Resistant pathogens are the cause of clinical
infections which threatening the patients lives and challenging the health systems through their economic importance. Therefore, new
antibacterial agents with a broader spectrum of activity that protect against development of resistance are required.
Tigecycline (
Tygacil, Wyeth) is a relatively new FDA and EMEA approved
glycylcycline antimicrobial with an expanded broad-spectrum activity against pathogens involved in complicated skin and skin structure
infections. In this study we evaluated the in vitro activity of
tigecycline in comparison to 14 other
antibiotics against 182 clinical pathogens by use of the micro dilution method. In overall,
tigecycline exhibited the lowest Minimum Inhibitory Concentration (MIC) values in almost all bacteria with a mean of 0.52 ± 1.25mg/L, followed by
meropenem and
levofloxacin (mean MIC values 1.29 ± 2.52 and 1.45 ± 3.078 mg/L, respectively). MIC50 and MIC90 values of
tigecycline were: 0.06 and 0.15 mg/L for E. coli, 0.12 and 1.00 mg/L for Klebsiella sp., 0.12 and 0.85 mg/L for various Enterobacter sp., 1.00 and 8.00 mg/L for Pseudomonas sp., 0.25 and 1.00 mg/L for Acinetobacter sp., 0.06 and 0.12 mg/L for Serratia sp., 0.12 and 0.25mg/L for Staphylococcus aureus, 0.5 and 5.00 mg/L for Streptococcus sp. The MIC values recorded were among the lowest in recent literature for Acinetobacter sp. (included A. baumannii), and comparable to those obtained for Klebsiella, Serratia and Enterobacter indicating that
tigecycline has a promising in vitro activity.