Poor clinical outcome for meningitis caused by Haemophilus influenzae serotype A strains containing the IS1016-bexA deletion

J Infect Dis. 2010 Nov 15;202(10):1577-84. doi: 10.1086/656778. Epub 2010 Oct 8.

Abstract

Since the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, meningitis caused by serotypes other than Hib has gained in importance. We conducted active hospital-based surveillance for meningitis over an 11-year period in Salvador, Brazil. H. influenzae isolates were serotyped and analyzed by polymerase chain reaction, pulsed-field gel electrophoresis, and DNA sequencing to identify strains with a specific deletion (IS1016) in the bexA gene (IS1016-bexA). We identified 43 meningitis cases caused by non-type b H. influenzae: 28 (65%) were caused by type a (Hia), 9 (21%) were caused by noncapsulated strains, and 3 (7%) each were caused by types e and f. Hia isolates clustered in 2 clonal groups; clonal group A strains (n = 9) had the IS1016-bexA deletion. Among children <5 years of age, meningitis caused by Hia from clonal group A had higher case-fatality than meningitis caused by clonal group B. Despite small numbers, these results indicate that the presence of the IS1016-bexA deletion is associated with enhanced virulence in non-type b H. influenzae.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / genetics*
  • Bacterial Proteins / genetics*
  • Base Sequence
  • Brazil / epidemiology
  • Child, Preschool
  • Female
  • Gene Deletion
  • Haemophilus / classification
  • Haemophilus / genetics*
  • Haemophilus / pathogenicity
  • Hospitals, Municipal
  • Humans
  • Incidence
  • Infant
  • Male
  • Meningitis, Haemophilus / epidemiology
  • Meningitis, Haemophilus / microbiology*
  • Molecular Sequence Data
  • Phylogeny
  • Sentinel Surveillance
  • Sequence Alignment
  • Virulence / genetics

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins