DNA tests that are quick and cheap could soon reveal which bugs are making a
patient ill and even whether bacteria are antibiotic-resistant. This will allow
doctors to speedily prescribe the most effective treatments, saving lives and
reducing the spread of antibiotic resistance.
At the moment doctors have to send samples to a lab to be identified, which
is expensive and slow鈥攊t can take up to three days to get the results. So
people with simple illnesses such as sore throats are often prescribed
antibiotics 鈥渏ust in case鈥�, even though the drugs don鈥檛 help most of these
patients because the infection is viral.
And if tests aren鈥檛 done, more serious conditions, such as dangerous urinary
tract infections in pregnant women, may go undetected and untreated.
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Now, however, Infectio Diagnostic, a company spun off from Laval University
in Quebec City, is developing a series of DNA test kits that can speedily detect
and identify bacteria. The kits will not only identify the species of
microorganism, but also whether a bacterium is antibiotic-resistant鈥攁nd if
so, to what. 鈥淔rom the minute the sample is in to the results takes only 40 to
60 minutes,鈥� says Jacques Milette, the company鈥檚 vice-president.
The company has spent the past few years finding and patenting hundreds of
DNA sequences from bacteria and fungi, and developing fast ways to detect these
genetic fingerprints. Its new kits work in two stages. First, a 鈥渓ysis鈥� solution
cracks open any bacterial cells in a sample, exposing the DNA. Infectio鈥檚
solution takes just 10 minutes to do its job, making it faster than many other
products, Milette says. Second, it uses its own primers and reagents to make
multiple copies of the DNA and see if any of it matches the known genetic
fingerprints of pathogenic organisms.
The kits will sell for between $10 and $40, Milette says, and
will help doctors treat bacterial infection more appropriately. For example, one
product, called AmpliStrepB, will identify the group B Streptococcus
bacterium, a leading cause of death among newborn infants in the US. It infects
around 8000 babies each year, killing about 500 and leaving the rest with severe
brain damage from meningitis.
About a third of all women will be infected by this bacterium at some time in
their lifetime, but often they have no symptoms. In North America, pregnant
women are encouraged to have a strep B test after 35 weeks, but an all-clear
then doesn鈥檛 mean they will be uninfected at the time of birth, at around 40
weeks.
Infectio says its test, which will be launched next year, can be done just
hours before the birth, allowing antibiotics to be given to women and their
unborn children if necessary.
Commenting on IDI鈥檚 development, Don Low, a microbiologist at the Mount Sinai
and Princess Margaret Hospitals in Toronto, says the firm is on the right track:
鈥淭his will let us know rapidly whether a bacterium is involved and, if so, which
antibiotic is appropriate.鈥�