Molecular analysis of volatile metabolites released specifically by Staphylococcus aureus and Pseudomonas aeruginosa.
Molecular analysis of volatile metabolites released specifically by Staphylococcus aureus and Pseudomonas aeruginosa.
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DOI：
10.1186/1471-2180-12-113
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发表时间：
2012-06-20
期刊：
影响因子：
4.2
通讯作者：
Amann A
中科院分区：
文献类型：
--
作者：
Filipiak W;Sponring A;Baur MM;Filipiak A;Ager C;Wiesenhofer H;Nagl M;Troppmair J;Amann A
常规使用的呼吸机相关性肺炎（VAP）微生物学诊断非常耗时，并且通常需要采用侵入性方法来收集人体样本（例如支气管镜检查）。因此，开发一种非侵入性方法来早期检测通气患者的细菌感染，最好能够识别特定的病原体是非常有意义的。目前的工作是尝试识别呼吸中病原体衍生的挥发性生物标志物，可用于呼吸机相关性肺炎（VAP）的早期和无创诊断。为此，我们对 VAP 患者中最常见的细菌（即金黄色葡萄球菌和铜绿假单胞菌）进行了体外实验，以研究挥发性有机化合物 (VOC) 的释放或消耗。在不同时间点收集顶空样品并在多床吸附管上预浓缩，随后使用气相色谱质谱法 (GC-MS) 进行分析。金黄色葡萄球菌和铜绿假单胞菌分别释放了多达 32 种和 37 种挥发性代谢物。我们发现细菌特异性 VOC 谱存在明显差异，尤其是醛类（例如乙醛、3-甲基丁醛），这些醛类仅被铜绿假单胞菌吸收，但由金黄色葡萄球菌释放。酸（例如异戊酸）、酮（例如乙偶姻、2-壬酮）、烃（例如 2-丁烯、1,10-十一碳二烯）、醇（例如 2-甲基-1-丙醇、2-丁醇）、酯（例如甲酸乙酯、2-甲基丁酸甲酯）、易挥发的 硫化合物（VSC，例如二甲硫醚）和挥发性氮化合物（VNC，例如 3-甲基吡咯）。重要的是，培养开始后 1.5 小时就发现了显着的 VOC 释放，对应的细胞数量约为 8*106 [CFU/ml]。获得的结果提供了强有力的证据，表明通过测定特征性挥发性代谢物可以实现细菌的检测甚至鉴定，支持临床使用呼吸气体分析作为早期检测细菌性肺部感染的非侵入性方法。
The routinely used microbiological diagnosis of ventilator associated pneumonia (VAP) is time consuming and often requires invasive methods for collection of human specimens (e.g. bronchoscopy). Therefore, it is of utmost interest to develop a non-invasive method for the early detection of bacterial infection in ventilated patients, preferably allowing the identification of the specific pathogens. The present work is an attempt to identify pathogen-derived volatile biomarkers in breath that can be used for early and non- invasive diagnosis of ventilator associated pneumonia (VAP). For this purpose, in vitro experiments with bacteria most frequently found in VAP patients, i.e. Staphylococcus aureus and Pseudomonas aeruginosa, were performed to investigate the release or consumption of volatile organic compounds (VOCs). Headspace samples were collected and preconcentrated on multibed sorption tubes at different time points and subsequently analyzed with gas chromatography mass spectrometry (GC-MS). As many as 32 and 37 volatile metabolites were released by S. aureus and P. aeruginosa, respectively. Distinct differences in the bacteria-specific VOC profiles were found, especially with regard to aldehydes (e.g. acetaldehyde, 3-methylbutanal), which were taken up only by P. aeruginosa but released by S. aureus. Differences in concentration profiles were also found for acids (e.g. isovaleric acid), ketones (e.g. acetoin, 2-nonanone), hydrocarbons (e.g. 2-butene, 1,10-undecadiene), alcohols (e.g. 2-methyl-1-propanol, 2-butanol), esters (e.g. ethyl formate, methyl 2-methylbutyrate), volatile sulfur compounds (VSCs, e.g. dimethylsulfide) and volatile nitrogen compounds (VNCs, e.g. 3-methylpyrrole). Importantly, a significant VOC release was found already 1.5 hours after culture start, corresponding to cell numbers of ~8*106 [CFUs/ml]. The results obtained provide strong evidence that the detection and perhaps even identification of bacteria could be achieved by determination of characteristic volatile metabolites, supporting the clinical use of breath-gas analysis as non-invasive method for early detection of bacterial lung infections.