Streptococcus pneumoniae inhabits the human respiratory tract and causes disease when it leaves the nasopharyngeal region and invades normally sterile sites. Asymptomatic carriage is far more common than disease, yet these bacteria are important causes of otitis media, pneumonia, meningitis, and bacteremia in young children. Despite advances in our understanding of the epidemiology and pathogenesis of these bacteria, the precise factors that predispose a pneumococcal strain for carriage versus disease are not known. S. pneumoniae strains differ in their propensity to cause disease, and the genetic background of a particular strain is likely to influence its ability to successfully invade different tissue sites. We propose an interdisciplinary molecular and epidemiologic approach to increase understanding of the differences between pneumococcal carriage and clinical isolates. Our overall aims are 1) to determine the molecular epidemiology of S. pneumoniae clinical and carriage isolates from children <5 years of age;2) to identify tissue specific virulence factors associated with S. pneumoniae strains that cause clinical disease in children <5 years of age and evaluate their distribution among a large collection of clinical and carriage strains;and 3) to evaluate candidate otitis media specific virulence genes in the chinchilla model of otitis media. Specifically, we will determine the association of S. pneumoniae clones with carriage and specific clinical diseases using multilocus sequence typing, identify individual genetic determinants of tissue specific virulence using genomic subtraction, and evaluate the relative importance of these putative virulence determinants at the population level using a dot blot hybridization screen of a large, clinically relevant collection of pneumococcal isolates. These isolates are from healthy children and children with bacteremia, pneumonia, meningitis and otitis media. S. pnueumoniae deletion mutants in otitis media associated genes will be created and their virulence tested in an experimental chinchilla model of otitis media. A greater understanding of the genetic factors that influence the virulence potential of pneumococcal clones is critical to our ability to develop effective methods to control, prevent, and treat these important infections.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI068043-04
Application #
7777360
Study Section
Clinical Research and Field Studies of Infectious Diseases Study Section (CRFS)
Program Officer
Khambaty, Farukh M
Project Start
2007-04-01
Project End
2012-06-30
Budget Start
2010-04-04
Budget End
2012-06-30
Support Year
4
Fiscal Year
2010
Total Cost
$571,527
Indirect Cost
Name
Yale University
Department
Public Health & Prev Medicine
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Pelton, Stephen I (2012) Regulation of bacterial trafficking in the nasopharynx. Paediatr Respir Rev 13:150-3
Pettigrew, Melinda M; Laufer, Alison S; Gent, Janneane F et al. (2012) Upper respiratory tract microbial communities, acute otitis media pathogens, and antibiotic use in healthy and sick children. Appl Environ Microbiol 78:6262-70
Sabharwal, Vishakha; Figueira, Marisol; Pelton, Stephen I et al. (2012) Virulence of Streptococcus pneumoniae serotype 6C in experimental otitis media. Microbes Infect 14:712-8
Laufer, Alison S; Metlay, Joshua P; Gent, Janneane F et al. (2011) Microbial communities of the upper respiratory tract and otitis media in children. MBio 2:e00245-10
Thomas, Jonathan C; Figueira, Marisol; Fennie, Kristopher P et al. (2011) Streptococcus pneumoniae clonal complex 199: genetic diversity and tissue-specific virulence. PLoS One 6:e18649
Thomas, J C; Kong, Y; Sabharwal, V et al. (2011) Streptococcus pneumoniae serotype 6C: an intra- and interclonal complex comparison. J Bacteriol 193:3409-10
Pettigrew, Melinda M; Gent, Janneane F; Pyles, Richard B et al. (2011) Viral-bacterial interactions and risk of acute otitis media complicating upper respiratory tract infection. J Clin Microbiol 49:3750-5
Byington, Carrie L; Hulten, Kristina G; Ampofo, Krow et al. (2010) Molecular epidemiology of pediatric pneumococcal empyema from 2001 to 2007 in Utah. J Clin Microbiol 48:520-5
Laufer, Alison S; Thomas, Jonathan C; Figueira, Marisol et al. (2010) Capacity of serotype 19A and 15B/C Streptococcus pneumoniae isolates for experimental otitis media: Implications for the conjugate vaccine. Vaccine 28:2450-7
Thomas, Jonathan C; Pettigrew, Melinda M (2009) Multilocus sequence typing and pulsed field gel electrophoresis of otitis media causing pathogens. Methods Mol Biol 493:179-90