Ação antimicrobiana do extrato da folha de Coffea arabica sobre cepas multirresistentes de Staphylococcus aureus e Streptococcus sp. isoladas de diferentes amostras de animais de companhia

Abstract

Staphylococci and streptococci are bacteria found on the skin and epithelial surfaces of numerous animal hosts. Staphylococcus aureus and some Streptococcus spspecies have pathogenicity and can cause clinical diseases in both humans and animals. The high frequency of S. aureus strains resistant to antimicrobials is another major concern for public and animal health organizations. In the face of this problem, the search for compounds extracted from plants has been increasingly explored as an alternative to the use of antimicrobials. Therefore, the aim of this study was to analyze the antimicrobial action of Arabica coffee leaf extract (Coffea arabica) in S. aureus and Streptococcus strains isolated from samples obtained from animals treated at the Hospital Veterinário da Universidade Federal de Uberlândia, with the aim of finding natural and effective alternatives to the use of antimicrobials. The antimicrobial action of Coffea arabica leaf extract (concentrations in mg/ml: 20; 10; 5; 2.5; 1.25; 0.625; 0.312; 0.156) was evaluated in 8 strains of S. aureus and 5 strains of Streptococcus, using the broth microdilution method to prepare the different concentrations of the plant extract and subsequently determine the minimum bactericidal concentration (MBC). Each strain was analyzed in triplicate. The association between different concentrations of the plant extract and bacterial growth was analyzed using the chi-square test, with the aid of Jamovi software. In cases where the expected frequencies were low, Fisher's exact test was applied to ensure greater accuracy in the data analysis. For Staphylococcus aureus, response or no growth was observed at the following concentrations: 2.5 mg/ml (1 strain – 12.5%), 5.0 mg/ml (1 strain – 12.5%), 10 mg/ml (2 strains – 25%), and 20 mg/ml (3 strains – 37.5%). One strain (12.5%) grew at all concentrations tested (p < 0.001). For Streptococcus sp., the minimum inhibitory concentration (MIC) was 20 mg/ml for 4 out of the 5 strains tested (80%), while one strain did not respond to any of the tested concentrations (p < 0.001). These results indicate that S. aureus showed a progressively increased response as the concentration of the coffee extract increased. These findings suggest that Coffea arabica extract has potential as an antimicrobial compound against both bacterial species tested, with particularly high efficacy against Staphylococcus aureus.