Coinfection with Haemophilus influenzae promotes pneumococcal biofilm formation during experimental otitis media and impedes the progression of pneumococcal disease.
BACKGROUND
Otitis media is an extremely common pediatric infection and is mostly caused by bacteria that are carried within the nasopharyngeal microbiota. It is clear that most otitis media cases involve simultaneous infection with multiple agents.


METHODS
Chinchillas were infected with nontypeable Haemophilus influenzae, Streptococcus pneumoniae, or a combination of both organisms, and the course of disease was compared. In vitro experiments were also performed to address how coinfection impacts biofilm formation.


RESULTS
The incidence of systemic disease was reduced in coinfected animals, compared with those infected with pneumococcus alone. Pneumococci were present within surface-attached biofilms in coinfected animals, and a greater proportion of translucent colony type was observed in the coinfected animals. Because this colony type has been associated with pneumococcal biofilms, the impact of coinfection on pneumococcal biofilm formation was investigated. The results clearly show enhanced biofilm formation in vitro by pneumococci in the presence of H. influenzae.


CONCLUSIONS
Based on these data, we conclude that coinfection with H. influenzae facilitates pneumococcal biofilm formation and persistence on the middle ear mucosal surface. This enhanced biofilm persistence correlates with delayed emergence of opaque colony variants within the bacterial population and a resulting decrease in systemic infection.
Weimer
Kristin E D
KE
Department of Microbiology and Immunology, Wake Forest University Health Sciences, Winston-Salem, North Carolina, USA.
Armbruster
Chelsie E
CE
Juneau
Richard A
RA
Hong
Wenzhou
W
Pang
Bing
B
Swords
W Edward
WE
D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D002682:Chinchilla; D004195:Disease Models, Animal; D018450:Disease Progression; D006192:Haemophilus Infections / Q000382:microbiology* / Q000473:pathology; D006193:Haemophilus influenzae / Q000254:growth & development*; D006801:Humans; D010033:Otitis Media / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000382:microbiology* / Q000473:pathology; D018805:Sepsis / Q000517:prevention & control; D013296:Streptococcus pneumoniae / Q000254:growth & development*