Abatih Emmanuel N, Alban Lis, Ersbøll Annette K, Lo Fo Wong Danilo M
Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Unit of Epidemiology, Grønnegaardsvej 8, 1870 Frederiksberg C, Denmark.
J Theor Biol. 2009 Feb 21;256(4):561-73. doi: 10.1016/j.jtbi.2008.10.017. Epub 2008 Oct 29.
There is increasing evidence showing that antimicrobial consumption provides a powerful selective force that promotes the emergence of resistance in pathogenic, commensal as well as zoonotic bacteria in animals. The main aim of this study was to develop a modeling framework that can be used to assess the impact of antimicrobial usage in pigs on the emergence and transmission of resistant bacteria within a finisher pig farm. The transmission dynamics of drug-sensitive and drug-resistant bacteria among pigs in the herd were characterized by studying the local and global stability properties of steady state solutions of the system. Numerical simulations demonstrating the influence of factors such as initial prevalence of infection, presence of pre-existing antimicrobial resistant mutants, and frequency of treatment on predicted prevalence were performed. Sensitivity analysis revealed that two parameters had a huge influence on the predicted proportion of pigs carrying resistant bacteria: (a) the transmission coefficient between uninfected pigs and those infected with drug-resistant bacteria during treatment (beta(2)) and after treatment stops (beta(3)), and (b) the spontaneous clear-out rate of drug-resistant bacteria during treatment (gamma(2)) and immediately after treatment stops (gamma(3)). Control measures should therefore be geared towards reducing the magnitudes of beta(2) and beta(3) or increasing those of gamma(2) and gamma(3).
越来越多的证据表明，抗菌药物的使用提供了一种强大的选择压力，促使动物体内致病性、共生性以及人畜共患病菌产生耐药性。本研究的主要目的是建立一个建模框架，用于评估猪使用抗菌药物对育肥猪场耐药菌出现和传播的影响。通过研究系统稳态解的局部和全局稳定性特性，对猪群中药物敏感菌和耐药菌的传播动力学进行了表征。进行了数值模拟，以证明感染的初始患病率、预先存在的抗菌耐药突变体的存在以及治疗频率等因素对预测患病率的影响。敏感性分析表明，有两个参数对携带耐药菌的猪的预测比例有巨大影响：（a）治疗期间未感染猪与感染耐药菌猪之间的传播系数（β(2)）以及治疗停止后的传播系数（β(3)），以及（b）治疗期间耐药菌的自发清除率（γ(2)）以及治疗停止后立即的自发清除率（γ(3)）。因此，控制措施应旨在降低β(2)和β(3)的幅度，或提高γ(2)和γ(3)的幅度。
