Germ Warfare

The Truth about Antibacterial Soap

by Isabelle T. walker

Antibacterial soaps are ubiquitous now. They’re dispensed in
millions of American homes, office buildings, and health clubs. In
a parade of décor-enhancing colors and aromas, it’s hard to resist
their promise of protection from real and imagined bugs lurking
about. But if I’ve learned anything during my journey to middle
age, it’s that there is no such thing as a free lunch. Ever. So
what’s the catch with these suds-upped soaps? Everybody knows
doctors have prescribed oral antibiotics so frequently to patients
in the past — even in cases when they aren’t actually needed — that
some bacteria have adapted to circumvent one or more drugs’ line of
attack. Sometimes physicians have to give patients a series of
progressively stronger antibiotics in order to finish off the
bacteria once and for all. In rare cases — usually among the frail
elderly — the bacteria win.

Are antibacterial soaps contributing to this process, too? To
find out, I called Mary-Louise Scully, the infectious disease
expert at the newly renamed, but same old, tried-and-true Sansum
Clinic. Scully didn’t fit my imagined prototype of an infectious
disease specialist. She doesn’t wear glasses or have a pocket
protector in her white coat. She doesn’t even wear a white
coat — to interviews, anyway. She’s young, has a girl-next-door
face, and a ready sense of humor, probably a prerequisite in her
line of work. Scully believes antibacterial soaps present us with a
Catch-22 situation. “My feeling is they can [contribute to
resistant strains]. Although you could flip it around and say we
wouldn’t be developing these products if we weren’t having a
problem with resistant bacteria.”

Scully sent me a copy of the Centers for Disease Control and
Prevention’s (CDC; www.cdc.gov) guideline on hand hygiene in
healthcare settings, and explained that there is a big difference
between hand hygiene in healthcare settings and hand hygiene in the
community. Since hospitals in particular are breeding grounds for
the gamut of bacteria, viruses, and fungi — including varieties
that are multi-drug resistant — the use of a range of potent soaps
and antiseptics there saves lives.

The active ingredient in most of the antibacterial soaps
available at drug stores and grocery markets is triclosan
(pronounced trick·lo·san). It’s a chemical that’s been around since
the 1960s and is becoming extremely popular. Sales of it are
expected to grow to about $6.9 billion by 2009. Triclosan is also
in some dishwashing liquids and toothpastes. The CDC
guideline — which is not a page-turner, I might add — indicates
that, so far, in real-life situations, bacteria aren’t mounting a
big resistance to triclosan, although the chemists and biologists
who study these things aren’t ruling out the possibility that they
might later on.

Killing disease-causing bacteria that have taken root in
someone’s body is complicated because not all bacteria are bad.
Some are not only good but necessary — especially the ones in the
digestive tract. Good bacteria (called “beneficial flora”) are
locked in an eternal battle with bad bacteria for dominance,
thereby keeping each other in check. When someone takes an
antibiotic, the good and the bad bacteria die, leaving the field
open for hardier, resistant strains to gain a toehold.

Apparently, on our hands, antibacterial soap kills bacteria that
have just arrived, i.e., the transient, surface stuff. So the
natural balance of good and bad organisms isn’t affected, according
to the CDC’s guideline.

It seems the bigger problems with triclosan start when it
disappears down the drain. Triclosan is considered a pre-dioxin,
meaning it can transform into compounds belonging to the class of
dioxins. As potentially carcinogenic dioxins go, the ones that
triclosan is prone to produce aren’t the worst of the bunch, but
that doesn’t make them good either. Triclosan is persistent in the
environment; researchers are finding it not only in stream and
river water, but in breast milk and in the bile of fish.

Rolf Halden, assistant professor at Johns Hopkins Bloomberg
School of Public Health, recently published a study in the journal
Chemosphere that analyzed what happens to triclosan when it arrives
at a wastewater treatment plant. He found that about 50 percent of
the mass coming into the plant was still there in the sludge that’s
produced as a byproduct of treatment. More disquieting is the fact
that many of our agricultural fields today use such treated sludge
as fertilizer. The City of Santa Barbara sends 90 percent of its
sludge to be used on Kern County’s cotton fields — providently, a
non-edible crop. But many scientists, including Halden, are
concerned about what it might be doing to the soil.

The best thing that can be said for triclosan is that it kills
one of the strains of resistant bacteria doctors are worried
about — methicillin-resistant staphylococcus aureus, a k a MRSA.
This strain of staph is difficult to eradicate because it’s
actually a human bacteria; it lives in people’s noses and on their
skin. I f it enters the body through a cut, problems can occur. It
wasn’t until a decade ago that MRSA began sickening people who
hadn’t been in or near a hospital. And, according to Scully, MRSA
infections have an annoying habit of coming back, which is why
infectious disease experts recommend antibacterial soap to people
who have it colonized on their body.

But what about those of us who aren’t colonizing MRSA and aren’t
working in a healthcare setting? Do we need to use antibacterial
soap too? Scully said no. “It’s sometimes appropriate to use these
things, to break the cycle [of a MRSA infection]. But for people
who are healthy and having no problems, basic good hand hygiene is
usually plenty,” she said. And in case you need a refresher, that
means washing with soap and water for at least 30 seconds
(preferably 60 seconds) after using the bathroom, changing a
diaper, scooping the dog’s poop, gardening, before preparing or
consuming food — you get the picture. It also means rubbing your
hands together for that length of time because it’s the friction
that loosens dirt and bacteria.

Here’s the good news in all of this. According to the CDC
guideline on hand hygiene, alcohol-containing hand sanitizers
killed more bacteria and viruses than either antibacterial or plain
soap, but only when the alcohol concentration was between 60 and 90
percent and only when the person used 3 milliliters of the gel.
They take the uzi approach to bactericide: few, if any, live to
tell the tale.

“They’re a pretty indiscriminant killer of bacteria,” said Frank
Alvarez, Santa Barbara County’s director of infectious diseases,
who recommends them. Of course, that also means they kill good
bacteria. But plain soap does, too. And so far, there doesn’t seem
to be any evidence that bacteria are finding ways to resist
alcoho