Zahraa Ghinem Yousef, Yazi Abdullah Jassim
Antibiotic-resistant Staphylococcus aureus is one of the most important pathogens associated with hospital-acquired infections, which calls for the search for effective treatment alternatives from natural sources. This study aimed to evaluate the antibacterial activity of propolis extract against antibiotic-resistant Staphylococcus aureus isolates isolated from different clinical samples, while identifying the active compounds responsible for this activity. 200 clinical specimens were collected, including urine, burns, sputum, skin infections, nasal swabs, blood and genital swabs. Bacterial isolates were diagnosed using standard implant and chemochemical tests, and antibiotic susceptibility testing was performed by tablet diffusion. Antipropolis efficacy was evaluated using measurement of inhibition zones at different concentrations, as well as the determination of the minimum inhibitory concentration (MIC) and the minimum lethal concentration (MBC). High-performance chromatography analysis (HPLC) was also performed for the qualitative and quantitative identification of phenolic compounds in propolis extract. The results showed that Staphylococcus aureus was 30% of the total samples, with high rates of resistance to some antibiotics. Propolis extract showed clear inhibitory activity against most of the isolates tested, with MIC values ranging from 1.56 to 25 μg mL-1, and MBC values between 3.125 and 50 μg mL-1. HPLC analysis also revealed active phenolic compounds, including gallic acid (632.40 ppm), caffeic acid (27.45 ppm), and catechin (98.0 ppm). These results suggest that propolis has a remarkable antibiotic efficacy against antibiotic-resistant isolates of Staphylococcus aureus, due to its richness in bioactive phenolic compounds, which supports the potential for its use as a promising natural resource in the development of therapeutic alternatives or adjuvant agents to conventional antibiotics. Keywords: antibiotic resistance; HPLC analysis; phenolic compounds; MIC and MBC.