الفهرس 
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Abstract
The current study was carried out on 486 samples randomly collected from different localities in Behera and Alexandria Provinces during the period extended from January 2018 till the end of December 2018 for determination of the rate isolation of Listeria spp. from animals, products as well as aborted females.
A total of 250 raw milk samples (500ml), were randomly collected from different animals species (150 cows, 50 buffaloes and 50 sheep) to be examined bacteriologically for isolation of Listeria. Also, a total of 186 fecal samples were collected from different farm animals including; cattle (65), buffaloes (34) and sheep (87) from some private farms of dairy animals and small holders. On the other side, 50 aborted women attending Al Shatbi Hospital, Alexandria were investigated; whole blood samples and vaginal swabs were collected from aborted women under supervision of medical staff of the hospital. Data concerning; milk consumption and presence of any type of farm animals´ contact were recorded.
All of the collected samples were subjected to bacteriological examination for isolation and identification of Listeria species beside application of multiplex PCR technique for molecular characterization of virulence factors of L. monocytogenes strains represented by listeriolysin O known as hemolysin (hylA) and actin polymerization protein (actA) gene.
The obtained results in the current work showed the following:
• The rate of isolation of Listeria spp. from milk samples was 7.33, 8 and 12% in the examined samples of cattle, buffaloes and sheep, respectively with statistically significant association between these rates of isolation where sheep milk showed the highest rate of isolation.
• Statistical analysis showed non-significant association at P < 0.05 between the rates of isolation of Listeria spp. from milk samples in relation to sources of samples although it was higher in milk samples collected from dairy farms (8.57%) compared to those collected from retailers (7.78%).
• Identification of Listeria spp. isolated from milk samples clarified the presence of L.
monocytogenes (2.4%), L. ivanovii (2%), L. innocua (1.2%) and L. grayi (2.8%) with significant association between the rates of isolation.
• Concerning cattle milk, identification of Listeria spp. clarified the presence of L. monocytogenes (3 isolates) at a percentage of 2%, L. ivanovii (2 isolates) at a percentage of 1.33%, L. innocua (2 isolates) at a percentage of 1.33% and L. grayi (4 isolates) at a percentage of 2.67%.
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Summary
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• Concerning buffalo’s milk, identification of Listeria spp. clarified the presence of L.
monocytogenes (1 isolate) at a percentage of 2%, L. ivanovii (2 isolates) at a percentage of 4%, and L. grayi (1 isolate) at a percentage of 2%.
• Concerning sheep milk, identification of Listeria spp. clarified the presence of L. monocytogenes (2 isolates) at a percentage of 4%, L. ivanovii (1 isolate) at a percentage of 2%, L. innocua (1 isolate) at a percentage of 2% and L. grayi (2 isolates) at a
percentage of 4%.
• The overall isolation rate of Listeria spp. from farm animals was 12.37 %.
• The rates of isolation of Listeria spp. from farm animals were 10.77, 14.7 and 12.64 % in the examined fecal samples of cattle, buffaloes and sheep, respectively with statistically significant association at P<0.01between them.
• Biochemical identification of Listeria spp. recovered from fecal samples clarified the detection of L. monocytogenes (3.23%), L. ivanovii (1.08%), L. innocua (1.08%), L.
grayi (2.67%), L. seeligeri (2.15%) and L. welshimeri (2.15%).
• Concerning cattle fecal samples, it was recorded that identification of Listeria spp. cleared the presence of L. monocytogenes (2 isolates) (3.08%), L. grayi (2 isolates) (3.08%), L. seeligeri (1 isolate) (1.54%) (2.15%) and L. welshimeri (2 isolates) (3.08%).
• Concerning buffaloes fecal samples, it was recorded that identification of Listeria spp.
cleared the presence of L. innocua (2 isolates) (5.88%) and L. grayi (3 isolates) (8.82%), L. seeligeri (1 isolate) (1.54%) and L. welshimeri (2 isolates) (3.08%).
• Concerning sheep fecal samples, it was recorded that identification of Listeria spp.
cleared the presence of L. monocytogenes (4 isolates) (4.6%), L. ivanovii (2 isolates) (2.3%), L. seeligeri (3 isolates) (3.45%) and L. welshimeri (2 isolates) (2.3%).
• Concerning aborted women, it was found that Listeria spp. were isolated from only 2 out of 50 vaginal swabs (4%) while we failed to isolate Listeria spp. from blood samples.
• The 2 isolates were identified as L. monocytogenes.
• Statistical analysis showed non-significant association between the manners of milk consumption and the rate of isolation of L. monocytogenes from aborted women where positive cases informed that they consumed milk in regular manner.
• Also, statistical analysis showed non-significant association between presence of direct animal contact and the rate of isolation of L. monocytogenes from aborted women where one positive case had animal contact and the other had no animal contact.
• Finally, multiplex PCR was employed successfully for detection of hylA and actA virulence genes of L. monocytogenes isolated from milk and faeces of farm animals as well as vaginal swabs of aborted women.