A Promising Antibacterial Inhibition of Propolis Extracts Against Carbapenem-Resistant Bacteria Isolated From Clinical Samples

The increasing inadequacy of antibiotics against multidrug-resistant pathogens is a growing concern. In this study, the antibacterial activity of propolis extracts with different phenolic profiles against carbapenem-resistant clinical isolates was investigated. The antimicrobial activity of propolis extract was tested against Acinetobacter baumannii (K17, K16, and K21), Klebsiella pneumoniae (K22, and K19), and Stenotrophomonas maltophilia (E5, E7, and E4) bacterial strains isolated from tracheal aspirate and blood cultures. The total phenolic content and phenolic composition of the extracts were analyzed. Antimicrobial activity values examined according to the disk diffusion method were measured as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The results showed that all propolis extracts showed different inhibition values against bacterial strains. As a result, the high inhibitory potential of the propolis extracts against resistant bacteria such as A. baumannii, K. pneumoniae, and S. maltophilia is promising for combating infections. However, the study needs to be supported by further randomized clinical studies.