Short communication: Antimicrobial susceptibility and frequency of resistance genes in Escherichia coli isolated from bovine mastitis

Abstract

Escherichia coli isolated from bovine milk samples submitted to the Ohio Agricultural Research and Development Center Mastitis Laboratory (Wooster) in 1985 to 1987 and in 2009 were compared for antimicrobial susceptibility and prevalence of antimicrobial resistance genes. Forty-four isolates from 1985 to 1987 and 55 isolates from 2009 were tested. Minimum inhibitory concentrations of 15 antimicrobials were determined using a commercially available broth microdilution system. Multiplex polymerase chain reaction was performed for gene detection. The percentage of isolates susceptible to trimethoprim/sulfamethoxazole, ampicillin, and kanamycin was lower in those collected in 1985 to 1987 than in isolates collected in 2009. Susceptibility did not differ between isolates from 1985 to 1987 and isolates from 2009 for the 12 other antimicrobials tested. A trimethoprim/sulfamethoxazole resistance gene was detected more frequently in isolates from 1985 to 1987 than in isolates from 2009. Gene frequencies for streptomycin resistance and tetracycline resistance were similar among 1985 to 1987 isolates and 2009 isolates. Resistance to most antimicrobials did not differ between isolates submitted to a mastitis diagnostic laboratory in 1985 to 1987 and those submitted in 2009. Changes observed indicated an increase in frequency of susceptibility in isolates to trimethoprim/sulfamethoxazole, ampicillin, and kanamycin in 2009 isolates compared with 1985 to 1987 isolates.

Antimicrobial susceptibility, phylotypes, and virulence genes of Escherichia coli from clinical bovine mastitis in five provinces of China

“…Antimicrobials are commonly used in the control and/or prevention of mastitis. Unfortunately, the misuse of antimicrobials contributes to the emergence of bacterial strains with antimicrobial resistance (Metzger & Hogan, 2013). In this study, a high percentage of strains were resistant to ampicillin (41.3%), followed by tetracycline (34.8%; Table 1), possibly due to the overuse of drugs in the provinces we selected.…”

Tasa de incidencia de mastitis clínica y susceptibilidad antibiótica de patógenos productores de mastitis en ganado lechero del norte de Antioquia, Colombia

“…La producción de BLEE por bacterias reduce la eficacia de un amplio rango de antibióticos betalactámicos como cafalosporinas de tercera generación y monobactámicos (38), y se ha documentado que los animales productores de alimentos son importantes reservorios de Enterobacteriaceae productora de BLEE (39). E. coli multiresistente ha sido aislada de leche bovina en varios estudios previos (40)(41)(42)(43)(44)(45)(46), lo que demanda muchos más estudios para establecer la importancia de este fenómeno en el ámbito nacional.…”

Antimicrobial Resistance inEscherichia coli

“…Two isolates each carried tet(A) + tet(B) or tet(B) + tet(C) (174). In 99 E. coli isolates from bovine mastitis in the United States collected from 1985 to 1987 and in 2009, the genes tet(A), tet(B), and tet(C) were detected, with tet(C) being present in more than half of the investigated isolates in each of the two time periods (175). Of 129 E. coli isolates from cases of bovine mastitis in the United States, 68 carried the gene tet(C), while another 14 isolates harbored tet(C) + tet(A) (176).…”