What is Bacteria Culture Test – Identification & Risk Factors

The bacteria culture test is the procedure used to analyse the disease. It is crucial for studying antibiotic susceptibility, genome sequence and virulence. Culture tests can diagnose harmful bacteria that cause disease in the human body.

A bacterial culture test requires a sample of your blood, urine, and saliva from the body. A bacterial culture is multiplying bacteria in a prepared laboratory medium.

A bacteria culture test can determine if you are suffering from an infection in your blood, urine, throat, and stool that affects your body.

If your doctor suggests a bacteria culture test, it is because, according to them, you are suffering from systemic infection, and they want to get sure of certain kinds of microbes.

A culture test of bacteria helps them prescribe medication and the proper treatment for the infection.

What are Bacteria?

Bacteria are the single-cell living micro-organism visible only with the help of a microscope. They are present in both the external environment and the living organism.

According to some research, bacteria are the first living organisms on Earth. They are dependent on both organic and inorganic for their survival.

Many kinds of bacterial classification are available, including respiration, shapes & sizes, nutrition, morphology, ph, and temperature.

In 1884, a microbiologist, Christian Gram, created differentiated bacteria based on the cell membrane.

Two types of bacteria have been classified based on cell membrane: –


The gram-positive bacteria are rod-shaped and do not contain the outermost cell wall. Some gram-positive bacilli are present on skin, nose, reproductive organs without causing any harm.

On the other hand, some of the group of these bacteria causes diseases known as Diphtheria, Anthrax, Listeriosis.


Several classes of antibiotics are prepared to kill the disease-causing gram-negative bacteria. The outmost layer of this group of bacteria consists of lipopolysaccharides.

They are consist of a thin peptidoglycan layer and contain the hard & protective out shell. They can cause serious illnesses, including plague, Salmonella, E.coli, and Pseudomonas.

Types of Bacteria Culture Test & Uses

Bacterial culture tests are performed to diagnose certain kinds of diseases or infections of patients. It is helpful in the diagnosis of harmful bacteria that causes infections in your body.

It is the primary diagnostic methodology tool used to determine the types of bacteria and their abundance in the sample. Moreover, bacterial culture helps check the sensitivity of antibiotics and other drugs.

The common types of bacteria culture tests are mentioned below

Blood Culture

A blood culture helps find the harmful microbes such as bacteria, yeast, and other microbes present in the blood. If your blood culture test is positive, that means your blood contain bacteria.

A blood culture test is performed when your health practitioner suspects you may have a severe illness.

Blood Culture Procedure

A lab technician or nurse will clean the patient’s skin and insert the thin needle into the vein to take out the blood.

In the laboratory, the taken blood sample mixed with culture media ( a medium that provides the environment to multiply the bacteria fast). After 24-48 hours, you will get the result about the kind of pathogen present in your body.

Blood Culture Normal Range:-

Blood Components Normal Levels
Red Blood Cell

Male:-4.32-5.72 million cells

Female:- 3.90-5.03


Male:-135 to 175gram/lit

Females- 120-155gram/lit

WBC (white blood cell) 3500/10,500 cells/mcl (both in male and female

In male:-38.8 to 50.0%

In females:- 34.9 to 44.5%

Platelet Count 150,000 to 45,0000/mcl

Urine Culture Test

The human urinary tract consists of the bladder, kidneys, and tubes that carry the pee. A urine culture test can find out the harmful bacteria and fungus present in the urinary tract. 

Bacteria like Escherichia coli which causes UTIs, can enter the urethra and develop rapidly. 

Bacterial culture


Urine Culture Procedure

Before starting the urine culture, you need to tell all the medications. Some medications and vitamins can interfere with the test. 

Lab assistance will provide you with a sterile bottle to collect urine. Follow the instructions carefully and collect the urine in the given bottle.

In the laboratory, the collected sample is mixed with bacteria growing media known as culture media. Final results may take 24-48 hours.

Throat Swab Culture

A throat culture test is commonly used to detect bacterial infection around the throat. Some microbes like  Streptococcus pneumonia causes pneumonia, tonsillitis, and meningitis.

bacterial culture of sputum

The objective of a throat culture is to diagnose the presence of unwanted or disease-causing microbes in the throat.

Throat Culture Procedure

A culture swab test for the throat is done with the help of a swab. The lab assistant will take a swab and insert it into your mouth to collect the sample from the tonsils and back of the throat.

Sputum Culture Test

Lungs produce the sputum, a mixture of saliva and mucous that causes trouble breathing and cough. Sometimes, bacteria develop in mucous and causes severe infection.

For the sputum culture, you are provided with a sterile cup. Lab assistants may instruct you to cough deeply to bring up the sputum from your lungs.

How is Culture Test Used to Diagnose the Microbes?

A culture test method is helpful in the diagnosis of microbes causing method. It helps identify the microbes from stool, blood, sputum, and urinary tract.

In dermatology, a culture test plays a crucial role in diagnosing whether a skin infection is caused and what kind of microbes are responsible for the infection. 

Types of Bacterial Culture Media based on Consistency

A culture media contains all the nutrients and environment essential for microbial growth.

A culture media has three types:

Culture test for bacteria

Solid culture

Solid culture media consist of agar at concentrations of 1.5 to 1.9 per cent or a  solidifying agent, which is good for the growth of microbes.

Solid culture provides the physical structure of bacteria, and they grow as colonies, and these kinds of structures help isolate bacterias.

Semisolid Medium

Semisolid medium consist of 0.5% of agar. It is a soft custard-like consistency, which helps cultivate microaerophilic bacteria or helps find out bacterial motility.

Liquid Medium / Broth Medium

Liquid culture media consist of specific types of nutrients without any trace of gelling agents (gelatin or agar). These kinds of mediums are helpful in bacterial propagation, fermentation studies, and other tests.

Why Do You Need a Bacteria Culture Test?

A culture test helps your healthcare practitioner to diagnose the kind of infection present in your body system. A culture test of blood, urine, stool, and another test helps a doctor to find the appropriate medication for your illness.

Some bacteria are harmful and cause a wide range of diseases in our bodies. A bacterial culture test can detect harmful bacteria and other microbes in your body.

In order to take the proper treatment, sensitivity check and identifying the microbes is important.

How Long Does a Bacteria Culture Take?

Culture test starts with the collecting of samples that would be blood, urine, sputum, and stools etc. Once the sample has been collected, it would take 1-2 days for the final results. 

What Does a Culture Test Detect?

Culture is the process of identifying the harmful bacteria and other harmful germs of your body. A bacterial infection in the blood, known as bacteremia is a serious illness because the blood can spread these bacteria from one part to another.

What Infections Does Blood culture Detect?

A culture test for blood can show various infections caused by the bacteria and also find the types of bacteria causing the infection. Meningitis, Sepsis, Pneumonia, and, kidney infection could detect through the blood culture test.


A microbial culture or a bacteria culture is the procedure of multiplying the microbes by providing them with an environment to grow in the laboratory. A culture test is used to determine the class of microbes and their abundance. Apart from this, a culture test is useful in detecting the sensitivity of antibiotics against bacteria. 

If your doctor asked for these tests, it is because he wants to provide you right suggestions or proper medication for the treatment of diseases. If enough microbes are detected in your sample, it likely means you are suffering from bacterial infection. Your doctor may ask for further tests to confirm the severity or he will prescribe some medications.

What is Bacteria Culture Test – Identification & Risk Factors

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