There can be a lot of information to take in when you are at an appointment with your vet. Especially if you are busy worrying about your poorly pet. One of the things that you may be a bit confused about is ‘culture and sensitivity. In this blog, we’ll explore what it is and why it’s so important.

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What is culture and sensitivity?

Culture and sensitivity refers to a test run by a laboratory to help work out what bacteria (if any) is present within a sample sent in by your vet. This helps your vet to know what is causing your pet’s infection. Which is very helpful when it comes to working out how best to treat it. The test also tells us what antibiotics might be most effective when treating the bacteria that has been identified. This can be useful for an array of different conditions such as suspected urinary tract infections, ear infections, and skin infections.

How is culture and sensitivity performed?

Here is a brief step by step as to how this test is performed –

  1. A sample is taken from your pet for analysis. For example, this could be a urine sample if there is a suspected urinary tract infection or a swab (long cotton bud) inserted in the ear to collect discharge in the case of an ear infection.
  2. The sample is carefully packaged so that it can be sent safely to the laboratory.
  3. The laboratory transfers the sample onto special plates (Petri dishes) containing nutrient rich growth media on them that helps bacteria to grow and multiply.
  4. After leaving the sample for a few days, the plate will be examined to see identify what has grown on it
  5. Different antibiotics are then placed near the bacteria to see which is most effective at killing them. This gives us a measure of the bacteria’s ‘sensitivity’ to various drugs
  6. The laboratory reports the results back to your vet, who will then be able to plan an appropriate course of treatment for your pet

If the sample is positive on culture this means that specific bacteria have been found. The next step can be taken to work out what antibiotics are most effective at treating them (sensitivity). Sometimes the sample is negative or just contains commensal organisms; which is a term used to describe the normal healthy bacteria found on your pet. Negative samples may mean no bacterial infection is present. But could also mean the sample was insufficient, and repeat samples may be needed.

A more detailed look at the process of culture and sensitivity is looked at here. Whilst some veterinary practices do process their samples on-site, most use an external laboratory to do it for them.

When might culture and sensitivity be performed?

Culture and sensitivity has a variety of applications. It is good practice to perform this any time a bacterial infection is suspected, not only confirming whether there are pathogenic (disease-causing) bacteria present but also to work out what treatment is best to tackle it.

Samples that can be sent for culture include urine, blood, pus, tissue, or other body fluids (like nasal secretions). It depends on the location of the sample as to whether your pet will need to be sedated or anaesthetised to collect it, but some of them can be taken whilst conscious. Your vet will discuss the process with you.

Why is culture and sensitivity important?

Antibiotic resistance is a genuine concern that not only affects animals but humans too. This describes bacteria that were once susceptible to certain antibiotics, but have now formed a resistance to them, no longer dying when exposed to these medications.

This is worrying as it could mean we will start to face infections for which there is no longer a cure and will inevitably mean that people start to have prolonged illness or even die from diseases that were once easily treatable with first-line treatments. People undergoing routine surgical procedures like Caesarean sections will become more at risk of complications. We are already seeing evidence of it through organisms like MRSA (methicillin-resistant Staphylococcus aureus).

Antibiotic resistance is more likely to develop when antibiotics are administered inappropriately. For example, when they are used if there is no actual bacterial infection present, or if the wrong type of antibiotic is chosen.

Vets, as well as doctors, are working hard to try and control antibiotic resistance by using tests like culture and sensitivity to help choose appropriate treatments for their patients, and ensuring antibiotics are only used when necessary.

Owners can play their part by allowing samples to be taken from their pets; following the instructions from the vet to correctly administer the course of treatment (making sure the treatment course is completed and not stopped halfway); and by listening when the vet recommends alternative treatments or doesn’t think that antibiotics are required e.g in viral infections. All services are chargeable in veterinary care, as there is no NHS for pets. So culture and sensitivity will be priced up as part of your pet’s investigation and treatment plan. 

Conclusion

Culture and sensitivity refers to a laboratory test that identifies the bacteria involved in infections and suggests appropriate treatment targeted towards them. As with all aspects of pet care, this is chargeable, so will appear on your veterinary bill. Your vet should discuss this with you though, as well as the reasons behind wanting to take the sample. Antibiotic resistance is a concern. We all need to play our part in slowing it, or we could face a very bleak future indeed.

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