Chlamydia testing
What is the most dangerous kind of infection? Is it one that makes
you cough, sneeze and take to your bed, or is it the stealthy kind you
don't know you have until you visit your GP several months later?
In the case of chlamydia, the sexually transmitted infection (STI)
that can cause infertility and pregnancy problems, the lack of symptoms
presents real danger.
Although easily combated by modern medicines, chlamydia is not as simple
to diagnose as other STI such as gonorrhoea and genital herpes.
Ruth Stanier, deputy head of sexual health and substance misuse at
the Department of Health, says the condition is a common cause of ectopic
pregnancy and pelvic inflammatory disease - conditions which, if left
untreated, can lead to infertility.
The financial burden is worrying too, with chlamydia costing the NHS
an estimated £50 million a year in referrals and treatment - a
figure many feel can be reduced by cutting waiting times for sample
testing.
Which is where Dstl came in:
"There is a real need to reduce the time it takes to diagnose
this condition and Dstl has hit upon a novel way of exploiting our inherent
military technology to do just that," says Hugh Ballantine Dykes
of Dstl's Detection Department at Porton Down.
Scientists there teamed up with experts at the Department of Health
and the Public Health Laboratory Service (PHLS) to deliver a new system
able to slash diagnosis of chlamydia from days to under 40 minutes.
Using an ultra-rapid DNA testing system, developed by Dstl for swift
detection of chemical and biological agents on the battlefield, the
team has built a screening unit successfully piloted in Portsmouth and
the Wirral.
The Government now wants 50 working units in place at Genito-Urinary
Medicine (GUM) clinics around Britain by June 2004 - all part of an
overall Government strategy launched last July for better sexual health
and battling HIV.
Inside the system
Dstl's new weapon in the chlamydia war benefits from several years'
research by Dr Martin Lee, Dr David Squirrell and colleagues in Dstl's
Detection Department at Porton Down.
The department's job is to protect the UK and its armed forces from
biological weapons. Ithas created and deployed a number of state-of-the-art
diagnostic systems for ultra-rapid detection and identification of such
agents.
A major catalyst for the chlamydia project has been the development
of instrumentation for fast detection of DNA sequences using Polymerase
Chain Reaction (PCR), which heats samples to amplify DNA.
The PCR method is used in labs around the world, but Dstl's version
is made faster through use of an innovative Electrically Conducting
Polymer (ECP) and a unique device developed at Porton Down.
The portable instrument speeds the process by using custom-built test
tubes containing the ECP, which can quickly heat and cool samples. The
device also allows a complete DNA amplification process to be carried
out automatically.
"It's a great example of spinning out Dstl technology for the
greater good," says Martin Lee, one of the brains behind the novel
polymer.
"Interestingly, the polymer we are using can be found in mundane,
everyday objects such as thermal cut-out fuses, boxes to keep pizzas
warm and heaters for baby wipes!"
Inside the clinic
Improvements Dstl offers to UK chlamydia testing will not only extend
to the new instrumentation. The organisation has also developed new
sample preparation and processing techniques to meet the need for speed
and accuracy in GUM clinics.
Sample preparation procedures that take 1-2 hours in a laboratory,
can now be automated into one 10-15 minute step.
"We want to make coming to a GUM clinic as painless an experience
as possible," says Dr Jean Tobin, consultant at the Genito-Medicine
Department, St Mary's Hospital, Portsmouth.
"Obviously, it can make patients anxious if they have to wait
for results for long periods of time. This system will cut the time
down dramatically, help reduce the need for follow-up visits and free
up valuable staff time."
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