The new molecular knowledge can be expected increasingly
to influence medical bacteriology from its diagnostic
beginning to its therapeutic aim by increasing the speed of
the former and the range and specificity of the latter. It will
also play an increasing part in reaching epidemiological
and preventive objectives. It is interesting to contemplate
the possibility that in future the targets of therapy may
move from structural components of the bacterial cell to the
mechanisms of pathogenesis that are the ultimate causes of
the disease syndromes as observed clinically. A first step in
this direction, at the beginning of the 20th century, was the
discovery of the toxins of Gram-positive organisms and
their neutralizing antitoxins. If, as a result of molecular
insights, the same were possible, for example, for the secretory
delivery systems of Gram-negative bacteria, might
some of the problems of antibiotic resistance be circumvented?
Such possibilities would not only cause excitement
in the research laboratory, but they would also dramatically
change practices and protocols in the diagnostic laboratory.
What seems certain is that the molecular approach will
increasingly change and enhance the understanding and
practice of medical microbiology.