The Journal of Medical Microbiology, Vol 46, Issue 3 204-207, Copyright © 1997 by Society for General Microbiology
Pyrolysis mass spectrometry in epidemiological and population genetic studies of Haemophilus influenzae
N. I. Leaves, P. R. Sisson, R. Freeman and J. Z. Jordens
Oxford Public Health Laboratory, John Radcliffe Hospital, Headington, Oxford.
Haemophilus influenzae serotype b (Hib) vaccines have reduced the amount of
invasive Hib disease in immunised infants. However, Hib disease remains in
unvaccinated infants and adults and non-capsulate H. influenzae (NCHi)
still causes infections, including outbreaks of respiratory disease.
Characterisation of strains and the bacterial population as a whole is
therefore necessary to detect outbreaks of infection with NCHi or changes
in the population, for example, to vaccine-resistant clones of Hib. The
rapid, simple and objective technique of pyrolysis mass spectrometry (PMS)
was investigated as an alternative to current complex, subjective methods.
PMS was compared with ribotyping and multilocus enzyme electrophoresis
(MLEE) for population genetic analyses of Hib and with ribotyping and
protein profiling for epidemiological analyses of NCHi. PMS clustered all
the isolates of Hib together whereas MLEE and ribotyping distinguished
certain clones - this is probably because the three methods examine
different (and unrelated) characteristics of the organisms. The PMS results
were essentially similar to those from ribotyping and protein profiling for
the epidemiological analyses of outbreaks of NCHi disease. Therefore, PMS
is probably unsuitable for comparisons of Hib populations but it is a
useful addition to the arsenal of techniques for the characterisation of
NCHi.
