Abstract

Background:
Although free-range chicken meat is widely consumed in Brazil, it may pose a public health risk due to contamination with pathogenic and antimicrobial-resistant bacteria, such as Escherichia coli (E. coli).

Aim:
This study aimed to investigate the occurrence of Escherichia coli, antimicrobial resistance, and biofilm formation in free-range chicken meat samples collected from restaurants in Petrolina, Pernambuco, Brazil.

Methods:
Microbiological and molecular methods were used to analyze 40 samples collected from eight restaurants to detect E. coli, evaluate antimicrobial resistance profiles, assess biofilm formation, and identify the presence of resistance genes.

Results:
The overall frequency of E. coli infection was 57.5%. All bacterial strains (100%) were resistant to at least one antimicrobial agent, and 78.2% (18/23) were classified as MDR, showing resistance to three or more classes of antibiotics, with the highest rates observed for ciprofloxacin and tetracycline. Among the detected resistance genes, the blaTEM gene had the highest prevalence (17.4%), followed by blaCTX-M1 (4.3%), while tetA and qnrS were not detected. A discrepancy was observed between high phenotypic resistance and low detection of resistance genes, suggesting the involvement of other mechanisms. In addition, 95.5% of the strains were classified as biofilm producers, although most exhibited weak biofilm formation.

Conclusion:
This study confirms the presence of multidrug-resistant E. coli strains in food served at restaurants, highlighting the risk of transmission of resistant bacteria to humans through the consumption of contaminated meat and reinforcing the need for continuous monitoring of food safety.

Key words: Biofilm; Escherichia coli; Poultry meat; Resistance genes.