Natural anti bacterial
(Track)
Evaluation of inhibitory activity of bacteriocin against Enterotoxigenic Escherichia coli K99
Yahya Tahamtan
Microbiology Dep.,
Razi Vaccine and Serum Research Institue-Shiraz
Shiraz,
Iran
Abstract:
Among the different types of bacteriocins, colicins have the greatest specificity. More than 25 different colicins have been characterized and these can be classified according to their action and their import pathways. Colicins are antimicrobial proteins produced by Escherichia coli strains against other pathogen E.coli. They are typically produced under stress conditions.
A total of 100 E.coli strains previously isolated were confirmed as E.coli by biochemical test being indole positive, methyl red positive, Voges-Proskauer negative and citrate negative. In this study we use seven pairs specific primers were designed by Gene Bank to verify posses the colicin gene. Polymerase chain reaction was used to detect bacteria those posses'' colicin genes. Different dilution of E.coli k99 (10 4 - 1010) and also colicin posses strains inoculated into Luria Bertani broth and grown overnight at 37C. Overnight cultures E.coli K99 was lawn onto LB agar containing 0.025 µg of mitomycin and allowed to dry. Mitomycin C induces the production of colicins. Fresh overnight culture (7µL) from test srtains was spotted onto LB plates previously lawn with K99 strains and allowed to dry and then incubated at 37 °C for 12 to 16 h. Zones of clearing the test strains were measured with digital calipers.
The number of putative colicins detected in our isolates by PCR were A.N.S4 (4), V(6), E2.E3.E3a.E4.E5.E6.E7.E8.E9 (8), UY(7), 5.10.K(6), E1(5), Ia.Ib(13). The zones of clearing was demonstrated that Enterotoxigenic Escherichia coli K99 inhibited by colicin strains.
Using antibiotic has many limitations such as antibiotic resistance so colicin is good and effective replacement. For your knowledge, we have demonstrated for the first time that selection of inhibitory E.coli that targets pathogenic E.coli k99 is an effective means of probiotic design.
