Melissa officinalis Extract as an Antimicrobial Agent Against Clinical Bacterial Strains Isolated from Urinary Tract Infections in Najaf, Iraq

Abstract

Background: Antibiotics are used to inhibit the growth of bacterial infections. However, antibiotic resistance is increasing due to their use. Plant extracts are natural compounds with unique medical properties. The current study investigated the effect of Melissa officinalis collected from Marivan, Iran, against urinary tract infection (UTI). Methods: The plant extract was prepared using the Soxhlet method. The bacterial strains were isolated from UTI patients at AlZahra Hospital in Najaf, Iraq. The antibacterial activity of M. officinalis extract was evaluated using the Kirby-Bauer disk diffusion method. The minimal inhibitory concentration (MIC) was also determined by the microdilution method. Results: According to the inhibition zone results, M. officinalis greatly affected Staphylococcus aureus, Proteus vulgaris, and Klebsiella pneumoniae. The plant extract showed the highest antimicrobial activity on the standard and clinical strains of S. aureus with the highest inhibition zone record of 8.4±0.163 and 9±0.0 mm and MIC of 0.09 and 0.06 mg/mL, respectively. Also, M. officinalis extract indicated an antimicrobial effect against the standard and clinical strains of K. pneumoniae with the highest inhibition zone record of 8±0.0 and 9±0.0 mm and MIC of 0.06 and 0.06 mg/mL, respectively. Furthermore, the plant extract showed the most antimicrobial activity on the standard and clinical strains of P. vulgaris, with the highest records of 7.9±0.23 and 9±0.0 mm and MICs of 0.14 and 0.06 mg/mL, respectively. Conclusion: Melissa officinalis extract can be a suitable candidate as an alternative to antibiotics for treating UTIs.