Romero-Muñoz María, Pulido Marina R, Recacha Esther, Díaz-Díaz Sara, Murillo-Torres Marina, Docobo-Pérez Fernando, Rodríguez-Martínez José Manuel
Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Avda Sanchez Pizjuán s/n, 41009, Seville, Spain.
Centro de Investigación Biomédica en Red en Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
Sci Rep. 2025 Jul 22;15(1):26632. doi: 10.1038/s41598-025-10760-1.
Gene expression heterogeneity has an impact on human bacterial pathogens responses, including antimicrobial resistance genes expression. Promoter region variability in resistance genes may include different regulatory boxes involved in metabolic processes essential for bacterial survival. In this study, a molecular tool was developed to characterize promoter region variability and resistance gene expression. For these, 46 bacterial clinical isolates were used. Sequence analysis of resistance genes promoter region showed the existence of different variants for each promoter and identified gene-specific regulatory boxes. Using a fluorescent transcriptional reporter, we analysed the most common promoter variants of the most prevalent acquired resistance genes in clinical isolates (qnrA, qnrB, bla, bla and bla, aac(6')-Ib-cr, and fosA). Gene expression fluctuations were found to be dependent on culture medium used. Specific gene promoter variants showed lower expression levels in poor (M9) medium (p < 0.0001) and an induction of expression under antimicrobials presence (tetracycline, quinolones and beta-lactams). qnrB1 genes were regulated by phoB and lexA boxes; bla was regulated by the argR box or fnr and arcA boxes. Differences in regulation of resistance gene promoter variants observed in this study suggest heterogeneity in expression under different bacterial culture conditions and a new link between metabolism and acquired resistance.
基因表达异质性会影响人类细菌病原体的反应，包括抗菌抗性基因的表达。抗性基因启动子区域的变异性可能包括参与细菌生存所必需代谢过程的不同调控元件。在本研究中，开发了一种分子工具来表征启动子区域变异性和抗性基因表达。为此，使用了46株细菌临床分离株。抗性基因启动子区域的序列分析表明每个启动子存在不同变体，并鉴定出基因特异性调控元件。使用荧光转录报告基因，我们分析了临床分离株中最常见的获得性抗性基因（qnrA、qnrB、bla、bla和bla、aac(6')-Ib-cr和fosA）的最常见启动子变体。发现基因表达波动取决于所用培养基。特定基因启动子变体在贫瘠（M9）培养基中表达水平较低（p < 0.0001），且在抗菌药物（四环素、喹诺酮类和β-内酰胺类）存在下表达会被诱导。qnrB1基因受phoB和lexA元件调控；bla受argR元件或fnr和arcA元件调控。本研究中观察到的抗性基因启动子变体调控差异表明在不同细菌培养条件下表达存在异质性，以及代谢与获得性抗性之间存在新的联系。
