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SCIENTIST AT WORK:
CHARLES GERBA; On Germ Patrol, at the
Kitchen Sink
By WENDY MARSTON
Published: February 23, 1999
http://query.nytimes.com/gst/fullpage.html
Dr. Charles Gerba's office is plastered
with photographs of parasites and
bacteria; his file drawers are full of
antibacterial soaps and disinfectants.
The counters of his lab are littered
with petri dish samples from various
public spaces in Tucson, where he is a
professor of microbiology at the
University of Arizona. He speaks with
reverence of Cloacina, the
long-forgotten Roman goddess of the
sewer, and hands a visitor a biography
of Thomas Crapper, inventor of the flush
toilet, saying, ''He doesn't get nearly
enough respect.''
For Dr. Gerba, 53, all roads lead back
to the toilet. A bearded, fidgety man in
yellow tinted glasses and blue jeans, he
has spent the last two decades ferreting
out where bacteria lurk in our daily
lives. But for much of that time, his
interest in the bathroom went unnoticed.
Dr. Gerba is best known in his field of
environmental microbiology for his work
in uncovering how viruses infiltrate
drinking water, and has consulted for
American cities and other countries on
how to improve water quality.
Dr. Gerba developed the first method to
test water for the presence of
cryptosporidium, a parasite responsible
for sporadic outbreaks of diarrhea in
the last decade. His papers, numbering
more than 400, make his name impossible
to ignore in his field, but his work in
household microbes has also been gaining
him wider recognition more recently.
''I'm the only scientist to publish
toilet paper,'' Dr. Gerba said with a
laugh.
Dr. Syed Sattar, director of the Center
for Research on Environmental
Microbiology at the University of
Ottawa, said: ''Twenty-five years ago,
when Gerba started, it wasn't
fashionable to be in environmental
microbiology. He did pioneering work in
how microbes got into our environment.
At that time, it didn't matter what
human beings got, because we could
always pump them with antibiotics. We
don't have that luxury anymore.''
Dr. Gerba's obsession began in the early
1970's when he was a postgraduate
student at Baylor University in Houston,
studying viruses in water. ''My adviser,
Craig Wallace, dragged me into the
bathroom. Then he flushed the toilet a
few times. 'Can you feel the aerosol?'
'' he kept asking.
That experiment led Dr. Gerba to create
what he calls a ''commodograph,'' a
method of determining patterns of
droplet emission from the bowl. He has
also used a strobe light to shoot a
time-lapse photograph of a flush, which
shows droplets of water, usually
invisible, each containing thousands of
bacteria and viruses, being ejected from
the bowl. ''Keep your toothbrush in the
medicine cabinet,'' Dr. Gerba advised.
Though Dr. Gerba never published the
photograph (he freely distributes it to
interested parties), research from that
experiment was published in 1975 in the
journal Applied Microbiology.
In 1981, Dr. Gerba landed at the
University of Arizona, near the home of
his youth, and continued his research
into water quality. But he remained
fascinated by household microbiology. In
the mid-1970's he numbered squares of
toilet paper in public restrooms, and
checked them hourly to gauge how many
were used. Twenty years later, with a
grant from the Scott Paper Company, he
did the same experiment, this time with
microprocessors in the dispensers, and
found that men used an average of two
squares per visit and women used seven.
He discovered which sex had dirtier
bathrooms (women, by far), and where the
bacterial hot zones were in bathrooms
(outside sanitary napkin disposals, the
floor and the sink, in that order; the
doorknob is surprisingly clean). The
average employee uses the bathroom 3.3
times per working day, and women spend
twice as much time in the bathroom as
men.
For Dr. Gerba, a man who exults in the
unspeakable, the toilet was only the
beginning. In a study published last
year in Applied Microbiology, Dr. Gerba
sampled spots all over the house and
found that in most homes, the bathroom
is much cleaner than the kitchen.
Because of contamination introduced by
meat and vegetables, sinks harbor the
most dangerous bacteria, and people who
appear cleanest -- who wipe down
counters regularly with their kitchen
sponge -- tend to have that bacteria all
over their kitchen.
But Dr. Gerba's latest project is the
laundry, a task he believes Americans
regard with not nearly enough caution or
diligence. He is preparing his latest
paper for presentation this spring at
the meeting of the American Society of
Microbiology. His study, survival of
microbial pathogens during laundry,
examines how fecal bacteria infiltrate
washing machines.
Focusing on four-person families in
Tucson, Dr. Gerba's team randomly
visited 60 homes and washed a sterile
washcloth in their machines. One-fifth
of the machines contained E. coli, while
a quarter were contaminated with fecal
matter.
The laundry, Dr. Gerba contends, is
becoming less clean. Fewer Americans
wash clothes in hot water, and only 5
percent use bleach, he said. Wash cycles
are only 20 minutes, while the average
drying time is only 28 minutes. Dr.
Gerba found that some salmonella and
hepatitis A survive through laundry --
including the dry cycle -- and remain on
clothes. ''We have no idea how well we
clean clothes,'' he said.
Dr. Gerba's own laundry machine yielded
E. coli, prompting him to change his own
washing habits. ''I always washed my
underwear last, in a separate load, but
I started using bleach, and now I run an
empty wash, with just bleach, when I'm
done. It's mouthwash for the machine.''
Although Dr. Gerba says he has covered
most of what he can in the household, he
has no fear that he will run out of
material. He predicts that infectious
disease, or microbe-caused illness will
become more prevalent, explaining that
antibiotic resistance, our aging
drinking water infrastructure, and
emerging pathogens will give microbes
the leverage they need in the next
century.
And his work may not be confined to this
planet. He is a consultant to National
Aeronautics and Space Administration,
advising it on dealing with human waste
during extended space travel.
Current ideas include drying out solid
wastes and diluting urine into potable
water, but he is not, he emphasizes, on
the panel that taste-tests the samples.
''Oh no, not me,'' he said. ''I have my
limits.'' |
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