Sánchez Alba, Benito Natividad, Rivera Alba, García Lucas, Miró Elisenda, Mur Isabel, González Yesica, Gutiérrez Cristina, Horcajada Juan Pablo, Espinal Paula, Navarro Ferran
Department of Microbiology, Hospital de La Santa Creu I Sant Pau, Institut D'Investigació Biomèdica Sant Pau (IIB Sant Pau), Barcelona, Spain; Genetics and Microbiology Department. Universitat Autònoma de Barcelona, Barcelona, Spain.
Infectious Diseases Unit, Hospital de La Santa Creu I Sant Pau, Institut D'Investigació Biomèdica Sant Pau (IIB Sant Pau), Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.
J Hosp Infect. 2020 Apr 24. doi: 10.1016/j.jhin.2020.04.026.
Staphylococcus epidermidis is a commensal of human skin flora and a frequent causative microorganism in prosthetic joint infections (PJIs). To date, no single marker has been identified to distinguish infecting strains from commensal S. epidermidis populations.
We aimed to find possible genetic markers to distinguish between the two populations.
We analyzed 50 S. epidermidis strains from patients with PJIs, 50 from skin of healthy individuals (commensal strains) and 17 from the surgical field of patients undergoing primary arthroplasty. In these three groups we studied the antimicrobial susceptibility profile, sequence type, biofilm formation, and virulence factors. Strains from the surgical field have not been compared previously with strains from the other two groups.
S. epidermidis strains from PJI patients were significantly more antibiotic resistant than commensal strains and surgical field strains. A wide variety of sequences types was found in commensal and surgical field strains. The predominant sequence type was ST2 and it was only present in PJI strains (44%). Differences in biofilm production did not differ between populations. Virulence genes sdrF and bhp, the complete ica operon, and the insertion sequence IS256 were significantly predominant in PJI strains. In contrast, embp and hld genes and the mobile element ACME were more prevalent in commensal strains. Surgical field strains could be a valid control group to discriminate between infecting and commensal strains.
A combination of characteristic features can differentiate between infecting and commensal S. epidermidis strains in PJI, while a single marker cannot.
表皮葡萄球菌是人体皮肤菌群的共生菌，也是人工关节感染（PJI）中常见的致病微生物。迄今为止，尚未发现单一标志物可区分感染菌株与表皮葡萄球菌共生菌群体。
我们旨在寻找可能区分这两种群体的基因标志物。
我们分析了50株来自PJI患者的表皮葡萄球菌菌株、50株来自健康个体皮肤的菌株（共生菌株）以及17株来自初次关节置换手术患者手术部位的菌株。在这三组中，我们研究了抗菌药物敏感性谱、序列类型、生物膜形成和毒力因子。手术部位的菌株此前未与其他两组的菌株进行比较。
PJI患者的表皮葡萄球菌菌株比共生菌株和手术部位菌株的抗生素耐药性显著更高。在共生菌株和手术部位菌株中发现了多种序列类型。主要序列类型是ST2，仅存在于PJI菌株中（44%）。不同群体之间生物膜产生的差异无统计学意义。毒力基因sdrF和bhp、完整的ica操纵子以及插入序列IS256在PJI菌株中显著占主导地位。相比之下，embp和hld基因以及移动元件ACME在共生菌株中更为普遍。手术部位的菌株可能是区分感染菌株和共生菌株的有效对照组。
一系列特征组合可区分PJI中感染性和共生性表皮葡萄球菌菌株，而单一标志物则无法做到。
