Microbial Biofilms in Pulmonary and Critical Care Diseases

Abstract

Microbial biofilms can colonize medical devices and human tissues, and their role in microbial pathogenesis is now well established. Not only are biofilms ubiquitous in natural and human-made environments, but they are also estimated to be associated with approximately twothirds of nosocomial infections. This multicellular aggregated form of microbial growth confers a remarkable resistance to killing by antimicrobials and host defenses, leading biofilms to cause a wide range of subacute or chronic infections that are difficult to eradicate. We have gained tremendous knowledge on the molecular, genetic, microbiological, and biophysical processes involved in biofilm formation. These insights now shape our understanding, diagnosis, and management of many infectious diseases and direct the development of novel antimicrobial therapies that target biofilms. Bacterial and fungal biofilms play an important role in a range of diseases in pulmonary and critical care medicine, most importantly catheter-associated infections, ventilator-associated pneumonia, chronic Pseudomonas aeruginosa infections in cystic fibrosis lung disease, and Aspergillus fumigatus pulmonary infections.

Protein Engineering Reveals Mechanisms of Functional Amyloid Formation in Pseudomonas aeruginosa Biofilms

“…Infections with P. aeruginosa often manifest in the form of ventilator-associated pneumonia, which demonstrates mortality rates as high as 30% in patients with comorbidities [4]. The plastic endotracheal tube readily provides a colonization site for P. aeruginosa , and aerosolization of the mature biofilm by mechanical ventilation or tracheal suctioning can lead to ventilator-associated pneumonia [5]. Mucoid, biofilm-associated P. aeruginosa , is also found in chronic lung infections of patients with cystic fibrosis [6].…”

Discovery of a Novel Nitric Oxide Binding Protein and Nitric-Oxide-Responsive Signaling Pathway in Pseudomonas aeruginosa

“…11,12 P. aeruginosa biofilm infections in the lung are the leading cause of death in cystic fibrosis patients. 13 Although P. aeruginosa is a model biofilming organism, assembly and dispersal of biofilm in P. aeruginosa is still poorly understood.…”

Host responses to mucosal biofilms in the lung and gut

“…There is a significant body of literature describing the presence of lung-associated bacterial biofilms using in vitro models as well as assessment of potential in vivo biofilms using patient samples. 43,44 Lung mucosal biofilms are unique because they are often dominated by a single bacterial species, such as P. aeruginosa or non-typeable Haemophilus influenzae (NTHi) and in contrast to multispecies colonic biofilms, have allowed for greater development of species-specific biofilm tools. For example, NTHi isolates cultured in vitro can be evaluated for biofilm formation by immune-transmission electron microscopy using a monoclonal antibody targeting a H. influenzae-specific lipooligosaccharide antigen.…”