Abstract The study aimed at investigating the antimicrobial resistance (AMR) profiles of bifidobacteria from fermented milk products sold in the UK that are claimed to have beneficial effects on humans, and assess the potential transferability of AMR to other bacteria. Isolates of different Bifidobacterium species were screened for their susceptibility to 24 antimicrobials and the presence of AMR genes [tet(M), tet(L), tet(S), tet(Q), tet(K), tet(O), tet(W), aph(3″)-I, ant(2″)-I, aph(3″)-III, strA, strB, aadA, aadE, erm(A), erm(B), and erm(C)]. The ability of Bifidobacterium animalis subsp. lactis isolates to transfer the tet(W) gene to Enterococcus faecalis JH2-2 and Enterococcus faecium BM4105 was investigated by conjugation. Potential E. faecalis transconjugants (PETs) were analysed by whole genome sequencing (WGS) for the presence of tet(W), other DNA fragments from the donor and single-nucleotide polymorphisms (SNPs). A high level of resistance to aminoglycosides and a moderate level of resistance to tetracycline were observed, while susceptibility to macrolides, vancomycin, chloramphenicol and beta-lactams was determined. Only the tet(W) gene was detected in all B. animalis subsp. lactis isolates. Some PETs exhibited a significant tetracycline MIC increase from 1 to up to 16 mg/L. WGS did not detect tet(W) in the PETs, but SNPs in the rpsJ gene encoding the ribosomal protein S10, which is part of the 30S ribosomal subunit and contains a proposed tetracycline binding site. Substitutions (Tyr-58→Asp, Tyr-58→Cys, Asp-60→Tyr, Tyr-58→Ser, Ser-61→Tyr, Ala-54→Glu, Asp-60→Tyr) and an insertion of Thr between Thr55 and His56 were detected. No E. faecium potential transconjugants were recovered. B. animalis subsp. lactis isolates did not transfer the tet(W) gene to the Enterococcus species. The majority of the PETs had mutations within or near the ribosomal protein S10 vertex loop suggesting that mutations in the rpsJ gene confer tetracycline resistance to E. faecalis JH2-2.

中文翻译：

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益生菌乳制品中双歧杆菌的抗菌敏感性以及肠球菌与动物双歧杆菌亚种体外结合后四环素耐药性遗传基础的测定。乳酸菌

摘要 本研究旨在调查在英国销售的发酵乳制品中声称对人类有益的双歧杆菌的抗菌素耐药性 (AMR) 谱，并评估 AMR 对其他细菌的潜在转移性。筛选了不同双歧杆菌属的分离株对 24 种抗菌剂的敏感性和 AMR 基因 [tet(M)、tet(L)、tet(S)、tet(Q)、tet(K)、tet(O)、 tet(W)、aph(3″)-I、ant(2″)-I、aph(3″)-III、strA、strB、aadA、aadE、erm(A)、erm(B)和erm( C）]。动物双歧杆菌亚种的能力。通过缀合研究了将 tet(W) 基因转移到粪肠球菌 JH2-2 和粪肠球菌 BM4105 的乳酸菌分离株。通过全基因组测序 (WGS) 分析潜在的粪肠球菌转导结合体 (PET) 是否存在 tet(W)，来自供体的其他 DNA 片段和单核苷酸多态性 (SNP)。观察到对氨基糖苷类的高度抗性和对四环素的中等抗性，同时确定了对大环内酯类、万古霉素、氯霉素和β-内酰胺类的敏感性。在所有动物双歧杆菌中仅检测到 tet(W) 基因。乳酸菌分离。一些 PET 表现出显着的四环素 MIC 从 1 增加到 16 mg/L。WGS 未在 PET 中检测到 tet(W)，但在编码核糖体蛋白 S10 的 rpsJ 基因中检测到 SNP，该蛋白是 30S 核糖体亚基的一部分，包含一个提议的四环素结合位点。取代（Tyr-58→Asp、Tyr-58→Cys、Asp-60→Tyr、Tyr-58→Ser、Ser-61→Tyr、Ala-54→Glu、Asp-60→Tyr）和插入 Thr检测到 Thr55 和 His56。没有 E。粪便潜在转接合子被回收。B.动物亚种。乳酸菌分离株没有将 tet(W) 基因转移到肠球菌属物种。大多数 PET 在核糖体蛋白 S10 顶点环内或附近具有突变，表明 rpsJ 基因中的突变赋予粪肠球菌 JH2-2 的四环素抗性。