Aim

Volatile organic compounds (VOCs) are being studied as potential biomarkers in many infections. Therefore, this study aimed to analyze the volatile profile of three Gram-positive bacteria of clinical relevance to identify potential volatile biomarkers that allow their differentiation.

Methods and results

L. monocytogenes, S. aureus, and E. faecalis clinical isolates were inoculated in a thioglycollate medium until grown. Then, VOCs were extracted by solid-phase microextraction, and the data obtained were subjected to multivariate analysis. According to our results, there was a high production of aldehydes in E. faecalis. In the case of alcohols, they only increased in L. monocytogenes, while ketones were produced significantly in all three bacteria, mainly due to acetoin. Acids were produced significantly in E. faecalis and L. monocytogenes.

Conclusions

Potential biomarkers of L. monocytogenes could be 1-butanol and 2-methylbutanoic acid. In the case of E. faecalis, the VOC most related to its presence was nonanal. Lastly, potential biomarkers of S. aureus could be isoamyl butanoate and methionol, although some pyrazines have also been associated with this bacterium.

Significance and impact of the study

The identification of potential biomarkers of these clinically relevant bacteria could open the way for the diagnosis of these infections through the analysis of volatile compounds.

中文翻译：

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具有临床相关性的革兰氏阳性菌的挥发性生物标志物作为感染诊断的工具

目的

挥发性有机化合物 (VOC) 正在作为许多感染的潜在生物标志物进行研究。因此，本研究旨在分析三种具有临床相关性的革兰氏阳性菌的挥发性特征，以确定允许其分化的潜在挥发性生物标志物。

方法和结果

将单核细胞增生李斯特氏菌、金黄色葡萄球菌和粪肠球菌临床分离株接种在巯基乙酸盐培养基中直至生长。然后，通过固相微萃取对VOCs进行萃取，并对所得数据进行多变量分析。根据我们的结果，粪肠球菌中醛类的产量很高。就醇类而言，它们仅在单增李斯特菌中增加，而酮类在所有三种细菌中均显着产生，主要是由于乙偶姻。粪肠球菌和单核细胞增生李斯特菌显着产生酸。

结论

单增李斯特菌的潜在生物标志物可能是 1-丁醇和 2-甲基丁酸。就粪肠球菌而言，与其存在最相关的挥发性有机化合物是壬醛。最后，金黄色葡萄球菌的潜在生物标志物可能是丁酸异戊酯和甲硫醇，尽管一些吡嗪也与这种细菌有关。

研究的意义和影响

这些临床相关细菌的潜在生物标志物的鉴定可以为通过分析挥发性化合物来诊断这些感染开辟道路。