"obtaining transconjugant escherichia coli costs isolated from chicken litter and chicks" "obtenção de cepas transconjugantes de escherichia coli isoladas de cama de frango e pintainhos"

It is known that chicken litter is home to many pathogenic and antimicrobial resistant bacteria, and in many cases, it is reused without prior treatment in the creation of subsequent batches. Thus, the work aimed to verify whether Escherichia coli strains that produce Extended Spectrum Beta-lactamases (ESBL) isolated from chicken beds in the state of Paraná, were able to transfer their genes to E. coli isolates from the intestinal microbiota of one day old chicks. For this study, four strains of E. coli producing ESBL were used, presenting the bla CTX-M1 gene isolated from chicken litter, to be the plasmid donors, and three strains isolated from chicks newly arrived at the shed, which showed resistance to only gentamicin. For the conjugation assays, the donor and recipient strains were used in a proportion of 1: 2 respectively, and the transconjugants selected for resistance to gentamicin and cefotaxime in specific concentrations. Transconjugant colonies were selected and their phylogenetic groups identified by the PCR technique. Of the 12 conjugations performed, three presented transconjugants harboring the bla CTX-M1 gene, indicating that there is a possibility that this gene could be transferred to E. coli of the microbiota. Thus, in the environment of the farms, the transmission of plasmids of resistance from bacteria present in the chicken litter to bacteria from the microbiota of the newly arrived chicks may occur. The fact that chicken litter is reused without proper treatment contributes to the maintenance and dissemination of genetic determinants for ESBL in broiler chickens.