Abstract

Nazila Arbab Soleimani*, Rooha Kasra Kermanshahi , Bagher Yakhchali and Taher Nejad Sattari

Staphylococcus aureus is one of the major pathogens which cause Bovine Mastitis (BM). Probiotic lactobacilli have the great potential to produce antimicrobial compounds that inhibit and control pathogenic bacteria. Antagonistic activity of probiotic lactobacilli ( L. acidophilus DSM 20079, L. plantarum ATCC 8014, L. casei ATCC 39392 and L. reuteri ATCC 23272) against S. aureus isolated from bovine mastitis (BM S. aureus) and standard S. aureus ATCC 25923 was the objective of this study. Antagonistic effect of probiotic lactobacilli was investigated by modified double layer method, well diffusion method, co -culturing assay and co-aggregation method. Among four lactobacilli, L. plantarum showed the greatest inhibitory activity. In modified double layer method the zone of inhibition of BM S. aureus and standard S. aureus ATCC 25923 by L. plantarum was 44 and 40 mm, respectively. Cell Free Supernatant (CFS) of probiotic lactobacilli in well diffusion method had inhibitory effect. Inhibition zone of BM S. aureus (13 mm) and standard S. aureus ATCC 25923 (9 mm) by L. plantarum was achieved. Co-culturing of L. plantarum with these two bacteria resulted in 87 and 77% inhibition growth of BM S. aureus and standard S. ureus ATCC 25923, respectively after 12 h. Coaggregation between L. plantarum with two mentioned S. aureus was obtained 88.4 and 76%, respectively. According to these data, L. plantarum and its antimicrobial compounds can be one of the selective choices to control the BM S. aureus.