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J Med Microbiol. 2011 Dec;60(Pt 12):1841-8. doi: 10.1099/jmm.0.034041-0. Epub 2011 Jul 28.

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

Author information

1
Rochester General Hospital, Research Institute, Center for Infectious Diseases and Immunology, Rochester, NY, USA.

Abstract

The phylogenetic relationships of non-typable Haemophilus influenzae (NTHi) strains prospectively isolated from healthy children and children with acute otitis media (AOM) were analysed using multilocus sequence typing (MLST). A total of 165 NTHi isolates were collected over a 3.5 year time frame during 2006 through 2009. The strains were tested for β-lactamase production; 28.5% were positive. Seventy different NTHi sequence types (STs) were identified of which 29 (41.4%) were novel. NTHi strains did not show any phylogenetic grouping or clustering among asymptomatic colonizing strains or strains that caused AOM, or based on β-lactamase enzyme production. Evaluation of triplets and other siblings over time demonstrated relatively frequent genetic exchanges in NTHi isolates in vivo in a short time frame and subsequent transfer among children in a family. Comparison of the MLST STs isolated at different time points showed that in ~85% of the nasopharynx (NP) colonizations, NTHi strains cleared from the host within 3 months, that sequential colonization in the same child involved different strains in all cases except one, and that NP and middle ear isolates were identical STs in 84% of cases. In this first study of its type to our knowledge, we could not identify predominant MLST types among strains colonizing the NP versus those causing AOM or expressing a β-lactamase enzyme conferring penicillin resistance in children.

PMID:
21799196
PMCID:
PMC3347915
DOI:
10.1099/jmm.0.034041-0
[Indexed for MEDLINE]
Free PMC Article

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