A skin or wound culture is a test to find and
identify germs (such as bacteria, a
fungus, or a virus) that may be growing on the skin or
in a wound. A sample of skin, tissue, or fluid is collected from the affected
area and placed in a container with a substance (called growth medium or
culture medium) that helps organisms grow. If nothing important grows, the
culture is negative. If something that can cause
infection grows, the culture is positive. The type of
organisms may be identified with a microscope, chemical tests, or both.
Most bacteria can grow in oxygen. They are called aerobic bacteria and
usually are found in wounds close to the skin surface (superficial). Bacteria
that cannot grow in the presence of oxygen (anaerobic) usually are found in
deeper wounds and
abscesses. A wound culture can find out whether
bacteria are aerobic or anaerobic.
A fungal culture is done to
find out if an infection is caused by a fungus. A
viral culture can be done to find out whether an
infection is caused by a virus.
Some types of bacteria that
normally live on or in the body can cause an infection if they go to parts of
the body where they are not normally found. For example, E. coli bacteria are normally found in the colon and anus. But if
E. coli bacteria spread from the
anus to the
urethra, the bacteria may cause a
urinary tract infection (UTI).
If a skin
or wound culture is positive, other tests may be done to help choose the best
medicine to treat the infection. This is called
Culture samples may
also be collected from the ear or eye, from open or closed sores, or from nails
Why It Is Done
A skin or wound culture is done
- Find the cause of an infection in a sore, burn,
surgical wound, or injury. An injury includes animal bites, human bites, marine
stings or scrapes, cuts, and puncture wounds that are more likely to get
- Make decisions about the best treatment for an infection.
This is called sensitivity testing.
How To Prepare
You do not need to do anything before
you have this test. If you are taking or have recently taken
antibiotics, tell your doctor.
your doctor about any concerns you have regarding the need for the test, its
risks, how it will be done, or what the results will mean. To help you
understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
To collect a tissue or fluid sample from
a wound, a sterile swab is inserted into the wound. The health professional
collecting the sample may press around the wound and gently turn the swab to
collect as much tissue or fluid as possible. The swab is then placed into
either an aerobic or anaerobic culture tube or both, depending on the type of