Science - September 15, 2011

Stop injecting

A drastic reduction is needed in the use of antibiotics in livestock farming if the spread of drug-resistant bacteria in the healthcare system is to be halted, say experts. How urgent is the problem really? And can livestock farmers survive without antibiotics?

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The spread of ESBL is perhaps the best illustration of how urgent the antibiotics problem has become. The bacteria responsible for ESBL were still a rarity in the Netherlands a few years ago but now 1 in 10 Dutch people are carriers - that's how fast things can change. The link between ESBL and poultry farming has now been proven beyond doubt.
The ESBL threat is one of the reasons for the Health Council's recommendation on 31 August to rigorously ban the preventive use of antibiotics in livestock farming. The Health Council feels the sector's voluntary measures to reduce drug use are not proceeding fast enough. The Council has also produced a list of antibiotics that are essential for tackling human infections. Its advice is that these antibiotics should no longer be used at all in livestock farming.
Three days later, the Van Doorn commission went one step further. This commission also recommended a ban on the preventive use of antibiotics and a total ban on certain antibiotics in livestock farming. But this is no government recommendation, it is an agreement to reduce the use of antibiotics throughout the food supply chain. The commission's name is that of Daan van Doorn, former boss of VION, the biggest meat processing company in the Netherlands. Nutreco, the main feed supplier for the livestock sector, also subscribes to the new rules. Moreover, seventeen supermarket chains - including market leader Albert Heijn - have agreed to the stringent antibiotics policy. 'The really innovative aspect of the proposals is the chain approach', said Van Doorn in his presentation.

Fall
Martin Scholten, director of the Animal Sciences Group, was a member of the commission. 'The agreement is that as of 1 January 2012 the supermarkets will no longer stock meat in which preventive antibiotics have been used. We want to move to antibiotics-free livestock farming in which only sick animals are treated on an individual basis. The Dutch supermarkets will be making that a requirement for all their meat, including meat from abroad. The meat processing companies will pass that requirement onto the farmers, who will only be able to supply meat if they comply with the new antibiotics stipulations. Drug use can be checked using farm audits and data provided by vets.' The meat processing companies that have signed the commission's guidelines account for 90 percent of all meat produced in the Netherlands.
'This will inevitably lead to a fall in livestock numbers', continues Scholten. 'That may not be the aim of these antibiotics measures but it is the result. The measures will lead to a slight rise in the cost of meat but the supermarkets have said they will be able to pass that on to consumers through a small price increase. The key factor for livestock farmers will be their healthcare management. Farms with persistently high infection levels will go under.'

Just like Greece
Jan Kluytmans agrees that there is a dire need for far-reaching measures to reduce antibiotics use. Kluytmans was a member of the Health Council's committee that drew up the recent recommendations. He is a doctor in Amphia hospital in Breda and a professor of Microbiology and Infection Prevention at VU University Amsterdam. He is also the researcher who showed that 90 percent of supermarket chicken meat is now infected with the antibiotics-resistant ESBL bacteria. This made it clear that drug-resistant bacteria were spreading through the Dutch food chain via intensive livestock farming.
He thinks the problem is rapidly becoming bigger in the Netherlands. 'There are fewer and fewer antibiotics that still work against these bacteria', says Kluytmans. 'We also know that the development of new antibiotics is stagnating - there are no new effective drugs coming on the market. So that is going to cause big problems.' The spectre for him is the situation that has arisen in Greece and Turkey. 'A lot of the patients in the intensive care departments there are infected with drug-resistant bacteria and can no longer be treated with antibiotics.'

Hospital plague
The most formidable bacteria for the healthcare system originating in livestock farming are the ESBL bacteria. But there are more dangers lurking that will require tough preventive measures. For instance, the Klebsiella bacteria claimed a lot of victims earlier this year in Maasstad hospital in Rotterdam. The bacteria are not found in livestock farming and are therefore still a rarity in Dutch hospitals. To keep it that way, Kluytmans thinks a specific group of antibiotics should be banned from veterinary use. Otherwise Klebsiella could also develop into a hospital plague. 'At the moment healthy people hardly ever become ill from Klebsiella but that could change if the bacteria continue to spread.'
Halving the use of antibiotics in livestock farming - the current cabinet's policy - is probably not enough to solve the problem, says Kluytmans. 'You need to reduce use to a fraction of current levels in order to cut back drug-resistant bacteria. Ideally we should move to a system of livestock farming without antibiotics. Wageningen has the know-how to achieve such sustainable farming through vaccines for animal diseases, better feed and better housing. But consumers will also have to pay more for meat as at present the livestock sector can't switch to more sustainable methods because of the low margins. Fortunately the livestock sector has now also realized this.'
Top three drug-resistant bacteria
The Health Council says there are three groups of drug-resistant bacteria that cause most problems for public health.
Methicillin-resistant Staphylococcus aureus (MRSA). The livestock-related MRSA can still be kept under control in hospitals but now seems to be appearing among the general population. Last year, Denmark had the first cases of people being infected with the pig type CC398 without having been in contact with pigs.
Extended Spectrum Beta-Lactamase (ESBL) producing bacteria. These bacteria spread rapidly and are not limited to hospitals; they are also found elsewhere, in particular as the cause of difficult-to-treat urinary tract infections.
Vancomycin-resistant Enterococcus (VRE). The Council says the link between the use of antibiotics in livestock farming and the incidence of VRE in hospitals is not as clear as was thought in the past.
Difficult but doable
Boekel in the Peel peat region. Geert-Jan van Veen studied Biology at Wageningen from 1983 to 1989. Now he has a pig farm with four hundred sows and ten thousand piglets. Van Veen has a letter from his vet on his kitchen table showing his antibiotics consumption over the past three years. And it turns out he has reduced his use of antibiotics by more than 80 (!) percent. How did he manage it?
For non-farming readers: piglets are initially kept in the nursery area with their mother, but after four weeks they get their own stall and switch from sow's milk onto solid food. This weaning reduces the piglets' resistance and that is the point when Van Veen tends to use antibiotics. He had to use a lot of antibiotics in 2009 to fight streptococcus among the weaned piglets. It was developing in the wounds the piglets had as a result of ear biting and was causing arthritis and meningitis. 'I had to take emergency measures.'
After that he made two changes. He swapped his boar, a Belgian PiƩtrain, for a German PiƩtrain. That meant a slight decrease in his pigs' meat production but also less ear biting. He also started buying different pig feed that was more digestible for the weaned piglets, which reduced the disease pressure.

Van Veen had not been thinking about reducing antibiotics consumption up to then. That changed when his old vet retired in 2010, to be replaced by the young graduate Antoine de Vocht. 'He questioned our use of antibiotics', says Van Veen. De Vocht had simple tips, such as  not selecting the piglets by weight after weaning but putting brothers and sisters in the same stall instead. The advantage of this is that they have already decided on the pecking order in the group so have fewer arguments. Also, each family got its own feed trough when it was moved from the nursery. 'That helps them eat properly and keeps their intestines in working order', says Van Veen.

This year he and his vet did a trial to see if he could manage without antibiotics. That went fine until May. 'Then I noticed black rings around the piglets' eyes, which is a sign of respiratory problems. The person I sell my piglets to also raised the alarm: this is not working. Then I went back to giving a course of antibiotics in the first few weeks after weaning.' That is why his dosage day score is now 4.25: each piglet gets antibiotics on an average of just over four days during the ten weeks on Van Veen's farm. In 2009 his dosage day score was 25.
So it is possible by making simple changes. Even so, not all pig farmers will manage this, says vet De Vocht. He prints out antibiotics consumption figures every three months to discuss with the pig farmers. 'There are also pig breeders who find it difficult to manage even a reduction of ten percent. Van Veen is not aiming for maximum production, which means his piglets are a bit stronger on average.'

De Vocht can point out areas for improvement but it is the farmer who decides many of the changes that improve animal health - e.g. the feed, climate and breeding targets - in his business plan. That is why it is important to raise awareness among farmers. The ban on antibiotics in animal feed as of 1 July is a good measure that will help reduce usage, says De Vocht. Now livestock farmers will have to mix the antibiotics into the feed themselves, which will help them think before using antibiotics. But halving antibiotics consumption levels will not work without additional policies. 'I can achieve an average reduction of 35 percent by making farmers more aware, but no more than that.' The livestock farmers with chronic problems on their farms often need to make far-reaching changes if they are to farm without antibiotics. That will probably not be feasible for many farmers. Or else they may turn to methods that are themselves questionable. 'Many pig farmers had a sickbay: the weak piglets were put together for treatment as a kind of intensive care', says pig breeder Van Veen. 'But that turned out to be a source of disease as well. Now that antibiotics consumption has to be reduced, many farmers are getting rid of their sickbays and injecting the piglets to death or getting rid of them.'
The urgency of the antibiotics problem has recently been brought home to Van Veen.  Each year he goes to the hospital for tests to see whether he has the MRSA bacteria. This year he tested positive for the first time.

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