Medical microbiology has long had a molecular
dimension. From the earliest days of microbiology the
phenotypic descriptions of microorganisms included biochemical
and physiological details that were in fact
molecular. The word ‘molecular’ seems first to have been
applied to microbiology by Zinsser and Parker in 1923 at
the Columbia University, New York, Department of
Bacteriology. In the course of their work on bacterial
‘hypersusceptibility’, they suspected that they were ‘dealing
with substances of lower molecular structure than proteins’
[1]. The term molecular microbiology as it has
more recently come into common use, describes an
approach to the study of microorganisms based to a great
extent on their genetic characteristics. The origins of this
trend, as of much else in modern biology, can be seen in
the seminal description of the structure of DNA by
Watson and Crick [2] and their immediate recognition
that implicit in this structure is the mechanism by which
genetic material is copied. The work of more than half a
century since the structure of DNA was elucidated has
yielded information that has radically changed views
about bacteria and not least those about pathogenic bacteria.
The recognition that this new approach has also fundamentally
changed medical and clinical microbiology
was the inspiration on which the first edition of
Molecular Medical Microbiology [3] was founded in
2002. The object was to provide a general review of the
bacteria of medical importance accessible to practitioners
who need an introduction to the molecular aspects of
medical bacteriology. The developments of the last
decade have meant that a second edition is now desirable.