Otitis Media (OM) is an extremely common and costly pediatric illness, with an economic burden exceeding $3 billion per year in the U.S. alone. OM is caused by dysfunction of the Eustachian tube, which facilitates persistent colonization of the middle-ear chamber by bacterial opportunists that normally reside within the nasopharyngeal microbiota. These bacteria persist within multicellular biofilm communities that afford inherent resistance to clearance. Recent work has demonstrated that bacterial biofilms observed in the chinchilla infection model for otitis media contain a significant proportion of host extracellular DNA, and fit many of the defining characteristics of neutrophil extracellular traps or NETs which have been proposed to mediate direct killing and augment phagocytic clearance of bacteria and other microbes. However, work from our laboratory and others using in vitro models have shown that NETs are not an efficient killing mechanism for major otopathogenic bacterial strains, and instead that nontypeable H. influenzae and encapsulated pneumococci survive within the NET structure. In this study, inflammatory exudate material was recovered from the middle-ear chamber of a patient undergoing tympanostomy surgery for chronic/ recurrent OM infections and used to address the hypotheses that: i) neutrophil extracellular traps occur in human patients and ii) as in our model studies, they lack the ability to resolve bacterial infection.
Swords et al. (2013)