La resistencia y multirresistencia a antibióticos constituyen uno de los problemas de salud pública más importantes considerando su transmisión genética entre microorganismos y también a las personas a través de alimentos de origen animal. El objetivo de este trabajo es determinar la frecuencia de patógenos aislados, el perfil de resistencia y multirresistencia a los antimicrobianos utilizados contra los principales agentes etiológicos aislados en muestras de leche bovina con sospecha de mastitis. Se procesaron 371 muestras de leche bovina cruda en los laboratorios del SENACSA entre enero del 2000 y marzo del 2006. Fueron analizados los microorganismos aislados, resistencia y multirresistencia a antimicrobianos. En la determinación de sensibilidad a través de prueba de difusión por discos se ensayaron como: ampicilina, penicilina, gentamicina, neomicina, kanamicina, estreptomicina, tetraciclina, sulfatrimetoprim y nitrofurantoina. Estos datos fueron analizados por estadística descriptiva en el programa Epiinfo 6,0. Se encontró Staphylococcus sp(46,4%, 172/371); Corynebacterium sp (18,3%, 68/371); Streptococcus sp(18,5%, 69/371); Klebsiella sp (12,93%, 48/371); Escherichia coli (3,77%, 14/371). Staphylococcus coagulasa negativos resistente entre 70%(120/172) y 80%(137/172) a neomicina y penicilina; mientras que los coagulasa positivos lo fueron a la penicilina y estreptomicina. Corynebacterium sp90%(61/68) resistente a neomicina, Streptococcus agalactiae (48%, 33/69) con 73% (24/33) de resistencia a penicilina y Klebsiella sp con 100% a penicilinas y Escherichia coli con 100% a la estreptomicina. Sólo Staphylococcus coagulasa negativo no mostro multirresistencia. La resistencia y la multirresistencia observadas son elevadas, estos resultados permiten disponer de información actualizada para orientar el uso racional de los antimicrobianos.

The antibiotic resistance and multiresistance constitute one of the most important problems of public health considering their genetic transmission among microorganisms and also to people through food of animal-origin. The objective of this work is to determine the frequency of isolated pathogens, the resistance and multiresistance profile to antimicrobials used against the main etiological agents isolated from samples of bovine milk with mastitis suspicion. Three hundred seventy one samples of raw bovine milk were processed in the laboratories of SENACSA between January 2000 and March 2006. The isolated microorganisms as well as the antimicrobial resistance and multiresistance were analyzed. In the sensitivity determination by disk diffusion test, ampicillin, penicillin, gentamicin, neomycin, kanamycin, streptomycin, tetracycline, sulfatrimethoprim and nitrofurantoin were assayed. These data were analyzed by descriptive statistics using Epiinfo 6,0. Staphylococcus sp. (46,4%, 172/371), Corynebacterium sp. (18,3%, 68/371), Streptococcus sp.(18,5%, 69/371), Klebsiella sp. (12,93%, 48/371) and Escherichia coli (3,77%, 14/371) were identified. Neomycin and penicillin-resistant coagulase-negative staphylococci were between 70% (120/172) and 80% (137/172) respectively while coagulase-positive ones were penicillin and streptomycin-resistant. Corynebacterium sp. was neomycin-resistant (90 %, 61/68). Streptococcus agalactiae (48%, 33/69) was penicillin-resistant (73%, 24/33); Klebsiella sp. was 100% penicillin-resistant and Escherichia coli was 100% streptomycin-resistant. Only coagulase-negative staphylococci did not show multiresistance. These resistance and multiresistance rates are high and allow the availability of updated information to guide a rational use of antimicrobials.