RESUMEN
The antimicrobial resistance of 96 Escherichia coli strains isolated from a stabilization pond system on a pig-breeding farm was evaluated. Strains were tested for their resistance against 14 antimicrobial using the agar diffusion method. E. coli strains showed resistance to tetracycline (82.3 percent), nalidixic acid (64 percent), ampicilin (41 percent), sulfamethoxazole/trimethoprin (36 percent), sulfonamide (34 percent), cloranphenicol (274 percent), ciprofloxacin (19 percent), cefaclor (16 percent), streptomicyn (7.3 percent), neomicyn (1 percent), amoxacilin/ clavulanic acid (1 percent), and amikacin (1 percent). No resistance was observed to gentamicin and tobramycin, and 37.5 percent of E. coli strains were resistant to four or more antimicrobials. The multiresistance pattern was found in strains isolated during all sampled period. Strains showed a high variability in the antimicrobial resistance pattern.