The evolution of human pathogens: examples and clinical implications.

Recent advances in sequencing of complete bacterial genomes, molecular typing of micro-organisms, and research on microbial pathogenicity factors changed our view on the evolution of human bacterial pathogens. We review current evolutionary concepts on plague and meningococcal disease to illustrate the interplay of molecular phylogeny, epidemiology, and pathogenicity research. Furthermore, examples of the tremendous velocity of bacterial evolution under changing environmental conditions will be discussed.