Rapid and Accurate Detection of Urinary Pathogens by Mobile IMS-Based Electronic Nose: A Proof-of-Principle Study

Abstract

Urinary tract infection (UTI) is a common disease with significant morbidity and economic burden, accounting for a significant part of the workload in clinical microbiology laboratories. Current clinical chemisty point-of-care diagnostics rely on imperfect dipstick analysis which only provides indirect and insensitive evidence of urinary bacterial pathogens. An electronic nose (eNose) is a handheld device mimicking mammalian olfaction that potentially offers affordable and rapid analysis of samples without preparation at athmospheric pressure. In this study we demonstrate the applicability of ion mobility spectrometry (IMS) –based eNose to discriminate the most common UTI pathogens from gaseous headspace of culture plates rapidly and without sample preparation. We gathered a total of 101 culture samples containing four most common UTI bacteries: E. coli, S. saprophyticus, E. faecalis, Klebsiella spp and sterile culture plates. The samples were analyzed using ChemPro 100i device, consisting of IMS cell and six semiconductor sensors. Data analysis was conducted by linear discriminant analysis (LDA) and logistic regression (LR). The results were validated by leave-one-out and 5-fold cross validation analysis. In discrimination of sterile and bacterial samples sensitivity of 95% and specificity of 97% were achieved. The bacterial species were identified with sensitivity of 95% and specificity of 96% using eNose as compared to urine bacterial cultures. In conclusion: These findings strongly demonstrate the ability of our eNose to discriminate bacterial cultures and provides a proof of principle to use this method in urinanalysis of UTI.

Electronic Nose in the Detection of Wound Infection Bacteria from Bacterial Cultures: A Proof-of-Principle Study

“…Our results on the principle of bacterial recognition by an IMS-based eNose from gaseous headspace are in line with a previous study on pathogens related to urinary tract infection [13]. Several previous studies on the detection of bacteria from gaseous headspace have been conducted using an eNose with entirely different operating principle [14, 17-19].…”

“…It is affordable, basically maintenance-free, and does not require extensive sample preparation. The eNose has been shown to detect bacteria from cultures [13, 14], and preliminary evidence suggests that it could be able to differentiate methicillin-resistant S. aureus (MRSA) from methicillin-sensitive S. aureus (MSSA) [15]. Compared to polymerase chain reaction-based methods which only show the presence of the pathogen, eNose also analyzes the potential host’s response to the infection.…”

New and developing diagnostic technologies for urinary tract infections

“…The eNose (Specific Technologies), a hand-held system, uses ion mobility spectrometry to assess a VOC profile in 15 minutes (REF. 114). Tests of the eNose system with cultured uropathogens isolated from patient samples achieved 95% sensitivity and 97% specificity 114 .…”

Application and Uses of Electronic Noses for Clinical Diagnosis on Urine Samples: A Review

“…The following sections provide an overview of the state-of-the-art of the application of electronic noses for the analysis of urine samples by classifying those applications depending on the target investigated, thus including the discrimination of bacteria cultures (Section 2.2) [49,50,51,52], or the detection of urinary tract infections (Section 2.3) [53,54,55,56,57,58], cancer diseases (Section 2.4) [59,60,61,62,63,64,65,66], diabetes (Section 2.5) [67,68], kidney diseases (Section 2.6) [69,74], bowel diseases (Section 2.7) [70,71,72] and exposure to toxic agents (Section 2.8) [73] (reference [74] wasn’t included in Table 1 since it refers to breath analysis).…”

“…Recently, Roine et al [55] demonstrated the applicability of a new model of electronic nose to discriminate the most common UTI pathogens from the gaseous headspace of culture plates. More in detail, culture samples containing four most common UTI bacteria ( E. coli , S. Saprophyticus , E. Faecalis , Klebsiella ) and sterile culture plates were analysed using a ChemPro 100i device (Environics Inc., Mikkeli, Finland), consisting of ion mobility spectrometry (IMS) cell and six semiconductor sensors; data were processed with LDA and LR (logistic regression).…”