Bacteriological and Molecular studies of Listeria species in milk and milk products at El-Kaliobia Governorate
Abd El Tawab, A., Maarouf, A., Mahdy, Z. (2015). Bacteriological and Molecular studies of Listeria species in milk and milk products at El-Kaliobia Governorate. EKB Journal Management System, 29(2), 170-181. doi: 10.21608/bvmj.2015.31698
Ashraf A. Abd El Tawab; Ahmed A. A. Maarouf; Zeinab A.M. Mahdy. "Bacteriological and Molecular studies of Listeria species in milk and milk products at El-Kaliobia Governorate". EKB Journal Management System, 29, 2, 2015, 170-181. doi: 10.21608/bvmj.2015.31698
Abd El Tawab, A., Maarouf, A., Mahdy, Z. (2015). 'Bacteriological and Molecular studies of Listeria species in milk and milk products at El-Kaliobia Governorate', EKB Journal Management System, 29(2), pp. 170-181. doi: 10.21608/bvmj.2015.31698
Abd El Tawab, A., Maarouf, A., Mahdy, Z. Bacteriological and Molecular studies of Listeria species in milk and milk products at El-Kaliobia Governorate. EKB Journal Management System, 2015; 29(2): 170-181. doi: 10.21608/bvmj.2015.31698

Bacteriological and Molecular studies of Listeria species in milk and milk products at El-Kaliobia Governorate

Benha Veterinary Medical Journal
Article 20, Volume 29, Issue 2, December 2015, Page 170-181  XML PDF (377.53 K)
Document Type: Original Article
DOI: 10.21608/bvmj.2015.31698
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Authors
Ashraf A. Abd El Tawab1; Ahmed A. A. Maarouf2; Zeinab A.M. Mahdy2
1Bacteriology, Immunology and Mycology Dep., Fac. Vet. Med. Benha Univ.
2Animal Health Research "Benha branch"
Abstract
A total of 200 random samples of raw milk, Fita cheese, Kariesh cheese and ice cream (50 samples each)
were collected from small retails and different supermarkets in El-Kaliobia Governorate to estimate the
prevalence of Listeria species in such products with special interest to L. monocytogenes. The
bacteriological examination of the samples resulted; 13(6.5%) isolates of Listeria species were
recovered from 200 samples, includes 10 L. monocytogenes (5.0%) and 3 L. grayi (1.5%). Moreover,
the other 4 species (L. ivanovii; L. innocua; L. seeligeri and L. welshimeri) were not isolated from all
samples (Listeria strains). The in-vitro antimicrobial sensitivity test showed that the isolated L.
monocytogenes were sensitive to amoxicillin; gentamycin; enrofloxacin; kanamycin and ampicillin.
While they were resistant to Nalidixic acid, streptomycin and tetracycline. The results of virulence tests
for isolated Listeria strains appeared that all of L. monocytogenes strains were virulent strains as all of
them were positive to CAMP test; showed narrow zone of β-hemolysis on sheep blood agar and were
positive for Anton’s test. Meanwhile, L. grayi strains were non-virulent, as none of them could produce
hemolysin (CAMP test negative) and negative for Anton’s test. The PCR results for L. monocytogenes
showed that all genes (16S rRNA; inlA; inlB; hlyA and prfA) were detected in five studied strains
(100.0%) i.e., all studied strains were L. monocytogenes and all of them were virulent strains
Keywords
milk products; Bacteriological Evaluation; L. monocytogenes
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