Inhibition of pathogenic <i>Salmonella</i> <i>enteritidis</i> growth mediated by <i>Escherichia coli</i> microcin J25 producing strains

Abstract

For the first time, microcin-producing strains showing inhibitory activities against enteropathogen Salmonella enteritidis were isolated from poultry intestinal contents. Among the numerous strains isolated, two strains of Escherichia coli, named J02 and J03, showing the greatest activities against S. enteritidis, were studied. Biochemical tests and purification identified the main antagonist compound produced as microcin J25. In order to evaluate the protective potential of E. coli J02 and J03 against S. enteritidis infection, the ability of these strains to inhibit growth of S. enteritidis was investigated in mixed culture. A strong antagonist activity was obtained with a preculture phase of the active strain in minimal medium before incubation with S. enteritidis. In a bioreactor experiment simulating the chicken gastric and intestinal tract environment, a mixture of the two strains E. coli J02 and J03, provided an enhanced inhibitory effect. Microcinogenic strain activities were not affected by bile, pancreatic enzymes addition, or acidic conditions. These results suggest the relevant role of microcin-producing microorganisms in microbial intestinal ecology. To conclude, this study shows that microcin J25 strains could exert a beneficial protective effect against S. enteritidis growth in situ.

Antimicrobial activity of endophytic fungi isolated and identified from salt marsh plant in Vellar Estuary

“…Alternaria sp. clearance on agar plates was used as an indicator of bioactive potential of the strain(Portrait et al, 1999).…”

Genetically Engineered Bacteriocins and their Potential as the Next Generation of Antimicrobials

“…Microcin B17, produced by E. coli, kills in a similar manner as the quinolones and the coumarins, thus defining a third class of DNA gyrase inhibitors [84]. Microcins J25 [85] and L [86], both produced by E. coli, exhibit strong antimicrobial activity against Salmonella enterica serovars typhimurium and enteritidis, which cause diarrheal illness in humans.…”

“…A bacteriocin active against a target pathogen can be cloned into an avirulent bacteria strain known to successfully colonize the intended host. Recent studies indicate that microcin 24, produced by E. coli, holds promise in the prevention of Salmonella contamination in chickens [79,107]. Wooley and colleagues transformed plasmids containing microcin 24 gene fragments into a nonpathogenic avian E. coli strain.…”

Dynamic phase portrait: New possibilities of detecting changes in populations

“…In ecology, analysis of changes in populations and communities in phase space is common (the socalled parametric phase portrait Odum, 1971), which uses a set of parameters as coordinates; for example, number of separate species, production, biomass, etc. (Gilpin et al, 1982;Knut, 1997;Portrait et al, 1999). A distinctive feature of the dynamic phase portrait method is the analysis of dynamics of the system within the space of its states, which are determined on the one hand by the parameter significant for its functioning (for example, number, structural parameter, density, biomass, etc.)…”