State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
BMC Microbiol. 2020 Nov 19;20(1):355. doi: 10.1186/s12866-020-02043-8.
Manure application and sewage irrigation release many intestinal pathogens into the soil. After being introduced into the soil matrix, pathogens are commonly found to attach to soil minerals. Although the survival of mineral-associated Escherichia coli O157:H7 has been studied, a comprehensive understanding of the attachment process and physiological properties after attachment is still lacking.
In this study, planktonic and attached Escherichia coli O157:H7 cells on quartz were investigated using RNA sequencing (RNA-seq) and the isobaric tagging for relative and absolute quantitation (iTRAQ) proteomic method. Based on the transcriptomic and proteomic analyses and gene knockouts, functional two-component system pathways were required for efficient attachment; chemotaxis and the Rcs system were identified to play determinant roles in E. coli O157:H7 attachment on quartz. After attachment, the pyruvate catabolic pathway shifted from the tricarboxylic acid (TCA) cycle toward the fermentative route. The survival rate of attached E. coli O157:H7 increased more than 10-fold under penicillin and vancomycin stress and doubled under alkaline pH and ferric iron stress.
These results contribute to the understanding of the roles of chemotaxis and the Rcs system in the attachment process of pathogens and indicate that the attachment of pathogens to minerals significantly elevates their resistance to antibiotics and environmental stress, which may pose a potential threat to public health.
粪便施用量和污水灌溉将许多肠道病原体释放到土壤中。进入土壤基质后，通常会发现病原体附着在土壤矿物质上。尽管已经研究了与矿物质结合的大肠杆菌 O157:H7 的存活情况，但对附着后的附着过程和生理特性仍缺乏全面了解。
在这项研究中，使用 RNA 测序 (RNA-seq) 和相对和绝对定量标记 (iTRAQ) 蛋白质组学方法研究了石英上浮游和附着的大肠杆菌 O157:H7 细胞。基于转录组学和蛋白质组学分析以及基因敲除，发现功能双组分系统途径是有效附着所必需的；趋化作用和 Rcs 系统被确定在大肠杆菌 O157:H7 附着在石英上起着决定性作用。附着后，丙酮酸代谢途径从三羧酸 (TCA) 循环转向发酵途径。附着的大肠杆菌 O157:H7 在青霉素和万古霉素胁迫下的存活率增加了 10 多倍，在碱性 pH 和铁胁迫下增加了一倍。
这些结果有助于了解趋化作用和 Rcs 系统在病原体附着过程中的作用，并表明病原体与矿物质的附着显着提高了它们对抗生素和环境胁迫的抵抗力，这可能对公共健康构成潜在威胁。
