Antibacterial and Biofilm Inhibitory Activity of Medicinal Plant Essential Oils Against Escherichia coli Isolated from UTI Patients

Abstract

Urinary tract infections (UTIs), caused by <i>Escherichia coli</i> 80% to 85% of the time, are one of the most important causes of morbidity and health care spending affecting persons of all ages. These infections lead to many difficult problems, especially increasing resistance to antibiotic drugs. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. In this study, we have investigated the antibacterial activity of five medicinal plant essential oils against UTIs caused by <i>E. coli</i> using disc diffusion and minimal inhibition concentration (MIC) methods. In addition, biofilm inhibitory action of oils was realized by crystal violet. Gas chromatography⁻mass spectrometry (GC⁻MS) analysis showed a variability between oils in terms of compound numbers as well as their percentages. Antibacterial activity was observed only in cases of <i>Origanum majorana</i>, <i>Thymus zygis</i> and <i>Rosmarinus officinalis</i>, while <i>Juniperus communis</i> and <i>Zingiber officinale</i> did not showed any effect towards <i>E. coli</i> isolates. <i>T. zygis</i> essential oil demonstrated the highest antibacterial activity against <i>E. coli</i> isolates, followed by <i>O. majorana</i> and <i>R. officinalis</i>. Further, oils showed high biofilm inhibitory action with a percentage of inhibition that ranged from 14.94% to 94.75%. <i>R. officinalis</i> oil had the highest antibiofilm activity followed by <i>T. zygis</i> and <i>O. majorana</i>. Accordingly, tested oils showed very effective antibacterial and antibiofilm activities against <i>E. coli</i> UTIs and can be considered as good alternative for antibiotics substitution.