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Molecular analysis of dermatophytes suggests spread of infection among household members

Mahmoud A Ghannoum1, Pranab K Mukherjee, Erin M Warshaw

  • 1Center for Medical Mycology, University Hospitals of Cleveland and Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH 44106, USA. Mahmoud.Ghannoum@case.edu.

Cutis
|June 18, 2013
PubMed

Insights

Certain Trichophyton rubrum strains, specifically TR-B or TR-D, are linked to the household spread of dermatophytoses. Concomitant tinea pedis and onychomycosis also increase infection transmission risk.

Area of Science:

  • Mycology
  • Infectious Diseases
  • Molecular Biology

Background:

  • Dermatophytoses are common superficial fungal infections.
  • Household transmission of dermatophytes is significant but often lacks molecular evidence.
  • Identifying specific strains and risk factors is crucial for effective control.

Purpose of the Study:

  • To identify dermatophyte species and strains within infected households using molecular methods.
  • To evaluate factors associated with the intrafamilial spread of dermatophyte infections.
  • To demonstrate the role of specific strains in household transmission.

Main Methods:

  • Polymerase chain reaction (PCR) was used to identify fungal species by targeting internal transcribed spacer (ITS) regions.
  • Restriction fragment length polymorphisms (RFLPs) with a ribosomal DNA probe differentiated strains.
  • Logistic regression analyses identified variables associated with infection spread.

Main Results:

  • Trichophyton rubrum was the most prevalent species, with 16 distinct strains identified.
  • Eight households showed evidence of multiple infected members (MIMs) due to specific strains.
  • Presence of T. rubrum strains TR-B or TR-D, history of tinea pedis and onychomycosis, and specific clinical signs were associated with spread (P<.05).

Conclusions:

  • Molecular methods confirmed the association of specific T. rubrum strains (TR-B, TR-D) with household transmission.
  • Clinical factors like combined tinea pedis and onychomycosis, plantar scaling, and nail discoloration are indicators of increased transmission risk.
  • This study provides molecular evidence for strain-specific transmission dynamics in dermatophytosis within households.

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