Application of an impedimetric technique for the detection of lytic infection of Salmonella spp. by specific phages

Abstract

This study was performed to evaluate the adaption of the impedimetric method to detect the lytic infection by Salmonella-specific bacteriophages and to provide a higher selectivity to this rapid method in detecting Salmonella spp. by using specific agents. Three bacteriophages and twelve strains of Salmonella spp. were tested. Each of the twelve strains was used separately to inoculate TSB together with each one of the phages. The inoculumconcentration was between 10 6 and 10 7 cfu/mL, at a cell: phage ratio of 1 : 100. From the sample analysis, based on conductance (G)measurements (37°C), the infection could be detected, by observation of both detection-time delay and distinct curve trends. The main conclusions were that kinetic detection by impedance microbiology with phage typing constitutes a method of determining whether a test microorganism is sensitive to the bacteriophage and a method to evaluate whether a lytic bacteriophage is present in a sample, by affecting bacterial growth rate/metabolic change. Copyright © 2009 Lara R. P. Amorim et al.