Application of an Impedimetric Technique for the Detection of Lytic Infection ofSalmonellaspp. by Specific Phages

Abstract

This study was performed to evaluate the adaption of the impedimetric method to detect the lytic infection bySalmonella-specific bacteriophages and to provide a higher selectivity to this rapid method in detectingSalmonellaspp. by using specific agents. Three bacteriophages and twelve strains ofSalmonellaspp. were tested. Each of the twelve strains was used separately to inoculate TSB together with each one of the phages. The inoculum concentration was between 106and 107 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.