الفهرس 
ABSTRACTOnly 14 pages are availabe for public view
 |  | from | 122 |  |  |
| | | from | 122 | | |
Abstract
Listeria monocytogenesis considered one of the most important food-borne pathogens that is transmitted to human mainly via contaminated food. In an attempt to throw more light on zoonotic importance of L. monocytogenesas food-borne pathogen, a total of 340 samples were used for this study; these samples included 250 food samples (50 beef burger, 50 sausages, 25 Luncheon, 25 minced meat, 50 raw milk and 50 kariesh cheese) were randomly collected from retail markets, groceries and restaurants in different localities in El Giza Governorate. In addition swabs were taken from 40 food refrigerators and stool samples from 50 diarrheic children. All samples were cultured for the isolation of L. monocytogenes using the conventional International Organization for standardization (ISO, 11290-1) method. The isolates were tested biochemically using Listeria Microbact 12L and confirmed by PCR. The results revealed that the isolation rates of L. monocytogenes were 8 %, 4%, 4% for beef burger, minced meat and Luncheon respectively, while sausage samples were totally negative. L. ivanovii and L.seeligeriwererecovered in a percentage of 2% for each in both sausage and beef burger samples. Moreover, 8% of raw milk samples were positive for L. monocytogenes, whereas kariesh cheese samples and refrigerator swabs were negative. Moreover Listeria grayi was isolated from human stool (2.5%) rising the question about the opportunistic nature of such nonpathogenic bacteria. DNA sequencing of hlyA gene for PCR products of the obtained meat products isolates and the deduced phylogenetic analysis revealed that the isolates were L. monocytogenes with homology results (98-99%). The next generation sequencing is helpful in rapid acquisition of sequence data to facilitate detection and characterization of pathogenic strains of L. monocytogenes.In conclusion, the high isolation rates of L. monocytogenes among the examined food stuffs highlighted the crucial role of food to be an important vehicle for such pathogen.