Acknowledgements
The authors would like to thank E. Foryciarz, B. Paradowska
and D. Stefanik for excellent technical assistance.
Conflict of interest statement
None declared.
Funding source
The contribution of H.S. and P.G.H. was supported by
a grant from Bundesministerium fu¨r Bildung und Forschung
(BMBF), Germany, Klinische Forschergruppe Infektiologie
(grant no. 01 KI 0771).