The present study was undertaken to assess fluoroquinolone resistance profile and mutations in gyrA and parC genes of Escherichia coli in bovine coliform mastitis. Fluoroquinolones (norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (NFX), levofloxacin (LEV), ofloxacin (OFL) were tested against E. coli isolated from bovine mastitis (100 milk samples) by disk diffusion method. To determine the extent of gyrA and parC mutations associated with fluoroquinolone resistance in E. coli, two isolates with the most intermediate resistance to each fluoroquinolone were submitted for the amplification and sequencing of the quinolone resistance-determining regions (QRDRs) of gyrA and parC genes. The disk diffusion method indicated that E. coli isolates had the highest intermediate resistance to OFL (16.7%), followed by NFX and NOR (15%), while they had low resistance to CIP and LEV (3.33%). A few silent mutations in gyrA (in codons 91, 100, 111, 131, 132) and in parC (in codons 91, 157, 159) were detected in QRDRs and mutations in nucleotides 65, 80 and 83 in gyrA and 195, 209, 212 in parC in the other isolate. These results showed that intermediate resistance rate of E. coli isolated from raw milk of cows with coliform mastitis to fluoroquinolnes was very low. Abbreviations

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