1. A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland
2. Expert Microbiology Unit, Finnish Institute for Health and Welfare, P.O. Box 95, FIN-70701 Kuopio, Finland
3. Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland