Evaluation of mutations in penicillin binding protein-3 gene of non-typeable Haemophilus influenzae isolated from the nasopharynx of children with acute otitis media

Acta Otolaryngol. 2005 Feb;125(2):180-3. doi: 10.1080/00016480410020301.


Conclusion: Younger children tend to harbor more resistant strains because they are exposed to these pathogens more often through contacts with siblings or attendance at day-care centers and are frequently treated with antibiotics. The high prevalence of BLNAR strains should be taken into account in the treatment of AOM in young children.

Objective: Non-beta-lactamase-producing ampicillin-resistant (BLNAR) strains with mutations in penicillin-binding protein (PBP) genes of Haemophilus influenzae have been prevalent recently among younger children.

Material and methods: We investigated mutations in the ftsI gene encoding PBP-3 of H. influenzae isolated from the nasopharynx of children with acute otitis media (AOM) using polymerase chain reaction (PCR).

Results: Strains containing the bla gene (beta-lactamase-producing ampicillin-resistant) were identified in 4.7% of cases. Strains with mutations in the ftsI gene (BLNAR) were identified in 23.3% of cases. Strains without mutations in the ftsI gene and that did not contain the bla gene (non-beta-lactamase-producing ampicillin-susceptible) were identified in 70.7% of cases. Strains with both expression of the bla gene and mutations in the ftsI gene (beta-lactamase-producing amoxicillin clavulanate-resistant) were identified in 1.3% of cases. The MICs of ampicillin against the strains evaluated in this study were 0.5-2.0 microg/ml. Cefditoren-pivoxil had the lowest MIC90 against the strains (0.06 microg/ml). Strains with mutations in the ftsI gene (BLNAR) were broadly identified among young children.

MeSH terms

  • Acute Disease
  • Bacterial Proteins / genetics
  • Child
  • Child, Preschool
  • DNA Primers / genetics
  • Female
  • Gene Expression / genetics*
  • Haemophilus Infections / complications*
  • Haemophilus influenzae / genetics*
  • Haemophilus influenzae / isolation & purification
  • Humans
  • Infant
  • Male
  • Nasopharynx / microbiology*
  • Otitis Media / genetics*
  • Otitis Media / microbiology*
  • Penicillin-Binding Proteins / genetics*
  • Point Mutation / genetics*
  • Polymerase Chain Reaction
  • beta-Lactamases / genetics


  • Bacterial Proteins
  • DNA Primers
  • Penicillin-Binding Proteins
  • AmpC beta-lactamases
  • beta-Lactamases