Portable Olfactory Sensor Designed for Diagnosis of Bacteria

A portable electronic "nose" (eNose) has been designed to rapidly detect and identify the most common bacteria causing soft tissue infections.

Rapid diagnosis of wound infections is based on bacterial stains, cultures, and polymerase chain reaction assays, and the results are available after several hours at the earliest, but more often not until after days of waiting. Therefore, antibiotic treatment is often administered empirically without a specific diagnosis.

To rectify this situation, a team of Finish bioengineers developed eNose, a device able to produce "an olfactory profile" for each molecular compound in gaseous headspace created by bacterial infection. The profile was analyzed by a computer programmed to differentiate between different compounds.

The investigators used the eNose system for a proof-of-concept study aimed at differentiating the most relevant bacteria causing wound infections. The study utilized a set of clinical bacterial cultures on identical blood culture dishes, and established bacterial lines from the gaseous headspace.

Results revealed that the eNose system was capable of differentiating both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa, and Clostridium perfringens with an accuracy of 78% within minutes without prior sample preparation. Most importantly, the system was capable of differentiating MRSA from MSSA with a sensitivity of 83%, a specificity of 100%, and an overall accuracy of 91%.

"Our aim was to create a method for the rapid diagnosis of soft tissue infections. If we had such a method, treatment could be started in a timely manner and targeted to the relevant pathogen directly. This would reduce the need for empirical treatments and shorten diagnostic delays," said first author Dr. Taavi Saviauk, a researcher in the faculty of medicine and life sciences at the University of Tampere (Finland). "The portable eNose device we used does not require laboratory conditions or special training, so it is well suited for outpatient use. The results of this study are a significant step towards our goal."

The eNose study was published in the January 2018 issue of the journal European Surgical Research.

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University of Tampere