was similar for Aboriginal and non-Aboriginal children (19 % vs. 16 %), but the prevalence of non-vaccine serotypes was higher in Aboriginal children (22 % vs. 7 %). A multi-resistant 6B clone (ST90) was found only in non-Aboriginal children. Aboriginal children who received three doses of 7vPCV had lower odds of carrying 7vPCV serotypes (odds ratio [OR] 0.19, 95 % CI 0.08-0.44) and higher odds of carrying non-vaccine serotypes (OR 2.37, 95 % CI 1.13-4.99) than unvaccinated Aboriginal children; this finding was not observed in non-Aboriginal children. CONCLUSIONS: This unique study shows important differences in pneumococcal serotypes, genotypes, and antimicrobial susceptibility between Aboriginal and non-Aboriginal children living in the same geographic area before widespread 7vPCV use, and highlights the need for ongoing post-vaccination surveillance in outback Australia.
ABSTRACT
BACKGROUND: Bacterial meningitis remains an important infection globally, with the greatest burden in children in low-income settings, including Papua New Guinea (PNG). We present serotype, antimicrobial susceptibility and outcome data from paediatric meningitis patients prior to introduction of Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines (PCVs) in PNG, providing a baseline for evaluation of immunisation programs. METHODS: Cerebrospinal fluid (CSF) was collected from children admitted to Goroka General Hospital with suspected meningitis between 1996 and 2005. Culture and sensitivity was conducted, and pneumococci and H. influenzae were serotyped. Laboratory findings were linked to clinical outcomes. RESULTS: We enrolled 1884 children. A recognised pathogen was identified in 375 children (19.9%). Streptococcus pneumoniae (n = 180) and Hib (n = 153) accounted for 88.8% of pathogens isolated. 24 different pneumococcal serogroups were identified; non-PCV types 2, 24 and 46 accounted for 31.6% of pneumococcal meningitis. 10- and 13-valent PCVs would cover 44.1% and 45.4% of pneumococcal meningitis respectively. Pneumococcal isolates were commonly resistant to penicillin (21.5%) and 23% of Hib isolates were simultaneously resistant to ampicillin, co-trimoxazole and chloramphenicol. The case fatality rate in patients with a recognised bacterial pathogen was 13.4% compared to 8.5% in culture-negative patients. CONCLUSIONS: If implemented in routine expanded programme of immunisation (EPI) with high coverage, current PCVs could prevent almost half of pneumococcal meningitis cases. Given the diversity of circulating serotypes in PNG serotype replacement is of concern. Ongoing surveillance is imperative to monitor the impact of vaccines. In the longer term vaccines providing broader protection against pneumococcal meningitis will be needed.
Subject(s)
Anti-Infective Agents/pharmacology , Haemophilus influenzae type b/isolation & purification , Meningitis, Bacterial/microbiology , Meningitis, Pneumococcal/microbiology , Streptococcus pneumoniae/isolation & purification , Female , Haemophilus influenzae type b/drug effects , Haemophilus influenzae type b/pathogenicity , Hospitals, General , Humans , Immunization Programs , Infant , Male , Meningitis, Bacterial/immunology , Meningitis, Bacterial/prevention & control , Meningitis, Pneumococcal/immunology , Meningitis, Pneumococcal/prevention & control , Microbial Sensitivity Tests , Papua New Guinea , Pneumococcal Vaccines/pharmacology , Streptococcus pneumoniae/drug effects , Streptococcus pneumoniae/pathogenicity , Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology , Vaccines, Conjugate/pharmacologyABSTRACT
This global perspective column focuses on a humanbecoming hermeneutic study of first semester graduate nursing students' reflections on an art museum exhibit titled; Bodies in Balance: The Art of Tibetan Medicine. The research question that guided the study was "what is the emerging meaning of living balance as depicted in the exhibit? The students' essays were interpreted in light of the humanbecoming perspective. The essays were summarized and yielded four themes; surprising and amazing, interconnectedness of all things, unexpected elements and commonalities, and attention to daily living. Parse's three core knowings of living quality (fortifying wisdom, discerning witness and penetrating silence) were considered with the emergent meanings from the students' essays on living balance as depicted in The Art of Tibetan Medicine exhibit. This study showed the use of art in the teaching about global health in graduate nursing education.
Subject(s)
Art Therapy , Education, Nursing, Graduate , Students, Nursing/psychology , Humanism , Humans , Museums , TibetABSTRACT
A long-term research programme has been underway in Ireland to evaluate the usefulness of badger vaccination as part of the national bTB (bovine tuberculosis) control strategy. This culminated in a field trial which commenced in county Kilkenny in 2009 to determine the effects of badger vaccination on Mycobacterium bovis transmission in badgers under field conditions. In the present study, we sought to optimise the characteristics of a multiplex chemiluminescent assay for detection of M. bovis infection in live badgers. Our goal was to maximise specificity, and therefore statistical power, during evaluation of the badger vaccine trial data. In addition, we also aimed to explore the effects of vaccination on test characteristics. For the test optimisation, we ran a stepwise logistic regression with analytical weights on the converted Relative Light Units (RLU) obtained from testing blood samples from 215 badgers captured as part of culling operations by the national Department of Agriculture, Food and the Marine (DAFM). The optimised test was applied to two other datasets obtained from two captive badger studies (Study 1 and Study 2), and the sensitivity and specificity of the test was attained separately for vaccinated and non-vaccinated badgers. During optimisation, test sensitivity was maximised (30.77%), while retaining specificity at 99.99%. When the optimised test was then applied to the captive badger studies data, we observed that test characteristics did not vary greatly between vaccinated and non-vaccinated badgers. However, a different time lag between infection and a positive test result was observed in vaccinated and non-vaccinated badgers. We propose that the optimized multiplex immunoassay be used to analyse the vaccine trial data. In relation to the difference in the time lag observed for vaccinated and non-vaccinated badgers, we also present a strategy to enable the test to be used during trial evaluation.
Subject(s)
Disease Reservoirs/microbiology , Enzyme-Linked Immunosorbent Assay/methods , Mustelidae/microbiology , Mycobacterium Infections/veterinary , Mycobacterium bovis/immunology , Tuberculosis, Bovine/prevention & control , Vaccination/veterinary , Animals , Cattle , Ireland , Mycobacterium Infections/diagnosis , Mycobacterium Infections/epidemiology , Sensitivity and Specificity , Tuberculosis, Bovine/epidemiology , Tuberculosis, Bovine/transmissionABSTRACT
Vaccination of badgers by the subcutaneous, mucosal and oral routes with the Pasteur strain of Mycobacterium bovis bacille Calmette-Guérin (BCG) has resulted in significant protection against experimental infection with virulent M. bovis. However, as the BCG Danish strain is the only commercially licensed BCG vaccine for use in humans in the European Union it is the vaccine of choice for delivery to badger populations. As all oral vaccination studies in badgers were previously conducted using the BCG Pasteur strain, this study compared protection in badgers following oral vaccination with the Pasteur and the Danish strains. Groups of badgers were vaccinated orally with 10(8) colony forming units (CFU) BCG Danish 1331 (n = 7 badgers) or 10(8) CFU BCG Pasteur 1173P2 (n = 6). Another group (n = 8) served as non-vaccinated controls. At 12 weeks post-vaccination, the animals were challenged by the endobronchial route with 6 × 10(3) CFU M. bovis, and at 15 weeks post-infection, all of the badgers were euthanased. Vaccination with either BCG strain provided protection against challenge compared with controls. The vaccinated badgers had significantly fewer sites with gross pathology and significantly lower gross pathological severity scores, fewer sites with histological lesions and fewer sites of infection, significantly lower bacterial counts in the thoracic lymph node, and lower bacterial counts in the lungs than the control group. No differences were observed between either of the vaccine groups by any of the pathology and bacteriology measures. The ELISPOT analysis, measuring production of badger interferon - gamma (IFN-γ), was also similar across the vaccinated groups.
Subject(s)
BCG Vaccine/standards , Mustelidae , Mycobacterium bovis/immunology , Tuberculosis/veterinary , Vaccination/veterinary , Administration, Oral , Animals , Interferon-gamma/metabolism , Lung/microbiology , Lymph Nodes/microbiology , Tuberculosis/microbiology , Tuberculosis/prevention & control , Vaccination/standardsABSTRACT
Estimates of population size and trappability inform vaccine efficacy modelling and are required for adaptive management during prolonged wildlife vaccination campaigns. We present an analysis of mark-recapture data from a badger vaccine (Bacille Calmette-Guérin) study in Ireland. This study is the largest scale (755 km(2)) mark-recapture study ever undertaken with this species. The study area was divided into three approximately equal-sized zones, each with similar survey and capture effort. A mean badger population size of 671 (SD: 76) was estimated using a closed-subpopulation model (CSpM) based on data from capturing sessions of the entire area and was consistent with a separate multiplicative model. Minimum number alive estimates calculated from the same data were on average 49-51% smaller than the CSpM estimates, but these are considered severely negatively biased when trappability is low. Population densities derived from the CSpM estimates were 0.82-1.06 badgers km(-2), and broadly consistent with previous reports for an adjacent area. Mean trappability was estimated to be 34-35% per session across the population. By the fifth capture session, 79% of the adult badgers caught had been marked previously. Multivariable modelling suggested significant differences in badger trappability depending on zone, season and age-class. There were more putatively trap-wary badgers identified in the population than trap-happy badgers, but wariness was not related to individual's sex, zone or season of capture. Live-trapping efficacy can vary significantly amongst sites, seasons, age, or personality, hence monitoring of trappability is recommended as part of an adaptive management regime during large-scale wildlife vaccination programs to counter biases and to improve efficiencies.
Subject(s)
Mustelidae/growth & development , Mustelidae/microbiology , Pest Control , Tuberculosis/prevention & control , Tuberculosis/veterinary , Animals , Ireland/epidemiology , Logistic Models , Models, Biological , Poisson Distribution , Population Density , Population Growth , Tuberculosis/epidemiologyABSTRACT
Review of the Magnet Recognition Program journey related to the partnership between nursing and quality in building a comprehensive, results-driven quality and safety program in a 5 hospital community system in suburban Philadelphia over a 5-year period (2006-2011).
Subject(s)
Benchmarking , Cooperative Behavior , Hospitals, Community , Quality of Health Care/standards , Sepsis/nursing , Humans , Leadership , PhiladelphiaABSTRACT
Affinity selection-mass spectrometry (AS-MS) is a sensitive technology for identifying small molecules that bind to target proteins, and assays enabled by AS-MS can be used to delineate relative binding affinities of ligands for proteins. 'Indirect' AS-MS assays employ size-exclusion techniques to separate target-ligand complexes from unbound ligands, and target-associated ligands are then specifically detected by liquid chromatography mass spectrometry. We report how indirect AS-MS binding assays with known reference control compounds were used as guideposts for development of an optimized purification method for CXCR4, a G-protein coupled chemokine receptor, for which we sought novel antagonists. The CXCR4 purification method that was developed was amenable to scale-up and enabled the screening of purified recombinant human CXCR4 against a large combinatorial library of small molecules by high throughput indirect AS-MS. The screen resulted in the discovery of new ligands that competed off binding of reference compounds to CXCR4 in AS-MS binding assays and that antagonized SDF1α-triggered responses and CXCR4-mediated HIV1 viral uptake in cell-based assays. This report provides a methodological paradigm whereby indirect AS-MS-based ligand binding assays may be used to guide optimal integral membrane protein purification methods that enable downstream affinity selection-based applications such as high throughput AS-MS screens.
Subject(s)
High-Throughput Screening Assays/methods , Mass Spectrometry/methods , Receptors, CXCR4/isolation & purification , Receptors, CXCR4/metabolism , Cell Line, Tumor , Chemokine CXCL12/metabolism , Humans , Ligands , Protein Binding , Receptors, CXCR4/antagonists & inhibitorsABSTRACT
Badgers (Meles meles) have been implicated in the transmission of Mycobacterium bovis infection to cattle in Ireland and UK. Recent studies in Ireland have shown that although the disease is endemic in badgers, the prevalence of disease is not uniform throughout the country and can vary among subpopulations. The extent to which the prevalence levels in badgers impact on the prevalence in cattle is not known. Previously, DNA fingerprinting has shown that M. bovis strain types are shared between badgers and cattle, and that there are a large number of strain types circulating in the two species. In this study we have carried out spoligotyping and variable number tandem repeat (VNTR) analysis of M. bovis isolates from two groups of badgers, representing a wide geographic area, with different tuberculosis prevalence levels. The results of the typing show that there is no geographic clustering of strain types associated with prevalence. However, two VNTR profiles were identified that appear to be associated with high- and low-prevalence M. bovis infection levels, respectively. In addition, spoligotyping and VNTR analysis has provided evidence, for the first time, of multiple infections of individual badgers with different M. bovis strains.