Electrochemical detection of redox molecules secreted by Pseudomonas aeruginosa - Part 2: Enhanced detection owing to PEDOT:PSS electrode structuration

Fast bacterial detection and identification is a crucial challenge in order to improve our antibiotics use and reduce the antimicrobial resistance. Electroanalysis of biological fluids is cheap and can be done in situ but the electrode material needs to be perfectly chosen. We previously studied electrochemical signature of Pseudomonas aeruginosa's secretome, thanks to glassy carbon electrode. Some conductive polymers are particularly efficient for biological use because of their antifouling properties, biocompatibility and way of processing. In this paper, we described the fabrication, characterization and utilisation of PEDOT:PSS film to detect and identify Pseudomonas aeruginosa through three of its secreted molecules: pyocyanin, Pseudomonas quinolone PQS and 2'-aminoacetophenone. The electrochemical responses, clearly amplified by PEDOT:PSS, can be used to identify these bacteria quickly and efficiently.

Electrochemical detection of redox molecules secreted by Pseudomonas aeruginosa - Part 1: Electrochemical signatures of different strains

During infections, fast identification of the microorganisms is critical to improve patient treatment and to better manage antibiotics use. Electrochemistry exhibits several advantages for rapid diagnostic: it enables easy, cheap and in situ analysis of redox molecules in most liquids. In this work, several culture supernatants of different Pseudomonas aeruginosa strains (including PAO1 and its isogenic mutants PAO1ΔpqsA, PA14, PAK and CHA) were analyzed by square wave voltammetry on glassy carbon electrode during the bacterial growth. The obtained voltamograms shown complex traces exhibiting numerous redox peaks with potential repartitions and current amplitudes depending on the studied bacterium and/or growth time. Among them, some peaks were clearly associated to the well-known redox toxin Pyocyanin (PYO) and the autoinducer Pseudomonas Quinolone Signal (PQS). Other peaks were observed that are not yet attributed to known secreted species. Each complex electrochemical response (number of peaks, peak potential and amplitude) can be interpreted as a fingerprint or "ID-card" of the studied strain that may be implemented for fast bacteria strain identification.

Electrochemistry provides a simple way to monitor Pseudomonas aeruginosa metabolites

Pseudomonas aeruginosa is one of the most common bacteria responsible for nosocomial infections. To imagine new therapies, understanding virulence mechanisms and the associated communication system of the bacterium (its quorum sensing) is a target of the first importance. Electrochemistry is a promising tool for real-time in situ monitoring of electroactive species issued from P. aeruginosa communication system. This contribution deals with the electrochemical characterization of the main bacteria electroactive metabolites: Pseudomonas Quinolone Signal, pyocyanin and 2'-aminoacetophenone. These metabolites were electrochemically characterized and further detected in supernatant of P. aeruginosa PA01 strain grown in LB medium.