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What is microbiology?

Closeup of hands with lab equipment and blood samples.

Microbiology is the study of microorganisms. This includes bacteria, viruses, fungi, and parasites. Microbiology helps find the disease-causing microorganisms in:

  • Tissue

  • Bone marrow

  • Blood

  • Urine

  • Sputum

  • Stool

  • Cerebrospinal fluid (CSF)

  • Other body fluids

The infectious agents can also be tested for sensitivity to certain antibiotics used to treat infections.

Microbiology uses many methods to find microorganisms, such as:

  • Chemical, immunological, and genetic tests

  • Exam under a microscope

  • Staining

Common microbiology tests



Blood culture

Can diagnose bacterial or fungal blood infections

Burn, tissue, and wound culture

Can find disease-causing organisms in many tissues

Sputum culture or nasal swab 

Can find bacteria that cause upper and lower respiratory tract infections, such as pneumonia

Stool culture

Can find parasites and bacteria that cause disease, such as salmonella or hookworms

Urine culture

Can find disease-causing bacteria in the kidneys and urinary tract

Throat swab or culture

Often used to diagnose or rule out strep throat

The culture may find there is an infection. Then the disease-causing microbe may be tested for antibiotic resistance. This is done to figure out its sensitivity to antibiotic or antimicrobial medicines. Sometimes, antibiotics that should work don't work because the microbes are resistant. This culture and sensitivity test can help the healthcare provider find the right medicine to treat an infection and stay away from antibiotics that may not work.

Cultures may take 24 to 48 hours for results. Some slow-growing microorganisms may take even longer. Antibiotic susceptibility studies may take another 24 to 48 hours.

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