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The objective of this study was to determine prevalence and perform genomic analysis of Salmonella spp. and Campylobacter spp. isolated from different stages of an integrated NAE broiler complex. Environmental samples were screened with 3M-Molecular Detection System (MDS) and MDS positive samples were further processed for confirmation of results and identification. Core genome-based phylogenies were built for both bacteria isolated from this study along with selected NCBI genomes. The odds ratios and 95% confidence limits were compared among stages and sample types (α < 0.05) using multivariable model. Based on MDS results, 4% and 18% of total samples were positive for Salmonella spp. and Campylobacter spp. respectively. The odds of Salmonella detection in hatchery samples were 2.58 times as likely as compared to its detection in production farms' samples (P = 0.151) while the odds of Campylobacter detection in production farms' samples were 32.19 times as likely as its detection in hatchery (P = 0.0015). Similarly, the odds of Campylobacter detection in boot swabs, soil, water, and miscellaneous samples were statistically significant (P < 0.05) as compared with fly paper as reference group. The serovars identified for Salmonella were Typhimurium, Barranquilla, Liverpool, Kentucky, Enteritidis, Luciana, and Rough_O:r:1,5. For Campylobacter, the species identified were Campylobacter jejuni and Campylobacter coli. Phylogeny results show close genetic relatedness among bacterial strains isolated from different locations within the same stage and between different stages. The results show possibility of multiple entry points of such bacteria entering broiler complex and can potentially contaminate the final raw product in the processing plant. It suggests the need for a comprehensive control strategy with strict biosecurity measures and best management practices to minimize or eliminate such pathogens from the poultry food chain.
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BACKGROUND: Down cow syndrome is commonly described in dairy cattle. The diagnosis and treatment of nonambulatory cattle is challenging and prognostic indicators of this condition in beef cattle have not been determined. OBJECTIVES: Evaluate records of beef cattle (≥2 years of age) presented to 2 referral hospitals for inability to stand and identify prognostic indicators for survival to discharge. ANIMALS: Sixty-three adult beef cattle treated for inability to stand at 2 referral hospitals. METHODS: Medical records of 63 beef cattle presented for inability to stand between January 2010 and December 2022 were retrospectively analyzed. Continuous and categorical variables were included in univariate and multivariate regression models to evaluate their association with outcome. RESULTS: Of 63 animals included in the study, 19% (12/63) were discharged, and the remaining 81% (n = 51) either died (11.1%) or were euthanized (69.8%). The odds of being discharged increased with each additional day of hospitalization (odds ratio [OR], 2.66; 95% confidence interval [CI], 1.39-6.89) and with each additional flotation therapy session (OR, 2.108; 95% CI, 1.209-4.219). Down beef cattle with a diagnosis of calving peripheral nerve paralysis and capable of walking out the tank after the first flotation session were 6.66 (95% CI, 1.58-35.51) and 30 (95% CI, 4.4-614.98) times more likely to be discharged compared with cattle that had other diagnoses and those that were unable to walk out the tank, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Treatment of nonambulatory beef cattle carries a poor prognosis. Practitioners can use information from our study as a guide for treatment or euthanasia decisions of nonambulatory beef cattle.
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Enfermedades de los Bovinos , Animales , Bovinos , Estudios Retrospectivos , Enfermedades de los Bovinos/terapia , Femenino , Pronóstico , Masculino , Hospitales VeterinariosRESUMEN
Antimicrobial residues excreted in the environment following antimicrobial treatment enhance resistant microbial communities in the environment and have long-term effects on the selection and maintenance of antimicrobial resistance genes (AMRGs). In this study, we focused on understanding the impact of antimicrobial use on antimicrobial residue pollution and antimicrobial resistance (AMR) in the environment of horse-breeding farms. Rhodococcus equi is an ideal microbe to study these associations because it lives naturally in the soil, exchanges AMRGs with other bacteria in the environment, and can cause disease in animals and humans. The environment is the main source of R. equi infections in foals; therefore, higher levels of multidrug-resistant (MDR) R. equi in the environment contribute to clinical infections with MDR R. equi. We found that macrolide residues in the environment of horse-breeding farms and the use of thoracic ultrasonographic screening (TUS) for early detection of subclinically affected foals with R. equi infections were strongly associated with the presence of R. equi carrying AMRGs in the soil. Our findings indicate that the use of TUS contributed to historically higher antimicrobial use in foals, leading to the accumulation of antimicrobial residues in the environment and enhancing MDR R. equi.
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OBJECTIVE: To determine the efficacy of primary or booster intranasal vaccination of beef steers on clinical protection and pathogen detection following simultaneous challenge with bovine respiratory syncytial virus and bovine herpes virus 1. METHODS: 30 beef steers were randomly allocated to 3 different treatment groups starting at 2 months of age. Group A (n = 10) was administered a single dose of a parenteral modified-live vaccine and was moved to a separate pasture. Groups B (n = 10) and C (10) remained unvaccinated. At 6 months of age, all steers were weaned and transported. Subsequently, groups A and B received a single dose of an intranasal modified-live vaccine vaccine while group C remained unvaccinated. Group C was housed separately until challenge. Two days following vaccination, all steers were challenged with bovine respiratory syncytial virus and bovine herpes virus 1 and housed in a single pen. Clinical and antibody response outcomes and the presence of nasal pathogens were evaluated. RESULTS: The odds of clinical disease were lower in group A compared with group C on day 7 postchallenge; however, antibody responses and pathogen detection were not significantly different between groups before and following viral challenge. All calves remained negative for Histophilus somni and Mycoplasma bovis; however, significantly greater loads of Mannheimia haemolytica and Pasteurella multocida were detected on day 7 postchallenge compared with day -2 prechallenge. CLINICAL RELEVANCE: Intranasal booster vaccination of beef steers at 6 months of age reduced clinical disease early after viral challenge. Weaning, transport, and viral infection promoted increased detection rates of M haemolytica and P multocida regardless of vaccination status.
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Administración Intranasal , Coinfección , Herpesvirus Bovino 1 , Inmunización Secundaria , Infecciones por Virus Sincitial Respiratorio , Virus Sincitial Respiratorio Bovino , Animales , Bovinos , Herpesvirus Bovino 1/inmunología , Masculino , Administración Intranasal/veterinaria , Virus Sincitial Respiratorio Bovino/inmunología , Inmunización Secundaria/veterinaria , Coinfección/veterinaria , Coinfección/prevención & control , Coinfección/microbiología , Infecciones por Virus Sincitial Respiratorio/veterinaria , Infecciones por Virus Sincitial Respiratorio/prevención & control , Rinotraqueítis Infecciosa Bovina/prevención & control , Rinotraqueítis Infecciosa Bovina/inmunología , Enfermedades de los Bovinos/prevención & control , Enfermedades de los Bovinos/microbiología , Enfermedades de los Bovinos/virología , Enfermedades de los Bovinos/inmunología , Vacunas Virales/inmunología , Vacunas Virales/administración & dosificación , Derrame de Bacterias , Anticuerpos Antivirales/sangre , Infecciones por Herpesviridae/veterinaria , Infecciones por Herpesviridae/prevención & control , Distribución Aleatoria , Vacunación/veterinariaRESUMEN
ConspectusLife as we know it is built on complex and perfectly interlocking processes that have evolved over millions of years through evolutionary optimization processes. The emergence of life from nonliving matter and the evolution of such highly efficient systems therefore constitute an enormous synthetic and systems chemistry challenge. Advances in supramolecular and systems chemistry are opening new perspectives that provide insights into living and self-sustaining reaction networks as precursors for life. However, the ab initio synthesis of such a system requires the possibility of autonomous optimization of catalytic properties and, consequently, of an evolutionary system at the molecular level. In this Account, we present our discovery of the formation of substituted imidazolidine-4-thiones (photoredox) organocatalysts from simple prebiotic building blocks such as aldehydes and ketones under Strecker reaction conditions with ammonia and cyanides in the presence of hydrogen sulfide. The necessary aldehydes are formed from CO2 and hydrogen under prebiotically plausible meteoritic or volcanic iron-particle catalysis in the atmosphere of the early Earth. Remarkably, the investigated imidazolidine-4-thiones undergo spontaneous resolution by conglomerate crystallization, opening a pathway for symmetry breaking, chiral amplification, and enantioselective organocatalysis. These imidazolidine-4-thiones enable α-alkylations of aldehydes and ketones by photoredox organocatalysis. Therefore, these photoredox organocatalysts are able to modify their aldehyde building blocks, which leads in an evolutionary process to mutated second-generation and third-generation catalysts. In our experimental studies, we found that this mutation can occur not only by new formation of the imidazolidine core structure of the catalyst from modified aldehyde building blocks or by continuous supply from a pool of available building blocks but also by a dynamic exchange of the carbonyl moiety in ring position 2 of the imidazolidine moiety. Remarkably, it can be shown that by incorporating aldehyde building blocks from their environment, the imidazolidine-4-thiones are able to change and adapt to altering environmental conditions without undergoing the entire formation process. The selection of the mutated catalysts is then based on the different catalytic activities in the modification of the aldehyde building blocks and on the catalysis of subsequent processes that can lead to the formation of molecular reaction networks as progenitors for cellular processes. We were able to show that these imidazolidine-4-thiones not only enable α-alkylations but also facilitate other important transformations, such as the selective phosphorylation of nucleosides to nucleotides as a key step leading to the oligomerization to RNA and DNA. It can therefore be expected that evolutionary processes have already taken place on a small molecular level and have thus developed chemical tools that change over time, representing a hidden layer on the path to enzymatically catalyzed biochemical processes.
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Rhodococcus equi, a gram-positive facultative intracellular pathogen and a soil saprophyte, is one of the most common causes of pneumonia in young foals. It poses a threat to the economy in endemic horse-breeding farms and to animal welfare annually. Many farms use thoracic ultrasonographic screening and antimicrobial treatment of subclinically affected foals as a preventive measure against severe R. equi infections. The wide use antimicrobials to treat subclinically affected foals has contributed to the emergence of multidrug resistant (MDR)-R. equi in both clinical isolates from sick foals and in the environment of horse-breeding farms. Alternatives to treat foals infected with MDR-R. equi are scarce and the impact of the emergence of MDR-R. equi in the environment of farms is still unknown. The aim of this review is to discuss the emergence of MDR-R. equi in the United States and the challenges faced to guide antimicrobial use practices. Reduction of antimicrobial use at horse-breeding farms is essential for the preservation of antimicrobial efficacy and, ultimately, human, animal, and environmental health.
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Infecciones por Actinomycetales , Enfermedades de los Caballos , Rhodococcus equi , Humanos , Animales , Caballos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana , Infecciones por Actinomycetales/tratamiento farmacológico , Infecciones por Actinomycetales/veterinaria , Enfermedades de los Caballos/tratamiento farmacológico , Enfermedades de los Caballos/epidemiologíaRESUMEN
BACKGROUND: Post-COVID syndrome (PCS) is defined by symptom persistence accompanied by daily life impairment (DLI). The association of somatic symptom disorder (SSD) and symptoms with DLI after SARS-CoV-2 infection in the general population is unclear to date. The main objective of the study was to investigate the association of possible SSD, depression, anxiety, and participant-reported symptoms with DLI in a local population sample. METHODS: Anonymised cross-sectional study. A symptom questionnaire, including the scales Patient Health Questionnaire PHQ-15 (somatisation module), SSD-12 (psychological distress in SSD), PHQ-2 (depression), GAD-2 (anxiety), and FAS (fatigue assessment scale) was sent in 02/2022 to all adult residents of the district Bad Tölz-Wolfratshausen, Germany, who were registered for SARS-CoV-2-infection between 03/2020 and 11/2021 (8925 delivered). Associations between DLI, symptoms and scales were estimated using binary logistic regression models and network analysis. RESULTS: 2828 questionnaires (31.7%) were complete. 1486 (52.5%) reported persistent symptoms, and 509 (18.0%) perceived DLI. DLI was strongest associated with self-reported fatigue (OR 7.86; 95%CI 5.63-10.97), dyspnea (3.93; 2.73-5.67), impaired concentration (3.05; 2.17-4.30), SSD-12 (4.36; 2.57-7.41), and PHQ-2 (2.48; 1.57-3.92). Self-reported fatigue showed the strongest correlation (rp = 0.248) and closest proximity to DLI in network analysis. CONCLUSION: PCS appears as a complex clinical picture in which SSD might play an important role when DLI is present. The pychological burden might partly be explained by the persistent symptoms, which are difficult to treat up to now. Screening for SSD could help in differential diagnostic decision-making to ensure that patients receive appropriate psychosocial interventions for disease coping.
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COVID-19 , Síntomas sin Explicación Médica , Adulto , Humanos , Estudios Transversales , COVID-19/complicaciones , SARS-CoV-2 , Síndrome , Fatiga/epidemiología , Fatiga/etiologíaRESUMEN
Thailand is undergoing rapid intensification of livestock production where small subsistence farms and medium sized commercial farms coexist. In medium farms, antimicrobials are prescribed by a veterinarian, whereas in small farms antimicrobial use remains largely unsupervised. The impact of these differences as well as other farming practices on the emergence and composition of antimicrobial resistance genes (ARGs) remains largely unknown. We analyzed 363 genomes of extended-spectrum ß-lactamase producing (ESBL) and/or AmpC producing Escherichia coli recovered from humans and pigs at small and medium farms from the Khon Kaen province, Thailand. We tested for genome-wide associations to identify links between ARGs, host, and farm size. Pig isolates from small farms were associated with mcr and qnr genes conferring resistance to colistin and fluoroquinolones, respectively. In contrast, pig isolates from medium farms were associated with ARGs conferring resistance to drugs commonly used on medium farms (i.e., streptomycin). ESBL plasmids from small farms co-carried ARGs conferring resistance to critically important antimicrobials more frequently compared to plasmid from medium farms. Frequent ARG combinations included blaCTX-M-55 + qnrS1 (29.8% vs 17.5% in small and medium farms, respectively), blaCTX-M-55 + qnrS1 + mcr-3.19 (5% vs 0%), blaCTX-M-14 + qnrS1 (9.3% vs 6.2%), and blaCTX-M-14 + qnrS1 + mcr-1.1 (3.1% vs 0%). The co-location on plasmids of ARGs conferring resistance to critically important antimicrobials as defined by the World Health Organization is concerning, and actions to curb their spread are urgently needed. Legislation on limiting antimicrobial sales and initiatives to better inform farmers and veterinarians on appropriate antimicrobial usage and farm biosecurity could help reduce antimicrobial use on farms.
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Antiinfecciosos , Infecciones por Escherichia coli , Proteínas de Escherichia coli , Humanos , Porcinos , Animales , Escherichia coli/genética , Granjas , Colistina/farmacología , beta-Lactamasas/genética , Tailandia , Infecciones por Escherichia coli/veterinaria , Plásmidos/genética , Antibacterianos/farmacología , Fluoroquinolonas , Estreptomicina , Proteínas de Escherichia coli/genéticaRESUMEN
Background: Body fat and overall weight gain are common after kidney transplantation and are associated with poor clinical outcomes. Therefore, identification of at-risk patients is relevant for preventive interventions. Clinical Question: What variables influence weight and fat gain in patients in the first year after kidney transplantation? Literature Search Prospective and retrospective cohort studies published in or after 2001 naming fat and/or overall weight gain during the first year after kidney transplantation as outcome variable(s) were systematically searched in Medline/Pubmed in November 2018 and March 2022. Clinical Appraisal: We identified 16 studies examining a wide variety of potential factors influencing weight and fat gain over the first posttransplant years. These included genetic, socio-demographic, behavioral, biomedical, psychological and environmental factors. For a number of variables, study results were contradictory: some studies indicated preventive impacts on weight or fat gain; others concluded that the same factors increased it. Cases were discussed with 2 clinical experts. We eventually agreed on 13 potentially relevant risk factors for post-transplant weight/fat gain: age, gender, genes, income, ethnicity, education, eating habits, physical activity, smoking cessation, baseline BMI, baseline fat, depression and perceived overall wellbeing. Integration into Practice Before integration into clinical practice, a critical evaluation of all potential risk factors' suitability for assessment will be necessary. In addition to feasibility, operational definitions and measurement methods must also be considered. Evaluation: To reduce the list of risk factors to the most relevant, a first testing within a prospectively collected data set is planned.
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Trasplante de Riñón , Humanos , Tejido Adiposo , Trasplante de Riñón/efectos adversos , Estudios Prospectivos , Estudios Retrospectivos , Factores de Riesgo , Aumento de PesoRESUMEN
Introduction: Weight gain is a risk factor for poor clinical outcomes following kidney transplantation. Research Question: This study's aim was a first testing of 2 models to identify patients early after kidney transplantation who are at risk for weight gain and increase in adipose tissue mass in the first year after kidney transplantation. Design: The literature-based models were evaluated on longitudinal data of 88, respectively 79 kidney transplant recipients via ordinary and Firth regression, using gains ≥ 5% in weight and adipose tissue mass respectively as primary and secondary endpoints. Results: The models included physical activity, smoking cessation at time of kidney transplantation, self-reported health status, depressive symptomatology, gender, age, education, baseline body mass index and baseline trunk fat as predictors. Area under the curve was 0.797 (95%-CI 0.702 to 0.893) for the weight model and 0.767 (95%-CI 0.656 to 0.878) for the adipose tissue mass model-showing good, respectively fair discriminative ability. For weight gain ≥ 5%, main risk factors were smoking cessation at time of transplantation (OR 16.425, 95%-CI 1.737-155.288) and better self-reported baseline health state (OR 1.068 for each 1-unit increase, 95%-CI 1.012-1.128). For the adipose tissue mass gain ≥ 5%, main risk factor was overweight/obesity (BMI ≥ 25) at baseline (odds ratio 7.659, 95%-CI 1.789-32.789). Conclusions: The models have potential to assess patients' risk for weight or adipose tissue mass gain during the year after transplantation, but further testing is needed before implementation in clinical practice.
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Trasplante de Riñón , Humanos , Trasplante de Riñón/efectos adversos , Aumento de Peso , Obesidad/etiología , Índice de Masa Corporal , Tejido AdiposoRESUMEN
OBJECTIVES: To compare initial titers, duration, and residual clinical protection of passively transferred bovine respiratory syncytial virus (BRSV) nasal immunoglobulin (Ig) G-1 and IgA, and serum neutralizing (SN) antibodies. ANIMALS: 40 three-month-old beef steers born either to unvaccinated or vaccinated cows. PROCEDURES: During the last trimester of gestation, cows were assigned randomly to either vaccinated or unvaccinated groups. Calves were grouped on the basis of whether they nursed colostrum from unvaccinated dams (NO-VACC group; n = 20) versus dams vaccinated with 2 doses of an inactivated BRSV vaccine (VACC group; n = 20). At 3 months of age, calves were challenged with BRSV. Respiratory signs were scored. Nasal BRSV IgG-1 and IgA and SN antibodies were compared before and after the challenge. The presence of BRSV in nasal secretions was evaluated by reverse transcription-PCR assays. RESULTS: Respiratory scores after BRSV challenge were similar between treatment groups. Nasal BRSV IgG-1 and SN antibodies were significantly greater in VACC calves at 48 hours of life; however, by 3 months of age, titers had decayed in both groups. Nasal BRSV IgA titers were minimal after colostrum intake and before the BRSV challenge, and increased in both groups after the challenge. The NO-VACC group had a significantly greater probability of shedding BRSV compared with VACC calves. CLINICAL RELEVANCE: At 3 months of age, titers of passively transferred BRSV antibodies in VACC and NO-VACC calves had decayed to nonprotective levels. Calves born to vaccinated dams had a decreased probability of BRSV shedding; however, this was not related to differences in SN or nasal BRSV antibody titers.
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Enfermedades de los Bovinos , Infecciones por Virus Sincitial Respiratorio , Virus Sincitial Respiratorio Bovino , Embarazo , Femenino , Bovinos , Animales , Calostro , Enfermedades de los Bovinos/prevención & control , Anticuerpos Antivirales , Inmunoglobulina G , Inmunoglobulina A , Infecciones por Virus Sincitial Respiratorio/prevención & control , Infecciones por Virus Sincitial Respiratorio/veterinariaRESUMEN
The rate of gut inflammatory diseases is growing in modern society. Previously, we showed that caloric restriction (CR) shapes gut microbiota composition and diminishes the expression of inflammatory factors along the gastrointestinal (GI) tract. The current project aimed to assess whether prominent dietary restrictive approaches, including intermittent fasting (IF), fasting-mimicking diet (FMD), and ketogenic diet (KD) have a similar effect as CR. We sought to verify which of the restrictive dietary approaches is the most potent and if the molecular pathways responsible for the impact of the diets overlap. We characterized the impact of the diets in the context of several dietary restriction-related parameters, including immune status in the GI tract; microbiota and its metabolites; bile acids (BAs); gut morphology; as well as autophagy-, mitochondria-, and energy restriction-related parameters. The effects of the various diets are very similar, particularly between CR, IF, and FMD. The occurrence of a 50 kDa truncated form of occludin, the composition of the microbiota, and BAs distinguished KD from the other diets. Based on the results, we were able to provide a comprehensive picture of the impact of restrictive diets on the gut, indicating that restrictive protocols aimed at improving gut health may be interchangeable.
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Dieta Cetogénica , Microbioma Gastrointestinal , Animales , Dieta , Ayuno , Tracto Gastrointestinal/metabolismo , RatonesRESUMEN
Rhodococcus equi is a common cause of severe pneumonia in foals. Emergence of macrolide-resistant R. equi isolated from foals and their environment has been reported in the United States. A novel erm(51) gene was recently identified in R. equi in soil from horse farms in Kentucky. Our objective was to determine the effect of the erm(51) gene and associated rpoB mutation on the fitness of multidrug resistant-R. equi (MDR-R. equierm(51)+, rpoB+) under different nutrient conditions. Bacterial growth curves were generated for 3 MDR-R. equierm(51)+, rpoB+ isolates and 3 wild-type (WTN) R. equi isolates recovered from environmental samples of farms in central Kentucky. Growth was measured over 30.5 h in brain-heart infusion broth (BHI), minimal medium (MM), and minimal medium without iron (MM-I). All isolates had significantly (P < 0.05) higher growth in BHI compared to either MM or MM-I. MDR-R. equierm(51)+, rpoB+ exhibited significantly lower growth compared to WTN isolates in BHI (nutrient-rich condition), but not in either MM or MM-I (nutrient-restricted conditions). This study indicates that under nutrient-rich conditions fitness of MDR-R. equierm(51)+, rpoB+ is reduced relative to susceptible isolates; however, under nutrient-restricted conditions MDR-R. equierm(51)+, rpoB+ isolates grow similarly to susceptible isolates. These findings indicate that MDR-R. equierm(51)+, rpoB+ might be outcompeted by susceptible isolates in nature when practices to reduce antimicrobial pressure, such as reducing antimicrobial use in foals, are implemented. But it also raises the concern that these resistant genotypes might persist in the environment of horse-breeding farms in the face of selective pressures such as antimicrobials or nutrient restriction.
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Infecciones por Actinomycetales , Enfermedades de los Caballos , Rhodococcus equi , Infecciones por Actinomycetales/veterinaria , Animales , Antibacterianos/farmacología , Enfermedades de los Caballos/microbiología , Caballos , Macrólidos/farmacología , Mutación , Rhodococcus equi/genéticaRESUMEN
To understand chiral symmetry breaking on the molecular level, we developed a method to efficiently investigate reaction kinetics of single molecules. The model systems include autocatalysis as well as a reaction cascade to gain further insight into the prebiotic origin of homochirality. The simulated reactions start with a substrate and only a single catalyst molecule, and the occurrence of symmetry breaking was examined for its degree of dependence on randomness. The results demonstrate that interlocking processes, which e.g., form catalysts, autocatalytic systems, or reaction cascades that build on each other and lead to a kinetic acceleration, can very well amplify a statistically occurring symmetry breaking. These results suggest a promising direction for the experimental implementation and identification of such processes, which could have led to a shift out of thermodynamic equilibrium in the emergence of life.
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Modelos Biológicos , Catálisis , Cinética , Estereoisomerismo , TermodinámicaRESUMEN
Studies suggest that high cortisol resulting from lameness-associated pain decreases testosterone and disrupts spermatogenesis leading to decreased fertility. The objective of this study was to investigate the effect of lameness on cortisol and testosterone concentrations and breeding soundness examination of beef bulls presented to a veterinary teaching hospital. Bulls, two-years of age or older, that presented for lameness, foot trim, and/or breeding soundness examination were enrolled. Blood samples were collected for cortisol and testosterone evaluation. A complete breeding soundness examination (BSE) was performed in all bulls. Subsequently, a complete lameness examination was performed, and limb/foot lesions recorded. A blinded evaluator used a lameness score of 1-5 to classify each bull as lame (>1) or not-lame (1). A total of 60 bulls were enrolled (34 with a satisfactory BSE and 26 with an unsatisfactory BSE result). Cortisol and testosterone were not different between the unsatisfactory and satisfactory groups (P = 0.26 and 0.32, respectively). The most common limb/foot lesions found in the unsatisfactory and satisfactory groups were laminitis-related (61.50% and 41.20%, respectively). There was no difference in the proportion of lame and not-lame bulls in the unsatisfactory and satisfactory groups (P = 0.17). The odds of a satisfactory BSE result were 4.40 times higher in not-lame bulls when compared with lame bulls. Therefore, lameness is associated with an unsatisfactory BSE result in beef breeding bulls.
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Enfermedades de los Bovinos , Cojera Animal , Animales , Bovinos , Enfermedades de los Bovinos/diagnóstico , Hospitales Veterinarios , Hospitales de Enseñanza , Hidrocortisona , Cojera Animal/diagnóstico , Masculino , Escroto , TestosteronaRESUMEN
Chiral compounds are ubiquitous in nature and play a pivotal role in biochemical processes, in chiroptical materials and applications, and as chiral drugs. The analysis and determination of the enantiomeric ratio (er) of chiral compounds is of enormous scientific, industrial, and economic importance. Chiral separation techniques and methods have become indispensable tools to separate chiral compounds into their enantiomers on an analytical as well on a preparative level to obtain enantiopure compounds. Chiral gas chromatography and high-performance liquid chromatography have paved the way and fostered several research areas, that is, asymmetric synthesis and catalysis in organic, medicinal, pharmaceutical, and supramolecular chemistry. The development of highly enantioselective chiral stationary phases was essential. In particular, the elucidation and understanding of the underlying enantioselective supramolecular separation mechanisms led to the design of new chiral stationary phases. This review article focuses on the development of chiral stationary phases for gas chromatography. The fundamental mechanisms of the recognition and separation of enantiomers and the selectors and chiral stationary phases used in chiral gas chromatography are presented. An overview over syntheses and applications of these chiral stationary phases is presented as a practical guidance for enantioselective separation of chiral compound classes and substances by gas chromatography.
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Estereoisomerismo , Cromatografía de Gases , Cromatografía Líquida de Alta PresiónRESUMEN
Pneumonia in foals caused by the bacterium Rhodococcus equi has a worldwide distribution and is a common cause of disease and death for foals. The purpose of this narrative review was to summarise recent developments pertaining to the epidemiology, immune responses, treatment, and prevention of rhodococcal pneumonia of foals. Screening tests have been used to implement earlier detection and treatment of foals with presumed subclinical R. equi pneumonia to reduce mortality and severity of disease. Unfortunately, this practice has been linked to the emergence of antimicrobial-resistant R. equi in North America. Correlates of protective immunity for R. equi infections of foals remain elusive, but recent evidence indicates that innate immune responses are important both for mediating killing and orchestrating adaptive immune responses. A macrolide antimicrobial in combination with rifampin remains the recommended treatment for foals with R. equi pneumonia. Great need exists to identify which antimicrobial combination is most effective for treating foals with R. equi pneumonia and to limit emergence of antimicrobial-resistant strains. In the absence of an effective vaccine against R. equi, passive immunisation remains the only commercially available method for effectively reducing the incidence of R. equi pneumonia. Because passive immunisation is expensive, labour-intensive and carries risks for foals, great need exists to develop alternative approaches for passive and active immunisation.
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Infecciones por Actinomycetales , Enfermedades de los Caballos , Neumonía Bacteriana , Rhodococcus equi , Infecciones por Actinomycetales/tratamiento farmacológico , Infecciones por Actinomycetales/epidemiología , Infecciones por Actinomycetales/prevención & control , Infecciones por Actinomycetales/veterinaria , Animales , Antibacterianos/uso terapéutico , Enfermedades de los Caballos/tratamiento farmacológico , Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/prevención & control , Caballos , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/epidemiología , Neumonía Bacteriana/prevención & control , Neumonía Bacteriana/veterinariaRESUMEN
Maternal antibodies interfere with BRSV vaccine responses and efficacy in young calves. The objective of this study was to determine if vaccination before the complete absorption of colostral antibodies results in adequate immune priming and clinical protection of beef calves. Within 6 h of life, calves were randomly assigned to 2 different treatment groups. Group Vacc (n = 25) received a single dose of a modified-live virus (MLV) BRSV vaccine intranasally (IN) and group Control (n = 25) received 2 mL of 0.9% saline IN. At approximately 3 months of age, all calves were experimentally challenged with BRSV. Serum and nasal secretion samples were collected before and after challenge for BRSV real-time RT-PCR and antibody testing. Respiratory signs were not observed before challenge. After challenge, respiratory scores were similar between groups. On the challenge day, >40% of calves in each group were febrile. The mean serum and nasal BRSV-specific antibody titers indicated natural BRSV exposure before the experimental challenge in both groups. All calves tested positive for BRSV and had a similar duration of shedding after challenge. Based on these results, vaccination at birth does not offer advantages for immune priming or clinical protection for beef calves in BRSV-endemic cow-calf herds.
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Antimicrobial use contributes to the global rise of antimicrobial resistance (AMR). In 2014, the poultry industry in Canada initiated its Antimicrobial Use Reduction Strategy to mitigate AMR in the poultry sector. We monitored trends in antimicrobial use and AMR of foodborne bacteria (Salmonella, Escherichia coli, and Campylobacter) in broiler chickens during 2013 and 2019. We quantified the effect of antimicrobial use and management factors on AMR by using LASSO regression and generalized mixed-effect models. AMR in broiler chickens declined by 6%-38% after the decrease in prophylactic antimicrobial use. However, the withdrawal of individual compounds, such as cephalosporins and fluoroquinolones, prompted an increase in use of and resistance levels for other drug classes, such as aminoglycosides. Canada's experience with antimicrobial use reduction illustrates the potential for progressive transitions from conventional antimicrobial-dependent broiler production to more sustainable production with respect to antimicrobial use.
Asunto(s)
Antiinfecciosos , Campylobacter , Animales , Canadá/epidemiología , Pollos , Farmacorresistencia Bacteriana , Escherichia coli , SalmonellaRESUMEN
In Thailand, pig production has increased considerably in the last decades to meet a growing demand for pork. Antimicrobials are used routinely in intensive pig production to treat infections and increase productivity. However, the use of antimicrobials also contributes to the rise of antimicrobial resistance with potential consequences for animal and human health. Here, we quantify the association between antimicrobial use and resistance rates in extensive and intensive farms with a focus on geographic proximity between farm and drugstores. Of the 164 enrolled farms, 79% reported using antimicrobials for disease prevention, treatment, or as a feed additive. Antimicrobial-resistant E. coli were present in 63% of farms. These drugs included critically important antimicrobials, such as quinolones and penicillins. Medium-scale farms with intensive animal production practices showed higher resistance rates than small-scale farms with extensive practices. Farms with drug-resistant Escherichia coli were located closer to drugstores and a had a higher proportion of disease than farms without drug-resistant E. coli. We found no association between the presence of resistance in humans and antimicrobial use in pigs. Our findings call for actions to improve herd health to reduce the need for antimicrobials and systematic training of veterinarians and drugstore owners on judicious use of antimicrobials in animals to mitigate resistance.