Department of Biomedical Sciences, Cardiff School of Health Sciences, Cardiff Metropolitan University, Western Avenue, Llandaff, Cardiff, CF5 2YB, UK.
School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
Pathog Dis. 2018 Feb 1;76(1). doi: 10.1093/femspd/fty003.
Debate regarding the co-existence of Staphylococcus aureus and Pseudomonas aeruginosa in wounds remains contentious, with the dominant hypothesis describing a situation akin to niche partitioning, whereby both microorganisms are present but occupy distinct regions of the wound without interacting. In contrast, we hypothesised that these microorganisms do interact during early co-colonisation in a manner beneficial to both bacteria. We assessed competitive interaction between S. aureus and P. aeruginosa in biofilm cultured for 24-72 h and bacterial aggregates analogous to those observed in early (<24 h) biofilm formation, and interaction with human keratinocytes. We observed that S. aureus predominated in biofilm and non-attached bacterial aggregates, acting as a pioneer for the attachment of P. aeruginosa. We report for the first time that S. aureus mediates a significant (P < 0.05) increase in the attachment of P. aeruginosa to human keratinocytes, and that P. aeruginosa promotes an invasive phenotype in S. aureus. We show that co-infected keratinocytes exhibit an intermediate inflammatory response concurrent with impaired wound closure that is in keeping with a sustained proinflammatory response which allows for persistent microbial colonisation. These studies demonstrate that, contrary to the dominant hypothesis, interactions between S. aureus and P. aeruginosa may be an important factor for both colonisation and pathogenicity in the chronic infected wound.
关于金黄色葡萄球菌和铜绿假单胞菌在伤口中共存的争论仍然存在争议，占主导地位的假说描述了一种类似于生态位分隔的情况，即两种微生物都存在，但不相互作用地占据伤口的不同区域。相比之下，我们假设这些微生物在早期共定植过程中相互作用，对两种细菌都有益。我们评估了金黄色葡萄球菌和铜绿假单胞菌在 24-72 小时培养的生物膜中的竞争相互作用，以及类似于早期 (<24 小时) 生物膜形成中观察到的细菌聚集体之间的相互作用，以及与人类角质形成细胞的相互作用。我们观察到金黄色葡萄球菌在生物膜和非附着细菌聚集体中占优势，作为铜绿假单胞菌附着的先驱。我们首次报道金黄色葡萄球菌介导铜绿假单胞菌对人角质形成细胞附着的显著增加（P < 0.05），并且铜绿假单胞菌促进金黄色葡萄球菌的侵袭表型。我们表明，共感染的角质形成细胞表现出与伤口闭合受损同时发生的中间炎症反应，这与持续的促炎反应一致，允许持续的微生物定植。这些研究表明，与主导假说相反，金黄色葡萄球菌和铜绿假单胞菌之间的相互作用可能是慢性感染伤口定植和发病的一个重要因素。
