![]() Culture plates are recommended over DTM vials, as the vial openings are too narrow to pass the toothbrush for inoculation or to sample fungal colonies for microscopic analysis. POC DTM plates are inoculated by lightly stabbing the toothbrush bristles with hairs onto the surface in 4–5 areas. The toothbrush samples are cultured on POC DTM culture plates or submitted to a reference lab for culturing. Multiple lesions should be brushed to collect as many hairs as possible. canis colony growth on a DTM plate after 7 daysįungal cultures are performed with dermatophyte test media (DTM) and samples acquired by brushing lesions with new soft-bristled toothbrushes. ![]() These studies showed that there is a high correlation between a positive Wood’s lamp examination and trichogram with a positive fungal culture.Ĭonfirming evidence of infection through direct examination with a Wood’s lamp and a trichogram allows ringworm treatment to begin before results of a fungal culture are available. The positive predictive value is the likelihood that a positive result is truly positive, and the negative predictive value is the likelihood that a negative result is truly negative. The trichogram positive and negative predictive values were 93%. In studies comparing Wood’s lamp exams and trichograms with M.canis fungal culture results, the Wood’s lamp exam had a positive predictive value of 90% and a negative predictive value of 94%. M canis produces “cuffs” of spores on the outside of infected hairs indicating ectothrix invasion. Infected hairs are much wider than normal hairs due to spores coating the shafts. A cover slip is applied for viewing under a microscope using the 10X objective. Plucked hairs from around the lesions are added to a drop of mineral oil on a glass slide. Trichograms, or direct microscopic exam of hairs is another POC diagnostic tool. canis -infected hairs are brown and thick with cuffs of fungal spores adhered to the shafts (ectothrix) Normal hairs are black and thin, while M. Trichograms Microscopic exam of plucked hairs in a drop of mineral oil using the 10X objective. As the infection resolves, progressively fewer fluorescent hairs are visible and fluorescence is confined to the distal shafts and eventually only the tips as hairs grow out. Early in the course of an infection, the entire hair will glow, including the hair bulb. In addition to initial diagnosis, the Wood’s lamp exam can be used to monitor response to treatment. Wood’s lamp exam of the same cat showed fluorescent hairs Wood’s lamp exam shows a large patch of fluorescent hairs in a cat with advanced M. Wood’s lamp exam shows distinct fluorescent hairs on a cat in the early phase of M.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |