Efficacy of <i>Rhamnus frangula</i> extract against <i>Acinetobacter baumannii</i> biofilms: Histopathological evidence from <i>ex vivo</i> goat models

<em>Acinetobacter baumannii</em> (<em>A. baumannii</em>) is a Gram‑negative pathogen notorious for causing severe nosocomial infections, largely due to its ability to form biofilms that enhance antibiotic resistance and complicate treatment strategies. The present study explored the therapeutic potential of <em>Rhamnus frangula</em> (<em>R. frangula</em>) extract in mitigating <em>A. baumannii</em>‑induced biofilm formation and related organ damage in goat tissue samples. The efficacy of the extract was assessed using minimum inhibitory concentration (MIC) tests, histopathological evaluations of heart, lung, liver, kidney and spleen tissues, biofilm inhibition assays, and growth curve analysis. The MIC assay demonstrated that <em>R. frangula</em> extract effectively inhibited <em>A. baumannii</em> growth at a concentration of 5 mg/ml. Histopathological analysis revealed significant reductions in bacterial load and inflammatory infiltrates across all examined organs, with notable improvements, such as decreased myofibril disintegration in cardiac tissue and reduced alveolar damage in lung tissue. Furthermore, at a sub‑MIC of 2.5 mg/ml, <em>R. frangula</em> extract reduced biofilm formation by 67.26%, while exhibiting no effect on planktonic bacterial growth, highlighting its specific antibiofilm activity. These findings underscore the potential of R. frangula extract as a promising natural therapeutic agent for the treatment of biofilm‑associated infections and mitigating tissue damage caused by <em>A. baumannii</em>. However, further investigations into its molecular mechanisms and potential clinical applications are warranted to address the escalating challenge of antibiotic resistance and improve infection management strategies.