Polyamine production by natural Escherichia coli strains isolated from various sources

Background . The polyamines putrescine and cadaverine serve as raw materials for the synthesis of polyamides; their production by microbial synthesis is a current issue of biotechnology, the development of which requires a search for effective producers and aminoacyl decarboxylases. In addition, polyamines are considered as factors of bacterial adaptation to the biotopes of the host and are associated with pathogenicity. The aim . Evaluating the ability of natural strains of Escherichia coli isolated from different sources to produce polyamines. Materials and methods . The objects of the study were the following strains of E. coli: isolated from the urine of patients with urinary tract infection (UPEC); isolated from the organs of broiler chickens with signs of colisepticemia (APEC); commensal, isolated from the feces of healthy farm animals (FEC) and healthy people (HFEC). Bacteria were cultured under basal (LB broth, 120 rpm, 37°C) and inducing conditions (M9 medium supplemented with 0.4 % glucose and 10 g/l ornithine/arginine/lysine, 0 rpm, 37°C). Quantitative analysis of polyamines was performed by thin-layer chromatography with preliminary derivatization with dansyl chloride. Results . The activity of the polyamine-synthesizing system of 121 strains of E. coli was studied. The strains that were capable of producing 3.5 mM putrescine from ornithine and 5 mM putrescine from arginine, as well as more than 5.5 mM cadaverine from lysine, which significantly exceeded the production of polyamines by the E. coli K12 strain (0.3,0.03, and 3 mM, respectively) were found. The mean value of putrescine production from ornithine of the APEC and UPEC strains was more than 2-fold higher as compared with HFEC and FEC strains. Under non-inducing conditions, the ability to produce cadaverine in strains isolated from humans (UPEC, HFEC) was 2-3 times lower compared to strains isolated from animals (APEC, FEC). Conclusion . A dependence of the ability of E. coli to produce polyamines on the source of isolation has been revealed.