Abstract：
Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) in animals are considered a human health threat, because this type of bacteria can serve as a reservoir of antibiotic resistant genes and act as a continuous threat of the emergence of new resistant bacteria, in addition to the direct effect of making infection untreatable. Although the prevalence of ESBL producing bacteria in broilers was drastically reduced in the Netherlands, chicken meat still has the highest prevalence among meat products. Therefore, further control of the ESBL-producing E. coli in the broiler production chain is important to reduce public health risks. The main objectives of this study were to evaluate the effectiveness of intervention scenarios to reduce the transmission of ESBL-producing E. coli in the broiler production chain and to quantitatively estimate the risk to public health. In this study, we developed two different types of transmission models that described the observed time-related decline in prevalence during a production round: one with time-dependent decline in susceptibility and one with partial immunity to phylogenetic groups. Both models incorporated the environmental contamination effect between production rounds and within flocks. The parameter values, including transmission rate and recovery rate, were estimated by Approximate Bayesian computation (ABC) method using data from a longitudinal study in a Dutch organic broiler farm. We applied the models to the three production stages in the broiler production chain, beginning from the Parent Stock (PS) farms, the hatcheries, and to the broiler farms. In our models, eggs were collected from different parent stock farms and transported to the hatchery and from there to a broiler farm.The size of a flock and the number of farms were adjusted to the Dutch situation. Both models were able to describe the observed dynamics within and between the production stages equally well, with estimated ESBL-producing E. coli prevalence of 8.98% and 11.47% in broilers at slaughter and 0.12% and 0.15% in humans due to chicken consumption. Both models indicated that improving farm management to eliminate the bacteria from the environment was the most effective intervention, making this outcome robust. Although chicken meat consumption is not a major risk factor for human carriage of the bacteria according to our models, reducing the bacteria in the PS and broiler farm environment to at least one percent can further decrease the prevalence in humans.
摘要：
产超广谱β-内酰胺酶（ESBL）的大肠杆菌（E.动物中的大肠杆菌)被认为是对人类健康的威胁，因为这种类型的细菌可以作为抗生素抗性基因的储库，并作为新的抗性细菌出现的持续威胁，除了使感染无法治愈的直接影响。尽管在荷兰，在肉鸡中产生ESBL的细菌的患病率急剧下降，鸡肉仍然是肉类产品中流行率最高的。因此,进一步控制肉鸡生产链中产生ESBL的大肠杆菌对于降低公共卫生风险非常重要。本研究的主要目的是评估干预方案的有效性，以减少产ESBL大肠杆菌在肉鸡生产链中的传播，并定量估计对公众健康的风险。在这项研究中,我们开发了两种不同类型的传播模型,这些模型描述了在生产周期中观察到的与时间相关的患病率下降:一种具有与时间相关的易感性下降,另一种具有对系统发育群体的部分免疫力.两种模型都结合了生产回合之间和羊群内的环境污染影响。参数值,包括传输速率和回收率，使用荷兰有机肉鸡养殖场的纵向研究数据，通过近似贝叶斯计算（ABC）方法进行估算。我们将模型应用于肉鸡生产链中的三个生产阶段，从母畜(PS)农场开始，孵化场,和肉鸡养殖场。在我们的模型中,从不同的亲本养殖场收集鸡蛋，然后运到孵化场，再从那里运到肉鸡养殖场。羊群的大小和农场的数量根据荷兰的情况进行了调整。两种模型都能够很好地描述生产阶段内部和之间观察到的动态，据估计，由于食用鸡肉，在屠宰时肉鸡中产生ESBL的大肠杆菌的患病率为8.98％和11.47％，在人类中为0.12％和0.15％。两种模型都表明，改善农场管理以消除环境中的细菌是最有效的干预措施，使这一结果稳健。虽然根据我们的模型，鸡肉消费不是人类携带细菌的主要危险因素，将PS和肉鸡养殖场环境中的细菌减少到至少百分之一可以进一步降低人类的患病率。
