Wednesday, June 08, 2005

Scientific Integrity II.

One area in science that possibly has the worst confidence from the public, particularly in New Zealand and in Europe is Genetic Engineering (GE). Genetic engineering has for some time now been demonised as being controlled mostly by greedy, monopolistic corporations that seem to be out to get everyone (including you!). With such a massive amount of distrust and the continual erosion of public confidence by some of the outright distortions of fact given by anti-GE proponents; you would not be fooled for thinking these companies would be highly rigourous in their methodology to keep what (little) public confidence there is.

Sadly once again, we see that the publics perception and confidence in science as a whole is shaken.
European regulators should pursue their own investigation into how the 'wrong' genetically modified corn was allowed on the market for years. Unfortunately, their US equivalents show little sign of rising to the challenge.

What happened here is that a breed of Bt10 corn that contains a gene for an insecticide produced by a bacterium, Bacillus thuringiensis and a gene for antibiotic resistance (ampicillin) was able to get onto the market. Although there is a legally available version of this crop, Bt11 that lacks the resistance gene, it went undetected for four years before anyone realised what was going wrong.

The obvious ramifications in this whole controversy is to make the companies involved look really stupid. If they are unable to tell what they are putting into their seeds, how are they to know what other components may or may not come along with their seeds? To the general publics perception this is probably going to be a disaster for those campaigning GE is a safe technology. This once again highlights the importance of scientific honesty and to be as transparent as possible about the methodology used to make these seeds.

In any event, we need to consider why this has caused such alarm within many in Europe. Although the insecticide is of debatable importance, the antibiotic ampicillin is still used in vetinary medicine in the UK (K. L. Goodyear et al. Journal of Antimicrobial Chemotherapy. 2004:54,959). The spread of the gene containing this resistance might spread to soil bacteria and then onto pathogens is a potential worry, according to Gundula Azeez in the letters page of Nature:
In addition, it is worth noting that the ampicillin-resistance gene in Bt10 maize and other genetically modified crops is a remnant of the bacterial plasmid inserted into these varieties, and would therefore function very efficiently if taken up by bacteria as a result of horizontal gene transfer.
Of course, if this was such a worry for the UK, then they are probably already in trouble.

Matthew Gibbs et al. Characterization of -Lactamases Responsible for Resistance to Extended-Spectrum Cephalosporins in Escherichia coli and Salmonella enterica Strains from Food-Producing Animals in the United Kingdom. Microbial Drug Resistance, 2004:10(1),1-9. Here in this paper it is reported that:
Synergism experiments with benzo(b)thiophene-2-boronic acid (BZBTH2B) and isoelectric focusing (IEF) revealed the presence of an AmpC -lactamase with a pI 9. amp C multiplex PCR, sequence, and Southern analyses indicated that only the Salmonella isolate had a plasmid-encoded AmpC -lactamase CMY-2 on a nonconjugative 60-MDa plasmid.
This is the first report of a CMY-2 Salmonella isolate in the United Kingdom. These data imply that -lactam resistance in animal isolates can be generated de novo as evidenced by the E. coli strains, or in the case of the Salmonella strains be the result of intercontinental transmission due to an acquired resistance mechanism.
So it appears that ampicillin resistance genes are already present in the UK and are already present in the food chain. Not to mention that these antibiotic resistance genes are arising not from HGT from this GE crop but they are arising from HGT from other strains in other countries. In short, if Ampicillin resistance, and indeed other antibiotic resistance is a considerable problem for the UK why are they still feeding antibiotics to farm animals as growth promotants? Not to mention that the anibiotics they are using aren't always stated either.

While I do think that the GE company here made a serious mistake in this case, I think there is a more direct and worrying source of antibiotic genes that needs attention. Rather than focusing on the 'coulds', 'ifs' and 'what abouts' of HGT from antibiotic resistance markers, perhaps we should be focusing on the 'definitely' of resistance arising from feeding animals antibiotics.