每年，因为感染性的疾病可以导致1300万人死亡，而且每年死亡的人数都在增加之中，这都归因于致病菌中的抗性基因，近日，一项刊登在国际杂志Antimicrobial Agents and Chemotherapy的一篇研究指出，在农田土壤中也存在着大量的抗性菌株，土壤中包含了众多不同的耐药细菌，而且这些细菌的耐药性比堆肥和森林土壤中细菌的耐药性都强，蔬菜菜园的土壤中当然也含有大量的耐药菌株，而且对于目前的三大抗生素都有着高度的耐药性。
来自波兰华沙大学的研究者Magdalena Popowska表示，我们的研究中发现了世界范围内的农田土壤中存在着高度耐药水平的耐药菌株。抗生素以及细菌的耐药基因的出现都是长期微生物在竞争地盘的斗争中慢慢进化来的，从土壤中分离出的至少50%的放线菌都有能力分泌抗生素，这种被分泌的抗生素残留长期存在于土壤中，但是日常生活中，我们在饲料中添加抗生素帮助家畜生长，但是不能被吸收的抗生素就会混合在粪肥中，这样一来，用粪肥灌溉农田以及菜园，时间一长，慢慢就会增加土壤中细菌的耐药性。
Popowska表示，多重耐药致病菌以及机会致病菌耐药性的普遍存在不仅仅会感染人和动物，而且这种耐药性也会随着遗传因子进行转移，比如通过质粒以及转座子介导的遗传转移，慢慢就会将耐药性转移到细菌相同的种中，也会转移到不同种的细菌中。她还补充道，研究结果还提示，在养鱼以及工业上，抗生素的合理利用对环境中耐药细菌的控制尤为重要，而且我们相信我们可以进行最优化的选择去和耐药细菌斗争或者用更好的化学药物来抵御耐药细菌的感染或者散布。
研究者最后还表示，对于危险严格的细菌感染，抗生素的使用必须尤为严格，而且监管力度也必须严格，但是目前看来，这些并没有被重视起来。
（生物谷：T.Shen编译）
doi:10.1128/AAC.05766-11
PMC:
PMID:
Influence of Soil Use on Prevalence of Tetracycline, Streptomycin, and Erythromycin Resistance and Associated Resistance Genes
Magdalena Popowskaa, Marzenna Rzeczyckaa, Antoni Miernika, Agata Krawczyk-Balskaa, Fiona Walshb and Brion Duffyb
This study examined differences in antibiotic-resistant soil bacteria and the presence and quantity of resistance genes in soils with a range of management histories. We analyzed four soils from agricultural systems that were amended with manure from animals treated with erythromycin and exposed to streptomycin and/or oxytetracycline, as well as non-manure-amended compost and forest soil. Low concentrations of certain antibiotic resistance genes were detected using multiplex quantitative real-time PCR (qPCR), with tet(B), aad(A), and str(A) each present in only one soil and tet(M) and tet(W) detected in all soils. The most frequently detected resistance genes were tet(B), tet(D), tet(O), tet(T), and tet(W) for tetracycline resistance, str(A), str(B), and aac for streptomycin resistance, and erm(C), erm(V), erm(X), msr(A), ole(B), and vga for erythromycin resistance. Transposon genes specific for Tn916, Tn1549, TnB1230, Tn4451, and Tn5397 were detected in soil bacterial isolates. The MIC ranges of isolated bacteria for tetracycline, streptomycin, and erythromycin were 8 to >256 μg/ml, 6 to >1,024 μg/ml, and 0.094 to >256 μg/ml, respectively. Based on 16S rRNA gene similarity, isolated bacteria showed high sequence identity to genera typical of soil communities. Bacteria with the highest MICs were detected in manure-amended soils or soils from agricultural systems with a history of antibiotic use. Non-manure-amended soils yielded larger proportions of antibiotic-resistant bacteria, but these had lower MICs, carried fewer antibiotic resistance genes, and did not display multidrug resistance (MDR).
