The colonization of broilers with extended-spectrum β-lactamase- (ESBL-) and plasmid-mediated AmpC β-lactamase- (pAmpC-) producing Enterobacteriaceae has been extensively studied. However, only limited data on intervention strategies to reduce the colonization throughout the fattening period are available. To investigate practically relevant management measures for their potential to reduce colonization, a recently published seeder-bird colonization model was used. Groups of 90 broilers (breed Ross 308) were housed in pens under conventional conditions (stocking of 39 kg/m², no enrichment, water and feed ad libitum). Tested measures were investigated in separate trials and included (I) an increased amount of litter in the pen, (II) the reduction of stocking density to 25 kg/m², and (III) the use of an alternative broiler breed (Rowan x Ranger). One-fifth of ESBL- and pAmpC- negative broilers (n = 18) per group were orally co-inoculated with two E. coli strains on the third day of the trial (seeder). One CTX-M-15-positive E. coli strain (ST410) and one CMY-2 and mcr-1-positive E. coli strain (ST10) were simultaneously administered in a dosage of 10² cfu. Colonization of all seeders and 28 non-inoculated broilers (sentinel) was assessed via cloacal swabs during the trials and a final necropsy at a target weight of two kilograms (= d 36 (control, I-II), d 47 (III)). None of the applied intervention measures reduced the colonization of the broilers with both the ESBL- and the pAmpC- producing E. coli strains. A strain-dependent reduction of colonization for the ESBL- producing E. coli strain of ST410 by 2 log units was apparent by the reduction of stocking density to 25 kg/m². Consequently, the tested management measures had a negligible effect on the ESBL- and pAmpC- colonization of broilers. Therefore, intervention strategies should focus on the prevention of ESBL- and pAmpC- colonization, rather than an attempt to reduce an already existing colonization.

用广谱β-内酰胺酶-（ESBL-）和质粒介导的AmpCβ-内酰胺酶-（pAmpC-）产生的肠杆菌对肉鸡的定殖已经得到了广泛的研究。但是，只有关于在整个育肥期内减少定植的干预策略的有限数据。为了研究其减少定殖潜力的实际相关管理措施，使用了最近发布的种鸟定殖模型。90只肉鸡（繁殖罗斯308）的组被安置在常规条件下的笔（放养39千克/米²，没有富集，水和饲料随意）。在单独的试验中对经过测试的措施进行了研究，包括（I）增加围栏中的垫料数量，（II）将放养密度降低至25 kg / m²，以及（III）使用替代肉鸡品种（Rowan x Ranger）。每组五分之一的ESBL和pAmpC阴性肉鸡（n = 18）与两个E一起口服接种。在试验的第三天（播种者）接种大肠杆菌菌株。其中CTX-M-15阳性ê。大肠杆菌菌株（ST410）和一个CMY-2和MCR-1阳性Ë。同时以10 ²的剂量施用大肠杆菌菌株（ST10）cfu。在试验过程中通过泄殖腔拭子评估了所有播种者和28个未接种肉鸡（前哨）的定殖情况，并进行了最终尸检，目标体重为2公斤（= d 36（对照组，I-II），d 47（III）） 。应用的干预措施均未减少产生ESBL和pAmpC的E对肉鸡的定殖。大肠杆菌菌株。产生ESBL的E的定殖减少取决于菌株。通过将放养密度降低至25 kg / m ^2，可以明显看出ST410的ST410大肠埃希菌菌株。因此，经过测试的管理措施对肉鸡的ESBL和pAmpC-定植影响可忽略不计。因此，干预策略应侧重于预防ESBL和pAmpC的定植，而不是试图减少已经存在的定植。