Objective： To investigate the effect of Qiguiyin Decoction （芪归银方, QGYD） on multidrug-resistant Pseudomonas aeruginosa infection in Sprague-Dawley （SD） rats. Methods： A pseudomonal infection model in SD rats was established by injecting multidrug-resistant P. aeruginosa intraperitoneally. Infected rats were randomized into four groups treated with Pure water, QGYD, ceftazidime, or combined QGYD and ceftazidime. Blood samples were obtained from the abdominal aorta. Serum was then collected and analyzed by peptide array for immune responsiveness to multidrug-resistant beta-lactamase proteins, including Verona integronencoded metailo-beta-lactamase 1 （VIM-l）, Sao Paulo metallo-beta-lactamase 1 （SPM-1）, and Temoniera （TEMs）. Blood levels of interleukin-113 （IL-113）, interleukin-4 （IL-4）, and interferon-γ （IFN-γ） were assessed by enzyme-linked immunosorbent assay. Results： QGYD enhanced antibody reactivity against VIM-1 [epitopes 7-11 and 36-40] and TEM-1 [epitopes 26-27, 52-55, and 66-70]. QGYD treatment restored the compromised antibody reactivity against VIM-1 [epitopes 53-54 and 56-58] and SPM-1 [epitopes 16-19 and 82-85] following pseudomonal infection. Serum levels of IL-113 and Thl/＇l-h2 in the rats were significantly elevated following pseudomonal infection （P〈0.05 or P〈0.01）. In contrast, QGYD and combination QGYD and ceftazidime treatment restored the elevated serum IL-1β and Thl/-rh2 levels to normal （P〉0.05）. Conclusions： QGYD improves the immune response to pseudomonal infection in rats by stimulating the production of protective antibodies against drug-resistant proteins VIM-1, SPM-1, and TEM-1. In addition, it protects the immune system and maintains immune responsiveness by restoring IL-1β and Thl/Th2 levels.
