Xu Congjuan, Liu Huimin, Pan Xiaolei, Ma Zhenzhen, Wang Dan, Zhang Xinxin, Zhu Guangbo, Bai Fang, Cheng Zhihui, Wu Weihui, Jin Yongxin
State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China.
Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China.
Front Microbiol. 2021 Jan 8;11:598291. doi: 10.3389/fmicb.2020.598291. eCollection 2020.
Treatment of infections by is difficult due to its high intrinsic and acquired antibiotic resistance. Upon colonization in the human hosts, accumulates genetic mutations that confer the bacterium antibiotic resistance and ability to better live in the host environment. Characterizing the evolutionary traits would provide important insights into the development of effective combinatory antibiotic therapies to cure infections. In this work, we performed a detailed analysis of the molecular mechanisms by which a clinical isolate (CSP18) yields a ciprofloxacin-resistant derivative (CRP42). Genomic DNA re-sequencing and RNAseq were carried out to compare the genomic mutational signature and transcriptional profiles between the two isolates. The results indicated that D87G mutation in GyrA, together with MexEF-OprN hyper-expression caused by F7S mutation in MexS, was responsible for the increased resistance to ciprofloxacin in the isolate CRP42. Further simulation of CRP42 by gene editing in CSP18 demonstrated that D87G mutation in GyrA rendered CSP18 a fourfold increase in minimum inhibitory concentration against ciprofloxacin, while F7S mutation in MexS conferred an additional eightfold increase. Our experimental results demonstrate for the first time that the clinically relevant F7S point mutation in MexS results in hyper-expression of the and thus confers resistance to ciprofloxacin.
由于其高度的固有和获得性抗生素耐药性，[细菌名称]感染的治疗很困难。在人类宿主中定殖后，[细菌名称]会积累基因突变，这些突变赋予细菌抗生素耐药性以及在宿主环境中更好生存的能力。表征其进化特征将为开发有效的联合抗生素疗法以治愈[细菌名称]感染提供重要见解。在这项工作中，我们对临床分离株（CSP18）产生环丙沙星耐药衍生物（CRP42）的分子机制进行了详细分析。进行了基因组DNA重测序和RNA测序，以比较这两个分离株之间的基因组突变特征和转录谱。结果表明，GyrA中的D87G突变，以及MexS中F7S突变导致的MexEF - OprN高表达，是分离株CRP42对环丙沙星耐药性增加的原因。通过在CSP18中进行基因编辑对CRP42进行进一步模拟表明，GyrA中的D87G突变使CSP18对环丙沙星的最低抑菌浓度增加了四倍，而MexS中的F7S突变又使其增加了八倍。我们的实验结果首次证明，临床上相关的MexS中的F7S点突变导致[基因名称]高表达，从而赋予[细菌名称]对环丙沙星的耐药性。
