Guo Huiling, Pan Lin, Li Lina, Lu Jie, Kwok Laiyu, Menghe Bilige, Zhang Heping, Zhang Wenyi
Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education PRC, Inner Mongolia Agricultural Univ., Hohhot, 010018, China.
J Food Sci. 2017 Mar;82(3):724-730. doi: 10.1111/1750-3841.13645. Epub 2017 Feb 9.
Lactobacilli are widely used as starter cultures or probiotics in yoghurt, cheese, beer, wine, pickles, preserved food, and silage. They are generally recognized as safe (GRAS). However, recent studies have shown that some lactic acid bacteria (LAB) strains carry antibiotic resistance genes and are resistant to antibiotics. Some of them may even transfer their intrinsic antibiotic resistance genes to other LAB or pathogens via horizontal gene transfer, thus threatening human health. A total of 33 Lactobacillus strains was isolated from fermented milk collected from different areas of China. We analyzed (1) their levels of antibiotic resistance using a standardized dilution method, (2) their antibiotic resistance gene profiles by polymerase chain reaction (PCR) using gene-specific primers, and (3) the transferability of some of the detected resistance markers by a filter mating assay. All Lactobacillus strains were found to be resistant to vancomycin, but susceptible to gentamicin, linezolid, neomycin, erythromycin, and clindamycin. Their susceptibilities to tetracycline, kanamycin, ciprofloxacin, streptomycin, quinupristin/dalfopristin, trimethoprim, ampicillin, rifampicin, and chloramphenicol was different. Results from our PCR analysis revealed 19 vancomycin, 10 ciprofloxacin, and 1 tetracycline-resistant bacteria that carried the van(X), van(E), gyr(A), and tet(M) genes, respectively. Finally, no transferal of the monitored antibiotic resistance genes was observed in the filter mating assay. Taken together, our study generated the antibiotic resistance profiles of some milk-originated lactobacilli isolates and preliminarily assessed their risk of transferring antibiotic gene to other bacteria. The study may provide important data concerning the safe use of LAB.
乳酸杆菌作为发酵剂或益生菌被广泛应用于酸奶、奶酪、啤酒、葡萄酒、泡菜、腌制食品和青贮饲料中。它们通常被认为是安全的（GRAS）。然而，最近的研究表明，一些乳酸菌（LAB）菌株携带抗生素抗性基因并对抗生素具有抗性。其中一些甚至可能通过水平基因转移将其内在的抗生素抗性基因转移到其他LAB或病原体中，从而威胁人类健康。从中国不同地区收集的发酵乳中总共分离出33株乳酸杆菌菌株。我们分析了：（1）使用标准化稀释法测定它们的抗生素抗性水平；（2）使用基因特异性引物通过聚合酶链反应（PCR）分析它们的抗生素抗性基因谱；（3）通过滤膜接合试验检测一些检测到的抗性标记的可转移性。所有乳酸杆菌菌株均被发现对万古霉素具有抗性，但对庆大霉素、利奈唑胺、新霉素、红霉素和克林霉素敏感。它们对四环素、卡那霉素、环丙沙星、链霉素、奎奴普丁/达福普汀、甲氧苄啶、氨苄青霉素、利福平和平氯霉素的敏感性各不相同。我们的PCR分析结果显示，分别有19株、10株和1株对万古霉素、环丙沙星和四环素具有抗性的细菌携带了van(X)、van(E)、gyr(A)和tet(M)基因。最后，在滤膜接合试验中未观察到监测的抗生素抗性基因的转移。综上所述，我们的研究得出了一些源自牛奶的乳酸杆菌分离株的抗生素抗性谱，并初步评估了它们将抗生素基因转移到其他细菌的风险。该研究可能为LAB的安全使用提供重要数据。
