The ability of Staphylococcus aureus to form biofilm and persister cells is the main cause of recurrent infections. This study aimed to evaluate the expression of toxin-antitoxin (TA) systems in persister cells within S. aureus biofilms. Time-dependent variation in the persister population present in biofilms of S. aureus was examined after treatment with bactericidal antibiotics. Then, the relative expression level of type II TA system (mazF, relE1, and relE2), type I TA system (sprG), and clpP protease genes in S. aureus strains were assessed by Real _Time PCR. Among the sixteen isolates, two isolates were found to be the strongest biofilm producers. The established biofilm of these isolates showed a comparable biphasic pattern at the lethal dose of the antibiotics. The expression level of TA system genes was increased and strain-specific expression patterns were observed under antibiotics stress conditions. Persisters within a biofilm may establish a reservoir for relapsing infection and could contribute to treatment failures. Hence, the possible role of the TA systems should be considered in biofilm and persister cell formation.

的能力，金黄色葡萄球菌，以形式生物膜和存留细胞是复发性感染的主要原因。本研究旨在评估金黄色葡萄球菌生物膜内持续细胞中毒素-抗毒素 (TA) 系统的表达。在用杀菌抗生素治疗后检查了金黄色葡萄球菌生物膜中存在的持久性种群的时间依赖性变化。然后，金黄色葡萄球菌中II型TA系统（mazF、relE1和relE2）、I型TA系统（sprG）和clpP蛋白酶基因的相对表达水平通过实时 PCR 评估菌株。在 16 个分离株中，发现两个分离株是最强的生物膜生产者。这些分离物的已建立生物膜在抗生素的致死剂量下显示出类似的双相模式。在抗生素胁迫条件下，TA 系统基因的表达水平增加并观察到菌株特异性表达模式。生物膜内的残留物可能会为复发性感染建立一个储存库，并可能导致治疗失败。因此，应考虑 TA 系统在生物膜和持久细胞形成中的可能作用。