Macrolide and tetracycline resistance among Moraxella catarrhalis isolates from 2009 to 2011

The activity of macrolides and other antimicrobials was evaluated by Clinical and Laboratory Standards Institute reference broth microdilution methods for Moraxella catarrhalis isolates collected during 2009-2011. In Europe, the United States, and Latin America, M. catarrhalis resistance to macrolides and tetracycline was <1%. However, in the Asia-Pacific region, clarithromycin and tetracycline resistance was 7.6% and 3.2%, respectively. The higher resistance rate in the Asia-Pacific region to clarithromycin and tetracycline was primarily due to isolates from multiple locations in China.