The objective of the present work is to study the biochemical properties of E. coli isolates and to determine their antibiotic sensitivity with regard to antibacterial drugs used in the agricultural field. The work was carried out in two farms of the Neklinovsky District of the Rostov Region in the period from 2015 to 2018. To determine the formation of indole, culture was plated in Hottinger Broth, five samples (#1, #2, #131, #139 and #1371) out of all sixteen collected samples revealed red layer on the surface of the culture fluid, indicating a positive response. A ring that appeared the next day confirmed the presence of indole. Meanwhile, to determine the ability to utilize citrate, cultures were plated on the surface of Simmons medium, and the same five samples (#1, #2, #131, #139 and #1371) gave green color for the medium changed to blue, indicating positivity. All the tested samples except sample #1371 fermented glucose, sucrose, lactose, and mannitol, which is typical for Escherichia coli. Likewise, further characterization to determine the formation of hydrogen sulfide, cultures were plated on three-sugar agar, and one sample out the previous five samples make blackening on the medium column, indicating the formation of hydrogen sulfide Thus, out of the sixteen studied cultures, sample # 1371 can be attributed to bacteria of the Pseudomonas aeruginosa species while the four cultures #1, 2, 131, and 139 belong to the E. coli Citrobacter freundii bacteria group, however the remaining 11 cultures belong to the Escherichia coli bacteria group. Sensitivity for the antibiotic susceptibility of genus Escherichia to antibacterial drugs (meropenem, imipenem, pefloxacin, enrofloxacin, carbenicillin, cefotaxime, ceftriaxone, vancomycin, furadonin, fosfomycin, gentamicin, netilmicin, colistin, levofloxacin, tetracycline, laevomycetin, ciprofloxacin, chloramphenicol, norfloxacin, furagin, vancomycin, spectinomycin, doxycycline, and norfloxacin) was determined using standard disks. This study shows that in eight cultures of genus Escherichia were most sensitive to fosfomycin, enrofloxacin, imipenem, meropenem, levofloxacin, vancomycin, and gentamicin while nine cultures were sensitive to enrofloxacin, imipenem, meropenem, levofloxacin, vancomycin, gentamicin, cefotaxime, and norfloxacin. While conducting the research, the bacterial microflora was identified, which was the causative agent of infectious diseases. An antibiotic sensitivity had also been identified, which allowed for more effective treatment regimen for cattle.
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