The volatile organic compounds detection in MDR Gram-negatives antimicrobial susceptibility testing: Results from a four-month laboratory experience

Systemic bacterial infections represent a significant clinical challenge due to the increasing resistance rate towards antimicrobials. An essential key to controlling antimicrobial resistance spread is to administer targeted therapy after a precise minimum inhibitory concentration reporting. Among the available fast technologies for antimicrobial susceptibility testing (AST), the VITEK^Ⓡ REVEAL™ (Biomerieux, Florence, Italy) proposes volatile organic compounds (VOC) colourimetric arrays to discriminate between susceptible and resistant Gram-negative isolates directly from positive blood cultures. We evaluated this methodology during a four-month laboratory experience on 40 positive blood culture samples, reporting a comparison to standard culture-based methods. The protocol revealed an essential agreement of 100 % between the conventional and the experimental procedures, while the categorical agreement resulted in 97.5 % due to one very major error (VME) for meropenem/vaborbactam in K. pneumoniae. Although further studies will be necessary to investigate its performance on rare microorganisms, the VITEK^Ⓡ REVEAL™ demonstrated an optimal sensitivity in defining MIC values for multi-drug resistant (MDR) microorganisms. These results encourage the application of the method in all high-risk epidemiological areas, confirming the effectiveness of VOC detection in monitoring bacterial susceptibility profiles.