engleski

Antimicrobial activity of different Croatian honey against multi-drug resistant Acinetobacter baumannii

Antibiotic resistance of bacteria is on the rise, thus the discovery of alternative therapeutic agents is urgently needed. Acinetobacter baumannii is an opportunistic pathogen that usually infects immunocompromised individuals through open wounds, catheters and breathing tubes. Multi-drug resistant A. baumannii has emerged as a major cause of nosocomial infection. Honey possesses therapeutic potential, including wound healing properties and antimicrobial activity. Although the antimicrobial activity of honey has been effectively established against an extensive spectrum of microorganisms, it differs depending on the type of honey. The objectives of this study were to test the antibacterial activity of 17 types of Croatian honeys against multi-drug resistant Acinetobacter baumannii. Using a broth dilution method, the antibacterial activity of 17 different types of honeys (3 samples of sage honey – Salvia officinalis L., 4 samples of honeydew – 3 fir honeydews (Abies alba Mill) and 1 maple honeydew (Acer spp.), chestnut – Castanea sativa Mill., locust tree – Robinia pseudoacacia L., lime tree – Tilia spp., indigo bush – Amorpha fruticosa L., rape seed – Brassica napus L., maple – Acer spp., mint – Mentha spp. and polifloral autum and spring meadow honeys) was evaluated against 6 strains of A. baumannii. The used strains were: multi-drug resistant strain ATCC BAA-1605 and drug sensitive strain ATCC 19606, as well as 4 clinical isolates (drug sensitive strain 771, and drug resistant strains: 53154, 56781 and 54531). Different concentrations of honey (0, 025 mg/mL – 0, 4 mg/mL) were tested against each bacterial strain. The minimum inhibitory concentrations (MIC) were determined by visual inspection as the lack of visual turbidity followed by evaluation of minimum bactericidal concentration (MBC). MBC was determined as no growth of bacteria after culturing on blood agar. Our results showed that the MICs of different honeys ranged from 0, 025 mg/mL to 0, 4 mg/mL. The lowest MIC value of 0, 025 mg/mL was obtained for fir honeydew honey (sample 3), 0, 05 mg/mL for fir honeydew honey (sample 4), mint honey and polifloral autum meadow honey against multi-drug resistant A. baumannii ATCC BAA-1605 as well as against clinical drug resistant strains. The lowest MBC value of 0, 05 mg/mL of honeydew honey (sample 3) was also showed against multi-drug resistant A. baumanii ATCC BAA-1605 as well as against clinical drug resistant strains. This result suggests that fir honedew honey, mint honey and polifloral autum honey could potentially be used as an alternative therapeutic agent against A. baumannii wound infection. However, this approach needs to be further studied.

honey; Acinetobacter; antibiotic resistance

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