通过模拟施肥的微观实验，采用培养依赖性方法和PCR检测评估了猪粪（PM）对施肥土壤中四环素抗性细菌（TRB）和相应的四环素抗性基因（TRG）的动态分布。可培养TRB在PM中含量最高，其次是施肥土和未施肥土。通过限制性片段长度多态性（RFLP）分析，TRB分配到PM，未施肥土壤和施肥土壤中的操作分类单元（OTU）分别为29个,20个和153个。经鉴定后，将它们进一步分为19,12和62种，表明施用PM后土壤中可培养TRB的多样性增强。与PM和未施肥土壤相比，施肥土壤中潜在致病性TRB的比例分别下降了69.35％和41.92％。蜡样芽孢杆菌可能在各种环境下广泛分布于TRB，红球菌和不动杆菌也可能广泛分布。可能通过施肥从PM传播到土壤。与PM相比，未施肥和施肥土壤中最常见的外排泵基因是tetL; tetB（P）和tet36在PM中很常见，而tetO在未施肥和施肥的土壤样品中占优势。测序表明超过65％的随机选择的施肥土壤中获得性抗性来自PM。

      By performing a microcosm experiment mimicking fertilization, we assessed the dynamic distribution of tetracycline-resistant bacteria (TRB) and corresponding tetracycline resistance genes (TRGs) from pig manure (PM) to the fertilized soil, by culture-dependent methods and PCR detection. Cultivable TRB were most abundant in PM, followed by fertilized soil and unfertilized soil. By restriction fragment length polymorphism (RFLP) analysis, TRB were assigned to 29, 20, and 153 operational taxonomic units (OTUs) in PM, unfertilized soil, and fertilized soil, respectively. After identification, they were further grouped into 19, 12, and 62 species, showing an enhanced diversity of cultivable TRB in the soil following PM application. The proportions of potentially pathogenic TRB in fertilized soil decreased by 69.35% and 41.92% compared with PM and unfertilized soil. Bacillus cereus was likely widely distributed TRB under various environments, andRhodococcus erythropolis and Acinetobacter sp. probably spread from PM to the soil via fertilization. Meanwhile, tetL was the most common efflux pump gene in both unfertilized and fertilized soils relative to PM;tetB(P) and tet36 were common in PM, whereas tetO was predominant in unfertilized and fertilized soil samples. Sequencing indicated that over 65% of randomly selected TRB in fertilized soil with acquired resistance derived from PM.

https://www.nature.com/articles/s41598-018-20050-8