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目的对杭州地区市售发酵乳制品中分离鉴定的乳酸菌进行耐药传播的安全性分析,旨在揭示发酵乳制品中是否存在可传递耐药基因的超级耐药菌。方法自行分离鉴定的耐药乳酸菌,提取质粒并电泳分析是否存在质粒;以耐受叠氮化钠的大肠埃希菌J53作为受体菌进行质粒接合试验;若乳酸菌存在耐药现象,发现存在耐药质粒,且耐药性可通过质粒传播,评定为3级。乳酸菌存在耐药现象,发现存在耐药质粒,但接合试验未能证明耐药性可通过质粒传播,评定为2级。乳酸菌存在耐药现象,但未检测出耐药质粒,评定为1级。结果美丽健产品中分离的双歧杆菌(MLJ-G-2)和乳杆菌(MLJ-G-1)检测出含有质粒,但不会发生耐药转移,三种菌耐药危害等级分别为2、2、1。伊利产品中分离的双歧杆菌(YL-G-3)、乳杆菌(YL-G-1)、嗜热链球菌(YL-Q)检测出含有质粒,但不会发生耐药转移,四种菌耐药危害等级分别为2、2、1、2。味全产品中分离的双歧杆菌(WQ-G-3)、乳杆菌(WQ-G-1)、乳杆菌(WQ-G-2)、嗜热链球菌(WQ-Q)均检测出含有质粒,其中乳杆菌(WQ-G-1)、乳杆菌(WQ-G-2)会发生耐药转移,四种菌耐药危害等级分别为2、3、3、2。光明产品中分离的乳杆菌(GM-G-2)、乳杆菌(GM-G-3)、嗜热链球菌(GMQ)检测出含有质粒,乳杆菌(GM-G-2)会发生耐药转移,四种菌耐药危害等级分别为2、1、3、2。蒙牛产品中只分离的嗜热链球菌(MN-Q)检测出含有质粒,不会发生耐药转移,耐药危害等级为2。结论发酵乳制品中分离所得的乳酸菌81.2%的菌能检测出质粒,耐药性可能与质粒相关,存在潜在的生物安全威胁;18.8%的菌的耐药性可通过质粒接合发生传播,存在直接的生物安全威胁。
Objective To analyze the safety of drug-resistant transmission of lactic acid bacteria isolated and identified from commercial fermented dairy products in Hangzhou, so as to reveal whether there are super-resistant bacteria in fermented dairy products that can transmit drug-resistant genes. Methods Resistant lactic acid bacteria were isolated by themselves, and plasmids were extracted and electrophoresed for the presence of plasmids. Plasmid conjugation experiments were conducted with sodium azide-resistant Escherichia coli J53 as the recipient bacteria. If there was resistance to lactic acid bacteria, Drug plasmids, and drug resistance can be spread through the plasmid, rated as 3. Lactobacilli are resistant and resistant plasmids are found, but conjugation tests have failed to demonstrate that drug resistance can be transmitted by plasmids and assessed as Grade 2. Lactobacillus there is resistance, but did not detect drug-resistant plasmids, was rated as level 1. RESULTS: Bifidobacteria (MLJ-G-2) and Lactobacillus (MLJ-G-1) isolated from Meijiang products were detected to contain plasmids but no drug-resistant metastasis. The resistance levels of the three strains were 2 , 2,1. Four isolates of YL-G-3, YL-G-1, and YL-Q isolated from Erie were found to contain plasmids, but no transfer of drug resistance occurred. Four Bacterial resistance levels were 2,2,1,2. Bifidobacterium (WQ-G-3), Lactobacillus (WQ-G-1), Lactobacillus (WQ-G-2) and Streptococcus thermophilus (WQ-Q) Plasmids, including Lactobacillus (WQ-G-1), Lactobacillus (WQ-G-2) will have drug-resistant metastasis, four strains of drug resistance hazard levels were 2,3,3,2. GM-G-2, GM-G-3, and GMQ were found to be resistant to plasmid-containing Lactobacillus (GM-G-2) Transfer, four kinds of bacteria resistance hazard levels were 2,1,3,2. Only isolated from Streptococcus thermophilus (MN-Q) in Mengniu products were detected to contain plasmids, and no transfer of drug resistance occurred. The grade of drug resistance was 2. Conclusion 81.2% of the isolated lactic acid bacteria in fermented dairy products can detect plasmids, and the drug resistance may be related to the plasmids, posing potential biosecurity threats. The resistance of 18.8% bacteria can be transmitted through plasmid conjugation, and there is direct Biosecurity threats.