Understanding persistent bacterial lung infections: Clinical implications informed by the biology of the microbiota and biofilms

The infections found in chronic obstructive pulmonary disease, cystic fibrosis, and bronchiectasis share a number of clinical similarities, the most striking of which is the bacterial persistence despite the use of antibiotics. These infections have been clinically described using culture-based methods usually performed on sputum samples, and treatment has been directed toward the bacteria found in this manner. Unfortunately, the clinical response to antibiotics is frequently not predictable on the basis of these cultures, and the role of these cultured organisms in disease progression has been debated. The past 20 years have seen a revolution in the techniques used to describe bacterial populations and their growth patterns. These techniques have revealed that persistent lung infections are vastly more complicated than described by traditional, and still widely relied upon, sputum cultures. A better understanding of the initiation and the evolution of these infections, and better clinical tools to describe them, will alter the way patients are cared for drastically. Although clinical tests to describe these infections more accurately are not yet available, the better appreciation of these infections afforded by current science should enlighten practitioners as to the care of their patients with these diseases.