The Accuracy of Histopathological and Cytopathological Techniques in the Identification of the Mycetoma Causative Agents

PLoS Negl Trop Dis. 2019 Aug 29;13(8):e0007056. doi: 10.1371/journal.pntd.0007056. eCollection 2019 Aug.

Abstract

Mycetoma is a devastating neglected tropical disease, caused by various fungal and bacterial pathogens. Correct diagnosis to the species level is mandatory for proper treatment. In endemic areas, various diagnostic tests and techniques are in use to achieve that, and that includes grain culture, surgical biopsy histopathological examination, fine needle aspiration cytological (FNAC) examination and in certain centres molecular diagnosis such as PCR. In this retrospective study, the sensitivity, specificity and diagnostic accuracy of grain culture, surgical biopsy histopathological examination and FNAC to identify the mycetoma causative organisms were determined. The histopathological examination appeared to have better sensitivity and specificity. The histological examination results were correct in 714 (97.5%) out of 750 patients infected with Madurella mycetomatis, in 133 (93.6%) out of 142 patients infected with Streptomyces somaliensis, in 53 (74.6%) out of 71 patients infected with Actinomadura madurae and in 12 (75%) out of 16 patients infected with Actinomadura pelletierii. FNAC results were correct in 604 (80.5%) out of 750 patients with Madurella mycetomatis eumycetoma, in 50 (37.5%) out of 133 Streptomyces somaliensis patients, 43 (60.5%) out of 71 Actinomadura madurae patients and 11 (68.7%) out of 16 Actinomadura pelletierii. The mean time required to obtain the FNAC result was one day, and for the histopathological examinations results it was 3.5 days, and for grain it was a mean of 16 days. In conclusion, histopathological examination and FNAC are more practical techniques for rapid species identification than grain culture in many endemic regions.

MeSH terms

  • Actinobacteria / isolation & purification
  • Actinomadura
  • Adolescent
  • Adult
  • Aged
  • Biopsy
  • Child
  • Child, Preschool
  • Diagnostic Tests, Routine / methods*
  • Female
  • Humans
  • Madurella / isolation & purification
  • Male
  • Middle Aged
  • Mycetoma / diagnosis*
  • Mycetoma / microbiology*
  • Mycetoma / pathology*
  • Mycetoma / surgery
  • Pathology, Molecular / methods*
  • Polymerase Chain Reaction
  • Retrospective Studies
  • Sensitivity and Specificity
  • Streptomyces / isolation & purification
  • Young Adult

Supplementary concepts

  • Actinomadura madurae
  • Actinomadura pelletieri
  • Streptomyces somaliensis

Grants and funding

The authors received no specific funding for this work.