The Prevalence of Esbl-Producing Strains of E.coli, Isolated from Calves with Colibacilosis - Preliminary Remarks

The animals producing food have become an increasing reservoir of extended spectrum beta-lactamase producing Enterobacteriaceae. The calves and cows are exposed to a greater quantity of antibiotics, but the data concerning the prevalence of ESBL-producing Enterobacteriaceae are not enough, in comparison with other species of animals used for human consumption, such as birds (Hordijk et al., 2013).The aim of this study was to determine the prevalence of ESBL-producing E. coli involved in some episodes of colibacilosis in calves. Faeces samples were collected from 33 calves with the age ranging between 1-2 weeks and that presented clinical signs of colibacilosis. The samples were collected in a sterile medium for the taxonomic isolation and identification of the etiological agent involved, the ESBL screening being conducted subsequently using the ESBL Agar Oxoid Brilliance chromogenic medium. The phenotypic confirmation of the ESBL-producing strains was conducted in accordance with the CLSI (2014) standard through the combined disc method. Following the tests conducted, out of the 33 strains of isolated E. coli, 9 (27, 27%) were phenotypically confirmed as being ESBL strains.The studies that were previously conducted on the dairy farms have pointed out that the young calves rapidly acquire bacterial strains resistant to antibiotics that are often ESBL strains (Hordijk et al., 2013). The prevalence obtained by us, as well as an insufficient quantity of information concerning the antimicrobial resistance on this segment of species of animals used for the human consumption, support conducting a more thorough study, as well as the identification of ESBL resistance genes, but also of the plasmids that encode the transmission of these genes.