Antibacterial effect of Thymus sp. and Boswellia sp. extracts on Streptococcus pneumoniae and Klebsiella pneumoniae isolates

The antimicrobial activity of essential oils of Boswellia and thyme (Boswellia sp., and Thyme sp.) was evaluated against 20 clinical isolates of Streptococcus pneumoniae and 5 isolates of Klebsiella pneumoniae. Essential oils were prepared using methanol and water (1:1) with HPLC technique. Antimicrobial activity and minimum inhibitory concentration (MIC) were measured using disk diffusion method against 20 isolates of S. pneumoniae and 5 isolates of K. pneumoniae isolated from different patients. Flavonoids and phenolic compounds are the main constituents of Boswellia and thyme which may have the antimicrobial activity. Boswellia extract was more efficient than thyme extracts; 60% of S. pneumoniae isolates and one K. pneumoniae isolate were sensitive to Boswellia extract, 30% of S. pneumoniae isolates were sensitive to thyme extract, and no effect on K. pneumoniae clinical isolates was observed. Inhibition zones ranged from 1-12 mm with thyme extract, while Boswellia extracts showed 2 to 30 mm diameters of inhibition zone. This study is significant due to the widespread problem of microbial drug resistance and the need for natural antibiotic to fight diseases.