Occurrence and significance of Trichophyton mentagrophytes var. Mentagrophytes on the bark of Eucalyptus camaldulensis trees in India

The isolation of Trichophyton mentagrophytes var. mentagrophytes [T. (rn.) mentagrophytes] is reported from 8 of 104 bark samples collected from Eucal yptus camaldulensis trees in Dehra Dun, India. Six of the 8 culture positiv e bark samples came from of a collection of 50 made on January 18, 1994, an d the remaining 2 from 54 collected on April 24, 1995. All of the isolation s were made by the mouse inoculation technique. The fungus was not found in any of the Eucalyptus tereticornis bark samples from the same site in Dehr a Dun, nor was it demonstrable in any of the 79 soil samples collected from the E. camaldulensis plantation area investigated by hair baiting, mouse i noculation and direct plating techniques. Mating of 6 of the isolates with the tester strains of Arthroderma vanbreuseghemii revealed that they repres ented the (+) mating type. The fungus was re-isolated from the liver and sp leen of mice up to 14 weeks post-experimental infection but there were no m acroscopic lesions on the abdominal viscera. In the immunosuppressed white mice, there was 100% mortality within 21-23 days of the intraperitoneal inf ection, and necropsy examination invariably revealed macroscopic mycotic le sions on the liver and occasionally on the spleen. The survival of T. (m.) mentagrophytes for as long as 14 weeks in the peritoneal cavity suggests th at the mouse inoculation can be used as a selective technique for isolation of this dermatophyte from environmental sources. The epidemiologic signifi cance of the afore-mentioned results is discussed. As far as we are aware, T. (rn.) mentagrophytes has not been reported to date from the bark of any tree or other plant material.