Center for Biofilm Engineering, Montana State Universitygrid.41891.35, Bozeman, Montana, USA.
Department of Chemical and Biological Engineering, Montana State Universitygrid.41891.35, Bozeman, Montana, USA.
Antimicrob Agents Chemother. 2022 Apr 19;66(4):e0002122. doi: 10.1128/aac.00021-22. Epub 2022 Mar 10.
Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown for 3 days and then challenged with respective antibiotics (ciprofloxacin, daptomycin, and tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells, and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of individual microorganisms in biofilms and contribute to antibiotic tolerance.
当细菌形成生物膜时,是否存在一种普遍的遗传编程防御机制,使它们对抗生素产生耐受?通过转录组学和代谢组学方法比较三种不同细菌的生物膜,没有发现证据表明存在这种防御机制。将三种细菌(铜绿假单胞菌、金黄色葡萄球菌和鲍曼不动杆菌)的单种生物膜培养 3 天,然后用相应的抗生素(环丙沙星、达托霉素和替加环素)处理 24 小时。与浮游培养物相比,所有三种微生物在生物膜中的敏感性都降低了。对生物膜与浮游培养物和抗生素处理生物膜与未处理生物膜的基因表达进行了全局转录组谱分析。测量细胞外代谢产物以表征生物膜、处理生物膜和浮游细胞之间碳源的利用情况。虽然这三种细菌都表现出了静止期的特定特征,但没有发现一致变化的保守基因、基因集或共同功能途径。在这三种细菌中,与浮游细胞相比,生物膜中葡萄糖的消耗增加,而生物膜中丙氨酸和天冬氨酸的利用减少。这些变化的原因在转录组中并不明显。在比较未处理和抗生素暴露的生物膜时,没有发现碳源利用模式的共同变化。总的来说,我们的测量结果不支持生物膜对抗生素的耐受存在共同的遗传或生化基础。相反,可能有无数的基因、蛋白质和代谢途径影响生物膜中单个微生物的生理状态,并有助于抗生素耐受。