Tigecycline activity against Staphylococcus aureus exhibiting multidrug-resistant phenotypes in Europe
Abstract number: P586
Sahm D., Draghi D., Pillar C., Thornsberry C., Dowzicky M.
Objective:Staphylococcus aureus (SA) can cause complicated skin and skin structure infections and complicated intra-abdominal infections. Recently in 2006, tigecycline (TIG) was approved in Europe (EU) to treat these infections. SA worldwide are becoming resistant to the most commonly prescribed antimicrobial treatments. TIG is used in healthcare settings where resistance (R), including multidrug resistance (MDR) has become prevalent. Recent outbreaks of this organism have shown clearly that resistance can develop to several different agents. Careful monitoring of new agents such as TIG has become imperative.
Methods: In total, 686 SA isolates were obtained from 28 hospitals in ten countries across EU during 2006 to 2007. Isolates were tested centrally by broth microdilution (CLSI M7-A7). TIG activity was analysed by oxacillin (OX) and MDR status defined as resistance to 3 agents which included OX, minocycline, erythromycin (ERY), clindamycin (CLI), gentamicin, and levofloxacin (LEV). EUCAST breakpoints were used to interpret TIG MIC results and CLSI (M100-S17) breakpoints were used to interpret all other agents, where applicable.
Results: The susceptibility rate overall for SA tested against TIG was 99.4%, with MICs ranging from 0.03 to 1 mg/L. Regardless of OX or MDR status, the TIG modal MIC and MIC90 (mg/L), remained consistent at 0.12 and 0.25, respectively. TIG maintained the lowest MIC90 of all comparators tested. The most common MDR phenotype was 3-drug R with concurrent R to ERY, LEV, and OX (18.1% of all isolates surveyed) followed by 4-drug R with concurrent R to CLI, ERY, LEV, and OX (17.3% of all isolates surveyed). Among MDR populations, TIG maintained >99% susceptibility rate.
Conclusion: TIG has exhibited exceptional in vitro activity against SA including MDR populations. The potential for R to emerge and spread is increasing among SA according to recent CDC reports, therefore continuous monitoring provided by this surveillance initiative is essential to guide clinicians for new therapeutic options.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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