Bacteriological diagnosis with volatile organic compounds – first experiences with an electronic nose
*使用電子鼻檢測揮發性有機化合物進行細菌學診斷
Eur Urol Suppl 2019; 18(1);e381
Heers H. 1 , Heinig J. 1 , Von Stauffenberg F. 1 , Hegele A. 1 , Hofmann R. 1 , Böselt T. 2 , Koczulla A.R. 2
1Philipps-Universität Marburg, Dept. of Urology and Paediatric Urology, Marburg, Germany, 2Philipps-Universität Marburg, Dept. of Pulmonology,
Marburg, Germany
Introduction & Objectives:Volatile organic compounds (VOCs) can help to diagnose a wide range of diseases. They may be disease-specific and can be detected for example from urine samples using “electronic noses”. Our group previously reported and published promising data on the detection of bladder tumours using this rapid testing system. Bacteriological diagnosis using urine cultures or swabs usually requires several days to establish a reliable diagnosis. The aim of this study was to investigate whether VOC detection can potentially represent a speedy alternative in the diagnosis of bacterial infections.
揮發性有機化合物(VOC)可以幫助診斷各種疾病。它們可能是疾病特異性的,并且可以用“電子鼻”從尿液樣本中檢測到。我們的研究小組以前報道并發表了利用這個快速檢測系統檢測膀胱腫瘤的有前景的數據。使用尿液培養物或拭子進行細菌學診斷通常需要幾天時間來建立可靠的診斷。本研究的目的是研究VOC檢測是否有可能成為細菌感染診斷的快速替代方法。
Materials & Methods:VOC measurements were carried out with Cyranose 320, an electronic nose measuring changes in resistance induced by VOCs competitively binding to an array of 32 polymer sensors. Statistical analysis was performed using principal component analysis and linear discriminant analysis. 71 urine samples of patients with confirmed urinary tract infection (UTI) or significant bacteriuria (≥ 104 colony forming units (CFU)/ml) as established by urine culture and 55 samples from healthy controls were collected and measured. Furthermore, broth cultures at 108 CFU/ml from 20 stock samples each of methicillin-resistant staphylococcus aureus (MRSA) and methicillin-sensitive staphylococcus aureus (MSSA) were tested against pure medium (brain heart infusion broth).
VOC測量采用Cyranose 320進行,這是一種電子鼻,用于測量VOC與32個聚合物傳感器陣列的競爭性結合導致的電阻變化。采用主成分分析和線性判別分析進行統計分析。收集經尿培養證實的尿路感染(UTI)或明顯細菌尿(菌落形成單位≥104 cfu/ml)患者的71份尿液樣本和健康對照者的55份樣本,并進行測量。此外,在純培養基(腦-心輸注肉湯)中檢測20個儲備樣品(每個耐**(MRSA)和*敏感*(MSSA))的108 cfu/ml肉湯培養物。
Results:Urine culture of the UTI samples showed solitary bacterial strains in 39 cases, two differenent strains in 22 cases, and three strains in 9 cases. The range of bacterial strains present were representative for UTI. For the separation of UTI versus healthy control, the electronic nose had a sensitivity of 81.7% and a specificity of 77.3%. Due to the small sample size, no significant differences in the measurement pattern of individual strains could be detected. The measurement of broth cultures from stock samples led to more meaningful results. MRSA was separated from medium with a sensitivity of 96% and specificity of 94%; MSSA vs medium sensitivity 81%, specificity 75%; MRSA vs MSSA sensitivity 100%, specificity 91%.
尿培養結果顯示,尿路感染者39例為孤立性細菌,22例為兩種不同的細菌,9例為三種細菌。存在的細菌菌株范圍代表了尿路感染。對于UTI與健康對照的分離,電子鼻的靈敏度為81.7%,特異性為77.3%。由于樣本量小,單個菌株的測量模式沒有顯著差異。對肉湯樣品培養基的測定得到了更有意義的結果。MRSA與培養基分離,敏感度96%,特異性94%;MSSA與培養基敏感度81%,特異性75%;MRSA與MSSA敏感度100%,特異性91%。
Conclusions:VOC-based detection of bacterial infections seems feasible. In purified culture, individual strains may show specific recognisable VOC patterns. Preliminary measurements from urine samples show good results in UTI detection. Further sample handling leading to higher bacterial concentrations may be necessary to allow recognition of individual bacteria. Updated data with further and confirmatory measurements including ion mobility spectrometry will be presented.
基于VOC的細菌感染檢測似乎是可行的。在純化培養基中,單個菌株可能表現出特定的可識別的VOC模式。尿液樣本的初步測量結果顯示,UTI檢測結果良好。進一步的樣品處理導致更高的細菌濃度可能是必要的,以便識別單個細菌。將提供包括離子遷移率光譜法在內的更新數據和進一步的驗證性測量。