河南某工厂附近农田土壤中抗生素抗性基因与可移动遗传元件的分布*
Prevalence of antibiotic resistance genes and mobile genetic elements in farmland soil near a factory of a certain city in Henan Province

目的:观察河南某工厂附近农田土壤中抗生素抗性基因和可移动遗传元件的分布。方法:分别于不同时间点采集河南某工厂主导风向下风向上距离为700～2 500 m不等的7块农田土壤的土样,提取总DNA,采用PCR法检测15种抗生素抗性基因(包括四环素类药物抗性基因tetA、tetC、tetE、tetM、tetQ、tetW,磺胺类药物抗性基因sulⅠ、sulⅡ,β内酰胺类药物抗性基因bla-TEM、SHV、CTX-M-1,喹诺酮类药物的抗性基因qnrA、qnrB、qnrS,链霉素类药物抗性基因strA)和4种可移动遗传元件(包括整合酶基因intI1、intI2,插入序列共同区基因orf513、ISCR2),PCR阳性产物送测序,通过BLAST与GenBank数据库进行同源性比对。结果:共检出8种抗生素抗性基因,分别是sulⅡ、tetC、bla-TEM、sulⅠ、tetA、strA、tetM和tetW; 3种可移动遗传元件intI1、intI2、ISCR2。各PCR扩增阳性产物经测序比对后,与GenBank已有序列识别度为95%～100%。各基因在不同距离土样中的阳性率比较差异均无统计学意义(P＞0.05),sulⅡ、tetC、bla-TEM和intI1在不同时间点的土样中阳性率比较差异有统计学意义(P<0.05)。结论:该工厂附近农田土壤中常见抗生素抗性基因及可移动基因元件为sulⅡ、tetC、bla-TEM、sulⅠ和intI1,除sulⅠ外,sulⅡ、tetC、bla-TEM 和intI1的分布均具有时间差异,但在不同距离农田土壤中分布稳定。
Aim: To investigate the prevalence of antibiotic resistance genes and mobile genetic elements in farmland soil near a factory of a certain city in Henan Province.Methods: Mixed soil samples of 7 pieces of farmland with different distance(700-2 500 m)from a factory at different time points in Henan Province were collected and total DNA was extracted by DNA extraction kit. Fifteen kinds of antibiotic resistance genes and 4 kinds of mobile genetic elements were detected by PCR,which included tetracycline resistance genes(tetA,tetC,tetE,tetM,tetQ,tetW),sulfonamides resistance genes(sulⅠ,sulⅡ), β-lactam resistance genes(bla-TEM,SHV,CTX-M-1), quinolones resistance genes(qnrA,qnrB,qnrS), streptomycin resistance gene(strA), class 1 and class 2 integron genes(intⅠ1,intⅠ2), and insertion sequence common region genes(orf513,ISCR2). Positive products of PCR were sequenced and compared with sequences in GenBank database by BLAST software.Results: Eight antibiotic resistance genes were found positive including sulⅡ, tetC, bla-TEM, sulⅠ, tetA, strA, tetM and tetW. Mobile genetic elements intI1, intI2, and ISCR2 were positive in 7 pieces of farmland. All sequences identified had greater than 95% homology with genes in GenBank by BLAST software. Genes positive rates from different soil samples were not found significantly different(P＞0.05), however, positive rates of sulⅡ, tetC, bla-TEM and intI1 in different time points were significantly different(P<0.05).Conclusion: Antibiotic resistance genes and mobile genetic elements sulⅡ, tetC, bla-TEM,intI1 and sulⅠ are found common in farmland near the factory. The distributions of sulⅡ, tetC, bla-TEM and intI1 except sulⅠ may vary with time and stabilize in the soil with different distance to the factory