MPO and Vancomycin-Resistant Staphylococcus Aureus Infection: NO level and MPO activity were significantly (P < 0.05) increased in spleen by 195.49% and 190.94%, respectively, due to VRSA infection as compared to control group, in which they were significantly (P < 0.05) decreased by 37.03% and 44.76% due to treatment of nanoconjugated vancomycin (Figure 3).