CHARACTERIZATION OF EXTENDED SPECTRUM β-LACTAMASES-PRODUCING Escherichia coli IN POULTRY PRODUCTION

In recent years, Brazilian poultry production has shown high rates of yield, leading to a significant feature in the world market. Additives, such as antimicrobials, are used to increase production; however, their incorrect use can lead to the emergence of resistant bacteria. One of the most concerning resistance mechanisms is the production of Extended Spectrum β-lactamases (ESBL). In this context, the objective was to characterize phenotypic and genotypically ESBL-producing samples. The samples were collected from five farms in the state of Rio Grande do Sul and three farms in Paraná, at three points during the fattening period (first day of production, between 20 and 25 days, and at the 40th day, before slaughter). In each farm, samples of feed, water, chicken litter and cloacal swab of 20 birds were collected. The phenotypic characterization was performed through the antibiogram test, according to the CLSI protocol. Genotypic characterization was performed by the detection of ESBL resistance genes (blaCTX-M, blaTEM and blaSHV) by PCR. 118 strains of E. coli were isolated, of which 60 were from Rio Grande do Sul and 58 from Paraná. Among the isolates from Paraná, 84.40% were positive in the phenotype test and 67.26% for genotype, in which 94.37% were positive for blaCTX-M and 17.94% for blaTEM. The third period of sample collection presented a higher number of positive isolates for ESBL genes (46.93%). Among the isolates from Rio Grande do Sul, 48.33% were positive in the phenotypic test and 31.66% for genotype, in which 84.21% were positive for blaCTX-M and 15.78% for blaTEM. The second period of sample collection presented a higher number of positive isolates for ESBL genes (48.27%). No blaSHV positive isolates were found in both states. Among the CTX-M group genes, it was observed a predominance of blaCTX-M1 in the state of Paraná and blaCTX-M2 in the state of Rio Grande do Sul. These data reveal the presence of ESBL-producing strains in southern region, especially in the two periods prior to slaughter. In addition, the state of Paraná showed greater diversity of ESBL genes, which is concerning, mainly for the possibility of transmission of these resistance gene to humans through the meat intake. Monitoring avian production should be carried out in order to control the number of resistant strains, given their importance in public health.