In Vitro Activities of Tigecycline in Combination with Imipenem Against Multi-drug Resistant and Pan-drug Resistant Acinetobacter Baumannii Isolates / 医药导报

ABSTRACT

Objective To evaluate the in vitro antimicrobial activity of tigecycline in combination with imipenem against multi-drug resistant and pan-drug resistant Acinetobacter baumannii isolates,so as to discuss the feasibility of drug combination and provide the basis for chnical rational use of antimicrobial agents.Methods Sixteen multi-drug resistant and pan-drug resistant Acinetobacter baumannii isolates were collected between January and April in 2015 from all kinds of infected specimens of Nanjing Drun Tower Hospital.The protocol was designed by checkerboard method,and the minimum inhibitory concentration (MIC) of antibiotics was determined by microdilution broth method,and the fractional inhibitory concentration (FIC) index was calculated according to MIC results.Results The average value of MIC (MICG),MIC50,MIC90 of tigecycline and imipenem single were 1.73,1,4 μg·mL-1and 31.00,32,64 μg·mL-1.When tigecycline was combined with imipenem,MICG,MIC50,MIC90 of tigecycline and imipenem were 0.24,0.25,0.50 μg·mL-1 and 8.16,8.00,16.00 μg·mL-1,respectively.Compared with the drug single use groups,MIC was significandy decreased in the drug combination group.In 6 strains (37.50％),synergy effect (FIC≤0.5) was observed,and in 10 strains (62.50％),additive effect (0.5 ＜ FIC ≤ 1) was found.No negative and independent effects were shown.Conclusion Both additive and synergistic action is observed when tigecyclineis combined with imipenem against multi-drug resistant and pan-drug resistant Acinetobacter baumannii isolates.No negative and independent effects are shown.This combination use against multi-drug resistant and pan-drug resistant Acinetobacter baumannii may be an effective therapy for clinical treatment.