Abstract

Bacteriocins are ribosomal synthesized antimicrobial peptides produced by one bacterium that are active against other bacteria, either in the same species (narrow spectrum), or across genera (broad spectrum).Thirty isolates of Lactic acid bacteria obtained from fermented milk and Yoghurt from various locations in Alnajaf were analyzed by PCR to rapid screening of pediocin, plantaricin and enterocin genes that present on the bacterial chromosome or on plasmidsMultiplex PCR method was used to detect the presence of bacteriocin gene by using specific primers to amplify a fragment from bacteriocin structural gene. Eighteen strains produced one of the PCR fragments with specific primers. Highest frequency of occurrence 11(61.1%) of isolates produced fragment of 428 bp indicate to presence of plantaricin gene, 5 (27.8%) produced fragment of 332 bp indicate to presence of pediocin gene whereas 2(11.1%) produced fragments of 412 bp indicate to presence of enterocin gene. The agar well diffusion methods was used to detect the selected strains with antibacterial activities against P. aeruginosa . The supernatant of the thirty LAB screened for bacteriocin production, eighteen (60%) were gave inhibition zones (12-20mm) onto the indicator pathogenic strain. Among LAB isolates, strain M5 plantaricin producer the most effective antibacterial compounds against P. aeruginosa. (20 mm as diameter of inhibition). The LAB isolates were: Lactobacillus plantarum, Pediococcus and Enterococcus. L. plantarum had the highest frequency of occurrence 11(61.1%), while, Pediococcus and Enterococcus had 5 (27.8%) and 2(11.1%) respectively.

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The article was added to IASJ on 2014-07-12

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