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A longitudinal perspective of tigecycline activity in the EU against Staphylococcus aureus, Enterococcus faecalis, and Streptococcusspp. including resistant and multidrug-resistant phenotypes

Abstract number: P1674

Draghi D., Pillar C.M., Dowzicky M., Sahm D.F.

Background: Due to the prevalence of methicillin resistant S. aureus (MRSA), penicillin resistant S. pneumoniae (PRSP), and erythromycin resistant S. pyogenes (SPY), agents used to treat Gram-positive (GP) infections should maintain activity against these resistant subpopulations. Tigecycline (TIG) is primarily intended for treatment of infections encountered in healthcare settings where resistance (R) is a continuous threat. It is important to understand current activity and trends in R to utilized agents, in particular those recently approved for use. This study reports the activity profile of TIG over 10 years spanning its development and approval for use against target GP organisms in Europe (EU).

Methods: TIG activity was profiled from 2000 until 2009 against a collection of 2195 S. aureus (SA), 88 vancomycin-susceptible E. faecalis (VSEf), 611 S. pneumoniae (SP), and 493 S. pyogenes (SPY) collected from 12 countries in EU. Isolates were tested by broth microdilution against TIG and comparators utilizing CLSI guidelines (M7-A9). EUCAST breakpoints (BPs) were applied to TIG results. CLSI (M100-S19) BPs were used to interpret all comparators (where applicable).

Results: Against SA, TIG maintained consistent activity from year to year with MIC50s of 0.06–0.12 mg/L and MIC90s of 0.12–0.25 mg/L, and >99% susceptibility. The TIG activity profile was not altered against MRSA or MDR subpopulations. SA also remained >99% susceptible to linezolid, vancomycin and daptomycin in contrast to other evaluated agents (e.g. clindamycin [CLI], erythromycin [ERY], levofloxacin). Similar to SA, TIG had a potent and consistent activity profile against both SP (MIC50s 0.015–0.03 mg/L and MIC90s 0.015–0.06 mg/L; 100%S) and SPY (MIC50s 0.015–0.03 mg/L and MIC90s 0.03–0.06 mg/L; 100%S) including PRSP and macrolide R SPY subpopulations. Excluding CLI and ERY, there was little observed R to the evaluated agents among the tested streptococci. TIG also was potent year to year against VSEf, with MIC50s 0.06–0.25 mg/L and MIC90s 0.12–0.5 mg/L. No TIG R was detected among VSEf across the evaluated period.

Conclusions: Over the years studied, TIG has maintained potent in vitro activity overall against target GP cocci with >99% susceptibility rate, including R and MDR isolates. Notable trends in decreased activity for TIG were not observed despite increased use since approval in 2006; however, continued surveillance is warranted as the threat of R development is ongoing.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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