Antibacterial activity of silver nitrate on Pseudomonas aeruginosa bacteria using Calvet calorimetry

Abstract

This study aimed to use microcalorimetry to analyze the real-time effect that silver nitrate has on one of the most common bacteria involved in severe infections in current medical practice. Using a Calvet microcalorimeter, the heat output produced by Pseudomonas aeruginosa was determined when exposed to concentrations of silver nitrate from 0 to 3 mol⋅m−3, and a saturated solution. Under physiological human body temperature, for 46 h, thermographic curves were obtained. The maximum voltage peaks (Vmax) and the total amount of heat exchanged (Q) were determined. The results showed a bactericidal effect, with a minimum inhibitory concentration (MIC) of silver nitrate of 0.75 mol⋅m−3, showing a Vmax of 93 μV and Q of 193 kJ. With higher concentrations of this metallic solution, the results highlighted the proportional negative effect that silver nitrate has in Pseudomonas aeruginosa growth.