Urine culture (clinical analyzes)



Urine culture is a microbiological investigation that is carried out on the urine. It is neither invasive nor painful.

The doctor prescribes it when he suspects a urinary tract infection that occurs with:

  • frequent need to urinate
  • burning and pain when urinating

Urine culture is also often performed during pregnancy, a period in which the woman is particularly exposed to the risk of urinary tract infections which often develop without causing disturbances (symptoms).

A urinary infection that is not treated properly can go back up to the kidneys causing serious complications such as pyelonephritis.

There are many bacteria that can cause urinary tract infection, but the most common include:

  • Escherichia coli
  • Proteus
  • Klebsiella

The test

No special preparation is required to carry out urine culture. It is sufficient to buy a special sterile container for urine at the pharmacy or parapharmacy.

Immediately before collecting the urine, it is necessary to wash your hands and the external area of ​​the genitals thoroughly to avoid any type of bacterial contamination.

The urine to be collected for the examination is early in the morning.With clean hands, and being careful not to touch the inside and edges of the sterile container, only the intermediate stream of urine should be collected, eliminating the first and last jet.
It is not necessary to fill the container, as small quantities are sufficient for the examination.

Subsequently, the sterile container must be closed with the supplied lid, labeled with your name and surname and brought to the analysis laboratory as soon as possible.

In the case of infants or very young children, the pediatrician may recommend the use of a sterile bag to apply, making it adhere well to the groin area after having thoroughly cleaned it. As soon as the child has urinated, and in any case no later than 20 minutes from its application, the bag must be removed using sterile gloves or clean hands and carefully closed according to the instructions on the package.

In the days of the menstrual period or during antibiotic therapy it is not indicated to carry out urine collection.

In the laboratory of analysis, the urine sample is placed on solid culture media (plates) for 24-48 hours to observe the number and type of microorganisms that may have grown.


If the urine culture result is defined positive it means that a number of colonies of microorganisms (usually bacteria) greater than 100 thousand per millimeter of urine has developed. In this case, there is a urinary infection that must be treated with antibiotics. The analysis laboratory, if the urine culture result is positive, identifies the species or species of microorganisms present and, if the doctor has requested it, carries out thentibiogram, test that tests different antibiotics on the colonies of microorganisms grown in order to find the most effective antibiotic.

The doctor, after evaluating the antibiogram, will prescribe the most suitable antibiotic that must be taken in the manner and at the times indicated by him.

If the urine culture result is defined negative, it means that the growth of microorganisms is absent or is less than 100 thousand colonies per millimeter of urine. In this case, there is no infection. If despite a negative result the disorders continue to be present, the doctor may deem it appropriate to repeat the analysis.

In pregnancy, if the urine culture result shows the presence of group B Streptococcus at the time of delivery, it is important to inform your gynecologist or the attending physician for any treatment with an antibiotic, even in the absence of disorders (symptoms) , to prevent possible infection of the unborn child.

In-depth link

Humanitas Research Hospital. Urinalysis or urine culture

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