Sustained Antimicrobial Activity of Tigecycline Against Methicillin-Resistant Staphylococcus aureus (MRSA) from United States Medical Centers from 2004 Through 2008

Tigecycline, a glycylcycline, has been approved by the United States Food and Drug Administration (USA-FDA) for the treatment of complicated skin and skin structure infections, intra-abdominal infections and community-acquired bacterial pneumonia. Based on broth microdilution minimum inhibitory concentration (MIC) testing, tigecycline demonstrated sustained high activity (MIC50/90, 0.12/0.25 mg/L) against a contemporary collection (10,242) of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA) collected from 32 USA hospitals over a 5-year period (2004-2008). Tigecycline MIC distribution did not vary significantly during the study period and only three isolates (0.03%) were non-susceptible at USA-FDA breakpoints. Vancomycin (MIC90, 1 mg/L), trimethoprim/sulfamethoxazole (MIC90, <= 0.5 mg/L) and linezolid (MIC90, 2 mg/L) were also very active. The results of this study indicate that tigecycline potency and spectrum against MRSA have not changed since its initial regulatory approval by the USA-FDA.