Ciesinski Lisa, Guenther Sebastian, Pieper Robert, Kalisch Martin, Bednorz Carmen, Wieler Lothar H
Centre for Infection Medicine, Institute of Microbiology and Epizootics, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
PLoS One. 2018 Jan 26;13(1):e0191660. doi: 10.1371/journal.pone.0191660. eCollection 2018.
High levels of zinc oxide are used frequently as feed additive in pigs to improve gut health and growth performance and are still suggested as an alternative to antimicrobial growth promoters. However, we have recently described an increase of multi-resistant E. coli in association to zinc feeding in piglets. This previous study focused on clonal diversity of E. coli, observing the effect on multi-resistant strains by chance. To shed further light into this highly important topic and falsify our previous findings, we performed a zinc pig feeding trial where we specifically focused on in-depth analysis of antimicrobial resistant E. coli. Under controlled experimental conditions, piglets were randomly allocated to a high dietary zinc (zinc group) and a background zinc feeding group (control group). At different ages samples were taken from feces, digesta, and mucosa and absolute E. coli numbers were determined. A total of 2665 E. coli isolates were than phenotypically tested for antimicrobial resistance and results were confirmed by minimum inhibitory concentration testing for random samples. In piglets fed with high dietary zinc, we detected a substantial increase of multi-resistant E. coli in all gut habitats tested, ranging from 28.9-30.2% multi-resistant E. coli compared to 5.8-14.0% in the control group. This increase was independent of the total number of E. coli. Interestingly, the total amount of the E. coli population decreased over time. Thus, the increase of the multi-resistant E. coli populations seems to be linked with persistence of the resistant population, caused by the influence of high dietary zinc feeding. In conclusion, these findings corroborate our previous report linking high dietary zinc feeding of piglets with the occurrence of antimicrobial resistant E. coli and therefore question the feeding of high dietary zinc oxide as alternative to antimicrobial growth promoters.
高剂量的氧化锌常被用作猪的饲料添加剂，以改善肠道健康和生长性能，目前仍被建议作为抗菌生长促进剂的替代品。然而，我们最近发现，仔猪喂食锌后多重耐药大肠杆菌数量有所增加。此前的这项研究聚焦于大肠杆菌的克隆多样性，偶然观察到对多重耐药菌株的影响。为了进一步阐明这个极其重要的课题并验证我们之前的发现，我们进行了一项仔猪锌喂养试验，特别着重于对抗菌耐药大肠杆菌进行深入分析。在可控的实验条件下，仔猪被随机分为高锌日粮组（锌组）和基础锌喂养组（对照组）。在不同年龄段采集粪便、食糜和黏膜样本，测定大肠杆菌的绝对数量。随后，对总共2665株大肠杆菌分离株进行了抗菌耐药性的表型测试，并通过对随机样本的最低抑菌浓度测试来确认结果。在喂食高锌日粮的仔猪中，我们检测到，在所有测试的肠道生境中，多重耐药大肠杆菌大幅增加，多重耐药大肠杆菌占比为28.9 - 30.2%，而对照组为5.8 - 14.0%。这种增加与大肠杆菌的总数无关。有趣的是，大肠杆菌的总量随时间减少。因此，多重耐药大肠杆菌数量的增加似乎与耐药菌群体的持续存在有关，这是由高锌日粮喂养的影响导致的。总之，这些发现证实了我们之前的报告，即仔猪高锌日粮喂养与抗菌耐药大肠杆菌的出现有关，因此对高剂量氧化锌作为抗菌生长促进剂替代品的喂养方式提出了质疑。
