1887

Abstract

Summary

Molecular characterisation is an important pre-requisite for post-vaccine studies of type b (Hib). Three capsular genotyping patterns, b(S), b(G) and b(V), have been described in the major phylogenetic lineage of Hib. However, in a recent series of prospective studies, three new hybridisation patterns were observed among 425 strains of Hib. Four pairs of polymerase chain reaction (PCR) primers were used to identify the capsular gene () structure of these Hib strains. This showed that the strains possessed simple DNA re-arrangements. In two instances a change in restriction enzyme recognition site was the most likely cause of the new hybridisation pattern. The third strain possessed a cap b locus consisting of intact tandem repeats of b in a b(S) background. It was reasoned that a similar b locus would not be readily recognised by hybridisation in a b(G) background, and b(G) strains were therefore characterised by the PCR method. This showed one of 35 b(G) strains to possess a cap locus with intact tandem repeat copies of b. The novel capsular genotypes described here are rare, but can be detected rapidly and accurately by a combination of PCR and capsular genotyping hybridisation patterns.

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1995-08-01
2024-03-28
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References

  1. Falla T. J., Anderson E. C., Chappell M. M., Slack M. P. E., Crook D. W. M. Cross-reaction of spontaneous capsule-deficient Haemophilus influenzae type b mutants with type specific antisera. Eur J Clin Microbiol Infect Dis 1993; 12:147–148
    [Google Scholar]
  2. Kroll J. S., Ely S., Moxon E. R. Capsular typing of Haemophilus influenzae with a DNA probe. Mol Cell Probes 1991; 5:375–379
    [Google Scholar]
  3. Falla T. J., Crook D. W. M., Brophy L. N., Maskell D., Kroll J. S., Moxon E. R. PCR for capsular typing of Haemophilus influenzae. J Clin Microbiol 1994; 32:2382–2386
    [Google Scholar]
  4. Musser J. M., Kroll J. S., Granoff D. M. Global genetic structure and molecular epidemiology of encapsulated Haemophilus influenzae. Rev Infect Dis 1990; 12:75–111
    [Google Scholar]
  5. Hoiseth S. K., Connelly C. J., Moxon E. R. Genetics of spontaneous, high-frequency loss of b capsule expression in Haemophilus influenzae. Infect Immun 1985; 49:389–395
    [Google Scholar]
  6. van Ketel R. J., De Wever B., Van Alphen L. Detection of Haemophilus influenzae in cerebrospinal fluids by polymerase chain reaction DNA amplification. J Med Microbiol 1990; 33:271–276
    [Google Scholar]
  7. Ward J., Brenneman G., Letson G. W., Heyward W. L., Alaskan H. influenzae vaccine study group. Limited efficacy of a Haemophilus influenzae type b conjugate vaccine in Alaskan native infants. N Engl J Med 1990; 323:1393–1401
    [Google Scholar]
  8. Santosham M., Rivin B., Wolff M. Prevention of Haemophilus influenzae type b infections in Apache and Navajo children. J Infect Dis 1992; 165: Suppl 1S144–S151
    [Google Scholar]
  9. Anderson P., Johnston R. B., Smith D. H. Human serum activities against Haemophilus influenzae type b. J Clin Invest 1972; 51:31–38
    [Google Scholar]
  10. Falla T. J. Molecular epidemiology of Haemophilus influenzae. PhD Thesis University of Wales; Cardiff: 1993
    [Google Scholar]
  11. Kroll J. S., Loynds B. M., Brophy L. N., Moxon E. R. The bex locus in encapsulated Haemophilus influenzae: a chromosomal region involved in capsular polysaccharide export. Mol Microbiol 1990; 4:1853–1862
    [Google Scholar]
  12. Kroll J. S., Loynds B. M., Moxon E. R. The Haemophilus influenza capsulation gene cluster: a compound transposon. Mol Microbiol 1991; 5:1549–1560
    [Google Scholar]
  13. Hoiseth S. K., Corn P. G., Anders J. Amplification status of capsule genes in Haemophilus influenzae type b clinical isolates. J Infect Dis 1992; 165: Suppl 1S114
    [Google Scholar]
  14. Kroll J. S., Moxon E. R., Loynds B. M. An ancestral mutation enhancing fitness and increasing the virulence of Haemophilus influenzae type b. J Infect Dis 1993; 168:172–176
    [Google Scholar]
  15. Kroll J. S., Moxon E. R., Loynds B. M. Natural genetic transfer of a putative virulence-enhancing mutation to Haemophilus influenzae type a. J Infect Dis 1994; 169:676–679
    [Google Scholar]
  16. Moxon E. R., Smith A. L., Averill D. R., Smith D. H. Haemophilusinfluenzae meningitis in infant rats after intranasal inoculation. J Infect Dis 1974; 129:154–162
    [Google Scholar]
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