Antimicrobial Activity and Resistance of Microorganisms Isolated from Honey Bees

Knowledge of composition of bee gut microbiota is important to ensure balanced gut microbiota and improve the health status of bees. The aim of the present study was to detect the microorganisms in gut of honey bee and to study their antimicrobial resistance and antimicrobial activity against three essential oils. Content of bees gut was studied with microbiological methods, and isolates were confirmed with MALDI TOF mass spectrometry. Isolated species were tested for antibiotic resistance to ciprofloxacin, levofloxacin, amikacin and gentamicin. For antimicrobial activity, essential oils of Abies alba, Pinus mugo and Pinus sylvestris were used. Gram-positive bacteria Bacillus oleronius, Micrococcus luteus, Staphylococcus epidermidis and three Gram-negative bacteria Pseudomonas oryzihabitans, Serratia fonticola, Serratia marcescens were isolated from bees gut. Antibiotic resistance was found in Gram-negative bacteria, while the Gram-positive bacteria were sensitive to all antibiotic tested. The best antibacterial activity of essential oils found against Gram-positive bacterial strains. Essential oils can be a potential sources of compounds with antimicrobial activity on Gram-positive isolates of bees gut.