Molecular Typing among Beef Isolates of Escherichia coli using Consensus Repetitive Intergenic Enterobacteria- Polymerase Chain Reaction (ERIC-PCR)

摘要

Genomic DNA of Escherichia coli were characterized by enterobacterial repetitive intergenic consensus- Polymerase chain reaction (ERIC-PCR) and the presence of Shiga toxin gene-I (Stx1) and Shiga toxin gene-2 (Stx2). These isolates were originated from imported raw beef which are come from two countries namely Australia and India. The isolation of E. coli was conducted by using Eosin Methylene Blue Agar (EMBA). A total of 94 strains had been isolated from 30 samples of imported raw beefand 42 strains had been detected positively E. coli by doing biochemical tests. All strains had been tested and the results of biochemical tests showed that 3 strains were from Australia samples while the other 39 strains were from India samples. The biochemical tests used are Indole test, Methyl Red test, Voges- Proskauer test and Citrate test. All the 42 strains were examined for Shiga toxin (stx1 and stx2) gene detection by two pair primers which are stx2F (5’-TTCTTCGGTATCCTATTCCC-3’), stx2R (5’-ATGCATCTCTGGTCATTGTA-3’), stx1F (5’-CAGTTAATGTGGTGGCGAAG-3’), and stx1R (5’-CTGTCACAGTAACAACCGT-3’). The results showed that none of the strains are positive for Shiga toxin gene. Application of ERIC-PCR method towards E. coli had successfully shown the high diversity polymorphism in 21 different genome types of DNA with primers ERIC1R (5’- CACTTAGGGGTCCTCGAATGTA- 3’) and ERIC2R (5’- AAGTAAGTGACTGGGGTGACGC- 3’).