TY - JOUR
T1 - Density, Serotype Diversity, and Fitness of Streptococcus pneumoniae in Upper Respiratory Tract Cocolonization with Nontypeable Haemophilus influenzae
AU - Lewnard, Joseph A.
AU - Huppert, Amit
AU - Givon-Lavi, Noga
AU - Pettigrew, Melinda M.
AU - Regev-Yochay, Gili
AU - Dagan, Ron
AU - Weinberger, Daniel M.
N1 - Publisher Copyright:
© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - Background. Coinfections by Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi) are frequently implicated in complex otitis media. Whereas upper respiratory tract carriage precedes disease for both pathogens, interactions between species in cocolonized hosts are poorly understood. We compared colonization densities and the diversity and fitness of pneumococcal serotypes in single-species and mixed-species colonization. Methods. We analyzed nasopharyngeal pneumococcal carriage and nasopharyngeal and oropharyngeal NTHi carriage in 13 541 samples collected over 6909 study visits from 769 children 2-30 months old in a 7-valent pneumococcal conjugate vaccine dosing trial. We measured density associations between the species and compared pneumococcal serotype diversity during and in the absence of NTHi colonization. We used logistic regression to quantify associations between NTHi colonization and previously published pneumococcal serotype factors related to fitness. Results. Densities of the 2 species were positively associated when they co-occur in the nasopharynx. NTHi colonization was associated with reduced pneumococcal serotype diversity among children 2-18 months old and was more prevalent among children carrying pneumococcal serotypes with greater capsular thickness, neutrophil resistance, and metabolic efficiency. Conclusions. Pneumococcal-NTHi cocolonization is associated with an elevated density of both species and with reduced diversity and increased fitness of pneumococcal serotypes. NTHi colonization may create a selective environment favoring pneumococci with immune-evasive phenotypes.
AB - Background. Coinfections by Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi) are frequently implicated in complex otitis media. Whereas upper respiratory tract carriage precedes disease for both pathogens, interactions between species in cocolonized hosts are poorly understood. We compared colonization densities and the diversity and fitness of pneumococcal serotypes in single-species and mixed-species colonization. Methods. We analyzed nasopharyngeal pneumococcal carriage and nasopharyngeal and oropharyngeal NTHi carriage in 13 541 samples collected over 6909 study visits from 769 children 2-30 months old in a 7-valent pneumococcal conjugate vaccine dosing trial. We measured density associations between the species and compared pneumococcal serotype diversity during and in the absence of NTHi colonization. We used logistic regression to quantify associations between NTHi colonization and previously published pneumococcal serotype factors related to fitness. Results. Densities of the 2 species were positively associated when they co-occur in the nasopharynx. NTHi colonization was associated with reduced pneumococcal serotype diversity among children 2-18 months old and was more prevalent among children carrying pneumococcal serotypes with greater capsular thickness, neutrophil resistance, and metabolic efficiency. Conclusions. Pneumococcal-NTHi cocolonization is associated with an elevated density of both species and with reduced diversity and increased fitness of pneumococcal serotypes. NTHi colonization may create a selective environment favoring pneumococci with immune-evasive phenotypes.
KW - carriage
KW - coinfection
KW - interspecies interaction
KW - nasopharynx
KW - nontypeable Haemophilus influenzae
KW - Streptococcus pneumoniae
UR - http://www.scopus.com/inward/record.url?scp=84994765138&partnerID=8YFLogxK
U2 - 10.1093/infdis/jiw381
DO - 10.1093/infdis/jiw381
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C2 - 27540112
AN - SCOPUS:84994765138
SN - 0022-1899
VL - 214
SP - 1411
EP - 1420
JO - Journal of Infectious Diseases
JF - Journal of Infectious Diseases
IS - 9
ER -