Background: Tigecycline is a new glycylcycline with broad-spectrum activity. Among these new agents, tigecycyline is unique in generally having good activity against Gram-negative bacteria. Tigecycline has been approved for the treatment of complicated intra-abdominal infections and complicated skin and skin structure infections. Tigecycline had good activity against most ESBL-producing Enterobacteriaceae and may be a therapeutic alternative to carbapenems in some infections caused by ESBL-producing isolates, many of which are also multiresistant to quinolones, aminoglycosides, and classical tetracyclines.
Material/Methods: One hundred and eight clinical isolates of Klebsiella spp. (64 K. pneumoniae and 44 K. oxytoca) were included. The susceptibility to selected antibiotics was tested by the disk-diffusion method. Tigecycline’s MIC was determined by the Etest.
Results: Of all the analyzed Klebsiella spp. strains, 31 (28.7%) produced ESBLs. Most of the Klebsiella spp. strains were susceptible to imipenem (100%), tigecycline (92.5%), and the combination of piperacilline and tazobactam (80.6%). Tigecycline exhibited high activity against Klebsiella strains, with MICs ranging from 0.19 to 4 microg/ml.
Conclusions: Tigecycline demonstrated excellent inhibitory activity against the analyzed strains. These data suggest that tigecycline, with an expanded broad-spectrum antimicrobial activity, may be an effective therapeutic option for the treatment of serious infections caused by Klebsiella strains.

Keywords: Klebsiella pneumoniae - metabolism, Klebsiella Infections - drug therapy, Klebsiella - metabolism, Enterobacteriaceae - metabolism, Drug Resistance, Multiple, Bacterial - drug effects, Drug Resistance, Bacterial, Cross Infection, Anti-Bacterial Agents - pharmacology, Microbial Sensitivity Tests, Minocycline - pharmacology, beta-Lactamases - metabolism