Electrochemical Quantification of Tobramycin Retention in Pseudomonas aeruginosa as Antimicrobial Susceptibility Indicator

Abstract

The emergence and spread of bacterial resistance to antibiotics has developed into one of the most challenging threats to public health. Antibiotic susceptibility tests (ASTs) for bacterial infections are now essential, because they provide guidance for physicians in the selection of antibiotics, to which bacteria will respond. Most current AST methods require long periods of time, because of bacterial growth and incubation, leading to a prolonged and overuse of broad-spectrum antibiotics. Thus, there is a growing demand for methods and technologies that enable rapid antibiotic susceptibility assessment. Due to advantages related to cost-effectiveness, rapid response time and high sensitivity, electrochemical detection methods are promising analytical tools that can successfully quantify antibiotic uptake and retention in clinically relevant bacterial strains. This study presents the electroanalytical quantification of tobramycin (TOB) retention in susceptible and resistant bacterial strains of Pseudomonas aeruginosa. The electrochemical behavior of TOB was characterized by voltammetry, identifying redox potentials, the current dependence on pH conditions, and the detection limit at unmodified glassy carbon electrodes. The presented methodology was able to distinguish between susceptible and resistant bacterial strains, and is also capable of identifying varying degrees of resistance against TOB. The presented approach detects the immediate interaction of bacteria with an antibiotic, without the need of complex and cost-intense equipment related to genomic testing methods.

Antibiotic Resistance Detection in Pseudomonas aeruginosa: Recent Strategies, Advances, and Challenges

“…Copyright © 2021 with permission from Elsevier Inc. D) Differential pulse voltammograms of different P. aeruginosa strains supernatants after a 15‐min incubation in the presence of 2 mM Tobramycin. Reproduced from ref [112] . Copyright © 2022 with permission from American Chemistry Society.…”

“…Aside from PYO, the detection of drug retention can also be used as resistance indicator. Lopes and co‐authors [112] employed a glassy carbon electrode to detect tobramycin retention in P. aeruginosa strains with different degrees of resistance. This approach not only distinguishes between susceptible and resistant bacterial strains, but it also quantifies varying degrees of resistance against tobramycin [30] (Figure 1D).…”