| Summary: | Newborn dairy calves are often colonized by multidrug-resistant (MDR) extended-spectrum β-Lactamase producing <i>Escherichia coli</i> (ESBL-EC), which pose significant risks to global healthcare. As the first meal of calves, the role of dairy colostrum as a potential source of MDR-<i>E. coli</i> has not been well-studied. Here, we report on similar antibiotic resistance patterns of <i>E. coli</i> strains, isolated from colostrum fed to dairy calves and their faeces. Four ESBL-EC strains from colostrum and faeces of newborn dairy calves were isolated by double-disc synergy testing and multiplex PCR. Strikingly, isolates from colostrum or faeces were found to have similar MDR profiles, showing a high resistance to cephalosporins and other conventional antibiotics. In addition, coexistence of <i>bla</i><sub>CTX-M-15</sub> and <i>bla</i><sub>TEM-171</sub> was detected on a self-transferable plasmid with a typical IncHI2 backbone. To the best of our knowledge, this is the first case reporting on ESBL-EC strains carrying <i>bla</i><sub>CTX-M-15</sub> and <i>bla</i><sub>TEM-171</sub> genes, and isolated from faeces and the colostrum stock fed to the dairy calves.
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