Caution at choosing a particular colony-forming unit from faecal Escherichia coli: it may not represent the sample profile

• DOI: 10.1111/lam.13252
• Publication Date: 2019-11-23T12:24:42Z
• Authors: J.F. Maciel; L.T. Gressler; B.P. da Silveira; E. Dotto; C. Balzan; L.B. Matter; F.M. Siqueira; A.P.C. de Vargas
• Keywords: Colony-forming unit

Data about phylogenetic classification of Escherichia coli colonizing calves, lambs and foals are routinely neglected restricted to outdated methodologies, even in the context antimicrobial susceptibility (AS) testing. Thus, aim this study was determine diversity AS profile E. colony-forming units (CFUs) from faecal samples healthy animals. Five CFUs were randomly selected each culture calves (n = 13), 13) totalizing 195 phylo-typed by quadruplex PCR. The five 15 (five animal species; n 75 isolates) against nine drugs determined agar diffusion test. We found belonging all phylo-groups already described, except D group, with predominance B1 (65% CFUs; 126/195) three-animal species sampled. Most (77%; 10/13) (69%; 9/13) harboured both pathogenic nonpathogenic coli. All showed diverse profile, highlighting ineffectiveness tetracycline, sulphonamide ampicillin. As a key point, our data reinforce importance select at least four for SIGNIFICANCE AND IMPACT OF THE STUDY: This provides relevant high observed bacteriological faeces lambs. selection pressure exerted herd treatment may directly impact intestinal microflora animals that have never been treated. Finally, we emphasize Clinical Laboratory Standards Institute guidelines recommended analyse determine, particular, isolates, independent animal's health status.