Acinetobacter baumannii is a multidrug-resistant pathogen that causes numerous infections associated with high mortality rates. Exposure to human body fluids, such as human pleural fluid (HPF) and human serum, modulates gene expression in A. baumannii, leading to changes in its pathogenic behavior. Diverse degrees of effects at the transcriptional level were observed in susceptible and carbapenem-resistant strains. The transcriptional analysis of AB5075, a hyper-virulent and extensively drug-resistant strain showed changes in genes associated with quorum sensing, quorum quenching, fatty acids metabolism, and high-efficient iron uptake systems. In addition, the distinctive role of human serum albumin (HSA) as a critical component of HPF was evidenced. In the present work, we used model strain to analyze more deeply into the contribution of HSA in triggering A. baumannii’s response. By qRT-PCR analysis, changes in the expression level of genes associated with quorum sensing, biofilm formation, and phenylacetic acid pathway were observed. Phenotypic approaches confirmed the transcriptional response. HSA, a predominant component of HPF, can modulate the expression and behavior of genes not only in a hyper-virulent and extensively drug-resistant A. baumannii model, but also in other strains with a different degree of susceptibility and pathogenicity.

鲍曼不动杆菌是一种多重耐药病原体，可引起多种感染并导致高死亡率。暴露于人体体液，例如人体胸膜液 (HPF) 和人体血清，会调节鲍曼不动杆菌的基因表达，导致其致病行为发生变化。在敏感菌株和碳青霉烯类耐药菌株中观察到转录水平上不同程度的影响。 AB5075 （一种高毒力和广泛耐药菌株）的转录分析显示，与群体感应、群体淬灭、脂肪酸代谢和高效铁吸收系统相关的基因发生了变化。此外，人血清白蛋白 (HSA) 作为 HPF 关键成分的独特作用也得到了证实。在目前的工作中，我们使用模型菌株来更深入地分析 HSA 在触发鲍曼不动杆菌反应中的贡献。通过qRT-PCR分析，观察到与群体感应、生物膜形成和苯乙酸途径相关的基因表达水平的变化。表型方法证实了转录反应。 HSA 是 HPF 的主要成分，不仅可以在高毒力和广泛耐药的鲍曼不动杆菌模型中调节基因的表达和行为，而且可以在具有不同敏感性和致病性的其他菌株中调节基因的表达和行为。