The Phenotypic and Genotypic Characteristics of Antibiotic Resistance in Escherichia coli Populations Isolated from Farm Animals with Different Exposure to Antimicrobial Agents.
Justyna Mazurek, Paweł Pusz, Ewa Bok, Michał Stosik, Katarzyna Baldy-Chudzik Pol J Microbiol 2013; 62 (2): ICID: 1055710 Article type: Original article IC™ Value: 10.00
Abstract provided by Publisher
The aim of the study was to determine the influence of the presence or the absence of antibiotic input on the emergence and maintenance of resistance in commensal bacteria from food producing animals. The research material constituted E.coli isolates from two animal species: swine at different age from one conventional pig farm with antibiotic input in young pigs and from beef and dairy cattle originated from ecological breeding. Antimicrobial sensitivity on 16 agents was examined, and the presence of 15 resistance genes was determined. In E.coli from swine the most prevalent resistance was the resistance to streptomycin (88.3%), co-trimoxazole (78.8%), tetracycline (57.3%) ampicillin (49.3%) and doxycycline (44.9%) with multiple resistance in majority. The most common observed resistance genes were: blaTEM (45.2%), tetA (35.8%), aadA (35.0%), sul3 (29.5%), dfrA1 (20.4%). Differences in phenotypes and genotypes of E.coli between young swine undergoing prevention program and the older ones without the antibiotic pressure occurred. The disparate resistance was found in E.coli from cattle: cephalothin (36.9%), cefuroxime (18.9%), doxycycline (8.2%), nitrofurantoin (7.7%), and concerned mainly dairy cows. Multidrug resistance was outnumbered by resistance to one or two antibiotics and the only found gene markers were: blaSHV (3.4%), tetA (1.29%), blaTEM (0.43%) and tetC (0.43%). Presented outcomes provide evidences that antimicrobial pressure contributes to the resistance development, and enteric microflora constitutes essential reservoir of resistance genes.