Progress toward the development of a lytic bacteriophages-based impedance microbiology for agro-food application

A novel approach to impedance microbiology (IM) has been under investigation. In our approach, solution resistance variations will be generated from bacteriophage (phage) lyses of host cell and the consequent release of endoplasmic material. To sensitively detect the lysis, bacteria cells have to be concentrated in a micro-electrochemical cell so that dilution of the released conductive molecules will be minimised. Therefore, the detection principle has been developed in conjunction with a sample preparation method for bacteria capture and concentration based on phage functionalised paramagnetic nanobeads and magnetic concentration. Escherichia coli has been used as target bacteria and the beads have been functionalised with selective lytic phages. The method has a potential detection limit slightly below 10 CFU/chamber. The whole assay detection time is bound to be below 30 min as it is strictly linked to the phages lytic cycle. The assay has potential for integration in automated systems.