Inflammatory / infectious


Editorial Board Member: David B. Chapel, M.D.
Deputy Editor-in-Chief: Jennifer A. Bennett, M.D.
Ali Ismail, M.B.B.S.
Ziyan T. Salih, M.D.

Last author update: 3 October 2022
Last staff update: 3 October 2022

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PubMed Search: Leptothrix vaginalis

Ali Ismail, M.B.B.S.
Ziyan T. Salih, M.D.
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Cite this page: Ismail A, Salih ZT. Leptothrix. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cervixleptothrix.html. Accessed June 1st, 2023.
Definition / general
  • Leptothrix are nonpathogenic, filamentous, gram positive, nonspore forming anaerobic organisms that may be seen in association with Trichomonas
Essential features
  • Nonpathogenic, filamentous, gram positive organism
  • Frequently identified along with Trichomonas
  • Mostly identified in cytology smears
  • Cervix, oral and vaginal cavities
Case reports
Cytology description
Cytology images

Contributed by Ziyan T. Salih, M.D.
Cytologic smear with <i>Leptothrix</i> Cytologic smear with <i>Leptothrix</i>

Cytologic smear with Leptothrix

Images hosted on other servers:
Filamentous Leptothrix in a cytologic preparation

Filamentous Leptothrix species



LBC: <i>Leptothrix</i> with <i>Trichnomonas</i>

LBC: Leptothrix with Trichomonas

Long, filamentous structure

Long, filamentous structure

Differential diagnosis
  • Lactobacillus:
    • Shorter than Leptothrix and does not form loops
    • Leptothrix is seen in conjunction with Trichomonas and may form colonies
Board review style question #1

Which of the following organisms is frequently identified in cytologic smears in patients with Trichomonas infections?

  1. Candida
  2. Herpes
  3. Leptothrix
  4. Sporothrix
Board review style answer #1
C. Leptothrix

Comment Here

Reference: Leptothrix
Board review style question #2
Which of the following characterizes the Leptothrix organisms in cervical smears?

  1. Filamentous, gram negative, nonpathogenic
  2. Filamentous, gram positive, nonpathogenic
  3. Spore forming, filamentous, nonpathogenic
  4. Spore forming, gram positive, pathogenic
Board review style answer #2
B. Filamentous, gram positive, nonpathogenic

Comment Here

Reference: Leptothrix
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