Your vet may have recommended sending a swab away to the laboratory for testing. A swab is a sterile tool for collecting a sample that looks a little like a cotton bud. Swabs are generally sent away when we suspect infection and could be of a wound or even from down an uncomfortable ear. At the lab, they will grow the bacteria and then test which antibiotics will kill it. But you may be thinking ‘why do I need a swab? Can’t I just have antibiotics?’, especially when we will often prescribe antibiotics once the swab has returned, or a particular antibiotic has always worked in the past.

Well, the answer to this involves two main reasons, both of which are intertwined with each other.

The first lies in the nature of antibiotics; not all antibiotics are equal. It is a myth that some antibiotics are stronger than other. They are all the same strength, however they all have a different role; rather like in a team sports game, each team member is just as important as each other, but each has their own spot. When we swab a wound or ear for instance, we are checking to see what bugs are down there, and which antibiotics will kill them. Consider placing a striker in a goalie position… sure they might save a few goals but it’s not what they are good at, and you’ll probably lose the match eventually. In comparison, with the wrong choice of antibiotic, we may see some improvement but not resolution of the problem, delaying healing of your pet, and costing you more money in the long term. Sometimes we can use broad spectrum antibiotics; the jack of all trades. These do a reasonable job of killing a wide range of bacteria and often can resolve the issue. But there are some bacteria they won’t work against, or that may have developed resistance, and in these cases, not knowing the best antibiotic for the job can allow infection to worsen. In some cases, antibiotics may not even be appropriate, and their use would not only be a waste of your money but also contribute to antibiotic resistance. For example, when we swab ears, we will sometimes see only yeast growth. Without a swab, we as vets are essentially guessing which antibiotic, or other treatment is best to try first.

The second huge reason why we may suggest swabbing a wound is the global problem of antibiotic resistance. Antibiotic resistance is one of the most frightening problems that we will face in the near future. Almost every strain of bacteria can now show resistance to one, or sometimes almost all antibiotic types, meaning they can be very hard to treat. Treating with the wrong antibiotic can allow further resistances to develop. This is not just a problem in veterinary medicine; it extends widely into human medicine as well. If we do not act to limit inappropriate antibiotic use, we may get to a point where we do not have working antibiotics for common infections and we could be back in a situation where small injuries can be lethal. When we send away a swab, we receive back a report from the lab stating what bacteria have been grown from the swab and which antibiotics will/will not kill them. We are now seeing more and more swabs coming back showing multi-resistant bacteria with many showing resistance to common broad-spectrum antibiotics as well as more specialist antibiotics. This seems to be a particular problem with ear swabs and anal gland swabs. We need to know which antibiotics will efficiently kill bacteria to avoid adding to the problem and to fix your pet as quickly as possible.

We understand it can be frustrating to add the extra cost of a swab to your treatment bill, but we do not recommend tests unless they are appropriate for the case. Swabs do not yield as useful results if taken after antibiotics have been given, so it is better to sample at the start of a problem. Once the sample is taken, we can get a tide-over medication on board to make your pet more comfortable until the results are back which is usually between three and six days. It can be a false economy to hedge your bets on a broad-spectrum antibiotic or ear treatment, and can delay resolution for your pet, not to mention potentially adding to the crisis of antibiotic resistance.