Detección fenotípica de mecanismos de resistencia antimicrobiana de Escherichia coli aisladas de infecciones entéricas de porcinos provenientes de granjas de producción tecnificada

The aim of this study was to detect the antimicrobial resistance mechanisms of 36 Escherichia coli isolates to beta-lactams, quinolones and aminoglycosides using the Kirby-Bauer technique. Thirty-six E. coli isolates from pigs of technified production farms obtained during the 2010-2015 period were used. Fifteen antimicrobials of importance in human and veterinary medicine were tested. The isolates showed resistance mainly to nalidixic acid (89%, 32/36), cloxacillin (83%, 30/36) and amoxicillin-clavulanic acid (69%, 25/36). Only 3% (1/36) were AmpC producers, 42% (15/36) showed a possible mutation in gyrA and 14% (5/36) at least two possible mutations in gyrA or gyrA+parC. In addition, 33% (12/36) showed high probabilities of presence of qnr genes. The enzymes associated to aminoglycoside resistance mechanism were positive in 39% (14/36) to AAC (6’), 28% (10/36) to ANT (2") and 11% (4/36) to AAC (3) IV.