Mouth swab

Mouth swabs are usually obtained in order to identify oral yeast infections (thrush) and less often Vincent’s angina – a rare oropharyngeal infection associated with Borrelia vincentii (a spirochete) and Fusobacterium spp. Mouth swabs are not useful specimens outside of these two indications as the mouth harbours large numbers of normal flora.

Setup

Direct Examination

Gram stain

  • Yeast: Examine for presence of pseudohyphae and/or budding yeasts.
  • Vincent’s angina: Examine for presence of spirochetes and/or fusiform bacilli and pus cells.

Culture

Not indicated.

Followup

Reporting

Negative Report

  • “No yeast or fungal element seen on direct examination. ”
  • “No organisms suggestive of Vincent’s angina seen” if specifically requested.

Positive Report

  • “Yeast” or “Yeast with pseudohyphae” seen on direct examination. Fungal culture not performed”
  • “Organisms suggestive of Vincent’s angina seen”

References

P.R. Murray, E.J. Baron, M.A. Pfaller, R.H. Yolken. 2003. Manual of Clinical Microbiology, 8th ed. ASM Press, Washington, D.C.

H.D. Izenberg. 2003. Respiratory Tract Cultures, 3.11.1.1 in Clinical Microbiology Procedures Handbook, 2nd ed. Vol.1 ASM Press, Washington, D.C.