In Depth Look Antibiotic Resistance by MikeJenny

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In Depth Look Antibiotic Resistance

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									In Depth Look: Antibiotic Resistance
Since Alexander Fleming discovered penicillin, the first antibiotic, in 1927, these
powerful drugs have revolutionized medicine (1); the number of lives antibiotics have
saved over the past 83 years is unfathomable. They have reduced the time people have
spent in hospitals, saved limbs, and prevented the spread of disease. After years of a
successful history, however, recent discoveries of antibiotic/antimicrobial resistant
strands of diseases and infections have been discovered. The Centers for Disease
Control and Prevention recognizes antimicrobial resistance as one of their top concerns,
and as one of the most pressing health-related issues facing the world today, thus
prompting the world to examine its use of antibiotics and evaluate where we go from
here.

Causes

How did bacteria become resistant to antibiotics and antimicrobials? The blame can be
assigned to many areas. First, people have taken antibiotics when not necessary. The
common cold and flu are caused by viruses, which cannot be killed by antibiotics. If
people take drugs that will not treat the condition they have, the only bacteria killed by
the antibiotics are the 'good guys', in turn, lowering the power of the immune system;
this can allow bad bacteria to proliferate unchecked. When individuals take antibiotics
when they are not necessary, or when patients do not follow their prescription (i.e.
stopping use of drugs when they see improvement, not allowing the prescription to run
its full course, getting off schedule), bacteria that cause illnesses can be exposed to
below-toxic levels of antibiotics. According to the World Health Organization, "bacteria
are particularly efficient at enhancing the effects of resistance, not only because of their
ability to multiply very rapidly but also because they can transfer their resistance genes,
which are passed on when the bacteria replicate" (2).


Second, bacteria naturally develop resistance to antibiotics, in part due to the
aforementioned rapid multiplication of bacteria cells. The Better Health Channel,
produced by a branch of the Austrailian government, uses the example of benzyl
penicillin; "[it naturally] has very little effect on most organisms found in the human
digestive system" (3). Additionally, over time, the antibiotics that used to work on
diseases such as staph infections, tuberculosis, and gonorrhea have lost their
effectiveness due to high demand and usage. This is not to say they were not used
prudently, there has just been such a need that enough bacteria has survived from prior
uses to morph into an altered state the antibiotic can no longer kill. As the CDC phrases
it, "exposure to antibiotics therefore provides selective pressure, which makes the
surviving bacteria more likely to be resistant" (4). Some diseases mutating into resistant
strains was basically inevitable.


Third, antibiotic resistance is being contributed to by the use of antibiotics in animals.
According to the WHO, "in North America and Europe, an estimated 50% in tonnage of
all antimicrobial production is used in food-producing animals and poultry" (5). Livestock
are often treated with antimicrobials to promote growth and to lower the risk of disease
entering a herd, thus reducing the risk of loss of animals and increasing profits for
growers. However, when these animals are butchered and added to the food chain,
consumers are eating meat that are potentially tainted with antimicrobials. Once again,
antimicrobial agents then have the opportunity to enter the human body at sub-toxic
dosages where bacteria are allowed to mutate and develop resistance. Infections
specifically impacted by this cause of antimicrobial resistance are those which can be
passed from animals to humans through the food chain.


Fourth, the increased use of antimicrobial products in household settings is suspected
to contribute to the development of antibiotic resistant bacteria. Not enough long-term
research has been conducted to prove that any resistance developing out of household
antibacterial/antibiotic use is at a level serious enough to cause major concern.
Regardless, "antibiotic use, appropriate or otherwise, contributes to the development of
antibiotic resistance" (6). In response to whether use of personal products (in this case,
acne medications) contribute to the dilemma, the CDC said, "this is true for acne
medications that contain antibiotics. Short and long-term use of antibiotics for treatment
or prevention of bacterial infections should be under the direction of a physician to
ensure appropriate use and detection of resistance" (7).


How do household products contribute?


Household products used to eliminate bacteria from the household contribute to
resistance in a similar manner as any other antibacterial/antimicrobial. When the kill rate
is less than 100%, the remaining bacteria cells develop an altered code that contains
resistance to the antimicrobial agent with which the kill attempt was made. These
leftover cells then multiply, developing new strands of disease and spreading resistance
from cell to cell.


Which products are to blame? It depends on how the product used to eliminate bacteria
goes about killing them. The main cause for concern is any product that leaves a
residue or kills over time. This includes products using common antimicrobial agents
like triclosan or nanosilver. “Triclosan is thought to cause... resistance to develop
because its mechanism of action is very specific and its use is becoming so
widespread. In fact, resistance to triclosan has already been observed in the laboratory"
(8). Triclosan kills by moving through the cell membranes and poisioning enzymes
required by the cell for growth. It causes cells to die slowly instead of quickly destroying
them.


Agents such as triclosan which, while they kill over 99% of bacteria, fail to eliminate all
bacteria on the surface washed and/or treated, leave behind bacteria that develop
resistance to the cleaning agents. Once bacteria develop resistance to one
antimicrobial, they strengthen and are better situated to develop resistance to other
antimicrobials than their weaker counterparts who fell victim to the cleaning agent.


This is not to say all cleaners are factoring into the resistance predicament. “Of course,
that concern [resistance] is irrelevant with substances that do not leave residues (e.g.,
alcohols, bleaches, and peroxides)” (9). Cleaning agents such as isopropyl alcohol and
chlorine bleach are physically destructive to cells, which means those cells that might
not be killed are just strong to begin with. With such an intense physical destruction,
there is no residue left behind for cells to adapt to.

Prevention

The easiest way to prevent antibiotic/antimicrobial resistance is by using these agents
sensibly. Only take prescribed antibiotics and take them for the entire prescription
period unless advised by a doctor to do otherwise. Discard of any remaining antibiotics
immediately, and do not share prescriptions with family or friends. When treating your
home with antimicrobial products, choose a product that kills physically rather than
using chemicals to mutate and slowly kill cells.

For more information on antibiotic resistance, visit the CDC
(http://www.cdc.gov/drugresistance/) or WHO
(http://www.who.int/mediacentre/factsheets/fs194/en/) online.

References:

(1) CDC, Antibiotic Resistance Questions & Answers
http://www.cdc.gov/getsmart/antibiotic-use/anitbiotic-resistance-faqs.html#f

(2) World Health Organization "Antimicrobial resistance"
http://www.who.int/mediacentre/factsheets/fs194/en/

(3)
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Antibiotic_resistant_bact
eria?OpenDocument

(4) CDC, Antibiotic Resistance Questions & Answers
http://www.cdc.gov/getsmart/antibiotic-use/anitbiotic-resistance-faqs.html#f

(5) World Health Organization "Antimicrobial resistance"
http://www.who.int/mediacentre/factsheets/fs194/en/

(6,7) CDC, Antibiotic Resistance Questions & Answers
http://www.cdc.gov/getsmart/antibiotic-use/anitbiotic-resistance-faqs.html#f

(8) Philip Dickey, “Antimicrobial Products: Who Needs Them?” Alternatives, A
Washington Toxics Coalition Fact Sheet

(9) Stuart B. Levy, Tufts University School of Medicine “Antibacterial Household
Products: Cause for Concern”

								
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