scholarly journals A review of the resistome within the digestive tract of livestock

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tao Ma ◽  
Tim A. McAllister ◽  
Le Luo Guan

AbstractAntimicrobials have been widely used to prevent and treat infectious diseases and promote growth in food-production animals. However, the occurrence of antimicrobial resistance poses a huge threat to public and animal health, especially in less developed countries where food-producing animals often intermingle with humans. To limit the spread of antimicrobial resistance from food-production animals to humans and the environment, it is essential to have a comprehensive knowledge of the role of the resistome in antimicrobial resistance (AMR), The resistome refers to the collection of all antimicrobial resistance genes associated with microbiota in a given environment. The dense microbiota in the digestive tract is known to harbour one of the most diverse resistomes in nature. Studies of the resistome in the digestive tract of humans and animals are increasing exponentially as a result of advancements in next-generation sequencing and the expansion of bioinformatic resources/tools to identify and describe the resistome. In this review, we outline the various tools/bioinformatic pipelines currently available to characterize and understand the nature of the intestinal resistome of swine, poultry, and ruminants. We then propose future research directions including analysis of resistome using long-read sequencing, investigation in the role of mobile genetic elements in the expression, function and transmission of AMR. This review outlines the current knowledge and approaches to studying the resistome in food-producing animals and sheds light on future strategies to reduce antimicrobial usage and control the spread of AMR both within and from livestock production systems.

2016 ◽  
Vol 311 (2) ◽  
pp. E405-E422 ◽  
Author(s):  
Sooyeon Lee ◽  
Shannon L. Kelleher

Lactation is a dynamic process that has evolved to produce a complex biological fluid that provides nutritive and nonnutritive factors to the nursing offspring. It has long been assumed that once lactation is successfully initiated, the primary factor regulating milk production is infant demand. Thus, most interventions have focused on improving breastfeeding education and early lactation support. However, in addition to infant demand, increasing evidence from studies conducted in experimental animal models, production animals, and breastfeeding women suggests that a diverse array of maternal factors may also affect milk production and composition. In this review, we provide an overview of our current understanding of the role of maternal genetics and modifiable factors, such as diet and environmental exposures, on reproductive endocrinology, lactation physiology, and the ability to successfully produce milk. To identify factors that may affect lactation in women, we highlight some information gleaned from studies in experimental animal models and production animals. Finally, we highlight the gaps in current knowledge and provide commentary on future research opportunities aimed at improving lactation outcomes in breastfeeding women to improve the health of mothers and their infants.


2015 ◽  
Vol 66 (12) ◽  
pp. 1213 ◽  
Author(s):  
A. R. Dechen ◽  
Q. A. C. Carmello ◽  
F. A. Monteiro ◽  
R. C. Nogueirol

The Second International Symposium on Magnesium was held in São Paulo, Brazil, in November 2014. An overview of the role of magnesium in food production was the theme of the opening session of that meeting. This paper considers agricultural production systems, mainly in terms of sustainability, fertiliser-use efficiency and food security, with emphasis on soils of tropical regions. Magnesium in soils and plants, as well as in relation to other nutrients and to other agricultural production factors, is especially covered. Finally, the role of magnesium is considered in terms of plant and animal health, nutrient management and the need of future research.


2020 ◽  
Author(s):  
Justin O.G. Kemp ◽  
Jessica J. Taylor ◽  
Lisa A. Kelly ◽  
Renée Larocque ◽  
Armando Heriazon ◽  
...  

Aquaculture has been one of the fastest-growing food production systems over the last decade and increased intensification of production has created conditions that favour disease outbreaks. Antibiotics are commonly applied in the animal food sector to fight against antibacterial infections, however their inappropriate use contributes to the emergence of antibiotic-resistant bacteria. Investment in research and capacity-strengthening, in parallel to enforcing existing regulations around antimicrobial use, are potentially powerful tools in tackling the threat of antimicrobial resistance (AMR) emanating from animal producing systems such as aquaculture. However, directing investment effectively is challenging due to the limited data available that hinders the identification of risk areas for current and future AMR emergence. Here, we aim to partially fulfill this gap by analyzing the current peer-reviewed literature reporting AMR genes in aquaculture food production systems and combining the data in a systematic map. Systematic searches of three bibliographic databases, a search engine, and 120 reviews returned 10 699 articles which were screened at title and abstract and then by full text (n = 1100). 218 articles, spanning 39 countries and 6 continents, met all inclusion criteria and were coded to retrieve bibliographic, methodology and study outcome data. AMR gene detections were associated with 44 families of fish and crustaceans and 75 genera of bacteria, with most studies employing primer-based methods to detect ARGs. A narrative synthesis explores implications for future research and policy as well as limitations of the systematic mapping methodology.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Maja Dorota Wojciechowska

Purpose The purpose of the paper is to present the latest scholarly trends in the field of social capital in libraries, to review research concepts published by LIS professionals and to suggest further research possibilities in this area. Design/methodology/approach This paper presents a review and critical analysis of literature associated with research on social capital in libraries to highlight its importance for the development of LIS and its impact on the functioning of environments linked with various types of libraries. The goal of literature analysis was to determine the current condition of research on social capital in libraries. The main trends were identified and the need for further qualitative analyses, which are missing at the moment, was confirmed. Findings It was determined that, so far, LIS professionals have focussed mainly on the role of municipal libraries in developing social capital, the problem of building trust, especially in immigrant circles and the impact of libraries on promoting a civil society. Academic libraries, rural libraries, organisational capital in libraries and individual social capital of librarians were a much less frequent subject of research. The role of libraries in developing social capital in educational (primary and secondary education) and professional (non-university professionals) circles is practically non-existent in research, and it will require in-depth studies and analyses in the coming years. Originality/value This paper constitutes a synthetic review of the latest research concepts concerning social capital in libraries. It identifies the most important research trends and areas that so far have not been explored and suggests research methods to help LIS professionals design future research in this area more effectively.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Manita Kusi ◽  
Fuqiang Zhao ◽  
Dinesh Sukamani

PurposeThe study aims to scrutinize the concomitant associations between corporate social responsibility (CSR), perceived organizational support (POS), green transformational leadership (GTL) and organizational performance (OP). This paper aims to explore the role of intervening variable to measure the strength on the relationship between CSR and OP.Design/methodology/approachThis research administered a survey through self-administered questionnaire among the staff-level employees of construction companies of Nepal. Fully filled 305 responses from the participants were analyzed using a structural equation model. The study used self-structured questionnaire as research tool and face-to-face meetings as data collection technique.FindingsThe research indicates that POS showed competitive partial mediation relation between CSR and OP. Besides, a novel exploration of the moderation effect of GTL displays a supportive role in harmonizing the CSR with organizational support to achieve better OP. This study enriches empirical evidence to understand the linkage between CSR and POS in staff-level employees in the construction area. Moreover, the research shed a light on GTL 's moderating influence on the mediated model of CSR, POS and OP.Research limitations/implicationsAlthough the results of the study add to the current knowledge base, several limitations highlight avenues for future research. Future studies can explore the relationship in other study areas with added evidence on a similar result with different analysis patterns and study sample. The research model studied in the context of Nepal creating evidence as a representation for the developing countries.Originality/valueThe intervening role of POS and GTL gives new insight for the research-based organization based social behavior and performance


ExRNA ◽  
2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Fangfang Jin ◽  
Zhigang Guo

Abstract The discovery of small non-coding RNAs, such as miRNA and piRNA, has dramatically changed our understanding of the role RNA plays in organisms. Recent studies show that a novel small non-coding RNA generated from cleavage of tRNA or pre-tRNA, called tRNA-derived small RNA (tsRNA), serves as a new regulator of gene expression. tsRNA has been determined participate in regulating some specific physiological and pathological processes. Although knowledge regarding the biological roles of miRNA and piRNA is expanding, whether tsRNAs play similar roles remains poorly understood. Here, we review the current knowledge regarding the mechanisms of action and biological functions of tsRNAs in intracellular, extracellular and intergenerational inheritance, and highlight the potential application of tsRNAs in human diseases, and present the current problems and future research directions.


Reproduction ◽  
2021 ◽  
Vol 161 (1) ◽  
pp. F1-F17
Author(s):  
Rocío Martínez-Aguilar ◽  
Lucy E Kershaw ◽  
Jane J Reavey ◽  
Hilary O D Critchley ◽  
Jacqueline A Maybin

The endometrium is a multicellular tissue that is exquisitely responsive to the ovarian hormones. The local mechanisms of endometrial regulation to ensure optimal function are less well characterised. Transient physiological hypoxia has been proposed as a critical regulator of endometrial function. Herein, we review the literature on hypoxia in the non-pregnant endometrium. We discuss the pros and cons of animal models, human laboratory studies and novel in vivo imaging for the study of endometrial hypoxia. These research tools provide mounting evidence of a transient hypoxic episode in the menstrual endometrium and suggest that endometrial hypoxia may be present at the time of implantation. This local hypoxia may modify the inflammatory environment, influence vascular remodelling and modulate endometrial proliferation to optimise endometrial function. Finally, we review current knowledge of the impact of this hypoxia on endometrial pathologies, with a focus on abnormal uterine bleeding. Throughout the manuscript areas for future research are highlighted with the aim of concentrating research efforts to maximise future benefits for women and society.


2018 ◽  
Vol 44 (08) ◽  
pp. 765-779 ◽  
Author(s):  
Sigrid Brækkan ◽  
John-Bjarne Hansen ◽  
Line Evensen

AbstractVenous thromboembolism (VTE) is a complex multifactorial disease that represents a growing public health concern. Identification of modifiable risk factors at the population level may provide a measure to reduce the burden of VTE. In this review, we summarize current knowledge of the role of physical activity on the risk of VTE and VTE-related complications. We also discuss methodological challenges related to research on physical activity, and put forward plausible mechanisms for an association between physical activity and VTE. Up to now, published studies have reported diverging results on the relationship between physical activity and VTE, and a complex picture has emerged. However, the available evidence appears to be balanced toward a small beneficial effect of physical activity on the risk of incident VTE, but not in a dose-dependent manner. Still, the lack of an operational definition and standardized assessment method for physical activity, as well as several sources of bias, impairs the interpretation of the available literature. Additional work is necessary to understand the role and how to apply physical activity in the VTE setting. Future research should utilize objective assessment strategies of physical activity and physical fitness, account for the fluctuating nature in habitual activity levels, and explore the role of physical activity in the areas of secondary prevention and VTE-related complications.


2020 ◽  
Vol 21 (7) ◽  
pp. 2602 ◽  
Author(s):  
Vânia M. Morelli ◽  
Sigrid K. Brækkan ◽  
John-Bjarne Hansen

MicroRNAs (miRNAs) are non-coding RNAs that execute their function by targeted downregulation of gene expressions. There is growing evidence from epidemiological studies and animal models suggesting that the expression level of miRNAs is dysregulated in venous thromboembolism (VTE). In this review, we summarize the current knowledge on the role of miRNAs as biomarkers for VTE and provide general insight into research exploring the modulation of miRNA activity in animal models of venous thrombosis. Up to now, published studies have yielded inconsistent results on the role of miRNAs as biomarkers for VTE with most of the reports focused on diagnostic research. The limited statistical power of the individual studies, due to the small sample sizes, may substantially contribute to the poor reproducibility among studies. In animal models, over-expression or inhibition of some miRNAs appear to influence venous thrombus formation and resolution. However, there is an important gap in knowledge on the potential role of miRNAs as therapeutic targets in VTE. Future research involving large cohorts should be designed to clarify the clinical usefulness of miRNAs as biomarkers for VTE, and animal model studies should be pursued to unravel the role of miRNAs in the pathogenesis of VTE and their potential as therapeutic targets.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S839-S840
Author(s):  
Jae Hyun Shin ◽  
Deiziane Viana da Silva Costa ◽  
Hardik Parikh ◽  
Katie E Barry ◽  
Amy J Mathers ◽  
...  

Abstract Background Clostridioides difficile infection (CDI) is the most common pathogen to cause healthcare-associated infections. Unlike some other bacterial pathogens antimicrobial treatment is seldom based on culture with susceptibility testing with infrequent surveillance for antimicrobial resistance. We have evaluated healthcare-onset CDI (HO-CDI) for both transmission and antimicrobial resistance emergence. Methods We identified cases of HO-CDI diagnosed by PCR within a 3 month period (October 1/2018–December 31/2018) at University of Virginia Health System with overlapping stays in the same inpatient units with other HO-CDI. Chart review of all cases was performed. C. difficile was cultured from stool, then DNA was extracted and underwent sequencing on Illumina Miseq platform. Antimicrobial resistance genes were screened using NCBI’s AMRFinder tool from the de-novo assembled contigs using SPAdes. All the C. difficile isolates underwent antibiotic susceptibility testing. Results Eleven patients were identified with overlapping stays from 5 units. Mean age was 64 years and 63.6% were female. 36.3% of cases were severe CDI with one case of fulminant CDI. There was one recurrence within 90 days (9.1%). Patients were treated with PO vancomycin (72.7%) or IV metronidazole and PO vancomycin (27.3%), none were treated with metronidazole alone. None of the hospital strains were genetically related. There were two isolates with binary toxin gene (cdtB), one ribotype 027 (CD196) and one ribotype 078 (M120). Ninety-one percent of isolates had vanG-like gene cluster and vanZ1 originally identified in Enterococcus sp. erm(B), tet(M), and cfr(C) genes were also detected in several strains. All isolates were susceptible to vancomycin, metronidazole, and tigecycline. There was one strain with moxifloxacin resistance associated with the presence of erm(B) gene. None of the isolates were susceptible to clindamycin. Conclusion There were no widely circulating clones or direct transmissions found in this small sample of HO-CDI cases at our hospital. Like others have we demonstrate carriage of many vanG/Z genes without conferring phenotypic resistance to vancomycin. The origin and function of Van genes in C. difficile could be an area of future research. Disclosures All authors: No reported disclosures.


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