Bacillus thuringiensis (Bt)

Monsanto patent US5229112 A  for BT producing Pseudomonas, Agrobacterium, Rhizobium, Erwinia, Azotobacter,
Azospirillum, Klebsiella, Alcaligenes and Flavobacterium was granted to colonize corn seed and plants.
Publication date        Jul 20, 1993
Filing date        Jun 7, 1989
They are all now documented human pathogens
November 1, 1982
PNAS, vol. 79 no. 22

Transfer of Bacillus thuringiensis plasmids coding for delta-endotoxin among strains of B. thuringiensis and B. cereus

The recently discovered high-frequency transfer of plasmids between strains of Bacillus thuringiensis was used to study the genetic
relationship between plasmids and production of the insecticidal delta-endotoxin crystal. Three strains of B. thuringiensis transmitted the
Cry+ (crystal-producing) phenotype to Cry- (acrystalliferous) B. thuringiensis recipients. Agarose gel electrophoresis showed that one
specific plasmid from each donor strain was always present in Cry+ "transcipients." The size of the transmissible crystal-coding plasmid
varied with the donor strain, being 75 MDal (megadaltons) in size in HD-2, 50 MDal in HD-73, and 44 MDal in HD-263. Immunological
analysis showed the Cry+ transcipients to be hybrid strains, having flagella of the recipient serotype and crystals of the donor serotype.
These results demonstrate that the structural genes for the delta-endotoxin are plasmid borne. Crystal-coding plasmids also transferred
into two strains of the related species Bacillus cereus and yielded transcipients that produced crystals of the same antigenicity as the
donor strain.

FEMS Immunol Med Microbiol. 1999 May;24(1):43-7.

Bacillus thuringiensis serotype H34 isolated from human and insecticidal strains serotypes 3a3b and H14 can lead to
death of immunocompetent mice after pulmonary infection.
Hernandez E1, Ramisse F, Cruel T, le Vagueresse R, Cavallo JD.
Author information
In 1995, we isolated a strain of Bacillus thuringiensis serotype H34 from severe human tissue necrosis. This bacterium
was able to induce myonecrosis in immunosuppressed mice after cutaneous infection. Its potential pathogenicity for
immunocompetent hosts was investigated in a mouse model of pulmonary infection. Mice infected intranasally by a
suspension containing 10(8) spores died within 8 h in a clinical toxic-shock syndrome. In the same conditions, infection
with a mutant without crystalline toxin, with the supernatant from a culture containing 10(8) bacteria ml(-1) and by the
insecticidal strain serotypes 3a3b or H14 led to identical results. Lower inocula simply induced a local inflammatory
reaction with bacterial persistence observed during the course of 10 days.

Full study -
FEMS Immunol Med Microbiol. 2000 Nov;29(3):177-81.

Super-infection by Bacillus thuringiensis H34 or 3a3b can lead to death in mice infected with the influenza A virus.
Hernandez E1, Ramisse F, Gros P, Cavallo J.
Author information
Bacterial super-infections are the main cause of complication and mortality after influenza virus (IAV) infection. Since
Bacillus thuringiensis (Bt) is considered non-pathogenic for humans and is widely sprayed in urban areas, the aim of
this work was to evaluate the potential pathogenicity of a combined infection Bt-IAV in a mouse model of pneumonia.
Bacteria used for super-infections were Bt serotype H34 isolated from human infection and the insecticidal strain 3a3b
obtained from a commercial source. Virus strain was A/Scotland/20/74 (H3N2) adapted to BALB/c mice by serial lung
passage. Combined infection with 4% of the viral lethal dose 50% (LD(50)) and 10(2) spores of Bt H34 killed 40% of the
mice. Mortality rates increased up to 55% and 100% when combined infections were done with respectively 10(4) and 10
(7) spores. The insecticidal strain Bt 3a3b was less pathogenic than Bt H34. A dose of 10(4) spores associated with 4%
of IAV LD(50) killed 50% of the mice. This inoculum must be compared with the doses usually sprayed in agriculture: 10
(11) spores m(-2). Total protection against super-infection was obtained when mice were treated with amantadine. Even
if only a few cases of Bt human infection have been reported, these results suggest a possible risk for workers spraying
Bt-based biopesticides during flu outbreaks.
Bacillus Thuringiensis, Bugs, and Humans
Posted by Shannah Schmitt on Aug 29, 2011 in Crop & Soil Research, Fields Report
Michael Fields Agricultural Institute

In the past, Bt corn had one gene inserted into its DNA to target a specific pest (e.g. European corn borers or corn
rootworms).  Now the makers of this seed are stacking up to six different genes – Bt genes and glyphosate-tolerant
genes – into one corn plant.  This seed comes with a requisite 5% refuge.  Rather than forestalling insect resistance,
this approach will probably accelerate it.  The EPA recently granted approval for Syngenta’s Agrisure 3122, corn seed
stacked with multiple genetically-modified traits.  According to the USDA, seed corn prices rose 146% from 1999-2011.
In the U.S., genetically-modified corn accounts for about 86% of the nation’s crop.  The Center for Food Safety
estimates that 70% of processed foods contain genetically-modified organisms.  The public knows very little about the
health effects of eating food with Bt genes.  Short term studies have shown signs of toxicity with kidney and liver damage
in mammals.  A 2009 study in the International Journal of Biological Sciences found a “clear negative impact on the
function of these organs in rats consuming GM maize varieties for just ninety days”.  What happens when humans and
livestock eat food with Bt for fifteen years?
When it was released, regulators claimed that Bt corn was safe because the Bt was degraded in the intestinal tract.  
Now the Bt toxin is showing up in the bloodstream of humans.  Researchers in Canada looked for signs of the bio-
pesticide in the blood of pregnant and non-pregnant women.  A study published in Reproductive Toxicology in February
2011 found the Bt toxin in 93% of maternal blood samples, 80% of fetal blood samples, and 69% of non-pregnant
women blood samples.
J. Clin. Microbiol. July 1998 vol. 36 no. 7 2138-2139

Bacillus thuringiensis subsp.konkukian (Serotype H34) Superinfection: Case Report and Experimental
Evidence of Pathogenicity in Immunosuppressed Mice


We present a case of severe war wounds infected by Bacillus thuringiensis serotype H34 and describe the experimental
protocol used to demonstrate its ability to infect mice after cutaneous inoculation. This case is interesting because B.
thuringiensis is considered to be a contaminant in laboratories and receives inadequate attention.


Infections in burn wounds