In Vitro Antibacterial Activity of Galla Chinensis Combined with Different Antibacterial Drugs against Carbapenem-Resistant E.Coli

Abstract

Objective: To evaluate the antibacterial effects of meropenem and levofloxacin respectively combined with Galla chinensis on carbapenem-resistant Escherichia coli in vitro. Methods： The protocol was designed with checkerboard method and the carbapenem-resistant E.coli was isolated in our hospital. The minimum inhibitory concentrations(MICs) of G. chinensis alone and combined with 2 antimicrobial agents against carbapenem-resistant E.coli were determined by broth dilution method and the fractional inhibitory concentration index (FICI) was calculated according to MICs results. Result： the combined use of G. chinensis and meropenem (or levofloxacin) significantly decreased both MIC50 and MIC90; After the combination of G. chinensis and meropenem, the synergistic effect was 86.7%, and the additive effect was 13.3%, no irrelevant and antagonistic effects. After combined use of G. chinensis and levofloxacin, the synergistic effect was 66.7%, and the additive effect was 33.3%. No irrelevant and antagonistic effects. Conclusion： Galla chinensis combined with meropenem or levofloxacin has synergistic and additive antibacterial effect, with certain combined antibacterial activity.