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Virulence profile of Escherichia coli O157 strains isolated from surface water in cattle breeding areas
Author(s) -
Tanaro J.D.,
Pianciola L.A.,
D'Astek B.A.,
Piaggio M.C.,
Mazzeo M.L.,
Zolezzi G.,
Rivas M.
Publication year - 2018
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12873
Subject(s) - biology , virulence , microbiology and biotechnology , escherichia coli , genotype , manure , veterinary medicine , bacteria , persistence (discontinuity) , feces , gene , ecology , genetics , medicine , geotechnical engineering , engineering
Shiga toxin‐producing Escherichia coli ( STEC ) O157:H7 is a worldwide concern. Cattle are their main reservoir and may contaminate watercourses through manure. We characterized a collection of 38 STEC O157:H7 strains isolated from surface water in feedlots areas (puddles inside pens formed after the rainfall or by spill around drinking troughs, and small water courses and lagoons, formed by runoff). Nineteen (50·0%) strains harboured stx 2a / stx 2c genes, 18 (47·4%) stx 2c and one stx 1a / stx 2c . All strains harboured eae , ehxA , rfb O157 and fli C H 7 genes, and the putative virulence determinants ECSP _0242, ECSP _2687 and ECSP _3620. All isolates tested as Lineage I/ II by lineage‐specific polymorphism assay‐6. Nineteen (50%) belonged to the high virulent clade 8. The q 21 allele was found in all strains and q 933 / q 21 alleles in 17 (44·7%). By Xba I‐pulsed‐field gel electrophoresis, 29 strains were grouped into seven clusters. Four clusters grouped isolates from distant places separated by 150–250 km. This may be related to vectors, like birds, involved in their spread. Otherwise, three clusters contained isolates recovered at same places with intervals of 1–9 months. This could be explained by the high environmental persistence of STEC O157:H7. These strains recovered from surface water showed similar genotypes to those found in the bovine reservoir and in human diseases, and could be linked to the high incidence of haemolytic uremic syndrome in Argentina. Significance and Impact of the Study The challenge for the growing global demand for food is to find sustained production strategies without collateral effects. Intensive livestock operations generate large volumes of manure that can contaminate a finite resource, the water. This study shows how water contaminated by confined feeding operations can transport dangerous pathogens and warns to pay more attention to control and sanitation systems to prevent this type of pollution.