Microevolução da transferência horizontal de genes: Perspectivas ampliadas pela intervenção de nanocompostos

Abstract

Antimicrobial resistance (AMR) is a natural phenomenon, but it can be maximized by horizontal gene transfer (THG) in environments that impose selection pressure. The first chapter of the thesis covers general conditions on THG through bacterial conjugation, antimicrobial resistance, the use of inhibitors of the conjugation process and important general concepts on lipid nanocarriers (NLC). The second chapter aimed to evaluate nano encapsulated and non-encapsulated copper conjugation inhibitors (COINs) on bacterial conjugation and to determine the influence of co-products from the animal products industry on conjugation frequency (CF). Bacterial conjugation was investigated in liquid media and the whole genome sequence (WGS) of the donor bacterium (Salmonella Heidelberg donor of the blaTEM-1 genes) and recipient bacterium (Escherichia coli J53 AzR), as well as the transconjugants after conjugation determined the interference of animal by-products chicken juice (CJ) and whey (SL) in THG, and the use of NCL in association with copper complexes (NCLDRI12) and unencapsulated copper complex (DRI12) as mitigators of this process. Whole genome sequencing (WGS) made it possible to determine the inhibition of the passage of plasmids with antibiotic resistance genes, as well as the use of synteny to visualize the exchange or deletion of gene blocks. The presence of coproducts stimulated an increase in CF, but this was reduced in the presence of DRI12. However, in the presence of SL, this compound allowed all the plasmids carrying antibiotic resistance genes to pass through. In the similarity analysis, it interfered with exchanges and deletions of collinearity regions. Compared to DRI12, NLCDRI12 did not reduce the number of transconjugants, but it did prevent the passage of the IncC and IncX1_1 plasmid. The third chapter aimed to evaluate the effect of the coproducts SL and CJ and NLC from sage and olibanum on CF. The SH strain was characterized phenotypically as multidrug-resistant and by conventional PCR to detect the blaTEM gene. A concentration of 0.39 mg/mL was used for the NLC inhibitors of sage and olibanum in the mitigation of THG. The tests showed that whey proved to be the main potentiator in THG (an increase of three orders of magnitude), but the sage and frankincense essential oil NLCs were able to reduce CF by more than 70 and 11 orders of magnitude, respectively, making them promising for controlling antimicrobial resistance in industrial environments where the control challenge is greater.