Ear, nose or throat culture

When to request this test

ENT infections: bacterial angina (throat), purulent sinusitis (sinus pus), otitis (ear)

Interferences and limitations

The presence of normal flora in the upper respiratory tract can complicate the identification of true pathogens. For example:

• Throat swabs may contain Streptococcus viridans, Neisseria spp., or Corynebacterium spp., which can obscure pathogenic bacteria like Streptococcus pyogenes
• Nasal and sinus samples can be contaminated with Staphylococcus epidermidis or Corynebacterium spp., making it difficult to differentiate from pathogenic Staphylococcus aureus
• Ear swabs might contain skin contaminants such as coagulase-negative Staphylococci or Propionibacterium spp

Improper collection techniques can contain too much flora and mask the true pathogens (e.g. swabbing the tongue or buccal mucosa when collecting a throat culture, using a nasal swab instead of a deep sinus aspirate).

Prior antibiotic treatment can suppress bacterial growth, leading to false-negative results.

3 days

• Sample nature: Purulent secretions
• Recommended volume: 1 swab
• Type of container: Swab (eSwab preferably) or sterile container if pus

<2h at room temperature