Analysis of mixed biofilm (<i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa)</i> by laser ablation electrospray ionization mass spectrometry

<i>Pseudomonas aeruginosa</i> and <i>Staphylococcus aureus</i> are ubiquitous pathogens often found together in polymicrobial, biofilm-associated infections. This study is the first to use laser ablation electrospray ionization mass spectrometry (LAESI-MS) to rapidly study bacteria within a mixed biofilm. Fast, direct, non-invasive LAESI-MS analysis of biofilm could significantly accelerate biofilm studies and provide previously unavailable information on both biofilm composition and the effects of antibiofilm treatment. LAESI-MS was applied directly to a polymicrobial biofilm and analyzed with respect to whether <i>P. aeruginosa</i> and <i>S. aureus</i> were co-localized or self-segregated within the mixed biofilm. LAESI-MS was also used to analyze ions following LL-37 antimicrobial peptide treatment of the biofilm. This ambient ionization method holds promise for future biofilm studies. The use of this innovative technique has profound implications for the study of biofilms, as LAESI-MS eliminates the need for lengthy and disruptive sample preparation while permitting rapid analysis of unfixed and wet biofilms.

铜绿假单胞菌（Pseudomonas aeruginosa）与金黄色葡萄球菌（Staphylococcus aureus）是广泛分布的致病菌，二者常共同存在于多微生物相关的生物被膜感染中。本研究首次采用激光剥蚀电喷雾电离质谱（laser ablation electrospray ionization mass spectrometry，LAESI-MS）对混合生物被膜内的细菌开展快速研究。快速、直接且无创的LAESI-MS生物被膜分析手段，可显著加速生物被膜相关研究进程，并能提供此前难以获取的生物被膜组成信息，以及抗生物被膜治疗的相关效应数据。研究人员将LAESI-MS直接应用于多微生物生物被膜，分析铜绿假单胞菌与金黄色葡萄球菌在混合生物被膜内究竟是共定位还是发生自我隔离。此外，本研究还利用LAESI-MS对经LL-37抗菌肽处理后的生物被膜内的离子组分进行了分析。这种环境电离方法在未来的生物被膜研究中具备广阔应用前景。该创新技术的应用对生物被膜研究具有深远影响：LAESI-MS无需耗时且具有破坏性的样品前处理流程，同时可对未固定的湿润生物被膜实现快速分析。