Global Prevalence, Genetics and Clonal Relatedness of Macrolide Resistance in Moraxella catarrhalis (2010-2012)

Objective: To evaluate the global prevalence of macrolide resistance (MAC-R) in Moraxella catarrhalis during 2010 to 2012 and to determine the genetic basis of resistance and clonal relatedness of strains. MAC-R is generally 90%) to ampicillin and other penicillins, due to the presence of BRO-1 (common) or BRO-2 (less common) β-lactamases. Resistance to other therapeutically useful agents, such as extended-spectrum cephalosporins, macrolides, trimethoprim/sulphamethoxazole, tetracyclines and fluoroquinolones, is very rare (<1% reported in several regions of the world). We previously reported on increasing macrolide resistance (up to 7.6%) in the Asia-Pacific region, specifically China, in isolates collected during 2009 to 2011 (Flamm RK, et al. 2012). In this study, we examined macrolide resistance in global isolates collected during 2010 to 2012 and determined the macrolide resistance mechanisms associated with this resistance. In addition, we investigated the genetic relatedness of these strains.