Objectives

Staphylococcus epidermidis is a leading cause of prosthetic joint infection. Its relevance is based on its high ability to develop biofilm and small colony variants. However, the clinical associations between this bacterial subpopulation and prosthetic joint infections remain highly uncertain. We aimed to define the clinical characteristics and outcome of patients affected by S. epidermidis small colony variants, as well as their antimicrobial susceptibility.

Methods

We conducted a retrospective cohort study of patients with monomicrobial prosthetic joint infection. Clinical data and time to remission after prosthesis removal was compared between groups. Antimicrobial susceptibility of small colony variants and wild type strains were analyzed.

Results

S. epidermidis small colony variants were identified in 16 (37.20%) cultures from eligible subjects. These patients were less likely to achieve remission throughout the follow-up period (Hazard ratio, 0.45 [95% CI, 0.22-0.89], p=0.02), compared to those with wild type strains. In vitro experiments showed higher resistant rates to trimethoprim/sulfamethoxazole (62.5%), and lower resistant rates to levofloxacin (37.5%), among small colony variants.

Conclusions

The isolation of small colony variants was negatively associated with remission achievement throughout management. The search for this bacterial subpopulation and its antimicrobial susceptibility may be appropriate to adjust treatment and clinical expectations.

中文翻译：

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表皮葡萄球菌小菌落变异，对假体关节感染患者具有临床意义的静止威胁

目标

表皮葡萄球菌是人工关节感染的主要原因。它的相关性基于其开发生物膜和小菌落变体的高能力。然而，这种细菌亚群与人工关节感染之间的临床关联仍然高度不确定。我们旨在确定受表皮葡萄球菌小菌落变异影响的患者的临床特征和结果，以及他们的抗菌药物敏感性。

方法

我们对单微生物假体关节感染患者进行了一项回顾性队列研究。比较各组之间的临床数据和假体移除后缓解时间。分析了小菌落变体和野生型菌株的抗菌敏感性。

结果

在来自符合条件的受试者的 16 个 (37.20%) 培养物中鉴定出表皮葡萄球菌小菌落变体。与野生型菌株相比，这些患者在整个随访期间实现缓解的可能性较小（风险比，0.45 [95% CI，0.22-0.89]，p=0.02）。体外实验表明，在小菌落变异体中，甲氧苄啶/磺胺甲恶唑的耐药率较高（62.5%），而对左氧氟沙星的耐药率较低（37.5%）。

结论

小菌落变异的分离与整个管理过程中的缓解成就呈负相关。寻找这种细菌亚群及其抗菌药物敏感性可能适合调整治疗和临床预期。