Conjugative transfer of antimicrobial resistance determinants between Enterobacteriaceae under subinhibitory concentrations

• Grant number: 21/04321-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2021
• End date: May 31, 2022
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Angelo Berchieri Junior
• Grantee: Isabella Cardeal Campos
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The indiscriminate use of antimicrobials in animal production has left residues in products of animal origin and in the environment, since after administration there is partial metabolization of the drug, and the remainder being excreted in an unalterable way or as active metabolites in feces and urine. This is often associated with increased bacterial resistance to different classes of antimicrobials, including those of last choice for treating infections in humans. Bacterial resistance genes can be transmitted horizontally through the transfer of plasmids by the conjugation mechanism, mediated by the T4SS system in Gram-negative bacteria. Escherichia coli and Salmonella enterica subps. enterica, with an emphasis on the Enteritidis, Typhimurium and Heidelberg serovars, are zoonotic bacteria present in poultry farming, often isolated from poultry litter, in addition to countless strains having multiple resistance profiles. Therefore, due to the importance of these mechanisms of transfer of bacterial resistance and the presence of several resistance genes in the bacteria mentioned, the objective was to investigate the conjugation between these species in the presence of subconcentrations of antimicrobials in substrates from poultry litter. The frequency of conjugation will be calculated by dividing the number of transconjugating bacteria by the number of total recipients. These data will be analyzed by two-way ANOVA followed by Bonferroni's Multiple Comparison Test (P <0.05) in the GraphPad Prism software version 8.1 for Mac OS. (AU)