Comparison of real time impedance monitoring of bacterial biofilm cultures in different experimental setups mimicking real field environments

Bacterial biofilms are presented in many different environments causing a wide variety of infectious processes. Biofilms at their mature stage are difficult to eradicate because of their inherent resistance to antimicrobial agents. Easy-to-integrate and in situ detection tools would provide early detection of bacterial presence allowing efficient prophylactic actions. Impedance microbiology has been postulated as a suitable technique that allows monitoring of bacterial biofilm growths in real time. In this work four different culturing setups were developed as testing platforms for measuring real time microbiological cultures that could mimic real field environments. Results suggest that the position of the sensors in regard to the dynamic conditions of the culture might affect the sensitivity and the target parameter. Capacitance and resistance are associated to different biological effects, surface coating and conductivity changes respectively. Relative variations of electrical parameters were recorded in the lab obtaining significant changes in few hours post-infection. It has been proven that biological coating cause largest variations in capacitance, up to 60%, while metabolic activity affects more the resistance giving a variation up to 15%. Fitting analysis has confirmed experimental results showing also the effect of the dead/alive ratio.