Objectives : This study aimed to characterize Escherichia coli isolates from cloacal samples of white stork nestlings, with a special focus on extended-spectrum β-lactamases (ESBLs)-producing E. coli isolates and their plasmid content. Methods : Cloacal samples of 88 animals were seeded on MacConkey-agar and chromogenic-ESBL plates to recover E. coli and ESBL-producing E. coli. Antimicrobial susceptibility was screened using the disc diffusion method, and the genotypic characterization was performed by polymerase chain reaction (PCR) and subsequent sequencing. S1 nuclease Pulsed-Field-Gel-Electrophoresis (PFGE), Southern blotting, and conjugation essays were performed on ESBL-producing E. coli , as well as whole-genome sequencing by short-and long-reads. The four bla ESBL-carrying plasmids were completely sequenced. Results : A total of 113 non-ESBL-producing E. coli isolates were collected on antibiotic-free MacConkeyagar, of which 27 (23.9%) showed a multidrug-resistance (MDR) phenotype, mainly associated with β-lactam-phenicol-sulfonamide resistance (bla TEM / cmlA / floR / sul1 / sul2 / sul3). Moreover, four white stork nestlings carried ESBL-producing E. coli (4.5%) with the following characteristics: bla SHV-12 /ST38-D, bla SHV-12 /ST58-B1, bla CTX-M-1 /ST162-B1, and bla CTX-M-32 /ST155-B1. Whole-genome sequencing followed by Southern blot hybridizations on S1-PFGE gels in ESBL-positive isolates proved that the bla CTX-M-1 gene and one of the bla SHV-12 genes were carried by IncI1/pST3 plasmids, while the second bla SHV-12 gene and the bla CTX-M-32 gene were located on IncF plasmids. The two bla SHV-12 genes and the two bla CTX-M genes had similar but non-identical close genetic environments, as all four genes were flanked by a variety of insertion sequences. Conclusion : The role played by several genetic platforms in the mobility of ESBL genes allows for interchangeability on a remarkably small scale (gene-plasmid-clones), which may support the spread of ESBL genes.