CONJUGATIVE PLASMIDS ISOLATED FROM ENTEROPATOGEN Shigella sonnei CODE ANTAGONIST SUBSTANCE(S) AND ANTIMICROBIAL RESISTANCE (Atena Editora)

Abstract

Shigella, an invasive enteropathogen, is responsible for bacillary dysentery or shigellosis, a severe diarrheal disease that mainly affects children in underdeveloped countries. The bacterium expresses several virulence factors, including antagonistic substances and antimicrobial resistance. These substances are often encoded by plasmid genes, which can be transferred by recombination processes such as bacterial conjugation. The present study was carried out with the objective of determining whether resistance to antimicrobials and the antagonist substance(s) synthesized by Shigella sleepy SS9 are encoded by plasmid genes. As a developer of plasmid antagonist and receptor expression, samples S. sonnei SS12 and Escherichia coli ATCC 25922, respectively, were used. For the SS9 and E conjugation assay. coli was evaluated for their antimicrobial susceptibility profiles. After antimicrobial selection, SS9 and E. coli were grown separately, cultures adjusted to 0.5 McFarland scale and diluted 1:50. An aliquot of each sample was added to the same tube and the material was incubated. At predetermined time intervals, aliquots were cultured on MacConkey Agar with and without antimicrobial. lac + colonies were evaluated for antagonism expression. Positive colonies were subjected to plasmid extraction and electrophoresis analysis. After culturing a transconjugant sample, the material was centrifuged and the supernatant analyzed by the antagonist assay. Analysis of the growth curve of the transconjugant with the synthesis of bioactive substance(s) was also performed. The results show that the transconjugant sample started to harbor conjugative plasmids with the presence of genes that encode resistance to the antimicrobials ampicillin and trimethoprim, in addition to the production of antagonist substance(s). Proving the presence of virulence factors, which can be transferred by conjugation, from the enteropathogen S. sonnei, which was recognized by the World Health Organization as one of the twelve pathogens that urgently need the development of new drugs.