Resistencia a antimicrobianos en E. coli y Salmonella spp. de terneros del sur de Chile

Abstract

Objective: Description of antimicrobial resistance in E. coli and Salmonella spp. isolates from calves <30 days of age from southern Chile. Material and methods: Necropsy and microbiology reports of 107 calves <30 days of age received at the Animal Pathology Institute between 2002 and 2015 were considered. Additionally, an antimicrobial resistance score was generated to allow comparisons among isolates with different antimicrobial susceptibility profiles. Results: There was no clear trend in antimicrobial resistance during the study period, with similar levels of resistance for E. coli, β-hemolytic E. coli and Salmonella spp. Approximately 50% of isolates were sensitive to antimicrobials, and between 19 and 36% of samples showed possible extended-or pan-drug resistance. Multiple different antimicrobial resistance patterns were found, including 32 for E. coli, 17 for β-hemolytic E. coli and 10 for Salmonella spp. Conclusions: Overall, E. coli samples were most sensitive to ceftriaxone; β-hemolytic E. coli to florfenicol; and Salmonella spp. to gentamicin. In contrast, these agents were resistant to amoxicillin, ampicillin and oxytetracycline respectively. This study is unique in its approach and provides useful information for veterinarians and producers on the antibiotic resistance patterns of bacteria posing a serious threat to calves. These results can help field veterinarians to control and treat bacterial diarrhea in calves.

Phenotypic and Genotypic Antimicrobial Resistance in Non-O157 Shiga Toxin-Producing Escherichia coli Isolated From Cattle and Swine in Chile

“…In contrast, in strains isolated from beef cattle, the highest resistance was to sulfamethoxazole/trimethoprim (10%), followed by oxytetracycline (4%) and ceftiofur (3%), with an 1.4% of MDR, where the most frequent resistance profile corresponded to sulfamethoxazole/trimethoprim (4%). In a more recent study, Hervé-Claude et al (53) evaluated AMR in 88 E. coli strains isolated from calves, where 87.5% were resistant to at least one antimicrobial, 16% showed MDR, and the most frequent resistance profile corresponded to oxytetracycline/sulfamethoxazole/trimethoprim (9.1%). On the other hand, Lapierre et al (54) evaluated the AMR of 87 strains of E. coli isolated from swine, registering 77% of resistance to tetracycline, 74% to streptomycin, and 38% to sulfamethoxazole/trimethoprim (38%), with a 74.7% of MDR, being tetracycline/streptomycin the most frequent resistance profile (33.3%).…”