Genetic Basis of Multiple Antibiotic Resistance of Pathogenic Escherichia coli Strains Isolated from Livestock Complexes in Krasnodar Krai, Russia

Antimicrobial resistance is a serious problem in veterinary medicine worldwide. Given that farm animals are considered to be among the sources of infectious disease pathogens in humans, studying the genetic diversity of pathogenic microorganisms isolated from them and identifying strains that are potentially pathogenic to humans is a primary research task nowadays. The current paper provides a comprehensive characterization of 4 <i>Escherichia coli</i> strains that caused colibacillosis in farm animals. Along with a description of morphological and biochemical characteristics, data on antibiotic sensitivity are presented, and a multiple antibiotic resistance index is calculated. In order to identify the genetic basis of antimicrobial resistance (AMR), whole-genome sequencing was performed, followed by phylogenetic analysis and identification of antibiotic resistance genes. It is shown that the studied strains possess genetic determinants of virtually all major molecular mechanisms of antibiotic resistance, a significant number of which are phenotypically expressed. The pronounced potential for acquiring new variants of resistance, in combination with the strains' virulence potential, determines the etiological significance of the <i>E. coli</i> isolates in relation to both farm animals and human beings. A comparison of the results obtained with other researchers' data indicates a coincidence in the trends of the multiple antibiotic-resistant strains spread in different countries and points to the need for the development and implementation of a unified global strategy to combat AMR.