Epidemiology of Nasopharyngeal Colonization with Nontypeable Haemophilus influenzae in the First 2 Years of Life

Abstract

Two hundred children were followed from birth through 2 years of age with nasopharyngeal cultures to determine the normal colonization pattern of nontypeable Haemophilus influenzae. Forty-four percent of the children were colonized on one or more occasions; the acquisition rate was greatest in the first year. Monthly prevalence rates were 11%. Colonization with the initial strain persisted 1-5 months (median, 2). Children carried 1 predominant strain at a time but became colonized with up to 7 different strains (mean, 2.2). Children colonized with a single strain for < or = 2 months produced a greater nasopharyngeal secretory IgA to nontypeable H. influenzae response than did children colonized with different strains (log 2.35 +/- 0.68 vs. 1.89 +/- 0.25 U of P6 secretory IgA/ng/mL of total secretory IgA, P < .01). The duration of colonization with a strain and acquisition of a new strain may be affected in part by the local production of specific secretory IgA.

Phylogenetic relatedness and diversity of non-typable Haemophilus influenzae in the nasopharynx and middle ear fluid of children with acute otitis media

“…When sequential NTHi NP colonization was observed at different time points in a child, different STs were involved. Faden et al (1995) found that NTHi strains cleared the NP in ,3 months in 90 % of the children they studied. We did not observe any reacquisition of previously carried NTHi strains, similar to previous studies by Spinola et al (1986) and Faden et al (1995).…”

“…Faden et al (1995) found that NTHi strains cleared the NP in ,3 months in 90 % of the children they studied. We did not observe any reacquisition of previously carried NTHi strains, similar to previous studies by Spinola et al (1986) and Faden et al (1995).Prolonged colonization of NTHi strains (.3 months) was observed in~25 % of the 33 children where NTHi colonization was observed more than once. ST146 and ST685 belong to the same clonal complex and have no predictor founder.…”

“…Non-typable Haemophilus influenzae (NTHi) is an important human-specific pathogen colonizing the nasopharynx (NP) of the upper respiratory tract (Faden et al, 1995;Murphy et al, 2009). NTHi strains are rarely associated with invasive disease in children, but they are associated with respiratory tract infections in both children and adults (Murphy, 2003;Kyd & Cripps, 1999).…”

“…Using outer-membrane profiles, Faden et al (1995) reported rapid disappearance of initial colonizing strains of H. influenzae. An immune response was shown to eliminate a particular strain and prevent its reacquisition but not the acquisition of heterologous strains.…”

“…In this study, we explored whether or not NTHi shows genetic relatedness in relation to b-lactamase enzyme production. It is also not known whether NTHi strains that cause disease such as AOM are genetically clustered and/or distinct from isolates associated with asymptomatic NP colonization.Using outer-membrane profiles, Faden et al (1995) reported rapid disappearance of initial colonizing strains of H. influenzae. An immune response was shown to eliminate a particular strain and prevent its reacquisition but not the acquisition of heterologous strains.…”