BVA urges caution over ‘Superbugs’ report – Soil Association response

30 March 2012

The Soil Association is pleased that the British Veterinary Association has supported its call for a stronger regulatory framework for newer antibiotics which are critically important in human medicine. [1]

The BVA, however, has disputed a Soil Association claim that there is now ‘overwhelming evidence’ that the use of antibiotics in UK farming is contributing to the rise of resistant human E. coli infections. The BVA suggests that the Soil Association’s claim is contradicted by a European Food Safety Authority report published last year about a highly resistant form of E. coli, called ESBL E. coli.

The Soil Association claim, however, does not relate specifically to ESBL resistance, but to antibiotic resistance in E. coli generally, including resistance to important antibiotics such as fluoroquinolones and aminoglycosides which are used to treat E. coli infections. [2] Human antibiotic use is also implicated in the spread of resistance to these antibiotics.

A Soil Association report, published yesterday, reviews a large number of scientific studies, including studies carried out by Defra scientists, which, taken together, provide overwhelming evidence linking antibiotic use in farm animals with resistance in human E. coli infections. [3]

One Defra scientist, for example, when referring to E. coli in a paper published in 2010, said that ‘These observations strongly support the premise that resistance genes present in the commensal flora of animals can spread to bacteria which can colonize or infect humans’. [4] As long ago as 1994, other British government scientists had concluded that their findings ‘support the view that resistance to gentamicin and apramycin in clinical isolates of E. coli results from the spread of resistant organisms from animals to man, with subsequent inter-strain or inter-species spread’. [5]

ESBL resistance has only emerged as a major problem in the past decade, so fewer studies are available, as mentioned in the EFSA report. This is now an area of active research, and already for some types of ESBL resistance there is strong evidence linking the human and animal epidemics.

For one type of ESBL resistance, called CTX-M-1, the EFSA report quoted by the BVA states that the existence of genetic similarities in resistance in humans and animals ‘strongly suggests an animal reservoir for this ESBL gene variant’. EFSA says that certain CTX-M-1 ESBL resistances in E. coli from poultry and in Salmonella in retail meat and food-producing animals are ‘highly related to those in the community and hospitals’. EFSA also says the research findings from the Netherlands ‘are suggestive of transmission of ESBL genes, plasmids and clones from poultry to humans most likely through the food chain’. [6]

The BVA also highlighted recent research from the University of Glasgow which has questioned the previously widely accepted conclusion that farm antibiotic use is the main cause of resistance in human Salmonella infections. [7] The journal which published this research, however, has already published two critical responses, one from US and Danish scientists, and one from the Soil Association, which claim that there are flaws in the Glasgow statistical analysis and that the study data is entirely consistent with farm animals being a major reservoir of resistant Salmonella. [8][9]

Ends

For press enquiries contact the Soil Association press office:
Clio Turton, press office manager - 0117 914 2448 / 07795 562 556
Josh Stride, press & e-communications officer – 0117 314 5170 / 07717 802 183
press@soilassociation.org

Notes to editor:

[1] Vets urge caution over Soil Association claims on superbugs, 29 March 2012 http://www.bva.co.uk/news/2773.aspx

[2] E. coli superbugs warning, http://www.soilassociation.org/news/newsstory/articleid/3221/e-coli-superbugs-warning

[3] E. coli superbugs on farms and food, http://www.soilassociation.org/LinkClick.aspx?fileticket=yCT9su5iViQ%3d&tabid=313

[4] Teale C.J., 2010. Journal of Antimicrobial Chemotherapy, 65 Suppl. 1, i8,  http://jac.oxfordjournals.org/content/65/suppl_1/i3.full.pdf+html  jac.oxfordjournals.org/content/65/suppl_1/i3.full.pdf+html

[5] Johnson A.P. et al., 1994. Journal of Medical Microbiology, 40: 221-6, http://jmm.sgmjournals.org/content/40/3/221.long

[6] p30 and p33 of EFSA, 2011. Scientific Opinion on the public health risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals, http://www.efsa.europa.eu/en/efsajournal/doc/2322.pdf

[7] Mather A.E. et al., 2012. Proceedings of the Royal Society Biological Sciences, 279:1630-39

[8] Nunan C. and Young R., 2012. Proceedings of the Royal Society Biological Sciences, http://rspb.royalsocietypublishing.org/content/early/2011/11/10/rspb.2011.1975.abstract/reply#royprsb_el_346

[9] Price L. et al., 2012. Proceedings of the Royal Society Biological Sciences, http://rspb.royalsocietypublishing.org/content/early/2011/11/10/rspb.2011.1975.abstract/reply#royprsb_el_346