Escherichia coli with anti-O157 activity isolated from bovine colon

ETCHEVERRÍA, ANALÍA I.; ARROYO, GUILLERMO H.; PERDIGÓN, GABRIELA; PARMA, ALBERTO E.

JOURNAL OF APPLIED MICROBIOLOGY

The Society for Applied Microbiology

Lugar: Bedford- Reino Unido; Año: 2006 vol. 100 p. 384 - 389

1364-5072

Aims: To isolate bacteria from bovine gastrointestinal tract and investigatetheir inhibitory effect on Escherichia coli O157:H7 in vitro.Methods and Results: A total of 2400 bacterial colonies were isolated fromcattle colonic mucous membrane. Thirteen strains demonstrated the ability toinhibit the growth of E. coli O157:H7. From these, seven were screened for thepresence of virulence factors as: stx1, stx2, ehxA, eae, st1a and lt1 by polymerasechain reaction. The selected bacteriocin-producing bacteria showed susceptibilityto most of the antibiotics used.Conclusions: The strains of E. coli isolated, which exhibit inhibitory activity onE. coli O157:H7 growth by the production of inhibitory substances, may beuseful in the control of this pathogen in reservoirs. An important characteristicof these strains was the absence of any of the virulence factors assayed and thesusceptibility to most of the antibiotics used for Gram-negative bacteria.Significance and Impact of the Study: These microorganisms might be used asprobiotic bacteria to reduce the carriage of E. coli O157:H7 in cattle, thuslimiting the contamination of carcasses at slaughter and subsequently the contaminationof foods and the transfer of this pathogen to man.