Mutant strain of antibiotic-resistant E. coli found in the UK

18 November 2008

The Soil Association is calling on the Government to issue guidelines that will limit the veterinary use of the most modern penicillin-type antibiotics. This is necessary to prevent the spread of a serious new superbug.

Recently released minutes of a Government committee [1] reveal that Ministers have been briefed about the emergence on a British dairy farm of a mutant strain of antibiotic-resistant E. coli which causes life-threatening cases of food poisoning, including hemorrhagic colitis and haemolytic uraemic syndrome, which are a particular threat to children. [2]

The bug, known as E. coli O26 is a vera-toxin producing E. coli (VTEC), similar to the infamous E. coli O157. What makes the discovery of this variant so significant is that this is the first time in the UK, and only the third time in the world, that VTEC E. coli has been found with an enhanced type of antibiotic resistance known as extended-spectrum beta-lactamase (ESBL), which makes it resistant to almost all antibiotics. [3] ESBL resistance has previously been found on 57 UK farms, [4] but until now only in strains of E. coli that cause urinary tract infections and blood poisoning.

Although antibiotics are not recommended for the treatment of VTEC E. coli [5] scientists warn that the emergence of resistance is undesirable because these resistant bacteria are encouraged every time certain antibiotics are used, resulting in increased spread and greater risk of contaminated food products. [6]

On non-organic dairy farms, cows are routinely given antibiotics at the end of their lactation to prevent mastitis. In addition, milk from cows given antibiotics for treatment, or prevention, is often fed to calves when it contains residues and cannot be sold. [7] However, because ESBL E. coli O26 is resistant to all the antibiotics used in ‘dry cow therapy’ and many of those used for treatment, the high use of antibiotics on dairy farms will promote the rapid spread of these dangerous bacteria. [8]

Soil Association Policy Adviser, Richard Young, said,
“This is one of the most worrying developments in the continuing rise of ESBL E. coli. Today is the first European Antibiotics Awareness Day, but there is a distinct lack of awareness that the continuing high use of antibiotics in farming is contributing to the increase in antibiotic-resistant infections in humans.

“The Government often calls on doctors to prescribe antibiotics less often. But similar advice needs to be given to veterinary surgeons and farmers. Half of all antibiotics are given to animals, [9] and there is mounting evidence that antibiotic-resistant bacteria in farm animals pass to humans. If we want antibiotics to save lives in the future as they have done in the past then the Government must provide specific recommendations based on scientific advice, and vets need to pull together with doctors to limit the use of problematic drugs.”

Government vets found that 19 of 20 calves and 3 of 40 cows were positive for E. coli O26 with ESBL resistance. The farm has not been identified, but the farmer has been given hygiene advice to protect his family. Surprisingly, no restrictions have been placed on animals from the affected herd, which are being sold locally to unsuspecting farmers and for export, so the Soil Association fears that the hyper-resistant strain will spread more widely.

ESBL resistance already affects an estimated 30,000 people in the UK each year [10] and contributes to thousands of deaths from urinary-tract and blood-poisoning infections, which are caused by non-VTEC types of E. coli. In September, the Health Protection Agency urged drug companies to redouble their efforts to develop new antibiotics to treat ESBL E. coli and certain other superbugs, [11] because we face the real possibility of being unable to treat some infections.

ESBL resistance is caused by the use of the most modern penicillin-type antibiotics, known collectively as third and fourth generation cephalosporins. Three of these antibiotics are licensed veterinary medicines [12] and their use has increased in line with that of all cephalosporins, which has more than doubled in the last four years. [13] According to the London-based European Medicines Evaluation Agency, there is ‘currently no harmonised approach on prudent cephalosporin use in animals’. Some EU countries, like Finland and Denmark place specific restrictions on the farm use of modern cephalosporins, [14] while others, like the UK, do not. Modern cephalosporins are also essential drugs in British hospitals and are classified by the World Heath Organisation as ‘critically important in human medicine’. [15]

The use of antibiotics on organic farms is already limited, but from January 2009, the Soil Association is introducing additional restrictions on the use of modern cephalosporins on the farms it certifies in order to prevent, if possible, the spread of ESBLs to organic animals. [16] The Soil Association is calling on the Government to bring in similar restrictions on all farms, whether organic or conventional.


For more information please contact Richard Young, Soil Association policy adviser: 01386 858235 /

Notes for Editors:

[1] Minutes from the Defra Antimicrobial Resistance Cooordination (DARC) Group on 13 May 2008 state:
Extended-Spectrum Beta-Lactamase (ESBLs) in cattle
6.1 Members were updated on the current situation with ESBLs in E. coli from cattle in the UK. VLA had revisited the dairy farm where a VTEC, serotype O26 had been detected and re-sampled cattle. Of the 20 calves, 19 were positive for VTEC O26 E. coli and 3 of the 40 cows were positive. The farmer had been given advice on hygiene precautions for protecting himself, his family and the public. There had only been two other reported cases in the world of a VTEC E. coli possessing ESBL genes. The farmer was still selling animals for local market and export. VLA had arranged a telephone conference to discuss the findings.

6.2 A document had been prepared on these findings for Ministers. Once Ministers had been advised, the Defra ESBL web pages would be updated. It was agreed that ARHAI and the ACMSF should be kept up to date with this issue.’

[2] See Health Protection Agency website, ‘Vero cytotoxin-producing Escherichia coli (VTEC) O157 clinical information’
As a VTEC E. coli, the symptoms caused by O26 are similar to those caused by O157.

[3] ESBL resistance makes bacteria resistant to nearly all beta-lactam antibiotics, the family of antibiotics containing penicillin, the cephalosporins and many other antibiotics. This makes them particularly difficult to treat, as beta-lactams are by far the most important antibiotics used in human medicine, accounting for over two thirds of total use (see pp. 26-27 of the Government report ‘Overview of antimicrobial usage and bacterial resistance in selected human and animal pathogens in the UK: 2004’, For further information on ESBL resistance, see the Health Protection Agency’s 2005 report ‘Investigations into multi-drug resistant ESBL-producing Escherichia coli strains causing Infections in England’,
[4] Personal communication from the Veterinary Laboratories Agency. The figure of 57 affected farms was provided in May this year, but further farms are known to have been affected since then. For further information on ESBL E. coli on farms see the Defra webpage: and earlier Soil Association press releases: 22 Dec 2006 and 24 Sept 2007

[5] Most people recover from VTEC infections naturally after about seven days and the most important treatment is to maintain sufficient intake of water. Antibiotics can speed recovery and have also been used successfully to eliminate VTEC carriage in adults who were able to infect others while not showing symptoms themselves. They are not normally used because several studies have found that they significantly increase the risk of life-threatening complications. Scientists in the US and elsewhere, however, have reviewed the evidence and concluded that under certain conditions some antibiotics appear to be safe. If guidelines were to change in the future, then the development of ESBL resistance in VTEC is additionally significant because it will compromise one of the few possible treatment options.

[6] Referring to antibiotic resistance in VTEC from farm animals, scientists from Australia have said,
‘While it is currently not considered appropriate to treat VTEC infections, such as HUS with antibiotics, there are significant disadvantages for VTEC infections to be caused by multiple resistant strains. In the presence of antibiotics such strains may have a selective advantage and therefore be more likely to cause an outbreak.’ Bettelheim, KA, Hornitzky MA, Djordjevic SP and Kuzevski A, 2003. ‘Antibiotic resistance among verocytotoxigenic Escherichia coli and non-VREC isolated from domestic animals and humans. Journal of Medical Microbiology 52: 155-162,

[7] In a submission to the European Medicines Evaluation Agency the Soil Association has set out a referenced case arguing that the principal problem with ESBL E. coli on dairy farms is due to the common practice of feeding milk containing antibiotic residues to calves during the period when milk has to be withdrawn from sale.

[8] Modern cephalosporins are widely used in non-organic cattle and pig farming and occasionally used on organic farms. All antibiotic ‘dry cow therapies’ contain beta-lactam antibiotics, the family of antibiotics containing penicillin and the cephalosporins, and ESBL resistance makes bacteria resistant to virtually all beta-lactams. The list of dry cow therapies can be viewed in the National Office of Animal Health (NOAH)’s Compendium,

[9] In 2004, total use of antimicrobials in human medicine (by weight of active ingredient) was 400.5 tonnes. Of this, 68.8 tonnes were prescribed in hospitals and 331.7 tonnes by GPs. Veterinary use was 454 tonnes, of which between 393 and 425 tonnes were used in food animals. See pp. 26-29 of the Government report ‘Overview of antimicrobial usage and bacterial resistance in selected human and animal pathogens in the UK: 2004’,

[10] See Health Protection Agency 2007 press release, ‘Infections caused by ESBL-producing E. coli’,

[11] ‘More antibiotic development needed warns Health Protection Agency’.
Health Protection Agency press release, 10 September 2008,

[12] Ceftiofur and cefoparazone are third generation cephalosporins, and cefquinome is a fouth generation cephalosporin.

[13] In 2002, by weight of active ingredient, 2,520 kg cephalosporins were sold. In 2007, this had risen to 6,215 kg. See p20 of ‘Sales of Antimicrobial Products Authorised for use as Veterinary Medicines 2008’,

[14] See pp. 7-8 of ‘Reflection paper on the use of 3rd and 4th generation cephalosporins in food-producing animals in the European Union: development of resistance and impact on human and animal health’, 18 Feb 2008,  

[15] World Health Organisation, 2007. ‘Critically important antimicrobials for human medicine – categorization for the development of risk management strategies to contain antimicrobial resistance due to non-human antimicrobial use’, Report of the second WHO Expert meeting, Copenhagen, 29-31 May 2007,

[16] Soil Association standard 10.09.08 reads, ‘From 1 January 2009 you must not use third and fourth generation cephalosporin antibiotics except with our permission and only to treat individual animals. We strongly recommend that you limit your use of these drugs before this date if possible.’
This places the same restriction on the use of modern cephalosporins that already applies to the use of fluoroquinolone antibiotics.

Join to help us stop the use of neonicotinoids and save our living landscapes

Donate to help us create healthy farmland and countryside without pesticides