Efeito antimicrobiano do extrato vegetal de Libidibia ferrea e Coffea arabica sobre cepas de Salmonella Typhimurium isoladas de carcaças de frango em diferentes regiões do Brasil

Abstract

Salmonella enterica serovar Typhimurium is a non-spore-forming, Gram-negative bacterium considered a major zoonotic pathogen in poultry and public health. It is characterized by the complexity of its antimicrobial resistance (AMR) mechanisms, which arise from genetic processes – such as horizontal gene transfer – and intrinsic structural and enzymatic adaptations. Under the One Health approach, its dissemination impacts animal, human, and environmental health, being particularly prevalent in foodborne disease outbreaks. Given the problem of conventional antimicrobial resistance and the One Health impact, the prospecting of plant derived bioactive compounds has intensified as a promising alternative strategy. Thus, the main objective of this study was to analyze and evaluate the antimicrobial effect of the plant extracts from "jucá" or "ironwood" (Libidibia ferrea) and "Arabica coffee" (Coffea arabica) on resistant S. Typhimurium strains isolated from chicken carcasses across different regions of Brazil. The antimicrobial activity of the L. ferrea pod extract (at concentrations in mg/ml: 31.25; 15.63; 7.81; 3.90; 1.95; 0.97; 0.48; 0.24) and the C. arabica leaf extract (at concentrations in mg/ml: 30; 15; 7.5; 3.75; 1.87; 0.93; 0.46; 0.23) was evaluated on seventeen S. Typhimurium strains using the broth microdilution method to prepare the different concentrations, followed by the determination of the Minimum Bactericidal Concentration (MBC). Each strain was analyzed in triplicate, and the association between the different plant extract concentrations and bacterial growth was analyzed using a descriptive method. For the L. ferrea plant extract, the absence of growth (MBC) was observed at the following concentrations: 7.81 mg/ml (1 strain – 5.88%), 15.63 mg/ml (14 strains – 82.35%), and 31.25 mg/ml (2 strains – 11.76%). For the C. arabica plant extract, the MBC was 30 mg/ml for 13 of the 17 strains evaluated (76.47%), while four strains (23.53%) did not respond to any of the tested concentrations, showing an MBC greater than 30 mg/ml. Based on these results, it was observed that S. Typhimurium showed a dose dependent response (decreased or absent growth) as the concentration of L. ferrea and C. arabica extracts increased. These results indicate that the extracts of L. ferrea (pods) and C. arabica (leaves) demonstrated antimicrobial potential against the tested strain. The L. ferrea extract stood out due to its higher efficacy, showing bactericidal activity at the lowest concentration evaluated, positioning both compounds as promising alternatives in the fight against global antimicrobial resistance.