Drug dilemmas

15-02-2010 | |
David Burch Pig health

With the long-awaited results of the EFSA breeding-herd survey on MRSA now available, it poses some real dilemmas for the European regulatory authorities, pharmaceutical industry and future pig industry.

The survey showed that 12 of the 24 reporting EU countries had positive findings in the breeding herds of MRSA (methicillin-resistant Staphylococcus aureus), almost wholly the farm animal associated clone ST398 (see Figure 1).

Figure 1. Percentage of breeding herds surveyed positive for MRSA.

Belgium, Germany and Spain appeared to have the highest infection rate, Italy was the only country to have a mixture of clonal species (14% ST398) and Netherlands, which was the initial country to detect the problem, was surprisingly low, at only 12.8% of herds. This was close to the EU average of 14%.

These findings, on the face of them, are quite frightening as people involved with pig production working on these units can become potential MRSA carriers too. Fortunately, the infection has not been a major cause of disease in man, in comparison with the hospital or health-care associated MRSA, and some specialists consider it as ‘a minimal health hazard’.

The authorities are concerned though in case it does become a more widespread problem in man. This could lead to restrictions, even withdrawal from use of certain key antibiotics. Calls to stop ‘critical’ human antimicrobial use in veterinary medicine are already being made for the third©and fourth generation cephalosporins and fluoroquinolones.

Future development
Hence the dilemma – if these substances are banned from use in veterinary medicine, will the animal health or pharmaceutical industry continue to develop new antibiotics for use in veterinary medicine? The new compounds are primarily coming out of human pharmaceutical research and the advances are therefore likely to be linked to future human pharmaceutical development. If they feel that the additional return from veterinary antibiotics is unlikely, they will not invest there at all and we will not have any new ones developed. New molecules take nearly ten years to bring to the market and they therefore only get ten years of patent protection from approval, to get their development money and a profit back before the generics start to attack the market.


This leads to the next dilemma, generics. In human medicine, the generic industry is very active and powerful and several major pharmaceutical companies have their own generic businesses as a result. Government health services wish to keep their drug bills down so actively support the concept of generic drug businesses.

On the veterinary side, there is a huge concern, over the use of antibiotics and the potential development and spread of antimicrobial resistance in animals and to man. This is sometime over-inflated for political reasons. In animal production, medication cost and economic return are major factors in determining a product’s use. Hence, when a generic is launched against the originator product, there is an immediate price battle, often halving of the price and doubling or trebling in volume use, as the economic returns increase.

With regard to antibiotics, there is then an increased risk of resistance development. In the EU, current human legislation supports generic use, this then spills over into the veterinary legislation with increased harmonisation and therefore availability across the EU market. We then get criticised for high antibiotic use and potential resistance development.

Quick fixes?
There are no quick fixes, unfortunately. Prolonging patent duration after product launch would encourage drug development but put up drug costs. If this was implemented on the veterinary side it would also possibly reduce the quantities of new antimicrobials used and thereby resistance development.©

From a farmer’s perspective this is bad news, as they usually want the availability of cheap but effective drugs to treat their pigs. Vets come in for a lot of criticism concerning over use of antibiotics, but they are commonly having to respond to a producer’s poor husbandry and hygiene practices and disregard for biosecurity, allowing diseases to come in e.g. from markets.

Responsible and prudent use of antibiotics
The current way forward leaves us with the responsible and prudent use of antibiotics. We do not want drugs to be withdrawn therefore we should only use them where necessary, after a diagnosis and ideally an antimicrobial susceptibility test. The critical human drugs should be used only as a last resort, rather than as a routine or for prophylaxis against Streptococcus suis where penicillin is still generally effective.

Vets and farmers need to work together to reduce the use of antibiotics. This way we can possibly avoid the withdrawal of key drugs and avoid the dilemmas turning into unfavourable decisions for all industries concerned.