Understanding the role of host-pathogen interactions and the impact of management system on antimicrobial resistance in Brazilian livestock systems

了解宿主-病原体相互作用的作用以及管理系统对巴西畜牧系统抗菌素耐药性的影响

• 批准号: BB/R022739/1
• 负责人: Caroline Rymer
• 金额: $ 9.43万
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FR022739%2F1
• 关键词: Understanding; role; host; pathogen; interactions

The Brazilian beef industry is immense, and is a vital source of foreign revenue for the country. Brazil is the second largest producer of beef in the world, and has the world's largest commercial herd of approximately 200 million head produced on 1.8 million farms ranging from small enterprises (<500 head p.a.) to commercialised beef production enterprises (>4000 head p.a.). Most animals are produced on pasture, many of them on soils of low to medium fertility in the cerrado (similar to savannas, an important biome in Brazil) with <7% of slaughtered animals being produced on feedlots. Despite this extensive system of beef production, antimicrobial consumption is high. In 2010, Brazil was ranked third highest in the world for antimicrobial consumption by food producing animals, and accounted for 9% of total global farm animal antimicrobial consumption. This high consumption of antimicrobials by farm animals increases the risk of the development of antimicrobial resistant (AMR) bacteria in the host animal's microbiome (the microbial population living in the animal's gut). There are many factors which might encourage the proliferation of AMR bacteria in the host gut, and the hypothesis on which this proposal is based is that changes in the host microbiome may affect the maintenance and prevalence of AMR strains of bacteria. Identifying interventions that may then encourage the development of a microbiome that suppresses AMR bacteria could then help control the development and spread of AMR in Brazilian beef cattle. We hypothesise that beef finished on pasture in Brazil will have a lower prevalence of faecal AMR bacteria compared with those finished in feedlots, because of the less intensive nature of the pasture based production system. Much of the pasture grazed in Brazil is suitable either for the growth of tropical grasses or, in more intensively managed pastures, legumes. Both tropical grasses and forage legumes contain tannins, which are known to have antimicrobial properties and antibiotic resistance modifying properties. However, the efficacy and mode of action of tannins as antimicrobials depends on their concentration and composition. Elucidating the relationship between tannin composition and intake, and the effect this has on the host animal's microbiome (and susceptibility to AMR bacteria) will be investigated in this project. In the first stage of the project, we will conduct a survey to determine the effect of animal age (yearling and finishing animal) and production system (cerrado grazing, more intensively managed pasture, feedlot) on the prevalence of AMR bacteria in faecal samples taken from beef cattle in Brazil. We will also determine the composition of the microbial population in the animal's gut (from the faecal sample) to investigate whether there are patterns of bacterial species which are associated with a lower prevalence of AMR bacteria. We will also take samples of the forages consumed by the animal and investigate whether the amount and composition of tannin that the animal consumes can explain differences in its gut microbiome and the prevalence of AMR bacteria. This will then enable us to develop management and feeding strategies (that would be investigated in the second stage of the project) that might reduce the prevalence of AMR bacteria in Brazilian beef cattle, improving the health status of the cattle themselves and improving the safety and marketability of the meat.

巴西牛肉行业是巨大的，是该国外国收入的重要来源。巴西是世界第二大生产商，拥有大约2亿头牛群的全球最大的商业牛群，在180万个农场上生产，从小型企业（<500 Head P.A.）到商业化的牛肉生产企业（> 4000 Head P.A.）。大多数动物是在牧场上生产的，其中许多是在塞拉多（Cerrado）低至中等生育力的土壤上（类似于萨凡纳斯（Savannas），巴西重要的生物群落），<7％的屠宰动物在饲养场上产生。尽管这种广泛的牛肉生产系统，但抗菌素消耗量很高。 2010年，巴西通过食品生产动物在世界上排名全球第三名，占全球全球农场动物抗菌消费量的9％。农场动物对抗菌剂的高消耗增加了宿主动物微生物组（生活在动物肠道中的微生物种群）中抗菌抗药性（AMR）细菌发展的风险。有许多因素可能会鼓励宿主肠道中AMR细菌的扩散，而该提案的基于的假设是，宿主微生物组的变化可能会影响细菌AMR菌株的维持和患病率。确定可能鼓励抑制AMR细菌的微生物组发展的干预措施，然后可以帮助控制AMR在巴西牛奶中的发展和传播。我们假设在巴西在牧场上完成的牛肉的患病率较低，而与饲养场中的牛肉相比，由于基于牧场的生产系统的强化性质较小，因此粪便AMR细菌的患病率较低。在巴西吃草的许多牧场都适用于热带草的生长，或者在更强化的牧场中，豆类。热带草和草料豆类都有单宁，已知具有抗菌特性和抗生素耐药性修饰特性。但是，单宁作为抗菌素的功效和作用方式取决于其浓度和成分。阐明单宁成分与摄入量之间的关系，以及该项目对宿主动物的微生物组（以及对AMR细菌的易感性）的影响。在项目的第一阶段，我们将进行一项调查，以确定动物时代（一岁动物和生产系统）和生产系统（Cerrado放牧，更强化管理的牧场，饲料）对来自巴西牛肉牛的粪便样品中AMR细菌的普遍性。我们还将确定动物肠道中微生物种群的组成（从粪便样品）来研究是否存在与AMR细菌患病率较低有关的细菌种类的模式。我们还将采集动物消耗的草料样本，并研究动物消耗的单宁的数量和组成是否可以解释其肠道微生物组的差异和AMR细菌的流行率。然后，这将使我们能够制定管理和喂养策略（这将在项目的第二阶段进行调查），从而可以降低巴西牛肉中AMR细菌的患病率，从而提高牛本身的健康状况并提高肉类的安全性和销售能力。

项目成果

Taxonomy and Functional Diversity in the Fecal Microbiome of Beef Cattle Reared in Brazilian Traditional and Semi-Intensive Production Systems.

• DOI: 10.3389/fmicb.2021.768480
• 发表时间: 2021
• 期刊: Frontiers in microbiology
• 影响因子: 5.2
• 作者: Corrêa PS;Jimenez CR;Mendes LW;Rymer C;Ray P;Gerdes L;da Silva VO;De Nadai Fernandes EA;Abdalla AL;Louvandini H
• 通讯作者: Louvandini H

Antimicrobial resistance in Brazilian cattle systems

巴西牛系统中的抗生素耐药性

• 发表时间: 2021
• 作者: Rodriguez Jimenez, C

Pasture management practices are associated with the prevalence of antimicrobial resistance in grazing cattle

牧场管理实践与放牧牛抗生素耐药性的流行有关

• 发表时间: 2019
• 作者: Rymer C