Hi biggi_e-ga,
I'd be happy to discuss this topic as I find it absolutely fascinating
--- and more than just a little bit frightening as well. Antibiotic
resistance and the evolution of the "superbug" is an increasingly
pertinent topic in today's world of global travel, widespread
antibiotic use, and the continued (albeit misplaced) confidence that
much of the developed world seems to have in our ability to treat
infectious disease.
As you probably know, we can no longer take for granted the fact that
a bacterial infection, whether topical or internal, can be
successfully treated with antibiotics. When it comes to bacteria,
instead of saying "resistance is futile" we might well say "resistance
is inevitable."
The emergence of resistant strains of common bacteria is a long story,
going back 100 years. Fortunately I have written on this topic
before, so know where to begin both the research and the story.
**********************************************
Prior to the 1940's bacteria were considered to be highly dangerous
entities. People regularly died of bacterial infections that we barely
think about today. If your parents or grandparents were alive during
that time, you probably have heard their continuous admonishments to
"sterilize that cut" or "stay out of the rain, you're going to catch a
cold." In all likelihood you consider their reactions to be overkill,
but in fact, in their day a minor cut or a "simple" bacterial
infection could quickly turn into a life-threatening event.
Bacterial infections that we seldom consider today such as lockjaw
(tetanus), gangrene, croup (diphtheria or strep throat), consumption
(tuberculosis), scarlet fever, camp diarrhea (typhoid), lung fever
(pneumonia) were unpreventable and incurable prior to the advent of
antibiotics.
The first hint of respite came in 1929 when Alexander Fleming isolated
a chemical he called "penicillin" from a mold, Penicillium notatum.
This chemical prevented growth of germs that had been colonizing the
same petri dish. Although he never purified penicillin, Dr. Fleming
became the first person to announce its ability to kill germs. It
took subsequent work by Howard Florey, Ernst Chain and Norman Heatley
at Oxford University in 1938 to developed methods for growing,
extracting and purifying enough penicillin to give it value as a drug.
Rapid advancements in antibiotic development during the late 1930's
and into the 1950's gave us a whole arsenal of drugs to fight the
various identified bacteria that had plagued humans to date. These
included – actinomycin A ("Actinomyces antibioticus") 1940;
streptomycin (Streptomyces griseus), 1944; neomycin (S. fradiae) 1949;
and candicidin (S. griseus), 1953.
One of the most medically significant antibiotics was streptomycin
which was successful in attacking the dreaded Mycobacterium
tuberculosis. Tuberculosis was the leading cause of the death in the
United States until the 1943 when streptomycin became available. Over
the next 40 years use of the drug raised cure rates 90%.
The advent of all these new antibiotics brought waves of relief to
health-care workers and to the public. Now there was a cure to all of
the day-to-day illnesses and injury complications that had always
bedeviled doctors' attempt to control them. Taken to be instant
cure-alls, antibiotics were dispensed at the drop of a hat. For
coughs, colds, cuts, and anything else that ailed you, doctors were
quick to prescribe antibiotics, and patients were happy to take them.
Little did the doctors or the patients know however, that you can't
win a race against an evolving species such as a bacterium. In their
race to win the war against infection, doctors ignored even Fleming
himself, who had cautioned that antibiotic misuse could result in
resistant strains of bacteria.
How can bacteria become resistant to an antibiotic? The best way to
illustrate this is to give a simplified example. Suppose you have
strep throat, meaning you are infected with the streptococcus
bacteria, and the doctor prescribes a 10-day regime of penicillin. If
you are like most people, you will probably take the antibiotic for 7
or 8 days and then forget about it because you feel better.
So what have you done? You've killed off all of the strep bacteria
except those that are strong enough to withstand 8 days of bombardment
by antibiotics. In other words you have left only the strongest
bacteria and killed off the weaker ones. As this bacteria is spread to
other people, it is further refined by the doses of antibiotics that
they are taking. Each time, only the weakest bacteria are killed, and
the strongest are left to survive and multiply. Do this often enough
and you have created a superbug.
So this is what began to happen with many of the bacteria that doctors
were routinely fighting with antibiotics.
The first major portent of trouble came just after 1984 when the
Centers for Disease Control (CDC) noticed that the incidence of
Mycobacterium tuberculosis was on the increase. The CDC reports that
after 1984, the number of TB cases reported in the United States began
to increase and by 1993 more than 25,000 new cases were being reported
annually.
During that time multi-drug resistant strains of tuberculosis (MDR-TB)
were discovered and in 1992 the National MDR-TB Task Force published
the National Action Plan to Combat Multidrug-Resistant Tuberculosis.
In 1993 The World Health Organization (WHO) declared tuberculosis a
global emergency. Today they now predict that between the years 2000
and 2020, nearly one billion people will be newly infected, 200
million people will get sick, and 35 million will die from TB. TB is
currently the leading cause of death among infectious diseases
worldwide.
Drug resistant strains of other types of bacteria have been developing
at an equally active rate ---
Staphylococcus aureus – this is the bacterium that causes the "staph"
infection, such as you might get as a consequence of an "infected"
skin rash or scrape. The bacteria itself is normally found on the skin
or in the nasal passages of healthy people. In its mildest form a
staph infection causes pimples or boils. At its worse it can develop
into blood infection or pneumonia.
Methicillin was the drug of choice against staph infections but some
staph bacteria have developed resistance to it. These resistant
bacteria are called methicillin-resistant Staphylococcus aureus, or
MRSA and are very hard to fight. In the past couple of years bacteria
that are resistant to Vancomycin, the drug normally used to fight
MRSA, have emerged.
Enterococcus is the bacterium that is normally found in the bowel and
in the female genital tract. When it reaches an infective rate it
causes bladder and other infections. In 1979 enterococus developed a
resistance to gentamicin. Shortly thereafter it strains resistant to
Penicillin emerged and then in 1988 Vancomycin-resistant enterococci
(VRE) was recognized in the U.S.
The Centers for Disease Control (CDC), reported a 34-fold increase in
the percentage of hospital-acquired infections caused by VRE between
1989 and 1993. VRE can cause life-threatening infections in infants,
elderly, and the infirm and cannot be controlled with antibiotics.
Streptococcus pneumoniae is the bacterium that causes the common ear
infection in children. It also causes meningitis, systemic infections,
and a half-million cases of pneumonia annually.
Penicillin, and its derivative amoxicillin, were successfully used to
treat S. pneumoniae until the mid 1980’s. Since then, the worldwide
spread of drug-resistant S. pneumoniae (DRSP) now accounts for 40% of
all incidences of S. pneumoniae infection. S. pneumoniae is now
considered to be the leading cause of illness and death in the United
States today.
Today, the CDC and the World Health Organization urge doctors and
patients to follow a number of guidelines to help contain the spread
of antibiotic resistant bacteria. In short, these include –
Do not take antibiotics for viral infections such as colds or flu
Always take medicine exactly as your doctor prescribes for the entire
duration of the prescription.
Do not save the medication to treat yourself later or share
medications with others.
Learn the best ways to prevent the transmission of infectious disease.
********** WORD COUNT TO HERE 1163 ***************
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SOURCES
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CDC – ANTIBIOTIC RESISTANCE
http://www.cdc.gov/drugresistance/community/
CDC – ANTIMICROBIAL RESISTANCE
http://www.cdc.gov/drugresistance/actionplan/html/index.htm
CDC EXECUTIVE SUMMARY - Mycobacterium tuberculosis
http://aepo-xdv-www.epo.cdc.gov/wonder/prevguid/m0035909/head002000000000000
CDC – TUBERCULOSIS
http://www.cdc.gov/niosh/tb-i.html
Penicillin: the first miracle drug
http://www.herb.lsa.umich.edu/kidpage/penicillin.htm
WORLD HEALTH ORGANIZATION – PRESS RELEASE
WHO CALLS FOR ACTION ON SPREAD OF DRUG-RESISTANT DISEASES
http://www.who.int/archives/inf-pr-1994/pr94-95.html
WORLD HEALTH ORGANIZATION
Emerging and other communicable diseases: antimicrobial resistance
Report by the Director-General
http://www.who.int/gb/EB_WHA/PDF/WHA51/ea9.pdf
INEFFECTIVE USE OF PENICILLIN
http://answers.google.com/answers/main?cmd=threadview&id=169472
Antibiotics, resistance, and efficacy after continued use
http://answers.google.com/answers/main?cmd=threadview&id=90234
WHO REPORT ON INFECTIOUS DISEASE
CH 12 - Medicines are losing their effectiveness
http://www.who.int/infectious-disease-report/pages/ch12text.html
RACING THE RED QUEEN
http://members.rogers.com/kmgerson/Page%20Gallery/Non-Fiction%20Pages/Non-Fiction%201.htm
If there is anything here that isn't clear to you, please use your
"Request Answer Clarification" button to let me know what you don't
understand, and I'll be happy to explain further.
Thanks for your most interesting question –
--K~
search terms –
Antibiotic resistant bacteria
Antimicrobial resistance
World Health Organization
Centers for Disease Control |
