The human nasopharynx harbors a diverse microbial community that includes nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae.  Although carriage of these organisms is usually benign and may actually have beneficial effects, in patients with mucociliary clearance defects these organisms can cause opportunistic infections.  These include middle-ear infections (otitis media) in children, and bronchopulmonary infections that are especially common in adults with chronic obstructive pulmonary disease.  These infections are among the most common and costly public health problems worldwide.  Our work is focused on defining and understanding bacterial attributes that promote persistence and recalcitrance to treatment in these settings.  In particular, I will discuss our work with bacterial biofilms and their role in resistance to host immune effectors.