In Vitro Activities of Cephalosporins and Quinolones againstEscherichia coliStrains Isolated from Diarrheic Dairy Calves

• DOI: 10.1128/aac.43.3.510
• Publication Date: 2018-10-09T00:34:19Z
• Authors: José Antonio Orden; José Antonio Rui...; Silvia García; Dolores Cid; Ricardo de la Fuente
• Keywords: Diarrhea; 0301 basic medicine; 4-Quinolones; Cephalosporin Resistance; Virulence; Colony Count, Microbial; Cattle Diseases; Drug Resistance, Microbial; Cephalosporins; 3. Good health; 03 medical and health sciences; Anti-Infective Agents; Escherichia coli; Animals; Cattle; Escherichia coli Infections

ABSTRACTThe in vitro activities of several cephalosporins and quinolones against 195 strains ofEscherichia coliisolated from dairy calves affected by neonatal diarrhea were determined. One hundred thirty-seven of these strains produced one or more potential virulence factors (F5, F41, F17, cytotoxic necrotizing factor, verotoxin, and theeaegene), but the remaining 58 strains did not produce any of these factors. From 11 to 18% of theE. colistrains were resistant to cephalothin, nalidixic acid, enoxacin, and enrofloxacin. However, cefuroxime, cefotaxime, and cefquinome were highly effective against theE. coliisolates tested. Some significant differences (P< 0.05) in resistance to quinolones between the strains producing potential virulence factors and nonfimbriated, nontoxigenic,eae-negative strains were found. Thus,eae-positive, necrotoxigenic, and verotoxigenic (except for nalidixic acid)E. colistrains were significantly more sensitive to nalidixic acid, enoxacin, and enrofloxacin than nonfimbriated, nontoxigenic,eae-negative strains. Moreover,eae-positive strains were significantly more sensitive to enoxacin and enrofloxacin than F5-positive strains. Thus, the results of this study suggest that the bovineE. colistrains that produce some potential virulence factors are more sensitive to quinolones than those that do not express these factors.