THURSDAY MARCH 22,2012
WESTCOAST NEWS II
A3
PUBLIC SAFETY
B.C. scientists engineer water-testing
tool kit that IDs bacteria by genetics
Faster detection of dozens of dangerous pathogens possible
BY RANDY SHORE
VANCOUVER SUN
Scientists in B.C. are developing new tools that will cut
the time needed for water testing from days to just hours and
allow public safety officials to
detect contamination in time
to head off illness.
Researchers at the British
Columbia Public Health laboratories are designing a completely new approach to water
testing using metagenomics, a
way to detect the genetic signature of dozens of organisms all
at the same time within hours
of sampling.
Metagenomic testing done at
the watershed rather than the
tap could shorten the response
time to contamination and
allow public health officials to
intervene in time to save people
from being sickened, explained
project co-leader Judith IsaacRenton.
"The tools we have at our
disposal are inadequate," said
Isaac-Renton.
Rather than performing individual tests for suspected pathogens, a metagenomic tool would
pulverize all the organisms in a
water sample and analyze bits of
genetic material in the resulting
soup. Computer-driven pattern
recognition software could then
match the recognizable material, known as genetic markers
or biomarkers, to the genetic
codes of bacteria that are indicators of unhealthy water.
"We aren't so much looking
for dangerous bugs, \yhich is
slow, inaccurate and too narrow, we are looking at the signature ofhealthy water," IsaacRenton explained.
Current testing regimes
involve transporting water
samples n:0Il?- all over the province to jabs at the BC Centre for,
Disease Control where samples
have to be cultured for one to
GENOMEBC
Current water testing methods can take days to generate results.
two days to detect bacteria such
as E. coli, the bug that sickened
thousands and killed seven
people in Walkerton, Ont., 12
years ago.
"It might take two days to
get the samples and then an
overnight delayto get the tests
done," said Jennifer Gardy, a
genome researcher at the BG
Centre for Disease Control,
a partner organization in ¢.e
research project.
Heavy rains sometimes wash
fecal contaminants from wild
animals or farms into watersheds, contaminants that 'can
make their way to your tap in
less than a day.
"By the time we come back
to a community and say there
was fecal contamination in their
water, it's an event that has come
and gone;" she said. "We can say
somebody pooped in your water
- a couple of days ago."
A more sophisticated tool
would be able to detect the
presence of viruses and parasites that conventional testing regimes do not, as well as
larger patterns in the population of organisms characteristic of both healthy and troubled
watersheds.
: Pathogens such as the diarrhea-inducing protoz.oan
cryptosporidium and the parasite toxoplasmosis found in
cat feces are difficult to test for,
but may cause serious illness
in humans when they enter the
water supply.
"We are missing a lot of key
pathogens in our current testing regime," Gardy said.
There are 49 boil water advisories due to contamination
in effect in the area served by
Vancouver Coastal Health, the
oldest one dating back to 1990.
The $3.2-million project
funded by Genome BC and
Genome Canada will include
development of a tool kit consisting offield-ready testing procedures that can be conducted
on basic equipment common
in labs all over the province and
software that can be used to
quickly detect the presence of
unhealthy conditions.
Identifying the genetic signature of certain pathogens will
also allow scientists to determine
the source ofthe contamination.
"If we know an E. coli is specific
to cattle we can look upstream
and find the farms and make
sure they use less water in their
manure runoffs or avoid using it
after· a heavy rainfall," she said.
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