Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu, P. R. China.
College of Marine and Bio-engineering, Yancheng Teachers University, Yancheng, Jiangsu, P. R. China.
Sci Rep. 2018 Jan 24;8(1):1489. doi: 10.1038/s41598-018-20050-8.
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, and Rhodococcus 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.
通过模拟受精的微宇宙实验，我们采用培养依赖方法和 PCR 检测，评估了来自猪粪（PM）的四环素耐药菌（TRB）和相应的四环素耐药基因（TRGs）向施肥土壤中的动态分布。可培养的 TRB 在 PM 中最为丰富，其次是施肥土壤和未施肥土壤。通过限制性片段长度多态性（RFLP）分析，TRB 在 PM、未施肥土壤和施肥土壤中分别被分配到 29、20 和 153 个操作分类单元（OTUs）。经鉴定后，它们进一步被分为 19、12 和 62 个种，表明 PM 施用后土壤中可培养 TRB 的多样性增加。与 PM 和未施肥土壤相比，施肥土壤中潜在致病 TRB 的比例分别降低了 69.35%和 41.92%。蜡样芽孢杆菌可能是各种环境中广泛分布的 TRB，红球菌和不动杆菌可能通过施肥从 PM 传播到土壤。同时，与 PM 相比，tetL 是未施肥和施肥土壤中最常见的外排泵基因；tetB(P)和 tet36 在 PM 中常见，而 tetO 在未施肥和施肥土壤样本中占优势。测序表明，在具有获得性抗性的施肥土壤中，随机选择的 TRB 中有超过 65%来自 PM。
