## 4 Discussion
coli_ in chickens can significantly affect animal health, production losses and the safety of the food produced, as well as increasing veterinary costs. Resistant strains of _E. coli_ can spread between chicken populations and other animals and humans, raising public health concerns. Resistant _E. coli_ can spread through environmental routes, such as manure, which affects ecosystems and can contribute to the spread of resistance. The consumption of contaminated chicken can lead to infections resistant to commonly prescribed antimicrobials, complicating treatment and increasing health risks and healthcare costs. The research conducted by [PERSON] et al. [47] and [PERSON] et al. [48] supports our findings, as they reported a high resistance rate (60.7-89.5%) among _E. coli_ strains from chicken samples to trimethoprim + sulfonamide, tetracycline, ampicillin, and ciprofloxacin. Many isolates studied were also resistant to tetracycline, doxycycline, nalidixic acid, amoxicillin-clavulanate, ciprofloxacin, trimethoprim + sulfonamide, chloramphenicol, gentamicin, azithromycin and erythromycinomycin [44; 45]. [PERSON] et al. [49] reported that \(\beta\)-lactams, tetracycline, sulfonamides, and quinolones are the most often utilized antimicrobials in global broiler chicken production. According to [PERSON] et al. [50], multidrug-resistant _E. coli_ bacteria are more frequent in animal samples than in human isolates. Poultry farms and their waste, which includes manure and wastewater, are a common source of antimicrobial-resistant and multidrug-resistant bacteria, as well as antimicrobial residues. These elements create a constant source of selection pressure that drives the evolution of resistance in bacterial populations [48]. Here, 60.95% of the one hundred and five _E. coli_ isolates tested were found to be resistant to at least one antimicrobial agent in our experiment. Multidrug-resistant strains together represented 28.57%, while the most common MDR profile was resistant to three different antimicrobials: AMP, CIP and TET. Studies by other authors have shown significantly higher rates of MDR _E. coli_ in chicken samples in Sri Lanka (82.6%) [51], Egypt (97.6%) [45], and Bangladesh (100%) [47]. These results are alarming because MDR bacteria are the cause of difficult-to-treat infectious diseases in both human and veterinary medicine [48]. Bacterial biofilm formation poses a difficulty in many areas, e.g., food processing facilities, food-producing animals, and veterinary practice. A significant problem in the food chain is the creation of biofilms by MDR bacteria [52]. Biofilms consist of microbial communities that irreversibly adhere to surfaces and are encased in an extracellular matrix. The matrix provides protection for microorganisms against unfavorable environmental conditions, and promotes the sharing of antimicrobial-resistant genes via horizontal gene transfer [53]. According to [PERSON] et al. [54], most _E. coli_ strains of avian origin form biofilms, which increases the persistence of these pathogens on chicken farms. In our study, the majority of _E. coli_ isolates did not form a biofilm, but we confirmed weak and strong biofilm formation. Our results indicate that the risk to the consumer associated with the presence of potentially highly pathogenic strains of _E. coli_ is relatively low. Similarly, in the study by [PERSON] et al. [55], the majority of _E. coli_ strains obtained from Italian retail chicken meat showed weak biofilm activity, while the _E. coli_ isolated from beef samples exhibited strong biofilm formation. In research conducted in China, [PERSON] et al. [56] reported that 81.6% of _E. coli_ isolated from poultry meat formed biofilms, with 25.4% being strong producers. [PERSON] et al. [57] reported that the biofilm formation of _E. coli_ acquired from chicken samples was categorized as moderate in 55.0%, weak in 22.9%, strong in 12.8%, and very strong in 2.8% of the cases. _E. coli_ strains can be classified into four phylogenetic groups, according to research conducted by [PERSON] et al. [31].