Shiga Toxin-Producing E.coli (STEC) Associated with Lebanese Fresh Produce


Shiga toxin-producing E. coli (STEC), the most common cause of food-borne illness, is associated with several human gastrointestinal and systemic diseases such as diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). In the present study, a total of 145 samples of Lebanese fresh produce were investigated for the occurrence of STEC, it was found that 9(26.8%) produce items were fecal E.coli contaminated, the highest contamination occurred in leafy green produce (purslane, thyme, parsley and lettuce) except peppermint items were fecal E. coli free. The isolates were subjected to PCR detection of STEC using primers specific for stx1, stx2, eaeA, ehlyA, and fliC virulence genes, it was showed that 7 produce samples were confirmed to contain STEC (two lettuce, two thyme, one tomato, one cucumber and one radish). Among seven STEC-positive isolates, six isolates were stx1-postive, three of which were fliC-postive and could be classified as O157:H7, on the other hand three isolates were stx2-postive and two isolates were eaeA-positive. However, ehlyA was not detected in any of the isolates. It was revealed that 8(46.2%) isolates were resistant to some of the antibiotics used in the present study, 9(23%) of which are considered to be multidrug resistant since they showed resistance to >= 3 antibiotic classes (β-lactam, tetracycline and folate inhibitor). The antibiotics to which resistance was detected are: Amoxicillin /Clavulanic acid, Piperacillin / Tazobactam, Tetracycline and Sulphamethoxazole /Trimethoprim. Wild type E.coli J53 AzideR acquired resistance to antibiotics mentioned above after conjugation with one of MDR isolates. This result indicates a high possibility of horizontal gene transfer between bacteria, via plasmids or transposons, and therefore contributing in the increase of the resistant genes in the environment.


Khawaja G.A.


Olama Z., Khatib A.G.

Journal/Conference Information

International Journal of Current Microbiology and Applied Sciences,2015, 4(2), 481- 496