Nasopharyngeal culture

Definition

Nasopharyngeal culture is a test that examines a sample of secretions from the uppermost part of the throat, behind the nose, to detect organisms that can cause disease.

Alternative Names

Culture - nasopharyngeal; Swab for respiratory viruses; Swab for staph carriage

How the Test is Performed

You will be asked to cough before the test begins and then tilt your head back. A sterile cotton-tipped swab is gently passed through a nostril and into the nasopharynx. This is the part of the pharynx that covers the roof of the mouth. The swab is quickly rotated and removed. The sample is sent to a laboratory. There, it is placed in a special dish (culture). It is then watched to see if bacteria, viruses, or other disease-causing organisms grow.

A nasopharyngeal culture is a test used to identify organisms that can be in nasal secretions causing disease. Nasopharyngeal cultures are useful in identifying Bordetella pertussis and Neisseria meningitidis (types of bacteria). The culture may be used to test for appropriate antibiotic therapy.

How to Prepare for the Test

No special preparation is needed.

How the Test will Feel

You may have slight discomfort and may gag.

Why the Test is Performed

The test identifies viruses and bacteria that cause upper respiratory tract symptoms. These include:

Bordetella pertussis, the bacteria that cause whooping cough
Neisseria meningitidis, the bacteria that cause meningococcal meningitis
Staphylococcus aureus, the bacteria that cause staph infections
Methicillin-resistant Staphylococcus aureus
Viral infections such as influenza or respiratory syncytial virus or SARS-CoV-2 (COVID-19)

The culture may be used to help determine which antibiotic is appropriate to treat an infection due to bacteria.

Normal Results

The presence of organisms commonly found in the nasopharynx is normal.

What Abnormal Results Mean

The presence of any disease-causing virus, bacteria, or fungus means these organisms may be causing your infection.

Sometimes, organisms like Staphylococcus aureus can be present without causing disease. This test can help identify resistant strains of this organism (methicillin-resistant Staphylococcus aureus, or MRSA) so that people can be isolated when necessary.

Risks

Minor nose bleed can rarely occur.

Gallery

References

L'Huillier AG, Torriani G, Pigny F, Kaiser L, Eckerle I. Culture-competent SARS-CoV-2 in nasopharynx of symptomatic neonates, children, and adolescents. Emerg Infect Dis. 2020;26(10):2494-2497. PMID: 32603290 pubmed.ncbi.nlm.nih.gov/32603290/.

Melio FR. Upper respiratory tract infections. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 65.

Patel R. The clinician and the microbiology laboratory: test ordering, specimen collection, and result interpretation. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 16.

Last reviewed December 6, 2021 by Denis Hadjiliadis, MD, MHS, Paul F. Harron Jr. Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team..

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