Summary of Workshop
The workshop on new, emerging, or atypical species contained a contradiction in se. Bacteria may be considered rare or unusual, because they are actually new or because they have recently been isolated for the first time. In general, it is rather unlikely that new species evolve from existing ones at such a high rate. Indeed, the number of new species that emerged during the past decade is far too large to be attributed to normal evolution. Only two decades ago, campylobacters were rarely isolated, and we know that many species are still difficult to cultivate. It is therefore more likely that the so-called “new” species are not at all new, but rather that, with our growing knowledge on campylobacters in general and improved culture conditions, we are now starting to isolate them. Campylobacter jejuni was considered a rare finding in humans in the 1970s and Helicobacter pylori was a very new bacterium in the early 1980s. Clearly, we must be sure that we know more about the real prevalence of each of these “new” species before we try to determine their clinical and epidemiologic relevance.