Schmitt Heike, Stoob Krispin, Hamscher Gerd, Smit Eric, Seinen Willem
Institute for Risk Assessment Sciences (IRAS), Utrecht University, PO Box 80176, 3508 TD, Utrecht, The Netherlands.
Microb Ecol. 2006 Apr;51(3):267-76. doi: 10.1007/s00248-006-9035-y. Epub 2006 Apr 6.
The influence of the use of antibiotics on the prevalence of resistance genes in the environment is still poorly understood. We studied the diversity of tetracycline and sulfonamide resistance genes as influenced by fertilization with pig manure in soil microcosms and at two field locations. Manure contained a high diversity of resistance genes, regardless of whether it stemmed from a farm operation with low or regular use of antibiotics. In the microcosm soils, the influence of fertilization with manure was clearly shown by an increase in the number of resistance genes in the soil after manuring. Spiking of the tetracycline compounds to the microcosms had only little additional impact on the diversity of resistance genes. Overall, the tetracycline resistance genes tet(T), tet(W), and tet(Z) were ubiquitous in soil and pig slurries, whereas tet(Y), tet(S), tet(C), tet(Q), and tet(H) were introduced to the microcosm soil by manuring. The diversity of tetracycline and sulfonamide [sul(1), sul(2), and sul(3)] resistance genes on a Swiss pasture was very high even before slurry amendment, although manure from intensive farming had not been applied in the previous years. The additional effect of manuring was small, with the tetracycline and sulfonamide resistance diversity staying at high levels for the complete growth season. At an agricultural field site in Germany, the diversity of tetracycline and sulfonamide resistance genes was considerably lower, possibly reflecting regional differences in gene diversity. This study shows that there is a considerable pool of resistance genes in soils. Although it is not possible to conclude whether this diversity is caused by the global spread of resistance genes after 50 years of tetracycline use or is due to the natural background in soil resistance genes, it highlights a role that environmental reservoirs might play in resistance gene capture.
抗生素的使用对环境中耐药基因流行情况的影响仍知之甚少。我们研究了在土壤微观世界以及两个田间地点，猪粪施肥对四环素和磺胺类耐药基因多样性的影响。无论猪粪来自抗生素使用量低或正常的养殖场，粪便中都含有高度多样的耐药基因。在微观世界土壤中，施肥的影响通过施肥后土壤中耐药基因数量的增加得以清晰体现。向微观世界中添加四环素化合物对耐药基因多样性的额外影响很小。总体而言，四环素耐药基因tet(T)、tet(W)和tet(Z)在土壤和猪粪中普遍存在，而tet(Y)、tet(S)、tet(C)、tet(Q)和tet(H)则是通过施肥引入微观世界土壤的。即使在施用粪肥之前，瑞士牧场中四环素和磺胺类（sul(1)、sul(2)和sul(3)）耐药基因的多样性就非常高，尽管前几年没有施用集约化养殖的粪便。施肥的额外影响很小，在整个生长季节，四环素和磺胺类耐药基因的多样性都保持在较高水平。在德国的一个农田地点，四环素和磺胺类耐药基因的多样性要低得多，这可能反映了基因多样性的区域差异。这项研究表明，土壤中存在大量的耐药基因库。虽然无法确定这种多样性是由于四环素使用50年后耐药基因的全球传播所致，还是由于土壤耐药基因的自然背景，但它凸显了环境储存库在耐药基因捕获中可能发挥的作用。
