Use of the Real Time xCelligence System for Purposes of Medical Microbiology

Abstract

Roche's xCelligence impedance-measuring instrument is one of a few commercially available systems of such type. According to the best knowledge of authors, instrument was tested so far only for eukaryotic cell research. The aim of this work was to estimate xCELLigence suitability for the microbiological tests, including (i) measurement of morphological changes in eukaryotic cells as a result of bacterial toxin activity, (ii) measurement of bacterial biofilm formation and (iii) impact of antiseptics on the biofilm structure. To test the infuence of bacterial LT enterotoxin on eukaryotic cell lines, Chinese Hamster Ovary (CHO) cell line and reference strain Escherichia coli ATTC 35401 were used. To investigate Roche's instrument ability to measure biofilm formation and impact of antiseptics on its development, Staphylococcus aureus ATTC6538 reference strain was used. The data generated during the experiments indicate excellent ability of xCelligence instrument to detect cytopathic effect caused by bacterial LT endotoxin and to detect staphylococcal biofilm formation. However, interpretation of the results obtained during real-time measurement of antiseptic's bactericidal activity against staphylococcal biofilm, caused many difficulties. xCelligence instrument can be used for real-time monitoring of morphological changes in CHO cells treated with bacterial LT enterotoxin and for real-time measurement of staphylococcal biofilm formation in vitro. Further investigation is necessary to confirm suitability of system to analyze antiseptic's antimicrobial activity against biofilm in vitro.

Effect of antibiotics on biofilm inhibition and induction measured by real-time cell analysis

“…In another approach, to test the system sensitivity to biofilm detachment, a proteic biofilm strain was treated with proteinase K. A marked decrease in curve slope was observed suggesting protein-based biofilm disruption. Taken together, the different assays support that this technology has a high sensitivity and that it consistently replicates biofilm formation results, in agreement with previous studies (Junka et al 2012). In addition, our results show that impedance measurements appear to combine both cellular growth and matrix production, representing a measurement of total biofilm mass in species with polysaccharide-based matrixes.…”

“…Therefore, sensitive, accurate, reproducible and fast methods are desirable for real-time monitoring of biofilms. In this regard, promising advances in impedance technology based on the ability of cells to impede the electrical current when adhered to MTP with gold electrodes have been developed in recent years (Junka et al 2012;Bruchmann et al 2015;Cihalova et al 2015).…”

“…The main purpose of this work was to study the effect of 10 antibiotics on biofilm formation dynamics in clinical isolates of S. aureus and S. epidermidis through an assay for monitoring biofilm development in real time using electronic impedance technology. Although real-time cell analysis (RTCA) assays were originally developed for monitoring eukaryotic cell lines status, and have been applied in a number of animal and human cell-based studies (Solly et al 2004), they have recently also been used for measuring bacterial biofilms and to study the effect of antimicrobial treatments on their growth (Junka et al 2012;Cihalova et al 2015). In the present study, we have applied electrode impedance measurements to test the therapeutic efficacy and effect on biofilm formation and growth of 10 antibiotics in clinically isolated bacterial strains.…”

Candida albicans Biofilm Heterogeneity and Tolerance of Clinical Isolates: Implications for Secondary Endodontic Infections

“…Briefly, this system is a real-time cell analysis instrument that uses patented microtitre plates (E-plates ® ) that contain gold biosensors embedded in the bottom of each well. Quantifiable data was expressed as cell index, which represents the cell impedance when the cells adhere, or associated matrix, to the electrodes [31]. These biosensors continuously and non-invasively monitor changes in cell number, cell size, cell-substrate attachment quality, and extrapolymeric substance (EPS) production.…”

Staphylococcus aureus and MRSA Growth and Biofilm Formation after Treatment with Antibiotics and SeNPs

“…Real-time cell analysis (RTCA) on xCELLigence device was used for this determination [ 26 , 27 ]. The method works on the principle of cell adhesion on the surface of electrodes, which modulates the resulting impedance [ 28 ]. In the case of bacteria adherence of biofilm on the surface of the electrodes occurs [ 29 ] and thereby the change of the relative impedance is observed [ 30 ].…”