The Phenotypic and Genotypic Characteristics of Antibiotic Resistance in Escherichia coli Populations Isolated from Farm Animals with Different Exposure to Antimicrobial Agents

Abstract

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 organic breeding farm. The sensitivity to 16 antimicrobial agents was tested, and the presence of 15 resistance genes was examined. In E. coli from swine, the most prevalent resistance was resistance to streptomycin (88.3%), co-trimoxazole (78.8%), tetracycline (57.3%) ampicillin (49.3%) and doxycycline (44.9%) with multiple resistance in the majority. The most commonly observed resistance genes were: bla(TEM) (45.2%), tetA (35.8%), aadA1 (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. A 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. Among isolates from cattle, multidrug resistance was outnumbered by resistance to one or two antibiotics and the only found gene markers were: bla(SHV), (3.4%), tetA (1.29%), bla(TEM) (0.43%) and tetC (0.43%). The presented outcomes provide evidence that antimicrobial pressure contributes to resistance development, and enteric microflora constitutes an essential reservoir of resistance genes.

The genetic background of antibiotic resistance among clinical uropathogenic Escherichia coli strains

“…The results presented by other authors show a similar distribution of these genes [ 68 , 69 ]. Completely different results were presented by Mazurek et al [ 70 ] where the presence of the studied genes was significantly lower. However, those E. coli strains were isolated from animals in Poland which could probably be an important reason for the differences [ 70 ].…”

“…Completely different results were presented by Mazurek et al [ 70 ] where the presence of the studied genes was significantly lower. However, those E. coli strains were isolated from animals in Poland which could probably be an important reason for the differences [ 70 ]. The rare occurrence of sul3 may prove that the synthesis of modified DHPS due to the presence of sul3 gene has recently appeared in resistant bacteria strains [ 71 ].…”

Prevalence of Virulence Determinants and Antimicrobial Resistance among Commensal Escherichia coli Derived from Dairy and Beef Cattle

“…Isolates from dairy cows showed higher resistance to 11 out of 13 tested antimicrobial agents, at a statistically significant level for six agents. It was reported [ 31 , 32 ] that dairy cattle usually carried more antimicrobial resistant enteric bacteria than beef cattle, due to the fact that dairies used more antimicrobials, particularly to treat mastitis. Some studies have shown that application of antimicrobial agents causes the increase in the level of resistance as a consequence of selective pressures exerted during animal production [ 33 ].…”

Effects of intramuscularly administered enrofloxacin on the susceptibility of commensal intestinal Escherichia coli in pigs (sus scrofa domestica)

“…Each administration of antibiotics in human and in veterinary medicine exerts a selective pressure and poses an increased risk of development and spread of antimicrobial resistance (AMR) [ 1 ]. This may affect not only zoonotic bacteria but also commensal bacteria in the intestine of food producing animals which are of special concern under public health aspects [ 2 – 4 ].…”