Semen Culture

What is Semen Culture?

Semen Culture is the laboratory testing of a semen sample. The test aims at detecting potential pathogen microorganisms that may cause infection of the male genitourinary tract. When the culture detects positive bacterial semen in the sample, an antibiogram follows informing the therapist physician about which antibiotic is the most appropriate one, so as to eradicate the pathogenic microorganism.    

Semen culture checks for the presence of common pathogenic microorganisms (aerobic and anaerobic), as well as of other bacteria, such as mycoplasmaa and ureoplasm. In addition, there can be optional detection of Chlamydia.

When is Semen Culture performed?

Semen Culture is essential when the man suddenly presents with symptoms of the lower urinary tract (LUTS) and genital system -such as painful ejaculation, haemospermia (presence of blood in the semen)- and also in cases of urinary frequency or urgency, dysuria etc.  Paricularly in the last cases, semen culture has to be combined with urine culture, for sometimes the pathogenic bacterium may be detected only in the urine or only in the semen.

What preparation is needed for Semen Culture?

No special preparation is needed for Semen Culture. However, some basic instructions should be given:

The patient should not be on any antibiotic treatment when Semen Culture is performed or at least 7-10 days before. Before obtaining semen sample, the patient has to wash thoroughly the region with clean water only -and avoid any antiseptic that might potentially contaminate the specimen.  In every case, there is risk for false negative results (i.e. culture may demonstrate the presence of pathogenic microorganisms in the semen sample while there are not actually any). 

How is Semen Culture performed?

It is essential to avoid contamination by microorganisms from other sources than semen, for example from the skin or an already contaminated container. When obtaining semen sample, you should make sure for the following:

  • The collecting container has to be sterile.
  • Urinate first.
  • Wash hands and penis thoroughly by using common soap, to remove all bacteria from the skin.
  • Rinse thoroughly with plenty of water.
  • Dry hands and penis thoroughly by using a clean towel.
  • Obtain sample through ejaculation, making sure that penis or fingers do not touch the interior of the collecting container.
  • Close the collecting container, making sure that fingers do not touch the interior of the collecting container.

Once collected, the semen sample has to be taken to the microbiological laboratory within less than three hours.

How are the results of Semen Culture interpreted?

In most cases, results are ready within 48 hours, that is the time it takes for common pathogenic microorganisms to incubate. Semen Culture may be found to be:

  • Negative: no pathogenic microorganism is found.
  • Positive: some pathogenic microorganism is found. In this case, an antibiogram follows with a list of antibiotic agents to which the microorganism is sensitive. With some pathogenic bacteria, such as mycoplasma and ureoplasm, the antibiogram is not necessary, as the therapy is very specific. However, the man has to consult his physician again for determining the proper dosage and duration of treatment.

Superinfection: Three or more bacterial strains are found in the sample, meaning either that sampling was not conducted under sterile conditions or the sample was contaminated by other external sources. In this case, semen culture has to be repeated.