Abstract The verocytotoxin genes in verocytotoxigenic Escherichia coli (VTEC) are carried by bacteriophages, incorporated into the bacterial genome (prophage). Antibiotics may promote phage replication and release to infect other cells (transduction), thus leading to the emergence of new VTEC strains. This study investigated transduction of a verocytotoxin2-encoding bacteriophage (3538(vtx2::cat)) under laboratory conditions, including the effect of antibiotic treatments. Luria-Bertani Miller broth and rumen fluid (raw and sterilised by irradiation) were inoculated with the donor (C600φ3538(Δvtx2::cat)) and recipient (E. coli C600::kanamycinR) strains (4 log10 cfu/mL) and incubated at 38°C. Antibiotic treatments (minimal inhibitory and sub-inhibitory concentrations of ampicillin, cefquinome, oxytetracycline and sodium sulfamethazine) were applied after 3 h. Samples were tested for donor, recipient, cell-free phage and transductants at times t = 0, 3, 4, 6, 27 (24 h post-antibiotic treatment) and 51 h. Free phage was detected in the untreated broth and rumen samples, as were the transductants confirmed by polymerase chain reaction. The antibiotic treatments did not significantly (P > 0.01) increase the concentrations of free phage or transductants detected. It was therefore concluded that, under laboratory conditions, the antibiotics tested did not induce bacteriophage lysis, release and infection of new bacterial cells beyond that constitutively found in the phage population.

中文翻译：

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牛瘤胃液和肉汤条件下抗菌素对verocytotoxin噬菌体转导的影响

摘要 verocytotoxigenic Escherichia coli (VTEC) 中的 verocytotoxin 基因由噬菌体携带，并整合到细菌基因组（原噬菌体）中。抗生素可能会促进噬菌体复制和释放以感染其他细胞（转导），从而导致新的 VTEC 菌株的出现。本研究调查了在实验室条件下编码 verocytotoxin2 的噬菌体 (3538(vtx2::cat)) 的转导，包括抗生素治疗的效果。Luria-Bertani Miller 肉汤和瘤胃液（生的并经辐照灭菌）接种供体（C600φ3538（Δvtx2::cat））和​​受体（大肠杆菌C600::kanamycinR）菌株（4 log10 cfu/mL）并孵育在 38°C。抗生素治疗（氨苄青霉素、头孢喹诺、3 小时后应用土霉素和磺胺二甲嘧啶钠。在时间 t = 0、3、4、6、27（抗生素治疗后 24 小时）和 51 小时，对样品的供体、受体、无细胞噬菌体和转导体进行测试。在未处理的肉汤和瘤胃样品中检测到游离噬菌体，正如通过聚合酶链反应证实的转导子一样。抗生素处理没有显着（P > 0.01）增加检测到的游离噬菌体或转导体的浓度。因此得出的结论是，在实验室条件下，所测试的抗生素不会诱导噬菌体裂解、释放和感染新细菌细胞，而不是在噬菌体群体中发现的。在未处理的肉汤和瘤胃样品中检测到游离噬菌体，正如通过聚合酶链反应证实的转导子一样。抗生素处理没有显着（P > 0.01）增加检测到的游离噬菌体或转导体的浓度。因此得出的结论是，在实验室条件下，所测试的抗生素不会诱导噬菌体裂解、释放和感染新细菌细胞，而不是在噬菌体群体中发现的。在未处理的肉汤和瘤胃样品中检测到游离噬菌体，正如通过聚合酶链反应证实的转导子一样。抗生素处理没有显着（P > 0.01）增加检测到的游离噬菌体或转导体的浓度。因此得出的结论是，在实验室条件下，所测试的抗生素不会诱导噬菌体裂解、释放和感染新细菌细胞，而不是在噬菌体群体中发现的。