市售牛奶中4种四环素类抗生素抗性基因的比较研究

目的研究市售牛奶商品中4种代表性四环素类抗生素抗性基因(antibiotic resistance genes,ARGs)的分布特征。方法以12种商品牛奶为研究对象,通过对样品中的4种四环素类ARGs和16S r RNA进行实时荧光定量PCR测定,分析ARGs的分布特征,并对样品的保存条件、保质期、成分含量做相关性分析。结果牛奶样品中普遍检出抗性基因Tet(A)、Tet(W),检出率为100%,其抗性机制分别是外排泵和细胞保护;Tet(32 s)和Tet(L)均未检出。比较样品中ARGs的相对丰度,Tet(A)最高达到2.28,最低为0.06;Tet(W)最高达到0.24,最低为0.03。牛奶的产品类型、包装形式、保存条件和保质期与Tet(W)的相对丰度显著相关。结论市售牛奶样品中存在ARGs,不同牛奶样品中ARGs的富集程度存在差异。牛奶样品中ARGs相对丰度受到多种因素影响,值得从食品安全的角度深入研究。

Comparative analysis of 4 kinds of tetracycline antibiotic resistance genes in commercial milks

Objective To study the distribution characteristics of 4 kinds of representative tetracycline antibiotic resistance genes (ARGs) in commercial milk products. Methods With 12 kinds of commercial milk as research object, the distribution characteristics of ARGs were analyzed by real-time quantitative PCR analysis of 4 kinds of tetracycline ARGs and 16S rRNA in the samples, and the correlation analysis was carried out on the preservation conditions, shelf life and composition of the samples. Results The resistance genes Tet(A) and Tet(W) were generally detected in milk samples, and the detection rate was 100%. The resistance mechanisms were efflux pump and cell protection and Tet(32 s) and Tet(L) were not detected. Comparing the relative abundance of ARGs in the sample, Tet(A) reached a maximum of 2.28 and the lowest was 0.06, and Tet(W) reached a maximum of 0.24 and the lowest was 0.03. The product type, packaging form, storage conditions and shelf life of milk were significantly related to the relative abundance of Tet(W). Conclusion ARGs exist in commercially available milk samples, and the degree of enrichment of ARGs in different milk samples is different. The relative abundance of ARGs in milk samples is affected by many factors, so that it is worthwhile to study in depth from the perspective of food safety.