ABSTRACT
<p><b>OBJECTIVE</b>To investigate the resistant effect of houttuyfonate sodium (SH) combined with imipenem (IMP) against Pseudomonas aeruginosa (Pa) biofilms.</p><p><b>METHOD</b>The two-fold dilution method was used to examine the minimum inhibitory concentration (MIC) of the tested drug. The crystal violet staining was applied to detect the effect of the combination of 1/2MIC, 1MIC, 2MIC of SH, single IMP, 1/2MIC of SH and IMP of various concentrations on the clearance rate of adherent bacteria, growth of biofilms and alginate production. Fluorescein diacetate (FDA)-propidium iodide (PI) doubling staining assay was employed to observe the bacterial viability and morphological changes after membrane dispersion of each drug group.</p><p><b>RESULT</b>Sodium houttuyfonate could enhance the effect of IMP against pseudomonas aeruginosa biofilms. Particularly, the combination group with the concentration of 2MIC showed the highest effect, with P < 0.001 compared with the negative control group. The above results were proved by the bacterial viability and biofilm morphology under fluorescence microscope.</p><p><b>CONCLUSION</b>After being combined with imipenem, sodium houttuyfonate shows a higher effect against biofilms. It is expected that the combination of the two drugs could improve the clinical efficacy of associated infections.</p>