Resistant Bacteria                                                                                                                                                           Staphylococcus aureus is a bacteria that is found on the skin and in the mucus membranes of the nose in some twenty percent of healthy people. It grows readily in the laboratory to form large colonies that are yellow in colour hence the name. Staphlococci and streptococci are known as gram positive organisms as they take up a violet dye when stained under the microscope and are thus able to be distinguished from E coli and Salmonella that tend to live in the gut. If you milk cows you will be familiar with Staph aureus as it is the cause of a chronic mastitis that is difficult to get rid of. This is also the organism that is present in skin infections when you get puss or in young animals that develop joint and navel infections.                                        

Monitoring                                                                                                                                                                               Why is Staph aureus important? Well it a sophisticated organism that has the ability to change and become resistant to the antibiotics that we use against it. Many infections such as foul in the foot and calf diphtheria come from soil organisms that are always sensitive to the commonly used antibiotics. Once identified there is no need to test them further as they have not learnt to resist the drugs that we use to treat the infections they cause. Staph aureus is monitored on human patients as it has been found that the ones that are resistant to Meticillin are particularly difficult to treat. Meticillin Resistant Staph aureus is usually abbreviated to MRSA.                                                 

Risk from Animals                                                                                                                                                                     Great care is taken to keep MRSA out of hospitals and medical environments. Patients are screened for it and visitors and health professionals are constantly disinfecting their hands to limit its spread amongst their patients. We too  occasionally come across MRSA in the patients we treat. Animals do sometimes get the infection, particularly if they are young or very old and especially if they are on long term drugs that affect their immune system. Generally when you come into contact with an animal you stroke its fur and don’t have so much contact with the bacteria that live on the skin.                                                      

Risk from Poultry                                                                                                                                                                       Last month AHVLA reported that they had identified Livestock Associated MRSA from a poultry farm in East Anglia. They seem confident that as long as the meat is handled hygienically the bacteria will not survive the cooking process. The strain involved does occasionally cause human health problems but it is not so difficult to deal with as some of the outbreaks of infection. On poultry units bacteria from the skin and feathers gets into the air and it is this that is the major concern for workers who have to deal with the flock every day. Broiler units operate an all in all out policy so normal disinfection procedures after destocking should clear the infection from the farm.                

Unknown Infections                                                                                                                                                                                                                                The concern is that the stock you handle every day could be carrying infections that are potentially harmful to us even when they show no signs of infection themselves. There is a potential for the more aggressive forms of MRSA to turn up on farms. Many people now are on long term immunosuppressive drugs as part of their treatment for allergies or cancer and are at increased risk from these infections.                              

Laboratory Closures                                                                                                                                                                  Since I last wrote Animal Health and the Veterinary Laboratories Agency have announced that it intends to close seven of its remaining fourteen Laboratories in England and Wales in an effort to improve the way that it does surveillance on farm animal diseases. Nobody is able to understand any of this. It is accepted that there is a need to save money, but the amounts involved, £2.4 million a year, are small when you take into account the losses that will occur when disease that affect animals and us are missed. They propose to use a network of vans to collect fallen stock for post mortems and transport them to the laboratories that remain open. We are fortunate that Shrewsbury is one of the few to survive, they already take in work from Anglesey and North Wales with the closures their area will extend into the East Midlands and mid Wales as well. It would seem to me that it is an expensive business to run a network of vans for this purpose and there will be as number of redundancies which will also have to be paid for from somewhere.                          

New Providers                                                                                                                                                                                                                                                   The plan is that they will encourage other providers to carry out post mortems. At the moment it is by no means clear exactly who these people are. In practice it is difficult to undertake comprehensive post mortems on farms. It is problematic to set up the right facilities to do a proper job and to safely dispose of the bits afterwards. Specimens for viral isolation need to be processed quickly and may be of little use if there is a delay before they are examined at a specialist laboratory. We spend a great deal of time encouraging you to think about biosecurity around your livestock. This new system goes directly against any improvements that you have been able to make and is a big step in the wrong direction.                                  

Possible Missed Diagnosis                                                                                                                                                                                                                                           In the relatively simple situation when a ewe aborts for diagnosis we need placenta, including at least three cotyledons, stomach contents from the foetus and fluid from the chest cavity or blood. The first one is easy to get and will reveal the major cause of abortion such as Enzootic, Toxoplasma, Salmonella , Campylobacter and Listeria which are the most important to you. It is so easy to overlook Q Fever and Yersinia, especially if we have already found something else, as these come from the samples that are more difficult to get but have more significance for human health as they can cause nasty zoonotic diseases.

Current Concerns                                                                                                                                                                         In recent years there have been a whole host of new diseases to deal with. Bluetongue, Schmellengberg, MRSA,   E coli 0157:H7, Bird Flu, Swine Flu, Johne’s disease, Liver Fluke not to mention the continuing Tuberculosis crisis. It is difficult for general practitioners to recognize the subtle changes of emerging diseases as we do not have the resources or facilities to investigate them properly. Every time there is a Bird Flu or Foot and Mouth crisis it is the vets from the laboratories that play a major role to co ordinate the response to the disease. There is as far as I am aware no plan to cope without this extra expert help. Just how AHVLA feel they can deal with these things with fewer resources is difficult to understand.     

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