###### Abstract  
_Escherichia coli_ isolates from intensive poultry production are associated with antimicrobial resistance and worldwide health problems. The aim of the study was to detect and evaluate the phenotypic and genotypic antimicrobial resistance, biofilm formation, phylogenetic typing, and virulence factors in _E. coli_ isolates from the rectal swabs of chickens from two farms and swabs of chicken meat purchased from Slovakian food markets. Interpretative readings of minimal inhibitory concentration (MIC) revealed dominant resistance to ampicillin (>50%) in both groups. We also detected higher resistance to ciprofloxacin (45%), tetracycline, ampicillin + sublactam, and trimethoprim + sulfonamide (each >30%). Here, 28.5% of the strains studied were multidrug-resistant (MDR). The formation of weak biofilms was confirmed in 8.8% of _E. coli_, while one of the strains obtained from chicken cloal swabs was classified as a strong biofilm producer. The most frequently confirmed phylogenetic groups in _E. coli_ were B\({}_{1}\) and A\({}_{1}\) in all groups. PCR detection revealed the presence of genes encoding tetracycline resistance (_tet_AB) and plasmid-mediated quinolone resistance (_qnr_ABS), and _Int1_ (52.9%), _Tr3_ (76.5%), _kpsMT_ II (8.8%), _fim_A (97.1%), _cva_C (38.2%), and _iut_A (76.5%) genes in the strains studied. Our results demonstrate that chickens and chicken meat were the source of antibiotic-resistant, biofilm-forming, and virulent _E. coli_, representing a potential risk from the point of view of the One Health concept. semicr: 24 September  
for 50-80% of the world's ATB production, which includes many ATB that are also medically important in human medicine. The agriculture and food sectors thus play a significant role in the emergence and spread of antimicrobial resistance [4]. Most _E. coli_ strains are harmless commensals that are part of the intestinal microflora of mammals and birds, and rarely cause disease [5]. Due to the high plasticity of the genome, commensal strains can acquire virulence factors and genes encoding resistance to antimicrobial substances through horizontal transfer or mutation, and act as their reservoir. _E. coli_ is among the bacteria that can act as both a donor and an acceptor of antimicrobial-resistant genes [6]. Resistant genes are encoded either chromosomally or transmitted via mobile genetic elements. Pathogenic _E. coli_ strains are the causative agents of intestinal (InPEC) or extraintesthal (ExPEC) diseases [5]. _E. coli_, as a ubiquitous bacterium, can be found in various elements of the environment (such as water, soil, wastewater, plants, animals, and food), in which several strains survive for a long time, reproduce, and further spread in the environment [7]. _E. coli_ is among the coliform bacteria, and its presence in drinking water, food, or the environment indicates fecal contamination, non-compliance with hygienic conditions, and the presence of other fecal microorganisms. Furthermore, _E. coli_ is also considered an indicator bacterium in ensuring the safety and hygiene of food production [8]. The manner in which animals are handled before, during, and after slaughter makes meat a potential source of pathogenic bacteria. The meat may be contaminated during skin removal or evisceration during the processing of carcasses. The food-producing environment, instruments, handling by workers, improper storage and transport, and failure to follow sanitary principles during marketing also contribute to the cross-contamination of meat [3; 9]. The consumption of raw or undercooked meat is also a threat [10]. The resistance of bacteria to antimicrobial substances (including quinolones and tetracyclines) has been increasing at a tremendous rate in recent years, meaning it is now considered by many to be one of the greatest threats of the 21 st century [11].