Moraxella (Branhamella)catarrhalis BRO β-Lactamase: a Lipoprotein of Gram-Positive Origin?

In the past 20 years, BRO beta-lactamase-producing Moraxella catarrhalis strains have emerged. We show that BRO is expressed as a 33-kDa lipoprotein associated with the inner leaflet of the outer membrane. To our knowledge, this is the first description of a lipidated beta-lactamase in a gram-negative species.