Probiotics have been used for over a century to prevent and treat disease, may reduce the effects of gastroenteritis, and are now used to treat acute diarrhea. In this study Co-aggregative effect of probiotics bacteria against diarrheal causative bacteria was evaluated. Eleven isolates of probiotics bacteria were used in the current study, including Lactobacillus plantarum, (1) Lactobacillus gasseri, (2) Lactobacillus fermentum, (3) Lactobacillus acidophilus, and (2) Lactococcus garvieae. All isolates were tested for antibiotic susceptibility, autoaggregation ability, adhesion ability, antibacterial activity, acid tolerance, and bile salts tolerance.The results showed most of them had the ability toauto aggregate after 4h, with the highest percentage of 57.14% for L. fermentum. For the antibiotic susceptibility test, all the isolates showed resistance ability against Trimethoprim/Sulfamethoxazole except one isolate. On the other hand, all the isolates except one were susceptible to both Vancomycin and Tetracycline. All tested isolates had adhesion ability with different survival rates, reached to 34.57% for L. plantarumin acidic conditions, and highest survival rate was 85.17% for L. garvieae for bile salt tolerance. Probiotics isolates had an antibacterial effect against diarrheal causative bacteria with inhibition diameter between (17-49) mm for different Lactobacillusspp. and Lactococcus spp. isolates. Also,the co-aggregative ability of probiotics isolates against diarrheal causative bacteria was studied, and results showed that probiotics isolates had a co-aggregative effect against diarrheal causative bacteriaE. coli, S. sonnei, and P. alcalifaciens, after 24h of incubation. The highest co-aggregative effect of probiotics isolates L. fermentum and L. acidophilus showed against P. alcalifaciens with a co-aggregation percentage reaching 100%, and the lowest co-aggregative effect was recorded at 14.29% against E. coli. The current study showed the probiotics properties and co-aggregative effect of probiotics bacteria against diarrheal causative bacteria. |