Effect of leaf extracts of Kalanchoe pinnata (Lam.) Pers. against multidrug resistant bacteria

Abstract

Medicinal plants are sources of bioactive molecules that can be used against bacterial infections. In this study, the antibacterial activity of the ethanolic extract of the leaves of Kalanchoe pinnata (Lam.) Pers. was tested against 68 multidrug-resistant bacteria, isolated from diabetic patients with foot lesions, and six reference strains of the American Type Culture Collection, using agar diffusion (DD) and broth microdilution (MC) methods. The correlation between plant extract and cefoxitin or amoxicillin/clavulanic acid antibiotics was also performed. Leaf extract presented antimicrobial activity in both methods, however, the MC method was more sensitive at the lower dilution (0,039 mg/mL) used. In these types of lesions, the strains more frequently found were inhibited by ethanolic extract, such as Staphylococcus aureus (40,91%), Staphylococcus saprophyticus (42,86%), Streptococcus pyogenes (100,00%), Streptococcus agalactiae (50,00%), Enterobacter spp. (33,33%), Pseudomonas spp. (66,67%), Proteus spp (28,57%). The association of extract with antibiotics did not potentiate the antibacterial activity, it suggested that extract and antibiotics have different mechanisms of actions. Our results showed that the ethanolic extract of the leaves of Kalanchoe pinnata (Lam.) Pers. has a good antimicrobial activity. However, additional studies should be performed to determine its efficacy and toxicity in the treatment of bacterial infections.