Urinary tract infection is a very common condition, especially in females. Data shows that almost every female has experienced urinary tract infection at least once in their life. According to the statistics, around 150 million cases of urinary tract infection occur every year around the globe. The estimated incidence of women affected with urinary tract infection is around 0.5-0.7. The urinary tract infection refers to the occurrence of infection in any part of your urinary system, which includes the ureter, kidney, urinary bladder, and urethra. Most commonly urinary tract infection occurs in the lower part of your urinary tract that includes the urinary bladder and the urethra. 

Urinary tract infection may look like a simple infection that goes away within a week but prolonged or the recurrence of urinary tract infection can lead to some serious health complications. Therefore, it is necessary that you get the main cause behind frequent urinary tract infection diagnosed at the earliest. An early and accurate diagnosis of urinary tract infection can not only help in treating the infection from its very core but also prevent it from causing any other health complications. Therefore, if you also suffer from urinary tract infection, make sure to get it diagnosed and treated.

Since, urinary tract infections are a common health condition, it is important that people know about the tests done for the diagnosis of the infection. Urine culture is the laboratory test done for the diagnosis of urinary tract infection. In this article, let us discuss in detail about urine culture including what it is, when it is done, why it is done, and how it is done.

What is urine culture?

Urine or your body’s liquid waste can contain various infection-causing microorganisms. Urine culture is a laboratory test done to check whether or not there are germs present in your urine sample. A growth-promoting substance is added to your urine sample in the laboratory. Thus, if bacteria or yeast is present in your urine, it will start multiplying. The growth of microbes indicates presence of urinary system infection. 

Why is urine culture done?

Urine culture is generally done for the diagnosis of urinary tract infections (UTIs). The urinary tract infection occurs due to the presence of bacteria in the urethra. The urinary tract infection starts from your urinary bladder and can reach your kidneys and prostate gland as well. The urine culture test identifies the type of bacteria or yeast causing the infection so that the most effective treatment plan can be decided for you. It also determines whether the bacterial infection is resistant to certain drugs or not.

What symptoms indicate the need for urine culture?

A urine culture test is generally done to determine whether or not you have urinary tract infection. However, there are certain symptoms due to which your doctor might recommend you to go for a urine culture test. The most common symptoms of a urinary tract infection include:

• A burning pain while urinating
• Increased frequency of urination
• An urgent need to urinate
• Fever and chills
• Cloudy appearance of the urine
• Passing smelly urine
• Pain in the lower belly or back area

 

When is a urine culture test done?

There are certain people who are at a higher risk of developing urinary tract infections. The urine culture test is generally done for people who have symptoms of urinary tract infection. Following are some common cases where a urine culture test is done because they are at a higher risk of developing urinary tract infections.

• If you get a urinary tract infection very frequently or the infection is not easily treatable.
• If you are diabetic
• If you have any kind of kidney disease or stones in the kidney
• If you have frequent intercourse with new partners
• If you use spermicides
• If you face a problem in draining your bladder completely 
• If you use a urinary catheter for draining urine
• If you have a weak immune system that can be due to any ongoing or previous cancer treatment, organ transplant, or autoimmune diseases.

How is the urine sample collected for a urine culture?

There are different types of urine samples that can be collected for urine culture. However, the mid-stream clean catch urine sample is the best and the most suitable sample for urine culture. The measures that you should take while collecting your urine sample are;

• Before you collect your urine, clean the genital area from front to back so that the urine is not contaminated with the bacteria or cells present in your surrounding skin.
• Wash your hands
• Firstly, urinate some amount into the toilet and then collect 1-2 ounces of urine into the bottle.
• Make sure that the container does not come in contact with your skin.
• Collect urine directly into the container and do not scoop it from the toilet.

The urine sample for the test is generally collected in a bottle provided by the path lab. However, there are various other ways to collect urine samples for people who cannot collect the sample on their own like extremely ill people, elderly people, and infants. The ways in which urine sample can be collected are:

• Catheterization: In this method, a catheter, that is, a flexible, thin tube is inserted into your urethra to reach the bladder. The urine present in your urinary bladder flows out of the catheter and gets collected into a sterile collection bag.
• Aspiration: In this method, the skin of your abdomen is numbed so that a thin needle can be inserted into your urinary bladder. This needle is used for the collection of urine into a bag.
• U bag or urine bag: This urine collection method is used for young children and infants. In this method, you can stick the urine bag through an adhesive to their penis or over their vulva. Once your child has urinated, you should collect the urine into a lidded container and keep it in a refrigerator until you have not submitted it to the testing laboratory.

How is a urine culture test done?

A urine culture is a simple microbiology test done in a laboratory to check whether or not you are infected by any microorganism. Following are the general steps involved in a urine culture test.

• For a urine culture test, agar plates are prepared by forming a thin layer of nutrient media.
• The urine sample is spread over one or more plates and incubated at body temperature for next 24 to 48 hours.
• After incubation for 2 days, the colonies on the agar plate are counted by a microbiologist. He also determines the type of bacterias that have grown on the plate. The colour, shape, and size of colonies helps in identifying the type of bacteria. The number of colonies present in a urine sample denotes the bacterial load, or the quantity of bacteria present in the urine sample. The different quantity of bacteria in the sample helps in differentiating between normal versus infectious conditions.
• Usually if a good clean catch sample is collected for the test, it will show the presence of only those bacteria which are responsible for UTI. Thus, typically only a single type of bacteria will be present in the urine culture in large numbers.
• If the infection is caused by more than one pathogen, then you might see the presence of more than one type of bacteria. However, there are high chances that different types of bacteria might be present due to the faecal, vaginal, or skin matter that can be picked up during the urie collection.
• Each different type of colony is picked up by the lab assistant to identify the type of microbe by performing other tests like gram staining.
• Susceptibility testing of each type of colony is done to determine the antibiotics that can effectively cure the infection.

How are urine culture test results interpreted?

The urine culture results can be either positive or negative. A urine culture test positive means that there is bacterial growth in your urine sample. A positive urine culture test and symptoms of infection or irritation in the bladder denote urinary tract infection. A positive urine culture test is indicated by the presence of more than 1,00,000 colony forming units (CFU)/ millilitre of any one type of bacteria. An antibiotic sensitivity test or the antibiotic susceptibility test is done to determine the presence of microbes in urine culture. The urine culture and sensitivity test identifies the type of bacteria responsible for causing infection.

The test also determines the antibiotics to which the bacteria is sensitive, that is, the antibiotics which are capable of killing the bacteria's present in the culture. This information is very useful in determining the medicine that can most effectively treat your infection. This is because different strains of bacteria are treated through different medicines. Those infections which are caused by the antibiotic resistant bacteria are harder to treat and thus, urine culture and sensitivity test results are essential for effective treatment of infection. On the other hand, if your urine culture test report is negative it means that your urine flora is normal and you do not have any bacterial or yeast growth in your urine sample confirming that you do not have any urinary tract infection. However, if you have a negative urine culture report along with hematuria (presence of blood in urine), or dysuria (painful urination), you might require to go through other imaging tests to know the exact cause of these symptoms.

What is the urine culture test price?

A urine culture test is not a costly test. The exact cost of the test depends upon your location and the centre where you are getting your test done. At Redcliffe labs, the cost of a urine culture test is around Rs 699/- across the country.

Takeaway

Urinary tract infection is a common problem. Females are more often diagnosed with urinary tract infection than males. A recurrent or prolonged urinary tract infection can be an indication of other related or unrelated health conditions. It is important to diagnose urinary tract infection. Urine culture is the major test done for the diagnosis of the urinary tract infection. The test also helps in predicting the main causative agent behind the infection. This helps the doctor in planning the treatment that is most effective against the microbes causing urinary tract infection. Now that you know about urine culture, how the test is done, the symptoms that can lead to a urine culture test, interpretation of urine culture test, and its cost, you will better be able to analyse your condition and your urine culture test reports as well.

Frequently Asked Questions (FAQs)

1. What bacteria's are present in urine?

Usually, your urine sample can be contaminated with bacteria like E.coli, Klebsiella, Staphylococcus, Enterobacter, Proteus, and Acinetobater.

2. How much time does it take for the urine culture test results to arrive?

A typical urine culture test report can take around 3 days after your urine sample is collected.

3. Are there any side effects of a urine culture test?

A urine culture test is extremely safe and there are no side effects of the test if the sample is collected naturally. However, if a catheter or a needle is used for collecting urine samples, there is a small risk of infection.