The study was performed to detect the in vitro activity of
tigecycline in multidrug-resistant Acinetobacter isolates from patients in Hacettepe University Adult Hospital, Turkey. The microorganisms were isolated from clinical specimens of patients with respiratory and
bloodstream infections. Thirty (66.7%) of the 45 inpatients were in ICUs. In vitro activity of
imipenem,
meropenem,
ceftazidime,
ciprofloxacin and
aztreonam in 124 Acinetobacter species isolated was evaluated by microdilution test. Overall, 51 (41%) Acinetobacter spp. were found to be resistant to > or = 3
antibiotics belonging to different antimicrobial classes and defined as multidrug-resistant (MDR). Among the MDR Acinetobacter spp. 32 (62.7%) were Acinetobacter baumannii and 19 (37.3%) Acinetobacter lwoffii. In vitro activity of
tigecycline against MDR isolates were studied by E-test. Each MDR isolate was also tested for metallo-
beta-lactamase (MBL) production using CLSI guidelines. Forty-five (88.2%) of the isolates were found to produce MBL. The MIC90s of all
antimicrobial agents tested except
tigecycline were > or = 64 microg/ml whereas the MIC50, and MIC90 of
tigecycline were found 1 microg/ml and 1.5 microg/ml, respectively. ERIC-PCR results revealed that bloodstream and respiratory isolates had nine and six different patterns, respectively. In conclusion,
tigecycline has been shown to have potent in vitro activity against MDR Acinetobacter spp. and might be of therapeutic value in the treatment of
infections due to MDR Acinetobacter spp., including those harbouring MBLs. Further clinical trials are needed to confirm the efficacy of
tigecycline in the management of MDR
Acinetobacter infections.