Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin Institute of Environmental & Operational Medicine, Tianjin, China.
Gut Microbes. 2022 Jan-Dec;14(1):2018901. doi: 10.1080/19490976.2021.2018901.
The gut microbiota represents an important reservoir of antibiotic-resistant bacteria (ARB), which poses a significant threat to public health. However, little is known about the emergence of ARB in the gut after the combined exposure to antibiotics and non-antibiotic pharmaceutics. Here, , a common opportunistic pathogen in the gut microbiota, was exposed to the antidepressant duloxetine (2.5 µg/L-25 mg/L) and/or chloramphenicol (6 µg/L-4 mg/L). The resistant strains were isolated to determine the minimum inhibition concentration (MIC) of 29 antibiotics. Then, genome-wide DNA sequencing, global transcriptomic sequencing, and real-time quantitative polymerase chain reaction were performed to quantify the synergy between duloxetine and chloramphenicol. Combined exposure synergistically increased the mutation frequency of chloramphenicol resistance by 2.45-9.01 fold compared with the independent exposure. A combination index reaching 187.7 indicated strong duloxetine and chloramphenicol synergy. The resultant mutants presented heritable enhanced resistance to 12 antibiotics and became ARB to eight antibiotics. Furthermore, combined exposure significantly increased the transcriptomic expression of , and in , and generated a more robust oxidative stress response. Together with the occurrence of DNA mutations in in the mutants, stronger triggers to the AcrAB-TolC transport system and the MlaFEDB ABC transporter via reactive oxygen species (ROS)-induced mutagenesis, verified by gene knockout, contributed to the synergistic enhancement of antibiotic resistance in the combined exposure group. Regardless of whether their formation was induced by duloxetine, chloramphenicol, or their combination, the mutants showed 1.1-1.7-fold increases in the expression levels of , and . This pattern indicated that the mutants shared the same resistance mechanisms against chloramphenicol, involving the improved efflux pumps AcrAB-TolC and . Our findings demonstrated that antibiotics and non-antibiotic pharmaceutics synergistically accelerate the evolution of ARB and may enhance their spread.
肠道微生物群是抗生素耐药菌 (ARB) 的重要储存库，对公共健康构成重大威胁。然而，人们对联合暴露于抗生素和非抗生素药物后肠道中 ARB 的出现知之甚少。在这里， 是肠道微生物群中的一种常见机会性病原体，暴露于抗抑郁药度洛西汀（2.5µg/L-25mg/L）和/或氯霉素（6µg/L-4mg/L）。分离出耐药株以确定 29 种抗生素的最小抑制浓度 (MIC)。然后，进行全基因组 DNA 测序、全转录组测序和实时定量聚合酶链反应，以量化度洛西汀和氯霉素之间的协同作用。与单独暴露相比，联合暴露将氯霉素耐药突变频率协同增加了 2.45-9.01 倍。组合指数达到 187.7 表明度洛西汀和氯霉素具有很强的协同作用。由此产生的突变体对 12 种抗生素表现出可遗传的增强耐药性，并对 8 种抗生素成为 ARB。此外，联合暴露显着增加了 中的 、 和 的转录组表达，并产生了更强大的氧化应激反应。与突变体中 中的 DNA 突变的发生一起，通过活性氧 (ROS) 诱导的突变，更强的触发物作用于 AcrAB-TolC 转运系统和 MlaFEDB ABC 转运体，通过基因敲除验证，有助于联合暴露组中抗生素耐药性的协同增强。无论其形成是由度洛西汀、氯霉素还是它们的组合诱导的， 突变体的 、 和 的表达水平均增加了 1.1-1.7 倍。这种模式表明，突变体对氯霉素具有相同的耐药机制，涉及改进的外排泵 AcrAB-TolC 和 。我们的研究结果表明，抗生素和非抗生素药物协同加速了 ARB 的进化，并可能增强其传播。
