Gut Health and Microbes, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK.
Microbes in the Food Chain, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK.
Sci Rep. 2021 Nov 8;11(1):21864. doi: 10.1038/s41598-021-01376-2.
Listeria monocytogenes is a rare cause of prosthetic joint infections (PJI). In this study, we describe a case of recurrent L. monocytogenes infections, 39 months apart, following debridement and retention of a prosthetic hip. Despite numerous studies reporting persistent L. monocytogenes in human infections, the genomic and phenotypic changes that clinically relevant strains undergo in the host are poorly understood. Improved knowledge of how PJI occurs is needed to improve the management of prosthetic infections. We used a combination of long- and short-read sequencing to identify any potential genomic differences between two L. monocytogenes isolates that occurred over 39-month incubation in the host. The isolates, QI0054 and QI0055, showed three single nucleotide polymorphisms and three insertions or deletions, suggesting that the recurrent infection was caused by the same strain. To identify potential differences in the capacity for persistence of these isolates, their biofilm-forming ability and potential to colonize prosthesis-relevant materials was investigated both in microtitre plates and on prosthetic material titanium, stainless steel 316 and ultra-high molecular weight polyethylene. Whilst the L. monocytogenes isolate from the most recent infection (QI0055) was able to form higher biofilm in microtitre plates, this did not lead to an increase in biomass on prosthetic joint materials compared to the initial isolate (QI0054). Both clinical isolates were able to form significantly more biofilm on the two metal prosthetic materials than on the ultra-high molecular weight polyethylene, in contrast to reference strain Scott A. Transcriptomics revealed 41 genes overexpressed in biofilm state and 643 in planktonic state. Moreover, genes with mutations were actively expressed in both isolates. We conclude the isolates are derived from the same strain and hypothesize that L. monocytogenes formed biofilm on the prosthetic joint materials, with minimal exposure to stresses, which permitted their survival and growth.
李斯特菌是一种罕见的人工关节感染（PJI）的原因。在这项研究中，我们描述了一例复发性李斯特菌感染的病例，间隔 39 个月，在清创和保留髋关节假体后发生。尽管有许多研究报告称人类感染中存在持续的李斯特菌，但临床相关菌株在宿主中经历的基因组和表型变化仍知之甚少。为了改善人工关节感染的管理，需要更好地了解 PJI 的发生机制。我们使用长读和短读测序的组合来确定在宿主中 39 个月孵育过程中两个李斯特菌分离株之间可能存在的任何潜在基因组差异。分离株 QI0054 和 QI0055 显示出三个单核苷酸多态性和三个插入或缺失，表明复发性感染是由同一菌株引起的。为了确定这些分离株持续存在能力的潜在差异，我们在微滴定板和人工关节材料钛、不锈钢 316 和超高分子量聚乙烯上研究了它们的生物膜形成能力和定植相关材料的潜力。虽然最近感染的李斯特菌分离株（QI0055）能够在微滴定板上形成更高的生物膜，但与初始分离株（QI0054）相比，这并没有导致在假体关节材料上的生物量增加。两个临床分离株都能够在两种金属假体材料上形成明显更多的生物膜，而不是在超高分子量聚乙烯上，这与参考菌株 Scott A 相反。转录组学揭示了 41 个在生物膜状态下过度表达的基因和 643 个在浮游状态下过度表达的基因。此外，突变基因在两个分离株中均被积极表达。我们得出结论，这些分离株来自同一菌株，并假设李斯特菌在假体关节材料上形成生物膜，很少受到压力的影响，这允许它们的存活和生长。
