Chitin is the most substantial natural polysaccharide after cellulose, found in the shells of crabs, shrimps, and other crustaceans. Several medical and environmental applications have been recognized for chitosan. Therefore, the present study aimed to evaluate the biological activity of laboratory-prepared chitosan from shrimp shells against pathogenic bacteria isolates. In the present study, chitosan was extracted from chitin acetate of shrimp shells at different temperatures (room temperature, 65 and 100 ° C) for equal amounts of shells at specified time intervals. The degree of acetylation of different treatments of RT1, RT2, and RT3 reached 71%, 70%, and 65%, respectively. The laboratory-prepared chitosan was examined and antibacterial properties were observed against clinical isolates of bacterial causative agents of urinary tract infections (E. coli, Klebsiella Pneumonia, Pseudomonas spp., Citrobacter freundii, and Enterobacter spp.). The inhibitory activity of all types of treatments ranged between 12 to 25 mm for all isolates with the highest for Enterobacter spp. and the lowest for Pseudomonas isolates. The results also indicated a large relative discrepancy between the inhibitory activity of laboratory-prepared chitosan and antibiotics. These results were in the S-R range of the isolates. The similarity of laboratory production conditions and treatments is due to the different proportions of chitin formed in shrimp, environmental conditions, nutrition factors, pH, the extent of heavy metals in the water, and the age of the organism.
Keywords: Antimicrobial Activity; Chitosan; Enterobacteriaceae.