Some strains now produce poisonous hydrogen sulfide (H2S) gas
Common Plant Vector Injects Genes into Human Cells
The genetic engineering community has assumed that Agrobacterium, a commonly used gene
transfer vector for plants, does not infect animal cells, and certainly would not transfer genes into
them. But this has been proved wrong. Prof. Joe Cummins warns of hazards to laboratory and
Agrobacterium tumefaciens is a bacterium that causes tumours to appear on the stems of
infected plants. The bacterium causes the tumours by transferring genes to the cells of the
infected plant cells from a tumour inducing plasmid (Ti). The Ti plasmid has virulence genes that
determine attachment to cells and transfer of a segment of the plasmid, T-DNA, to the plant cell.
The transferred DNA is integrated essentially randomly (no apparent sequence bias at the site of
insertion) into the plant chromosomes and normally add bacterial genes that stimulate plant
tumour cell growth.
In crop genetic manipulation (GM), the growth-stimulating genes that give rise to tumours are
replaced by GM constructs which include genes for antibiotic resistance, plant viral promoters
and genes for desired crop traits such as herbicide tolerance.
Until quite recently, the genetic engineering community has assumed that
Agrobacterium does not infect animal cells, and certainly would not transfer genes into
them. But this has been proved wrong.
A paper published earlier this year reports that T-DNA can be transferred to the chromosomes of
human cancer cells . In fact, Agrobacterium attaches to and genetically transforms several
types of human cells. The researchers found that in stably transformed HeLa cells, the
integration event occurred at the right border of the Ti plasmid's T-DNA, exactly as would happen
when it is being transferred into a plant cell genome. This suggests that Agrobacterium
transforms human cells by a mechanism similar to that which it uses for transformation of plants
The paper shows that human cancer cells along with neuron and kidney cells were transformed
with the Agrobacterium T-DNA. Such observations should raise alarm for those who use
Agrobacterium in the laboratory.
The integrated T-DNA will almost certainly act as a mutagen as it integrates into human
chromosomes. Cancer can be triggered by activation of oncogenes (ie, cancer genes) or
inactivation of cancer suppressing genes. Furthermore, the sequences carried within the T-DNA
in the transforming bacterium can be expressed in the transformed cells (the viral promoter CaMV
has been found to be active in HeLa cells ) and constructions currently being tested include
pharmaceutically active human genes such as the interleukins .
It is clear that little has been done to prevent environmental escape of the transforming bacteria
or to quantify such releases. In conclusion, a study of cancer incidence among those exposed to
Agrobacterium tumefaciens in the laboratory and
in the field is needed. It would be worthwhile to screen workers for T-DNA sequences.
Kunik T, Tzfira T, Kapulnik Y, Gafni Y, Dingwall C, and Citovsky V. Genetic transformation of
HeLa cells by Agrobacterium. PNAS USA, 2001, 98, 1871-87.
Ho MW, Ryan A and Cummins J. CaMV 35S promoter fragmentation hotspot confirmed and it is
active in animals. Microbial Ecology in Health and Disease, 2000, 12, 189.
See "GM AIDS virus more deadly" by Joe Cummins & Mae-Wan Ho ISIS Report, July 19, 2001
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J Clin Microbiol. 1993 September; 31(9): 2541–2543.
Recovery of a strain of Agrobacterium radiobacter with a mucoid phenotype from an
immunocompromised child with bacteremia.
W M Dunne, Jr, J Tillman, and J C Murray
Department of Pathology, Texas Children's Hospital, Houston 77030.
Agrobacteria are associated more commonly with plant than with human disease. The isolation of
Agrobacterium radiobacter from blood cultures of an immunocompromised child with a
transcutaneous catheter prompted a review of human infections caused by Agrobacterium
species. Only 12 reports describing 19 cases of Agrobacterium infections in humans have
appeared in the literature. Sixteen of the patients (84%) were equipped with implantable or
transcutaneous medical devices at the time of infection, and 14 of the 19 (80%) patients could be
considered immunocompromised because of underlying disease processes. Unlike those in
previous reports, however, this patient was infected with a novel mucoid phenotype of A.
radiobacter. Because of the significant relationship between infection and biomedical implants, we
evaluated the adhesion of this mucoid strain and a nonmucoid strain of A. radiobacter to plastic
by using two in vitro assays. No adhesion or biofilm formation was detected for either strain, but
nonetheless it is clear from this review that the isolation of Agrobacterium spp. from patients with
indwelling medical appliances should not be dismissed as an environmental contaminant.
Agrobacterium in humans
Although generally seen as an infection in plants, Agrobacterium can be responsible for
opportunistic infections in humans with weakened immune systems, but has not been shown
to be a primary pathogen in otherwise healthy individuals. A 2000 study published by the National
Academy of Sciences suggested that Agrobacterium attaches to and genetically transforms
several types of human cells by integrating its T-DNA into the human cell genome. The study was
conducted under laboratory conditions and states that it does not draw any conclusions
regarding related biological activity in nature.
There is a conjectured connection with Morgellons syndrome. Dr. Stricker, along with Dr.
Citovsky, MRF board member from the State University of New York at Stony Brook and an expert
on plant pathogens, reported in January, 2007, that Morgellons skin fibers appear to contain
cellulose. Five skin samples of Morgellons patients contained evidence of DNA from
Agrobacterium yellow group: bacteremia and possible septic arthritis following
peripheral blood stem cell transplantation
A 47-year-old male patient developed sepsis and monoarticular arthritis following
autologous stem cell transplantation for recurrent Hodgkin's disease. Blood cultures
were positive for Agrobacterium yellow group. The knee pain and swelling responded
promptly to the institution of empirical broad-spectrum antibiotics. Recurrent
bacteremia developed necessitating Hickman line removal for eventual resolution of
the infection. Transplant physicians should be aware of this unusual pathogen and the
potential for both persistent line-related sepsis and possible septic arthritis.
Bone Marrow Transplantation (2000) 26, 101-104.