Effect of Probiotics on Some Virulence Factors of Pseudomonas Aeruginosa Isolated From Clinical Samples

Abstract

This study aimed to detect the inhibitory effect of some probiotics against pyocyanin and lipases activity produced by Pseudomonas aeruginosa, and comparing this effect with that of the commonly used antibiotics. From a total of 209 bacterial isolates collected from different clinical sources (Urine, ear, sputum, congenital disorder fluids, pus, and wounds) of two hospitals in Baghdad, 16 of them were identified as P. aeruginosa. When the sixteen isolates were examined for pyocyanin and lipases production on glycerol supplemented nutrient agar and tween 80 agar, respectively, all isolates, except one, were positive for pigment and enzymes production. Four probiotic microorganisms namely (Lactobacillus acidophilus, Lb. fermentum, Lb. plantarum and Saccharomyces boulardii) were propagated in their media. After incubation, their fermented aliquots were centrifuged and filtered which were considered as unconcentrated filtrates. From these filtrates, one, two and three-fold concentrated filtrates were prepared. Antibiotic solutions of Amikacin, Ceftazidime, Imipenem and Tobramycin were also prepared at a concentration of 10μg/ml for comparison. Results revealed that the three-fold concentrated filtrate of Lb. acidophilus was able to inhibit pyocyanin activity strongly (almost entirely) and lipases moderately, followed by those filtrates of Lb. fermentum and Lb. plantarum which were less strongly in their inhibition. On the other hand, the three-fold filtrate of S. boulardii was weakly effective in this regard. Regarding the antibiotics used in this study, Ceftazidime was the most effective one, followed by Imipenem and Tobramycin with moderate effect, then Amikacin with the least effect, while neither Imipenem nor Tobramycin were unable to show any effect on lipases produced by P. aeruginosa. From the results, it can concluded that among all