Rapid identification of Escherichia coli microcin J25 producing strains using polymerase chain reaction and colony blot hybridization

Abstract

To screen, isolate, and characterize bacterial populations producing microcin J25, we report here two rapid, reliable, and sensitive methods, using polymerase chain reaction and colony blot hybridization with a digoxigenin-labelled probe. A sample of 26 Escherichia coli strains isolated from poultry intestinal contents was evaluated to detect the sequence of mcjA, the gene encoding the MccJ25 precursor. The two molecular techniques were compared with the commonly used cross-immunity tests. They generate accurate data with no obvious cross-reactions with other microcins. The results display that the producers of MccJ25 were widely distributed in the poultry intestinal habitat. The applications of these molecular methods will be useful in future studies of microcinogenic populations, and thus contribute to understand the relationships within the complex intestinal microbial ecosystem.

Microcins, gene-encoded antibacterial peptides from enterobacteria

“…247 MccJ25-producing strains were observed to be widely distributed in poultry intestinal habitats. 248 Moreover, an Mcc24-producing E. coli was shown to inhibit the growth of pathogenic Salmonella and Escherichia O157:H7 in the intestinal tract of chickens. 238 Further studies should help defining how far microcins contribute to the prevention of intestinal infections.…”