## 3 Results
### In-Silico Docking of Metronidazoleazole into P. mirabilis QS Essential Proteins  
To give a hint into the capability of metronidazoleazole to antagonize the QS essential proteins; the interaction between metronidazoleazole and QS proteins was evaluated. _P. mirabilis_ QS protein was retrieved from UniProtKB (PMI1345) and molecular docking was carried out. The results showenin Figure 6, displayed that thereceptor well accommodating metronidazoleazole inside the binding cavity and establishing appropriate interactions involved the formation of three hydrogen bonds; the proton of OH group engaged in one hydrogen bond with Glu57. The oxygen atom of NO\({}_{2}\) involved in the formation of two hydrogen bonds with Gly129 and Thr130 amino acid residues. Additionally, the oxygen of OH group and the oxygen of NO\({}_{2}\) group of metronidazoleazole engaged in the formation of two important metal acceptor bonds with ZN:1. Moreover, metronidazoleazole incorporated in many hydrophobic interactions with His54, Glu57, Cys128 and ZN:1. These results may explain the possible reasons for enhanced anti-QS activity of metronidazoleazole.  
Figure 3: Effect of metronidazoleazole in sub-MIC on _P. mirabilis_ motility. One-way ANOVA test was used to compare between the metronidazoleazole in \(\frac{1}{2}\) MIC or \(\frac{1}{4}\) MIC treated and untreated bacterial cultures. The data were shown as mean \(\pm\) standard error of percentage change from untreated cultures; and were considered statistically significant when \(p\) values \(<\) 0.05. (**A**) Light microscope image of simple stained _P. mirabilis_ at the center (non-swarmer cells), the edge of swarming (elongated larger swarmer cells) and swarmer cells in presence of metronidazoleazole. Clearly, the swarmer cells in presence of metronidazoleazole is smaller than those in absence of metronidazoleazole. (**B**,**C**) Metronidazoleazole in sub-MIC significantly reduced the swarming motility (\(p\)\(<\) 0.0001). (**D**,**E**) The diameters of swimming motiliy were significantly decreased in presence of meetronidazoleazole in sub-MIC (\(p\)\(<\) 0.0001). *** = \(p\)\(<\) 0.001.  
Figure 4: Effect of metronidazolezole in sub-MIC on _P. mirabilis_ adhesion. (**A**) Adhesion to epithelial cells: epithelial cells from urine of pregnant were occultured with _P. mirabilis_ treated or untreated with metronidazolezole in \(\frac{1}{2}\) MIC or \(\frac{1}{4}\) MIC. (**B**) Metronidazolezole significantly reduced the number of adhered bacterial cells to epithelial cells (_p_ < 0.0001 and 0.0095 for \(\frac{1}{2}\) MIC or \(\frac{1}{4}\) MIC, respectively). (**C**) Adhesion to abiotic surface: _P. mirabilis_ was cultured in presence or absence of metronidazolezole in \(\frac{1}{2}\) MIC or \(\frac{1}{4}\) MIC, incubated at 37 \({}^{\circ}\)C for 60 min. The adhered cells were crystal violet stained and their optical densities were measured at 590 nm. Significantly, metronidazolezole reduced the bacterial adhesion (_p_ < 0.0001). One-way ANOVA test was used to compare between the metronidazolezole in \(\frac{1}{2}\) MIC or \(\frac{1}{4}\) MIC treated and untreated bacterial cultures. The data were expressed as mean \(\pm\) standard error of percentage change from untreated cultures; and were considered statistically significant when \(p\) values < 0.05. (**D**) Interactions of metronidazolezo into the active site of _P. mirabilis_ adhesin MrpH (PDB: ID 6Y4F): (**i,ii**) three dimensional and (**iii**) two dimensional interactions. \({}^{**}=p<0.01\), \({}^{**}=p<0.001\).