Otitis media with effusion (OME) is a significant health problem of children. Haemophilus influenzae is one of the major causes of this disease. Features of H. influenzae OME include frequent recurrences and a failure of eradication with antibiotic administration. One hypothesis explaining these features of H. influenzae OME is that the organism is growing as a biofilm in the middle ear. Bacterial biofilms are characteristically insensitive to antibiotic treatment, as well as incapable of elimination by the host inflammatory response. Evidence of a H. influenzae biofilm in children with OME consists of the presence of short-lived, Haemophilus-specific mRNA in the middle ear fluid of these children. Gram-negative bacterial biofilm formation is dependent upon the synthesis of quorum-sensing transcriptional activators, called autoinducers. We have found that H. influenzae; including those isolated from the middle ear possess a gene (HI0491) capable of synthesizing an autoinducer (AI-2). Insertional inactivation of HI0491 in the H. influenzae laboratory strain Rd KW20 results in a mutant, which lacks the ability to form mature biofilm structures, and has decreased susceptibility to antibiotics, a decreased conjugation frequency and decreased survival in an animal model of OME. ? ? In this application, we are seeking to characterize biofilm formation by several prototypic """"""""otitic"""""""" H. influenzae in vitro, assess experimental OME caused by these strains in the weanling rat and chinchillas, determine the role of the autoinducer in this disease and define the role of AI-2 in biofilm development in vitro and in vivo. Understanding the role of AI-2 and biofilm formation in OME will permit strategies to prevent or treat this disease to be devised. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC005833-04
Application #
6926067
Study Section
Special Emphasis Panel (ZDC1-SRB-A (36))
Program Officer
Watson, Bracie
Project Start
2002-09-20
Project End
2007-08-31
Budget Start
2005-09-01
Budget End
2006-08-31
Support Year
4
Fiscal Year
2005
Total Cost
$429,750
Indirect Cost
Name
Seattle Biomedical Research Institute
Department
Type
DUNS #
070967955
City
Seattle
State
WA
Country
United States
Zip Code
98109
Smith, Arnold L; Erwin, Alice L; Kline, Toni et al. (2007) Chloramphenicol is a substrate for a novel nitroreductase pathway in Haemophilus influenzae. Antimicrob Agents Chemother 51:2820-9
Erwin, Alice L; Smith, Arnold L (2007) Nontypeable Haemophilus influenzae: understanding virulence and commensal behavior. Trends Microbiol 15:355-62
Erwin, Alice L; Bonthuis, Paul J; Geelhood, Jennifer L et al. (2006) Heterogeneity in tandem octanucleotides within Haemophilus influenzae lipopolysaccharide biosynthetic gene losA affects serum resistance. Infect Immun 74:3408-14
Erwin, Alice L; Allen, Simon; Ho, Derek K et al. (2006) Role of lgtC in resistance of nontypeable Haemophilus influenzae strain R2866 to human serum. Infect Immun 74:6226-35
Daines, Dayle A; Bothwell, Marcella; Furrer, Jason et al. (2005) Haemophilus influenzae luxS mutants form a biofilm and have increased virulence. Microb Pathog 39:87-96
Coleman, Hannah N; Daines, Dayle A; Jarisch, Justin et al. (2003) Chemically defined media for growth of Haemophilus influenzae strains. J Clin Microbiol 41:4408-10