Antibiotic Marker Gene in GE Cotton
May Harm Tuberculosis Patients

The Times of India
November 2, 2001

BT GENE COTTON CAN AFFECT TB PATIENTS

Going by the claims of researchers, a seemingly harmless
genetically-engineered cotton plant can build resistance against antibiotics
like streptomycin and spectinomycin and make treatment of diseases like
tuberculosis and gonorrhoea less effective.

Though the probability is small, a copy of the streptomycin or spectinomycin
resistance gene contained in the transgenic seeds as a marker gene, can be
transferred to human pathogens such as the tuberculosis mycobacterium and
neisseria gonorrhoea, the bacterium responsible for gonorrhoea.

The 'aad' gene, which confers resistance to the antibiotics streptomycin and
spectinomycin, is present in both Bollgard (insect-protected) and Roundup
Ready (herbicide tolerant) transgenic cottons. "Risk is a composite of
probability of occurrence and consequences. However, the potential
consequences of such transfer are grave, particularly with respect to
streptomycin and tuberculosis in India. It is for this reason that medical
societies and governments around the world have called for the phase out of
the use of antibiotic resistance genes," believes scientific advisor of the
environmental organisation Greenpeace International, Doreen Stabinsky.
In her recent scientific presentation before the Genetic Engineering
Approval Committee (GEAC) of the Union government, she feared that such a
phenomenon could not be ruled out.

Researchers believe that as these antibiotic marker genes are present in
every cell of the engineered plant, when such food is ingested, the
antibiotic resistance gene is also ingested. Such genes can be transferred
to bacteria in the guts of animals or humans, or to bacteria in the
environment, and diseases could become resistant to many important
antibiotic drugs.

In case of cotton; cotton-seed oil, cattle feed, clinical cotton, tampons,
sanitary napkins, diapers, dressing bandage and other cotton can play the
culprit.

With one TB patient dying every minute in India, TB prevalence of 250
patients in one lakh individuals _ and streptomycin one of the cheapest
antibiotics being administered to over one-third of patients _ consequences
can be serious for India.

Ahmedabad City TB Control Society member secretary Dr Jeetendra Adhia says,
"Streptomycin resistance can play havoc in India, where we succeed in
finding 250 patients per lakh, though there could be many more patients.
Being cheap and effective, it is used largely in re-treatment of TB."
The principle use of streptomycin is as a second-line drug for tuberculosis.
But it is in the treatment of gonorrhoea that spectinomycin is most
important. It is the drug of choice for treating strains of N gonorrhoea
already resistant to penicillin and third generation cephalosporins,
especially during pregnancy.

Gujarat University department of biotechnology head Dr Y K Agarwal, however,
alleviates such fear. "Such incidents are not known. Besides a combination
therapy of much more advanced drugs is prescribed for TB. However, all
precaution should be taken."

Geneticists Dr Jayesh Sheth and Dr Frenny Sheth do not rule out spread of
resistance to the streptomycin if such products are consumed.
"Though streptomycin is not very commonly used, we should still be cautious
about growing such seeds. They should be grown for some time in isolations
and their effect should be studied."

The European Union rejected permission to sell trangenic seeds in Europe in
1999. In the United Kingdom, the House of Lords Select Committee on the
European Communities recommended that such genes should be phased out as
swiftly as possible.

Once dubbed as a biotech success story, a gene from the soil bacterium
Bacillus Thuringiensis (Bt gene), was first transplanted into corn and then
into cotton, for controlling cotton bollworms. This bacterium produces a
crystalline (cry) protein which breaks down the intestinal lining of many
species of insects, causing death.