Molecular Subtyping Methods for Listeria monocytogenes: Tools for Tracking and Control

Listeria monocytogenes is a foodborne pathogen linked to high mortality rates and significant economic losses. Molecular subtyping methods are crucial for epidemiologic investigations and case-attribution of L. monocytogenes. Such methods exploit different principles e.g. endonuclease restriction (PFGE); PCR (AFLP, rep-PCR, MLVA, RAPD, RISA); hybridization (DNA probes, microarray), and sequencing (whole genome sequencing, MLST, MVLST, prophage and SNPs subtyping). PFGE is the current gold standard technique, but less time and resource demanding PCR-based methods have recently been developed. However, standardized and internationally accepted protocols are not yet available for these methods, hindering the exchange of results between laboratories. The application of hybridization methods for molecular subtyping, even if promising, is still impaired by its high costs. Recently developed sequence-based methods provide unequivocal results in a timely manner and with good discriminatory power, and will most likely be the future gold standard methods for subtyping L. monocytogenes isolates.