University of Arizona Health Science Center
The germ detective solves a household mystery By Anita Bartholomew
The moring bell rings, and 25 or so adorable five-and six-years-old enter their
bright tidy classroom. It's a typical day in a typical kindergarten. And
the boys and girls are doing what they typically do. They select toys and
books, and felt-tip markers, then several kids stick their selections in their
mouths
Two little ones wips their drippy noses with a finger and sleeve. Another
little boy sticks the corner of a book into his mouth. Moments later he and
three other kids are reading it, taking turns flipping the pages. Each
child is touching whatever traces of saliva the first child left behind, each one
picking up germs.
I'm grossed out. The the slight gray-bearded man beside me, University
of Arizona environmental microbiologist Check Gerba, beams in delight. Just
as he anticipated this seemingly clean classroom is not a ssanitary as it looks.
He should know. Dr. Gerba is what you might call a germ detective. A well known
authority on germs that make us sick, he specializes in hunting down disease causing
microbes wherever they hide. His investigations have taken him from private kitchens
to public restrooms to the food-expert centers of South America. He seems
to greet the discovery of bacteria, viruses, and parasites with the glee most of
us reserve for opening Christmas gifts. It's no wonder his job has earned him
the nickname Dr. Clean.
Some of what he's turned up may surprise you. "Your dog got it right;
drinking out of the toliet wasn't such a bad idea"> The scientist chuckles
noting that his studies found more fecal bacteria in the average kitchen sick
(from contaminatioed raw rood, washed there) than in the typical flushed
toliet bowl.
In a recent test of more than 800 public areas-such as shopping malls,
workplaces and day-care centers-Gerba and his colleagues discovered
residues of blood, mucus, saliva and uring on many types of surfaces-
elevator buttons, shopping-carts handles and escalator hand rests among them.
But the places that were most contaminated? Childrens palygrounds (36 %
of surfaces tested) and day-care centers (46 precent of surfaces tested)
. That particularily bad news because children are more susceptible than
adults to the random germs that surround us all.
Dr. Gerba is attending kindergarten today at the request of Reader's Digest. We
asked him to spend sometime with the Kelly family or Sarastoa, Fla-Bryan and
Danielle and their two children, six year old T.J. and two year old Shannon.
The Kellys seem constantly to be passing around colds, flu and other viruses-
which make them like more families with kids.
It's been show that once you have children, the number of colds per audyt
in the family at least doubles," Gerba says.
But annoying sniffles are the least of it. Many microbiologist believe
there has been a steady increase of the number of infections in kids that lead to
intestinal and stomach upset.
Why? "It may be because children are going into day-care centers and into
school at a younger age," Gerba says. "so they're exposed to more germs
earlier on. We also take the children to large play areas, like playgrounds
at fast-food restaurants. Not to mention trips to the mall"
So exactly what kind of germs are out there waiting for our kids? And can
we minimize our children's exposure by keeping certain surfaces clean? We
We're about to find out.
The slim, bespectacles scientist sits in a kiddie-size chair at the
back of the classroom and sets out test rubes, swabs, and chamicals-his ad hoc lab. With a Q-Tip like
swab he dabs on a spot on the table's surface. "I'm going to look for
fecal bacteria, slaavia, blood, mucus, and a measure of good filth",
he announces as he drops the swab into a test tube".
If the liquid in the test tube turns dark in the next ten minutes,
bodily fluids are present. And if bodily fluids are present, we know that
germs could be present too. As there are hundreds of possibilities including
viruses that cause colds, flu, and diarrhea, and bacteria such as
Stalphylococcus aurens (staph) and strep and parasites-this test dosen't
look for specific microbes.
Gerba dabs again at the same spot, using a second swab, which he places
in a separate tube. This test is for coliform bacteria and E. coli, baoth
present in fecal matter. The E. coli he's testing for does not cause
disease like the strain responsible for recent outbreaks of food poisioning
but if they type is present, the other more dangerous variety may be as well.
How might bacteria from feces find it's way onto these surfaces? Improper hand
washing after going to the bathroom, says Gerba.
It will be about 24 hours before we'll have the fecal-bacteria results.
As he shakes the test tubes I scan the rom. One child picks his nose, then wanders
over to the supply shelves for a bottle of paper paste. He handles
a number of bottles before he decondes on the one he wants. Gerba also
watches intently, then scurries over and swabs a paste bottle as well as several
markers on the shelf.
Through the moring, as the kids sing and play, Gerba swabs the surfaces they
touch most; toys, computer, play areas. He also checks a sponge on the
sink where the kids wash up before lunch. "A sponge is a great area
for microorganisms to grow", Gerba says. "So life is teriffic in a
sponge if your a bacteria".
At each desk is a water bottle and a pull-top; each is labeled with
a child's name. Gerba swabs one pull-top.
When the children leave for the cafeteria, Dr. Gerba examines the first
set of test tubes. He finds the heaviest concentration of bodily fluids
on the computer mouse, the supply shelves where paste, markers, and crayons
are store, and the kids favorite puzzle.
But what does this mean? Could T.J. Kelly pick up a cold, flu, or
dirrhea from these objects?" If somebody in the classroom had it, of course"
says the germ detective. "If the surfaces are heavily contaminated with such
fluid as saliva or blood, then they're also heavily contaminated with any
germs growing in those fluids
Soon whe're off to the playground where T.J. and his classmates enjoy
exuberant fun before clas resumes. Spoilsport that he is, Gerba is right
behind them, swabbing money bars, play tunnels, and slides.
The we head for a favorte fastfood restaurant, which has a big playroom
with plastic tunnels, pens, and slides. Gerba is one stop behind curly headed
Shannon as she crawls through a certain of clear vinyl streamers into
a blud padded playpan. One look at the vinyl stips and Gerba knows
he his pay dirt. "Gross!" he shouts, a little too enthusiastically for
my taste. "Ever kid pushes through this with his face and wipes his
nose on it on the way in". He also testes the blue pen behind the
vinyl stips and one of the tunnels.
While we devour our fried food, the swabbed samples develop. Within
minutes as Gerba guessed, we learn that the vinyl shield is the most
heavily contaminated with bodily fluids. The playpen and Tunnels are
contaminated too. These fries that I enagerly gobbled are suddenly not
sitting so well.
The next day, the University of Florida lab in St. Petersburg, Dr. Gerba
examined the second set of test tubes. We're look for bacteria that
originate in fecal materials onthe surfaces that we tested yesterday".
He explains. "If the bacterial are present, we"ll get a yellow color
in these test tubes." Several samples have definitely changed color.
Gerba points to the sample he took from the sponge. The fluid is very
yellow, as in the sample from the classroom sink.
What other surfaces are heavily contaiminated with fecal bacteria?
The fast-food restaurant play areas, the school playground and pull
top from the water bottles that the childrne had in the classroom. Gerba
grins at this last discovery. It's clear that the school intended to
minimize the spread of germs by labeling the bottles. But the plan
backfired. "You have to use your fingers to close the cap. Then if
bacteria get on there, it's going to survive for a long time because
the cap is moist."
Gerba does one final test on our second set of samples, shining an ultraviolet
light on the test tubes on search for E. coli which will glow if present.
He finds it in one tube, but not from a sample taken in T.J.'s classroom.
It's on the baseball bat that all the neighborhood kids shared. E.coli
bacteria survive only a few hours, but if the kids didn't wash their hands
thoroughly before dinner, E. coli germs may well have spread through
several homes....
His most important advice? It's what mothers have advised for the past couple of centuries: wash your hands-when you come in from the outside, before meals, after handling food, after using the bathroom, and any other time you thing you might have come in contact with germs. According to Dr. Clean, it's still your first, last, and best defense.