Department de Microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montreal, Montreal, Quebec, H3T 1J4, Canada.
Environ Microbiol. 2022 Mar;24(3):1133-1149. doi: 10.1111/1462-2920.15762. Epub 2021 Sep 15.
Antimicrobials are commonly used in prevention of infections including in aquaculture, agriculture and medicine. Subinhibitory concentrations of antimicrobial peptides can modulate resistance, virulence and persistence effectors in Gram-negative pathogens. In this study, we investigated the effect of subinhibitory concentrations of polymyxin B (PmB) on the secretome of Vibrio cholerae, a natural inhabitant of aquatic environments and the pathogen responsible for the cholera disease. Our proteomic approach revealed that the abundance of many extracellular proteins is affected by PmB and some of them are detected only either in the presence or in the absence of PmB. The type VI secretion system (T6SS) secreted hemolysin-coregulated protein (Hcp) displayed an increased abundance in the presence of PmB. Hcp is also more abundant in the bacterial cells in the presence of PmB and hcp expression is upregulated upon PmB supplementation. No effect of the T6SS on antimicrobial resistance was observed. Conversely, PmB increases the T6SS-dependent cytotoxicity of V. cholerae towards the amoeba Dictyostelium discoideum and its ability to compete with Escherichia coli.
抗生素常用于预防感染，包括水产养殖、农业和医学领域。亚抑菌浓度的抗菌肽可以调节革兰氏阴性病原体的耐药性、毒力和持久性效应器。在这项研究中，我们研究了亚抑菌浓度多粘菌素 B（PmB）对霍乱弧菌分泌组的影响，霍乱弧菌是水生环境的天然居民，也是导致霍乱病的病原体。我们的蛋白质组学方法表明，许多细胞外蛋白的丰度受到 PmB 的影响，其中一些蛋白仅在存在或不存在 PmB 的情况下被检测到。T6SS 分泌的溶细胞核心蛋白（Hcp）在 PmB 的存在下丰度增加。在 PmB 的存在下，Hcp 在细菌细胞中的丰度也更高，并且在添加 PmB 时 hcp 的表达上调。T6SS 对抗菌耐药性没有影响。相反，PmB 增加了 T6SS 依赖的霍乱弧菌对变形虫 D.discoideum 的细胞毒性及其与大肠杆菌竞争的能力。
