 |
|
Considering
freshening up your walls? How about
Sterile Steel Blue? Perhaps
Bacteriocidal Beige? Antibacterial Alabaster?
|
At
this point, there isn’t a soul on the planet that hasn’t heard about the growing
threat of “super bugs”, previously treatable bacteria that no longer respond to
antibiotics. The recent UK Review on Antimicrobial Resistance predicts
our antibiotics will be ineffective by the year 2050. And 10 million people will die each year of
previously minor infections and common medical procedures. C-sections, hip replacements and transplants
will no longer be considered relatively safe and routine. Depressing.
While I originally planned on writing an article highlighting what I
think is a very promising avenue of research into antibiotic alternatives
called “bacteriophages” (viruses that kill bacteria), a few days ago I found
myself in the glowing grip of a TV commercial I had never seen before. Let me set the scene for you:
An attractive woman
in her late 30’s, early 40’s, is painting a wall in her house a soothing sage
green. The room is bathed in natural
light and the woman is smiling placidly as her brush goes up and down, up and
down, in a fluid motion. The voiceover
begins and says, “This is how you apply antibacterial paint”, implying that it
is just as easy as applying regular paint.
<End scene>
My
brow furrowed. Did I hear that right? Antibacterial paint? A few clicks of the
keyboard confirmed that what I had just seen on the TV had actually been
announced more than 8 months ago. The
paint company, Sherwin-Williams, is now selling a product called Paint Shield®; a collection
of 550 colors of paint infused with a patented antimicrobial compound. The company is claiming the paint kills 99.9%
of bacteria including Staph, E. coli, MRSA, VRE and Enterobacter
aerogenes on painted surfaces within two hours of exposure, and continues
to kill 90% of bacteria for up to four years as long as the paint surface is
intact. And it will be selling at a
ridiculous premium, going for $84.99 a gallon (compared to $29.99 for a
regular, old, can of paint at my local hardware store).
I’m
not going to take issue with their antibacterial claims. They have the EPA certification to back it up,
indicating that the paint underwent rigorous testing at a third party lab to
support those statements. But the EPA was
only assessing the scientific claims at hand; it wasn’t assessing any claims
about the usefulness or wisdom of actually using such a product. And
herein lies my problem with it. Sherwin-Williams’
website says the product was originally developed for hospitals, athletic
facilities, schools and daycares, but that it is also an excellent choice for
the home, in kitchens and bathrooms and laundry rooms. What irritated me was when I went digging for more
information on Paint Shield® and came across some of the original
news releases. Each article featured
some version of the line “new paint may
save thousands of lives”, citing the need to combat the growing number of
hospital-acquired infections, a quote which at best is yet another example of
journalistic exaggeration, and at worst is utter hogwash (see
an example here).
While
hospital-acquired infections definitely are a big problem, unless
patients are routinely licking the walls I don’t think they are at great risk
of acquiring an infection from them. And
I could find no
research implicating walls in the issue.
In fact, paints (and other surface finishes and fabrics) incorporating
antibacterial compounds have been around for quite some time, and large
hospitals like Kaiser
Permanente actually recommended against their use a few years ago, citing a
lack of evidence that they do anything to prevent infections and a lack of
safety data concerning long term use.
In
a hospital chock-full of very sick people, the fewer germs, the better. It is true that bacteria and viruses can
sometimes remain infectious on surfaces for days or even weeks. We call these surfaces “fomites” for their
ability to transmit disease, and this is why regular disinfection of hospital
floors, walls, and surfaces is already de
rigeur. But the fomites we’re
concerned about are ones that we are in regular contact with, things like counter
tops, doorknobs, and sinks, which we touch with our hands and then
absentmindedly touch our mouths, eyes, and faces. Even Doctor’s
neckties and their classic white coats have been demonstrated to be potentially
dangerous vectors of disease (and being married to a Doc, I can say that I do
not allow these items to enter my house).
What I’m trying to say is that claims
that painting hospital walls with Paint Shield® will “save thousands
of lives” are absolutely overstated.
That
said, in a hospital setting, antimicrobial paint probably couldn’t do much
harm, though I have serious doubts hospitals will deem this product useful
enough to shell out for its hefty price tag.
What is much more concerning to me, however, is the suggestion that this
paint should be used in the home. A
quick search of the patent
literature reveals that the patented technology in Paint Shield® is
a quaternary ammonium compound (or QAC for short), which they’ve managed to
stabilize in the paint. QACs are nothing
new; they have been used for decades in detergents, cleaners and fabric
softeners, and are believed to work by disrupting cell membranes. And they are considered very effective, hence
their widespread usage. But with such
widespread usage comes the inevitable: mounting evidence of microbial resistance.
The
evidence for resistance is in the presence of genes that enable bacteria to
escape the action of antibacterial compounds.
The unnecessary overuse of antimicrobial compounds and chemicals in our
homes, which subsequently winds up in the waste run-off in our environment,
doesn’t actually manage to kill all bacteria.
Instead, some bacteria see repeated, sub-lethal exposure to the
chemicals, which drives the development of resistance genes like the “qac-genes” (reviewed here). The qac-genes
(named for the QAC compounds they function against) encode multi-drug efflux
pumps, which contribute to antibacterial resistance by pumping QACs and other
germ-fighting compounds out before they have a chance to kill the organism, rendering
these chemicals less effective or useless. Eventually this process results in strains of
bacteria that are totally unaffected by these products. And sometimes this resistance to
disinfectants can also result in cross-resistance to antibiotics, making
the problem antibiotic resistant infections worse. This type of resistance is well documented in
Staphylococcus aureus for example, one of the organisms Paint Shield® is touted to kill,
and the famous cause of nightmare-inducing MRSA infections.
Making
this all the more relevant is the very
recent announcement by the FDA of a ban on the marketing of antibacterial soaps
and other products containing over 19 different compounds, due to a lack of
evidence that these products are safe and actually work. That’s
right folks, there is no scientific evidence that antibacterial hand soaps work
better than regular hand-washing with soap and water. Manufacturers of these products will have one
year to remove the chemicals from the products or stop marketing them
altogether. And this is great news,
since several studies published over the last decade have demonstrated that use
of many of these chemicals, Triclosan in particular, not only lack any benefit,
but also contribute to growing bacterial resistance (see here
and here).
So,
in short, will I be running out and buying antibacterial paint for my
home? No thanks. If the cost alone wasn’t enough to keep me
away, the fact that I may actually be making my home and the environment that
absorbs my household waste into a breeding ground for resistant bacteria does. The reality of the coming post-antibiotic age
is certainly frightening, but we would do much more to slow it down by limiting
our use of products that may contribute to this phenomenon, rather than by
trying to encase our families in sterile, little bubbles.
And
for goodness sake, finish
your course of antibiotics!
