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Updated: Aug 22, 2026

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Molecular basis of quinolone resistance in Escherichia coli from wild birds
P A Jiménez Gómez1, J E García de los Rios, A Rojas Mendoza
1Sección de Microbiología, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo C.E.U. Ctra. Boadilla del Monte Km, 5 300, Madrid, Spain. pgimgom@ceu.es
Abstract:
Nine quinolone resistant (minimal inhibitory concentration [MIC] was > 32 microg/mL for nalidixic acid, > 1 microg/mL for ciprofloxacin) isolates of Escherichia coli have been found in wild birds with septicemia. All of the isolates were aerobactin positive. The mechanisms of resistance were characterised by sequencing the quinolone resistance-determining region (QRDR) of the gyrA, gyrB, parC, and parE genes. Sequence analysis of the gyrA gene in all isolates identified only 1 nucleotide substitution at codon Serine-83 for Leucine-83. Sequence analysis of the gyrB, parC, and parE QRDR genes revealed no mutations in any of the isolates. This study was conducted to determine the importance of these genes in the susceptibility of E. coli strains isolated from wild birds to quinolones.
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