The poultry production chain is highly efficient and effective, employing a production system that consists of maximizing production in a smaller location. With many animals in a closed environment, the frequency of illnesses tends to increase, causing loss of animals and higher costs for the producer. Escherichia coli (E. coli) has been widely studied, being an agent disseminated in the environment, causing diseases in both humans and animals (colibacillosis in broilers), representing a threat to public health, with a high level of resistance to antibiotics. Therefore, the current study monitors the resistance profile in poultry farms for multiresistant E. coli bacteria, also researching genes that encode resistance to beta-lactams such as CTX-M1, CTX-M2, CTX-M8, CTX-M9, and CTX-M25. Bacteria were isolated from four farms in the state of Paraná. Biochemical series was used to identify E. coli bacteria, to monitor multi-resistance and to verify the expression of the production of Extended Spectrum β-lactamases (ESBL) using Disc Diffusion method, with 17 antimicrobials, following the norms of the “Clinical and Laboratory Standards Institute” (CLSI, 2020) and resistance genes were searched through the PCR technique. Strains were isolated from poultry litter, and cloacal swab and Alphitobius diaperinus beetle. In a total of 60 strains, fifteen per aviary, approximately 69% of the strains (41) had ESBL production, the antimicrobial that showed the highest frequency of resistance was Ampicillin, with 94% of the strains (56), followed by Cefazolin and Enrofloxacin with 92% (55), being Enrofloxacin widely used for treating broilers affected with colibacillosis. The antimicrobial with the lowest frequency of resistance and which could be used in poultry to treat a possible disease was Florfenicol with 38% of the strains resistant, and there are several products on the market with this active ingredient. The CTX-M1 gene had the highest frequency 26% among the others, and recently its appearance has surpassed the CTX-M2 which had been reported most frequently gene in epidemiological data. Resistance epidemiological data are of great importance for the production, as they help in more specific treatments for animals, which usually does not exist in the production, and for public health, clearly indicating the growing and worrying increase in multi-resistant bacteria in animal production and human clinic, as these two in many studies are shown to be related.