Staphylococcus aureus (S. aureus) is a leading cause of hospital-acquired infections, such as bacteremia, pneumonia, and endocarditis. Treatment of these infections can be challenging since strains of S. aureus, such as methicillin-resistant S. aureus (MRSA), have evolved resistance to antimicrobials. Current methods to identify infectious agents in hospital environments often rely on time-consuming, multistep culturing techniques to distinguish problematic strains (i.e., antimicrobial resistant variants) of a particular bacterial species. Therefore, a need exists for a rapid, label-free technique to identify drug-resistant bacterial strains to guide proper antibiotic treatment. Here, our findings demonstrate the ability to characterize and identify microbes at the subspecies level using Raman microspectroscopy, which probes the vibrational modes of molecules to provide a biochemical “fingerprint”. This technique can distinguish between different isolates of species such as Streptococcus agalactiae and S. aureus. To determine the ability of this analytical approach to detect drug-resistant bacteria, isogenic variants of S. aureus including the comparison of strains lacking or expressing antibiotic resistance determinants were evaluated. Spectral variations observed may be associated with biochemical components such as amino acids, carotenoids, and lipids. Mutants lacking carotenoid production were distinguished from wild-type S. aureus and other strain variants. Furthermore, spectral biomarkers of S. aureus isogenic bacterial strains were identified. These results demonstrate the feasibility of Raman microspectroscopy for distinguishing between various genetically distinct forms of a single bacterial species in situ. This is important for detecting antibiotic-resistant strains of bacteria and indicates the potential for future identification of other multidrug resistant pathogens with this technique.

中文翻译：

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耐药金黄色葡萄球菌菌株通过拉曼显微光谱揭示独特的生化特征

金黄色葡萄球菌( S. aureus ) 是菌血症、肺炎和心内膜炎等医院获得性感染的主要原因。这些感染的治疗可能具有挑战性，因为金黄色葡萄球菌菌株，例如耐甲氧西林金黄色葡萄球菌（MRSA），已经进化出对抗菌药物的耐药性。目前在医院环境中识别传染源的方法通常依赖于耗时的多步骤培养技术来区分特定细菌物种的有问题的菌株（即抗菌剂耐药变体）。因此，需要一种快速、无标记的技术来识别耐药菌株，以指导正确的抗生素治疗。在这里，我们的研究结果证明了使用拉曼显微光谱在亚种水平上表征和识别微生物的能力，拉曼显微光谱探测分子的振动模式以提供生化“指纹”。该技术可以区分不同的物种分离株，例如无乳链球菌和金黄色葡萄球菌。为了确定这种分析方法检测耐药细菌的能力，对金黄色葡萄球菌的同基因变体进行了评估，包括比较缺乏或表达抗生素抗性决定子的菌株。观察到的光谱变化可能与氨基酸、类胡萝卜素和脂质等生化成分有关。缺乏类胡萝卜素产生的突变体与野生型金黄色葡萄球菌和其他菌株变体不同。此外，还鉴定了金黄色葡萄球菌同基因细菌菌株的光谱生物标志物。这些结果证明了拉曼显微光谱法在原位区分单一细菌物种的各种遗传上不同形式的可行性。这对于检测细菌的抗生素耐药菌株非常重要，并表明未来利用该技术识别其他多重耐药病原体的潜力。