ZAAPS Program results for 2010: an activity and spectrum analysis of linezolid using clinical isolates from 75 medical centres in 24 countries

Abstract

The Zyvox® Annual Appraisal of Potency and Spectrum (ZAAPS) Program monitors the in vitro activities of linezolid and comparator agents for Gram-positive organisms in Latin America, Europe, Canada, and the Asia-Pacific. For the 2010 Program a total of 6305 Gram-positive strains were collected from 75 medical centres on five continents (24 countries). Reference broth microdilution susceptibility tests were performed on organisms from the following groups: Staphylococcus aureus (2875), coagulase negative staphylococci (CoNS) (855), enterococci (787), Streptococcus pneumoniae (926), viridans group and other streptococci (325), and beta-haemolytic streptococci (507). Linezolid demonstrated a 99·81% susceptibility rate among 6305 strains tested from 24 nations. Of the resistant isolates, four linezolid-resistant strains of enterococci (two each for Enterococcus faecalis and Enterococcus faecium) were found in four nations (China, Thailand, Germany, and Brazil). Eight CoNS (Staphylococcus epidermidis, Staphylococcus hominis) isolates were observed to be resistant to linezolid (MIC, ≧8 μg/ml). Two strains from Mexico were determined to be from an ongoing epidemic, and investigations showed that isolates from Italy and Brazil were also from circulating resistant clones discovered in earlier years. MRSA rates varied by region and between nations, as did resistances to other potential therapeutic agent options frequently listed for MRSA therapy such as clindamycin, fluoroquinolones and trimethoprim/sulfamethoxazole. In summary, the 2010 ZAAPS Program demonstrated that linezolid activity remains stable around the world with >99% susceptibility.

Keywords:

• Linezolid
• Oxazolidinones
• Surveillance
• ZAAPS

The co-authors express their appreciation for technical support and contributions to the preparation of this manuscript, A. Small, D. J. Biedenbach, P. R. Rhomberg, M. Castanheira, G. J. Moet. The authors thank all the global surveillance centres that contributed isolates to this study as well as Jan Bell and John Turnidge for their assistance with sample collection and testing of isolates from the APAC region. All co-authors are employees of JMI Laboratories who were paid consultants to Pfizer in connection with the development of this manuscript. Laboratory testing of clinical isolates was performed by JMI Laboratories via the SENTRY Antimicrobial Surveillance platform and funded by Pfizer Inc.