en باکتری شناسی Bactriology پژوهشي Research <div style="text-align: justify;"><span style="font-size:16px;"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><b><span style="line-height:115%">Introduction:</span></b><span style="line-height:115%"> Antimicrobial resistance has become a serious global health issue; hospital-acquired infections are now much harder to treat effectively. <i>Stenotrophomonas maltophilia</i> emerges as an opportunistic Gram-negative bacterium with built-in resistance to numerous antimicrobial agents. The present work examined the antibacterial and anti-biofilm effects of <i>Satureja khuzestanica</i> essential oil and coumarin against a standard strain of <i>Stenotrophomonas maltophilia</i>.</span></span></span><br> <span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><b><span style="line-height:115%">Materials and Methods: </span></b><span style="line-height:115%">Essential oil was extracted by hydrodistillation from the aerial parts of <i>Satureja khuzestanica</i>. Agar well diffusion tested basic susceptibility. Broth microdilution measured minimum inhibitory concentration </span><span dir="RTL" lang="FA"><span style="line-height:115%">)</span></span><span style="line-height:115%">MIC</span><span dir="RTL" lang="FA"><span style="line-height:115%">(</span></span><span style="line-height:115%"> and minimum bactericidal concentration </span><span dir="RTL" lang="FA"><span style="line-height:115%">)</span></span><span style="line-height:115%">MBC) values. Crystal violet assay assessed biofilm inhibition at sub-inhibitory concentrations </span><span dir="RTL" lang="FA"><span style="line-height:115%">)</span></span><span style="line-height:115%">sub-MIC</span><span dir="RTL" lang="FA"><span style="line-height:115%">(</span></span><span style="line-height:115%"> concentrations of the essential oil.</span></span></span><br> <span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><b><span style="line-height:115%">Results: </span></b><span style="line-height:115%">Inhibition zones measured 40.0 mm for the essential oil and 30.0 mm for coumarin. The oil gave an MIC of 31.25 &micro;g/mL and an MBC of 62.50 &micro;g/mL. A ratio of 2.0 indicated bactericidal activity. Coumarin displayed poor solubility with precipitation in broth medium; reliable MIC and MBC values remained undetermined. Biofilm formation fell by 62.1% at half the MIC of the essential oil (p < 0.001).</span></span></span><br> <b><span new="" roman="" style="font-family:" times="">Conclusion: </span></b><i><span new="" roman="" style="font-family:" times="">Satureja khuzestanica</span></i><span new="" roman="" style="font-family:" times=""> essential oil effectively killed planktonic cells of <i>Stenotrophomonas maltophilia</i> and substantially reduced biofilm development. Data support the potential application of this oil in plant-derived therapies for multidrug-resistant strains and chronic biofilms in clinical settings. Improved formulations may yield viable options in the near term. Addition to conventional antibiotics could prolong their utility.</span></span></div> Anti-Bacterial Agents, Anti-Biofilms Agents, Coumarins, Satureja khuzestanica, Stenotrophomonas maltophilia C 0 0 http://ijml.ssu.ac.ir/browse.php?a_code=A-10-468-2&slc_lang=en&sid=1 Kimiya Khani-Chegeni کیمیا خانی-چگنی kimiyakhanichegeni@gmail.com No Department of Biology, Khor.C., Islamic Azad University, Khorramabad, Iran Department of Biology, Khor.C., Islamic Azad University, Khorramabad, Iran. Samaneh Sedighi-Khavidak سمانه صدیقی-خویدک sedighi.s@iau.ac.ir No Department of Biology, Ashk.C., Islamic Azad University, Ashkezar, Iran Department of Biology, Ashk.C., Islamic Azad University, Ashkezar, Iran. Farhad Gilavand فرهاد گیلاوند farhad98@iau.ac.ir Yes Department of Biology, Khor.C., Islamic Azad University, Khorramabad, Iran Department of Biology, Khor.C., Islamic Azad University, Khorramabad, Iran.