Detection of virulence genes in diarrhoeagenic E.coli isolated from different sources using Real Time PCR

A., Gad El-Said W.; Tolba, Sahar T.M.; El-Shafii, Soumaya S.A.; Abdelmonem, Mohamed A.; A., Shaimaa R.; Kelany, Mohamed A.

doi:10.21608/ejceh.2015.254003

Detection of virulence genes in diarrhoeagenic E.coli isolated from different sources using Real Time PCR

Document Type : Scientific and Research

Authors

¹ Microbiology department, Faculty of Veterinary Medicine, Cairo University

² Micribiology Department, Faculty of Science, Ain Shams University

³ Bacteriology Department, Animal Health Research Institute (AHRI)

⁴ Microbiology Department, Central laboratory of residues analysis of Pesticides and heavy metals in food (QCAP)

10.21608/ejceh.2015.254003

Abstract

The present study aimed to investigate the diarrheagenic E.coli from different sources and study their genetic relationship and diversity. Different types of samples (cattle fecal samples and internal organs; different types of plants; conduit; environmental samples; drinking water and soil samples (1105 samples) were collected). The isolated (if you identified them, then why you subject them further identification?)serotypes were subjected for detection of different virulence genes. The isolated strains (97.5%) were serogrouped to O26 (3.1%), O111 (3.4%), O101 (1.2%), O55 (1.5%), O148 (0.45%), O158 (0.63%), O78 (1.9%), O1 (0.63%), O2 (0.45%) O157:H7 (1.08%) and O157: H- (1.62%) and 28 isolates of E.coli were untypable (2.5%) . E.coli O104:H4 2011 German strain was not detected in all DNAs extracted from all isolates. Bovine internal organs (liver; intestine and spleen) of cattle showed the highest rate of O157: H- isolation (2%). While the rate of O157: H7 isolation was similar in calves and cattle fecal samples (2%). Internal organs of poultry (liver, intestine and spleen) showed the presence of E.coli O157:H7 (2%). The clinical mastitic milk showed absence of E.coli O157:H7, but it was isolated from market milk. In minced meat the rate of O157:H7 was 4%. , sewage and conduit in rates of 3.6%, 10% and 3.3% respectively. Twenty six isolates express enterohemorrhagic virulence genes (stx1, stx2 and eae genes). The most predominant virulence gene detected was stx1 gene in combination with eae gene (9 isolates) followed by 6 isolates express stx2 alone, 6 isolates harbor both stx1 and stx2, 3 isolates express combination of stx1, stx2 and eae genes, only one isolate harbor eae gene alone. It was concluded, emphasizes the importance of safe water supply, good hygiene and sanitation practices in rural communities.

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