An electronic nose effectively detected Staphylococcus aureus in children with cystic fibrosis, based on data from 100 individuals.
Staphylococcus aureus is the most common pathogen found in children with cystic fibrosis (CF), but current detection strategies are based on microbiology cultures, wrote Johann-Christoph Licht, a medical student at the University of Toronto, and colleagues.
Noninvasive tools are needed to screen children with CF early for respiratory infections, the researchers said.
The electronic Nose (eNose) is a technology that detects volatile organic compounds (VOCs). Although exhaled breath can be used to create distinct profiles, the ability of eNose to identify S. aureus (SA) in the breath of children with CF remains unclear, they wrote.
In a study published in the Journal of Cystic Fibrosis, the researchers analyzed breath profiles data from 100 children with CF. The study population included children aged 5-18 years with clinically stable CF who were recruited from CF clinics during routine visits. Patients with a CF pulmonary exacerbation were excluded.
The children’s median predicted FEV1 was 91%. The researchers collected sputum from 67 patients and throat cultures for 33 patients. A group of 25 age-matched healthy controls served for comparison.
Eighty patients were positive for CF pathogens. Of these, 67 were positive for SA (44 with SA only and 23 with SA and at least one other pathogen).
Overall, patients with any CF pathogen on airway cultures were identified compared to airway cultures with no CF pathogens with an area under the curve accuracy of 79.0%.
Previous studies have shown a high rate of accuracy using eNose to detect Pseudomonas aeruginosa (PA). In the current study, the area under the curve accuracy for PA infection compared to no CF pathogens was 78%. Both SA-specific and PA-specific signatures were driven by different sensors in the eNose, which suggests pathogen-specific breath signatures, the researchers wrote.
The study findings were limited by several factors including the small number of patients with positive airway cultures for PA and the lack of data on variability of measures over time or treatment-induced changes, the researchers noted.
However, the results confirm the value of the eNose in real-time point-of-care detection of airway infection in children with CF, and this is the first study known to suggest the potential of an eNose to detect SA infection in particular in a routine clinical setting, the researchers wrote in their discussion.
Other points in favor of eNose compared to current practice include “low cost, ease of use and portability to the point-of-care,” they said. The eNose provides an opportunity for early detection of pathogens that challenges conventional microbiology testing, they concluded.
The study received no outside funding. Two coauthors disclosed fees and/or an interest in the company Breathomix BV.