Invasive infections due to H. influenzae have increased considerably in the past years. The increase is mostly due to disease in the elderly. Interestingly, strains without a capsule, a well-known pathogenicity factor, are most frequent. These strains are referred to as non-typeable, because serotyping of the capsule polysaccharide is not possible. It has been a matter of debate, whether the genetic elements to synthesize the capsule and to export it to the outside are missing completely in all non-typeable strains from invasive infections. T.T. Lam et al. now show an analysis of 783 strains collected as part of the national laboratory surveillance conducted by the reference laboratory. They report that invasive strains without capsule expression invariably are the result of a lack of these genetic elements. Future research should address the question which other bacterial factors contribute to the success of non-typeable strains in certain groups of the population such as the elderly or pregnant women and their neonates.
Lâm TT, Claus H, Frosch M, Vogel U. Analysis of non-typeable Haemophilus influenzae in invasive disease reveals lack of the capsule locus. Clin Microbiol Infect. 2015 Oct 7. pii: S1198-743X(15)00897-6. doi: 10.1016/j.cmi.2015.09.027.
03.11.2015, 14:17 Uhr