David Woodland's recent account of the
ongoing world-wide scourge of tuberculosis is a significant step forward in
making the public aware of the spread of this “white plague.”
It is
formidable for us living in the United States, and in other well-developed
countries, to comprehend that an estimated 4,000 people each day are dying
world-wide from tuberculosis. Woodland explains very well the development of
drug resistance that has evolved with this bacterium, with its rapid rate of
replication, its thick protein outer coat protective against penetration of
many antibiotics, and humans infected with reticence in completing a full
course of therapy.
Yet,
tuberculosis is only one among many bacteria that have been involved in plagues
throughout history, past and present. The Industrial Revolution and opening up
of trade routes during the 13th and 14th centuries, with introduction of hordes
of rats and their pestis-infected fleas led to the massive spread of the “black
death” in congested and filthy population centers. Wars and conflicts, where
soldiers have been closely assembled in unsanitary environments, have also led
to massive spread of infections. The bacterial causes for these outbreaks were
not known until the late 19th century when Robert Koch discovered Vibrio
cholera as the culprit in his investigation of contaminated water supplies,
causing pandemics in Egypt and cities in Asia Minor.
Yet,
even in our modern scientific, sophisticated societies, bacterial plagues
remain, although better controlled. The pumping of contaminated pond and stream
water into environmentally controlled water tanks led to the proliferation and
distribution of Legionella bacteria into air conditioning ducts, leading to
widespread pneumonia among elderly sleeping legionnaires attending the 1976
convention in Philadelphia, fatal for many. Just last year, a minor similar
outbreak occurred in a posh hotel in Las Vegas. What about the recent outbreak
of listeria infection from the ingestion of contaminated cantaloupes, of all
things; or the recent emptying of grocery meat shelves to curb outbreaks of E.
coli and other bacteria. Currently, the majority of staphylococci recovered in
hospital environments are drug resistant, the so-called “MRSA” strains.
Bacteria
are complex forms of living matter, the behavior of which is dependent upon the
life sustaining action of a single chromosome, with complex arrangements of DNA
strands that provide for production of nutrients and, unfortunately, toxins as
well. What may be a non-threatening environment in a natural niche, or as
commensal within a plant or animal, becomes a pathologic agent when transferred
into another host, particularly into humans. When bacteria are not completely
controlled, mutations occur that either makes them more aggressive within the
new host; or, that become “superbugs,” resistant to a variety of anti-bacterial
agents that continue to be developed, often with only temporary effect.
The
unfortunate conclusion is that, as evidenced by the continuing spread of
tuberculosis and the habitation of hospital environments with MRSA, bacteria
will remain in our environment, either as harmless commensals, or as aggressive
mutants resulting in morbidity or mortality. Prevention is the only answer to
curbing infections and outbreaks, often compromised by economic considerations,
such as the raising of animals in enclosed, often unclean environments. The
indiscriminate use of antibiotics, such as used for empiric therapy in humans,
or their massive use in feeds to protect animals while being raised for
slaughter are other factors. As concluded by Woodland in his article, “we all
have a stake in resolving this global health crisis.” This superbug “crisis” in
various forms, remains also local, regional and national.
Elmer
W. Koneman
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