Publication Date:
2012-01-01
Description:
Previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by Mexican strains ofBacillus thuringiensisagainstB. cereus183. Here we standardize this method to efficiently determine the activity of bacteriocins against both Gram-positive and Gram-negative bacteria. It was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is,~4 × 108 cell/mL and~7 × 108 cell/mL, respectively, for target Gram-positive and Gram-negative bacteria. Comparative analyses of the fluorogenic and traditional well-diffusion assays showed correlation coefficients of 0.88 to 0.99 and 0.83 to 0.99, respectively, for Gram-positive and Gram-negative bacteria. The fluorogenic method demonstrated that the five bacteriocins ofB. thuringiensishave bacteriolytic and bacteriostatic activities against all microorganisms tested, including clinically significant bacteria such asListeria monocytogenes, Proteus vulgaris,andShigella flexnerireported previously to be resistant to the antimicrobials as determined using the well-diffusion protocol. These results demonstrate that the fluorogenic assay is a more sensitive, reliable, and rapid method when compared with the well-diffusion method and can easily be adapted in screening protocols for bacteriocin production by other microorganisms.
Print ISSN:
2356-6140
Electronic ISSN:
1537-744X
Topics:
Natural Sciences in General
Permalink