鸡饲料中抗生素耐药菌和耐药基因污染初探

Preliminary study on contamination of antibiotic resistant bacteria and antibiotic resistance genes in chicken feed

利用超高效液相色谱串联质谱法测定12份饲料样品中80种抗生素的残留情况,用抗性培养基筛选法对6类耐药细菌进行分离、计数,并用荧光定量PCR法对17个耐药基因进行定量分析。结果表明:仅食槽样品中发现磺胺氯吡嗪、强力霉素、氟苯尼考3种抗生素的残留,残留量分别为0.082 mg∕kg、0.005 mg∕kg、0.014 mg∕kg。多数饲料样品中均检出环丙沙星(Ciprofloxacin,Cip)、头孢噻肟钠(Cefotaxime Sodium Salt,Ctx)、盐酸强力霉素(Doxycycline hyclate,Dox)、四环素(Tetracycline,Tet)、红霉素(Erythromycin, Erm)、磺胺甲恶唑(Sulfamethoxazole,Sul)的耐药菌,浓度在10^(3)—10^(7)CFU∕g。样品中耐药基因总数在10^(5)—10^(8) copies∕g,其中tet类和sul2基因在食槽饲料样品中的含量较高,且与其他几类饲料样品具有显著性差异。推测鸡饲料中的抗生素耐药菌是禽源耐药菌的潜在来源之一。

Residues of 80 kinds of antibiotics in 12 feed samples were determined by HPLC tandem mass spectrometry,6 kinds of antibiotic resistant bacteria were isolated and counted by screening the resistant medium,and 17 kinds of antibiotic resistance genes were quantified by fluorescence quantitative PCR.The results showed that,only one sample was found to have residues of sulfaclozine,doxycycline,florfenicol,the residues were 0.082 mg∕kg,0.005 mg∕kg and 0.014 mg∕kg,respectively.Ciprofloxacin(Cip),Cefotaxime Sodium Salt(Ctx),Doxycycline hyclate(Dox),Tetracycline(Tet),Erythromycin(Erm)and Sulfamethoxazole(Sul)antibiotic resistant bacteria were detected in most of feed samples.The concentration of antibiotic resistant bacteria was 10^(3)-10^(7) CFU∕g.Antibiotic resistance genes were detected to varying degrees in the samples,and the total number of antibiotic resistance genes was 10^(5)-10^(8) copies∕g.Copy number of tet and sul2 genes were bigger in the trough feed samples,which was significantly different from other feed samples.Therefore,antibiotic-resistant bacteria in chicken feed may be one of the potential sources of antibiotic-resistant bacteria in poultry.