A short time after the death of Semmelweis,
Louis Pasteur
showed the existence of bacteria and their role in some forms of
disease, which came to be known as the germ theory.
Robert Koch reinforced the cause and effect relationship
between bacteria and disease.
Joseph Lister introduced other forms of administering
chemical compounds to reduce the spread of disease in operating
theatres.
Much later
Alexander Fleming, in conjunction with
Howard
Florey and
Ernst Chase (and others) introduced a
different class of chemical control using antibiotics which
resulted in another level of reduction in disease. However this is
more closely targetted on the bacteria causing disease and also
paradoxically more subject to failure than antiseptic chemicals.
At about the same time other physicians had made links between
surgical procedures and the spread of disease, but possibly they
were less systematic in their use of antiseptic chemicals, and had
less clear-cut information on which to base their theories. In
1843 in the USA,
Oliver Wendell Holmes (senior) came to
similar conclusions about childbed fever. This formed the basis of
a storyline in a recent (fiction) book
The Bone Garden
by Tess Gerritsen.