Incidence of lysogenic, colicinogenic and siderophore-producing strains among human non-pathogenicEscherichia coli

Abstract

The current incidence of Escherichia coli strains in healthy humans capable of producing the inhibitory exoproducts, such as temperate bacteriophages, corpuscular or HMW (high-molar mass) and proteinaceous or LMW (low-molar mass) colicins and siderophores was determined. Fifty-three E. coli strains were collected from the colons of 53 healthy human volunteers in Brno (Czechia) and tested for spontaneous and induced production of inhibitory exoproducts in a cross-test against each other. Of the strains tested, 37.7% produced bacteriophages, 41.5% produced from one to several LMW colicins, 11.3% formed HMW colicins and 15.1% (eight strains) produced exocellular siderophores different from enterochelin. Of these, seven strains formed aerobactin and one strain formed an untyped siderophore. E. coli strains differ greatly in the incidence of colicinogeny and lysogeny from its closest systemic relatives in the genus Escherichia and therefore should not be regarded as a model bacterium in this respect.

Unique Activity Spectrum of Colicin FY: All 110 Characterized Yersinia enterocolitica Isolates Were Colicin FY Susceptible

“…Detection of colicin activity was performed as described previously [38]. Briefly, the agar plates were inoculated with a stab from the bacterial culture ( Y. frederiksenii Y27601, E. coli TOP10F' carrying pDS1068, and E. coli TOP10F' carrying pBAD-A), incubated at 37°C for 48 hours and the resulting macrocolonies were killed with chloroform vapors.…”

Novel Colicin F Y of Yersinia frederiksenii Inhibits Pathogenic Yersinia Strains via YiuR-Mediated Reception, TonB Import, and Cell Membrane Pore Formation

“…Detection of colicin production was performed as described previously (69). Briefly, the agar plates were inoculated by a stab of the producer being tested and incubated at 37°C for 48 h. The macrocolonies were killed using chloroform vapors (30-min exposure), and each plate was then overlaid with a thin layer of top agar containing 10 8 cells of an indicator strain.…”

Bacteriocin synthesis in uropathogenic and commensal Escherichia coli: colicin E1 is a potential virulence factor

“…A described set of E. coli indicator strains was used to identify the colicin and microcin types produced: E. coli K12-Row, C6 (ϕ), B1, P400, and Shigella sonnei 17 [1]; additionally, one recently verified indicator strain, E. coli S40, was also used [41]. Together, these indicator strains are capable of detecting all known colicin types including colicin L (P400) and colicin Js ( S.s .…”