Resistance of Clinical Isolated Gram Negative Bacilli to Tigecycline / 现代检验医学杂志

ABSTRACT

Objective To investigate the resistance of clinical isolated gram negative bacilli to tigecycline.Methods One hun-dred and fifteen Escherichia coli isolates,110 Klebsiella pneumoniae isolates and 99 Acinetobacter calcoaceticus-Acinetobact-er baumannii complex isolates were collected from Affiliated Second Hospital of Zhejiang University College of Medicine from the year 2012.The other 393 A.calcoaceticus-A .baumannii complex isolates were collected from 15 hospitals of nine cities in Zhejiang province during September to October 2012.Species identification and susceptibility test were confirmed by VITEK-2 compact system,while the 393 A.calcoaceticus-A .baumannii complex strains isolated from Zhejiang province were identified by MALDI-TOF MS.Moreover,159 A.baumannii isolates with tigecycline MIC value ≥8 μg/ml or 4 μg/ml and part of the MIC value ≤0.5 μg/ml,1 μg/ml and 2 μg/ml which were firstly determined by VITEK 2 GN AST-16 Suscepti-bility card were then determined by Etest.Results The 393 A.calcoaceticus-A .baumannii complex strains were identified as 317 of A.baumannii,32 of A.pittii and 44 of A.nosocomialis.When using the FDA breakpoints,the resistance rate of tige-cycline against 115 E.coli isolates,110 K.pneumoniae isolates and 99 A.calcoaceticus-A .baumannii complex isolates were 0.0%,7.3% and 6.1%,respectively.Interestingly,85.7% of the tigecycline-resistant gram negative bacilli were resistant to carbapenems.However,only 10.0% of the carbapenem-resistant gram negative bacilli were resistant to tigecycline.Conclu-sion Tigecycline had a good activity against clinical isolated multi-drug resistant or even pan-drug resistant gram negative bacilli.No matter which criteria for tigecycline was referred to,the resistance rate oftigecycline was slightly lower by Etest than by GN AST-16 Susceptibility card.