Poster presentation at |CA|MA|2013| (Trani, Italy, 3-7 June 2013)

Biodiversity of L. monocytogenes and E. coli O157:H7 strains isolated from rocket (Eruca sativa), cucumber (Cucumis sativus) and strawberry (Fragaria ananassa) samples


Hadjilouka A., Katsarou A., Paramithiotis* S., Drosinos E.H.


The aim of the present study was to assess the biodiversity of 22 L. monocytogenes and 12 Escherichia coli ??157:????7 strains isolated from rocket, cucumber and strawberry samples, as well as the detection of virulence-associated genes. Furthermore, L. monocytogenes isolates were serotyped by targeting lmo0737, ORF2110, lmo1118 and ORF2110 by multiplex PCR. Genotypic diversity of both pathogens was assessed by RAPD-PCR using M13, UBC155 and HLWL85 as primers and by rep-PCR using (GTG)5 as primer. It has been exhibited that all L. monocytogenes strains belonged to 4b serotype. Genotyping was very effective as it managed to differentiate all isolates, even if they originated from the same sample. Many virulence associated genes such as plcB, plcA, actA, hlyA regarding L. monocytogenes and stx2, eae and some of their variants regarding E. coli O157:H7 have been detected. However, none of the isolates contained all necessary genes required for pathogenicity, as detected by published specific-PCR protocols, most probably due to variations in the primer hybridization sequences.