Stable isotope profiles reveal active production of VOCs from human-associated microbes
Stable isotope profiles reveal active production of VOCs from human-associated microbes
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DOI：
10.1088/1752-7163/aa5833
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发表时间：
2017-03-01
影响因子：
3.8
通讯作者：
Whiteson, Katrine
中科院分区：
文献类型：
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作者：
Phan, Joann;Meinardi, Simone;Whiteson, Katrine
从呼气中测量的挥发性有机化合物(VOCs)在细菌感染的诊断中具有很大的前景。然而，确定呼气中检测到的VOCs的人类或微生物来源仍然是一个巨大的挑战。例如，最近在囊性纤维化(CF)患者的呼吸中发现了微生物发酵产物2，3丁二酮；对相同样本的平行培养独立元基因组测序显示，链球菌和罗氏菌。具有生产2，3-丁二酮的遗传能力。为了研究在后基因组中发现的遗传能力是否转化为细菌产生感兴趣的VOCs，如2，3丁二酮，我们给从患者身上分离的三个细菌菌株喂入稳定的同位素：两个革兰氏阳性细菌，粘性罗氏菌和唾液链球菌，以及一个显性的机会革兰氏阴性病原菌，铜绿假单胞菌。用气相色谱系统收集和分析培养顶空，以量化感兴趣的VOCs的丰度；使用质谱学来确定是否加入了稳定的同位素标记。我们的结果表明，粘质葡萄球菌和唾液葡萄球菌消耗D-葡萄糖-C-13(6)来产生标记的2，3-丁二酮。当(H2O)-H-2培养时，粘质葡萄球菌和唾液葡萄球菌也会产生标记乙醛和乙醇。此外，我们还发现，铜绿假单胞菌在培养过程中暴露于乳酸环境中，其生长和二甲基硫化物的产量都会增加。这些结果突出了由铜绿假单胞菌、粘性葡萄球菌和唾液葡萄球菌产生的VOCs作为微生物群落中的营养物质和信号的重要性，以及作为CF感染的潜在生物标志物的重要性。
Volatile organic compounds (VOCs) measured from exhaled breath have great promise for the diagnosis of bacterial infections. However, determining human or microbial origin of VOCs detected in breath remains a great challenge. For example, the microbial fermentation product 2,3butanedione was recently found in the breath of Cystic Fibrosis (CF) patients; parallel culture-independent metagenomic sequencing of the same samples revealed that Streptococcus and Rothia spp. have the genetic capacity to produce 2,3-butanedione. To investigate whether the genetic capacity found in metagenomes translates to bacterial production of a VOCs of interest such as 2,3butanedione, we fed stable isotopes to three bacterial strains isolated from patients: two gram-positive bacteria, Rothia mucilaginosa and Streptococcus salivarius, and a dominant opportunistic gramnegative pathogen, Pseudomonas aeruginosa. Culture headspaces were collected and analyzed using a gas chromatographic system to quantify the abundance of VOCs of interest; mass spectroscopy was used to determine whether the stable isotope label had been incorporated. Our results show that R. mucilaginosa and S. salivarius consumed D-Glucose-C-13(6) to produce labeled 2,3-butanedione. R. mucilaginosa and S. salivarius also produced labeled acetaldehyde and ethanol when grown with (H2O)-H-2. Additionally, we find that P. aeruginosa growth and dimethyl sulfide production are increased when exposed to lactic acid in culture. These results highlight the importance VOCs produced by P. aeruginosa, R. mucilaginosa, and S. salivarius as nutrients and signals in microbial communities, and as potential biomarkers in a CF infection.