Pan-resistance to commonly used antibiotics and nonsusceptible to tigecycline Acinetobacter baumannii clinical isolates

Abstract number: R2296

Stylianakis A., Papaioannou V., Pantazis E., Lykou D., Merianos I., Koutsoukou A.

Objectives: To describe five panresistant to commonly used antibiotics and intermediately susceptible or resistant to tigecycline Acinetobacter baumannii clinical isolates.

Methods: We examined five A. baumannii isolates originated from equal numbered patients treated in different wards of our hospital. Four out of five patients were hospitalised in two different ICUs and the fifth in the neurosurgical ward. The sources of the examined isolates were blood (n = 1), vein catheter (n = 1) and bronchoalveolar excretions (n = 3). The identification of the isolates and the susceptibility testing were performed using the automated VITEK 2 system (Biomerieux, France). The resistance to colistin was confirmed by E-test method (AB Biodisk, Solna, Sweden) according to CLSI guidelines. The tigecycline MIC levels were also determined using E-test strips in accordance to the manufacturer's recommendations. Isolates having MIC values between 2 to <8 mg/L were considered as intermediately susceptible to tigecycline and MIC values geqslant R: gt-or-equal, slanted8 mg/L as resistant to tigecycline according to breakpoints recommended by the British Society of Antimicrobial Chemotherapy [1].

Results: The examined five A. baumannii isolates were resistant to all aminoglycosides, b-lactams, carbapenems, monobactames, quinolones and colistin. The obtained tigecycline MIC values were 3 mg/L (blood and vein catheter samples, n = 2), 4 mg/L (bronchoalveolar excretions samples, n = 2) and 8 mg/L (bronchoalveolar excretions sample, n = 1).

Conclusion: The nonsusceptible to tigecycline and panresistant to the commonly used antibiotics A. baumannii isolates rapidly nullify the whole of our therapeutic armamentarium leading to therapeutic failure. It is very challenging to reach the knowledge of the tigecycline-nonsusceptible mechanisms of this bacterium and to discover newer antimicrobials to reduce the abilities of this dangerous pathogen.


1. R. Hope et al.: Determination of disc breakpoints and evaluation for Etests for tigecycline susceptibility testing by the BSAC method. Journal of Antimicrobial Chemotherapy (2007) 60, 770–774.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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