In vitro susceptibility of pathogenic bacteria to extracts of Rosmarinus officinalis and Caesalpinia spinosa

Abstract

Introduction: Bacterial resistance to drugs affects the health and economy of thousands of families. An alternative is found in medicinal plants whose properties would allow treating or curing microbial infections. Objective: To evaluate the in vitro susceptibility of Escherichia coli strains that produce extended-spectrum beta-lactamases (ESBL), Pseudomonas aeruginosa and Staphylococcus aureus to ethanolic extracts of Rosmarinus officinalis L. and Caesalpinia spinosa. Methods: Quantitative, experimental and prospective research where ethanolic extracts of Rosmarinus officinalis and Caesalpinia spinosa at different concentrations (100, 200, 300, 400 and 500 mg/mL) were tested against 3 strains of Escherichia coli ESBL, Pseudomonas aeruginosa and Staphylococcus aureus. The in vitro antibacterial potential of the extracts was established by the disk diffusion method, and the minimum concentrations to inhibit bacterial growth were also determined. Results: Rosmarinus officinalis extract at 500 mg/mL inhibited the in vitro growth of Staphylococcus aureus, observing an average inhibitory halo of 22.7 mm in diameter, but did not affect Escherichia coli ESBL and Pseudomonas aeruginosa. Likewise, with a concentration of 500 mg/mL of Caesalpinia spinosa, the multiplication of Escherichia coli ESBL (16.7 mm), Pseudomonas aeruginosa (15.6 mm) and Staphylococcus aureus (31.8 mm) was inhibited. Conclusion: Staphylococcus aureus strains are susceptible to ethanolic extracts prepared from Rosmarinus officinalis leaves and Caesalpinia spinosa pods. In addition, they inhibit the growth of Escherichia coli ESBL and Pseudomonas aeruginosa strains when exposed to Caesalpinia spinosa extract.

Keywords

• escherichia coli
• extractos vegetales
• resistente a los betalactámicos
• pseudomonas aeruginosa
• staphylococcus aureus.