The role of the clpB gene encoding HSP/chaperone ClpB was evaluated in the multiresistant antibiotic cells of Acinetobacter baumannii (RS4 strain) under stress-induced heat shock and different beta-lactams. The expression of the clpB gene was assessed by qPCR during heat shock at 45 °C and subinhibitory concentrations of ampicillin (30 μg mL-1), amoxicillin + sulbactam (8/12 μg mL-1), cefepime (30 μg mL-1), sulfamethoxazole + trimethoprim (120/8 μg mL-1) and meropenem (18 μg mL-1). The results indicated a transient increase in clpB transcription in all treatments except cefepime. Both in the presence of ampicillin and amoxicillin/sulbactam for 20 min, the mRNA-clpB synthesis was 1.4 times higher than that of the control at time zero. Surprisingly, the mRNA-clpB levels were more than 30-fold higher after 10 min of incubation with meropenem and more than eightfold higher in the presence of trimethoprim/sulfamethoxazole. In addition, western blot assays showed that the RS4 strain treated with meropenem showed a marked increase in ClpB protein expression. Our data indicate that during exposure to beta-lactams, A. baumannii adjusts the transcription levels of the clpB mRNA and protein to respond to stress, suggesting that the chaperone may act as a key cellular component in the presence of antibiotics in this bacterium.

中文翻译：

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鲍曼不动杆菌中热休克和β-内酰胺类抗生素对clpB基因的上调。

在压力诱导的热休克和不同的β-内酰胺条件下，在鲍曼不动杆菌（RS4菌株）的多抗性抗生素细胞中评估了编码HSP /伴侣ClpB的clpB基因的作用。通过qPCR在45°C的热休克期间和亚抑制浓度的氨苄西林（30μgmL-1），阿莫西林+舒巴坦（8/12μgmL-1），头孢吡肟（30μgmL-1）的抑制作用下评估clpB基因的表达），磺胺甲恶唑+甲氧苄氨嘧啶（120/8μgmL-1）和美洛培南（18μgmL-1）。结果表明在除头孢吡肟外的所有治疗中，clpB转录均瞬时增加。在氨苄青霉素和阿莫西林/舒巴坦存在下20分钟，mRNA-clpB的合成比零时的对照高1.4倍。出奇，与美罗培南一起孵育10分钟后，mRNA-clpB水平高出30倍以上，而在甲氧苄啶/磺胺甲恶唑存在下，mRNA-clpB水平高出八倍。此外，western blot分析表明，用美罗培南处理的RS4菌株显示ClpB蛋白表达显着增加。我们的数据表明，在暴露于β-内酰胺的过程中，鲍曼不动杆菌会调节clpB mRNA和蛋白质的转录水平以应对压力，这表明在这种细菌中存在抗生素时，分子伴侣可能是关键的细胞成分。