title: Phylogenetic relatedness and diversity of non-typable Haemophilus influenzae in the nasopharynx and middle ear fluid of children with acute otitis media.
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.
authors.affiliation: Rochester General Hospital, Research Institute, Center for Infectious Diseases and Immunology, Rochester, NY, USA.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Kaur
authors.affiliation: Rochester General Hospital, Research Institute, Center for Infectious Diseases and Immunology, Rochester, NY, USA.
authors.forename: Arthur
authors.initials: A
authors.lastname: Chang
authors.affiliation: Rochester General Hospital, Research Institute, Center for Infectious Diseases and Immunology, Rochester, NY, USA.
authors.forename: Qingfu
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Legacy Pediatrics, Rochester, NY, USA.
authors.forename: Janet R
authors.initials: JR
authors.lastname: Casey
authors.affiliation: Rochester General Hospital, Research Institute, Center for Infectious Diseases and Immunology, Rochester, NY, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Pichichero
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015373:Bacterial Typing Techniques; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D004432:Ear, Middle / Q000382:microbiology*; D005260:Female; D006192:Haemophilus Infections / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D009305:Nasopharynx / Q000382:microbiology*; D010034:Otitis Media with Effusion / Q000188:drug therapy / Q000382:microbiology*; D010802:Phylogeny; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases