Culture and Sensitivity: What It Tells Your Vet

A culture and sensitivity test grows the germs from a sample, such as urine, pus or an ear swab, and then checks which antibiotic medicines can stop them. The result helps your vet choose a medicine that suits the germ instead of guessing. A registered veterinarian reads the report with the animal's signs, and the test never replaces a physical examination.

What happens to the sample in the lab?

Germs are far too small to see, so the lab gives them food and warmth and lets them multiply. The sample is spread on a plate holding a jelly-like food and kept warm. If germs are present, they grow into small visible spots called colonies. Each kind of germ makes spots with its own look, and further checks help to name it.

All this growing takes time, which is why a culture report is not instant. The lab confirms the reporting time when you book.

What do "sensitive" and "resistant" mean?

Once a germ is growing well, the lab places small amounts of several antibiotics near it and watches what happens. If the germ stops growing around a medicine, the report calls the germ sensitive to it. If the germ keeps growing right up to the medicine, the germ is resistant, which means that medicine did not hold it back in the test.

These words describe a germ and a medicine in a dish. They do not promise what will happen inside the animal. Your vet also weighs the animal's age, the part of the body involved and how sick it is. Medicines used without a vet's advice can make germs harder to treat later, which is one reason this test is so useful.

Why should the sample be taken before antibiotics?

An antibiotic already in the body, or spread on a wound, can slow or kill germs. When the lab then tries to grow them, nothing may appear, or the real culprit may be hidden behind a harmless germ. A "no growth" result would then mislead everyone.

So tell your vet about any medicine your animal has had recently, and ask whether the sample should be taken first. This does not mean delaying care. A very sick animal needs a vet at once, and the vet will decide the order of steps.

Which samples are used?

The lab can test several kinds of samples, and the lab confirms which suits which animal when you book:

• Urine, for Urine Culture & Sensitivity. A clean catch or a sample taken by the vet is preferred, because urine left standing lets germs multiply in the container.
• A wound swab, for Wound Swab Culture & Sensitivity. The vet uses a sterile swab and tries to avoid the dirt on the surface.
• An ear swab, for Ear Swab Culture & Sensitivity. Healthy ears carry some germs of their own, so the vet decides which ones matter.
• Pus from a swelling, for Abscess / Pus Culture & Sensitivity. The vet draws it with a needle or swab and tries to keep the sample as clean as possible.

Dogs, cats, cows, buffaloes and horses can all get wounds, discharges and swellings. For a horse or a farm animal, the vet usually takes the sample. Use the sterile container or swab that the vet or lab gives you, keep it closed and cool, and bring it quickly.

What can a culture not tell you?

A culture may find no growth even when an infection is present. The animal may already have had medicines, the germ may be fussy about how it grows, or the sample may have been kept badly. A culture may also grow germs that live quietly on skin or in ears, and your vet has to judge whether they truly cause the trouble.

It also covers only germs that grow on this kind of plate. Some illnesses come from viruses, parasites or other causes, and they need different tests.

Some germs found in wounds, pus, urine or birth material can pass to people. Wear gloves, wash your hands well after handling samples or animals, and speak to a doctor if you feel unwell.

Read next

Culture is one of the slower tests because germs need time to grow, so How Long Do Lab Reports Take, and Why It Varies explains why report times differ from test to test. If you keep cows or buffaloes, Abortion in Cattle and Buffalo: Which Samples and Tests shows where culture fits among the other tests when a pregnancy is lost.

Testing in Bhopal

To book a culture, call or WhatsApp +91 88175 01118 and describe the sample and the animal. The lab at C-200, C Sector, Shahpura collects free from your home anywhere in Bhopal, and it confirms the method, sample needs and reporting time when you book. Other districts can send the sample by courier, bus parcel or through the local vet.