Aims. The aim of this study was to evaluate the antimicrobial effects of five natural substances against 50 clinical isolates of Mycoplasma hominis. Methods and Results. The in vitro activity of selected natural compounds, cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene, was investigated against 50 M. hominis isolates cultivated from cervical swabs by the broth dilution method. All showed valuable antimicrobial activity against the tested isolates. Oil from the bark of Cinnamomum zeylanicum (MBC 90 = 500 μg/mL) however was found to be the most effective. Carvacrol (MBC 90 = 600 μg/mL) and eugenol (MBC 90 = 1000 μg/mL) also possessed strong antimycoplasmal activity. Conclusions. The results indicate that cinnamon bark oil, carvacrol and eugenol have strong antimycoplasmal activity and the potential for use as antimicrobial agents in the treatment of mycoplasmal infections.

Members of the genus Mycoplasma are parasitic bacteria that are widespread in nature. Several Mycoplasma species are important causative agents of various infections of mucosal surfaces in humans, especially in the urogenital or respiratory tracts. Pathogenetic mechanisms of mycoplasmas are intensively studied. The "gold" standard of mycoplasma detection is cultivation, which is very difficult and time-consuming. The other options for identifying mycoplasmas include direct antigen detection or molecular-biology methods, such as polymerase chain reaction, DNA-hybridization and sequencing. Mycoplasmas are naturally resistant to beta-lactam antibiotics because of lack of cell wall. Tetracyclines or fluoroquinolones are regarded as the first choice in the treatment of mycoplasma infections. Several reports have documented resistance of mycoplasmas to macrolides worldwide. This report summarizes our current knowledge of laboratory diagnosis and treatment of mycoplasma infections.