ABSTRACT

Bacterium Acinetobacter baumannii is a leading cause of nosocomial infections. The occurrence of antibiotic-resistant A. baumannii isolates outside hospitals suggests that monitoring of this pathogen in environmental samples is needed. Survival of pandrug-resistant A. baumannii was followed on selective plates with and without carbapenems in water and soil. After a few days of starvation, A. baumannii lost the ability to be cultivated at 44°C on plates supplemented with carbapenems. Once cultivated on plates without carbapenems and/or at 36°C, A. baumannii could grow again at 44°C in the presence of carbapenems. Comparative proteomic analysis revealed that impaired membrane integrity and reduced function of efflux pumps due to elevated temperature combined with antibiotic exposure were the main reasons for this phenomenon. Loss of thermotolerance in the presence of antibiotics points to the need for temperature adjustment in long-term monitoring of A. baumannii in environmental samples, to avoid the underestimation of viable bacteria.

摘要

鲍曼不动杆菌是导致医院感染的主要原因。医院外出现耐抗生素鲍曼不动杆菌分离株表明需要监测环境样本中的这种病原体。在水和土壤中添加和不添加碳青霉烯类的选择性平板上跟踪泛耐药鲍曼不动杆菌的存活情况。经过几天的饥饿，鲍曼不动杆菌失去了在补充有碳青霉烯类的平板上在 44°C 下培养的能力。一旦在不含碳青霉烯类和/或 36°C 的平板上培养，鲍曼不动杆菌在碳青霉烯类存在的情况下，可在 44°C 下再次生长。比较蛋白质组学分析表明，由于温度升高和抗生素暴露导致膜完整性受损和外排泵功能降低是这种现象的主要原因。在抗生素存在下失去耐热性表明需要在长期监测环境样品中的鲍曼不动杆菌时调整温度，以避免低估活细菌。