Abstract：Objective To investigate the synergy effects of tigecy cline combind with commonly used other antibacterial agents against the carbapenem-resistant Enterobacteriaceae (CRE). Methods A total of 235 non-repetitive CRE collected from clinical isolates in 2014 to 2016. The antimicrobial susceptibility of tigecycline and 9 kinds of commonly used antibacterial agents were determined by the ager dilution method. The 35 strains that were not sensitive to tigecycline were studied. Synergistic effects between tigecycline and other antibacterial agents, including imipenem, meropenem, ceftazidime, cefotaxime, levofloxacin, piperacillin/tazobactam, amikacin, aztreonam, and cefoperazone/sulbactam against 35 strains of CRE were determined by the chequerboard assay. Results The drug-resistant rates of tigecycline were 5.1% (7/137) in Klebsiella pneumonia, 5.6% (1/18) in serratia, 7.7% (1/13) in Enterobacter aerogenes, 8.3% (1/12) in Enterobacter cloacae. Tigecycline in combination with ceftazidime and piperacillin/tazobactam showed the best activity against CRE with synergy rate of 28.6% (10/35). Tigecycline in combination with cefotaxime(9/35, 25.7%), levofloxacin(8/35, 22.9%) and cefoperazone/sulbactam (7/35, 20.0%) also prsesnted good activity against CRE. No antagonism was demonstrated among all of combinations. Conclusion A combination of tigecycline and ceftazidime or piperacillin/tazobactam shows good activity, combined treatments may be more effective than tigecycline alone. It provides a new strategy in the campaign against serious infections caused by CRE.
