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The Discovery of
Bacteriophage Bacteriophages are bacterial
viruses that attach to their specific hosts and kill them by
internal replication and bacterial lysis. According to most
estimates, bacteriophages inhabited Earth about 3-5 billion
years ago, and since that time they have controlled the levels
of bacteria in the environment via a classical “predator-prey”
relationship. However, the existence of bacteriophages was not
known until the early part of the 20th century, when they were
first identified by Frederick Twort and Felix d’Herelle who
called them bacteriophages or bacteria-eaters (from the Greek
phago meaning to eat or devour). At that time,
with the age of antibiotics still in the future, bacteriophages
were considered to be a powerful cure for bacterial infections,
and they were therapeutically utilized throughout the world
during the pre-antibiotic era. Although exact numbers are
impossible to calculate, it is likely that millions of people
have been treated with various therapeutic phage preparations.
Bacteriophages naturally inhabit various parts of the human body
(e.g., the mouth, skin, gastrointestinal tract, etc.) and humans
daily eat many foods containing bacteriophages.
Numerous published studies have indicated that the
therapeutic use of phages in humans and animals is very safe;
i.e., serious adverse reactions have never been reported.
However, since some early studies reported that phage therapy
was not always effective, the advent of antibiotics (which
seemed to be like “magic bullets” against numerous pathogenic
bacteria) gradually caused phage therapy to fall out-of-favor in
the United States and Western Europe. Several factors (reviewed
in more detail in 1,2), including the lack of a
general understanding of phage biology and imperfections in the
diagnostic bacteriology techniques available at that time,
contributed to the failure of some of the early phage therapy
studies and to the associated decline of interest in phage
therapy in the West. However, at the same time, phage therapy
continued to be utilized in the former Soviet Union (FSU) and in
various other countries of Eastern Europe. In the FSU and
Eastern Europe – and during the “pre-antibiotic era,” in the
United States, Western Europe and Australia – phage therapy was
used to treat a wide range of bacterial infections, ranging from
skin infections to septicemia. Among the many routes of phage
administration, oral and topical routes were the most frequently
used.
The rapid and alarming emergence of antibiotic-resistant
“superbugs” has rekindled interest in phage therapy in the West.
Intralytix, Inc., is one of the pioneering USA companies
working to develop and commercialize therapeutic phages. Our
approach is based on the results of research supporting the
belief that bacteriophages can help to solve problems regarding
(i) bacterial contamination during food processing, (ii)
hospital and environmental sanitation, and (iii) human and
animal diseases caused by pathogenic bacteria, including
antibiotic-resistant bacteria.
References:
1. Summers, W. C., Bacteriophage therapy, Annu Rev Microbiol
55, 437-51, 2001.
2. Sulakvelidze, A., Alavidze, Z., and Morris, J. G., Jr.,
Bacteriophage therapy, Antimicrob Agents Chemother 45 (3),
649-659, 2001.
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