Examining Trichophyton tonsurans genotype and biochemical phenotype as determinants of disease severity in tinea capitis.
Trichophyton tonsurans infections occur in various host populations, on various body sites and with varying degrees of inflammation. This investigation was undertaken to determine whether fungal factors could explain the degree of severity in clinical symptomatology among infected children. Otherwise healthy children (n=54) presenting with tinea capitis were enrolled in this study. A thorough history was performed, the extent and severity of infection graded and a fungal specimen collected from each child. Strain type was determined by genotyping for 11 sequence variations in the rDNA and ALP1 loci. Secreted protease activity was quantitated after 5 days of growth in aqueous medium. Forty participants were evaluable. Infection duration ranged from 1 day to 3 years and clinical severity score (CSS) from 4-19. Seventeen unique fungal genotypes were present. Keratinase, collagenase and elastase activity varied 32.7-fold, 64.9-fold and 303.3-fold, respectively. A significant association was observed between genotype and disease severity with the rDNA sequence variations accounting for over 50% of the variation observed in CSS (r2=0.539; P<0.001). Phylogenetic analyses appear to suggest that the ancestral strain types of T. tonsurans cause more severe disease. These observations are consistent with reports that recently diverge anthropophilies are associated with diminished inflammatory involvement.
Abdel-Rahman
Susan M
SM
Division of Pediatric Clinical Pharmacology, The Children's Mercy Hospitals and Clinics, and Department of Pediatrics, University of Missouri-Kansas City, School of Medicine, Kansas City, MO 64108, USA. srahman@cmh.edu
Talib
Nasreen
N
Solidar
Ada
A
Nopper
Amy Jo
AJ
Wyckoff
Gerald J
GJ
D002648:Child; D002675:Child, Preschool; D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005260:Female; D005656:Fungal Proteins / Q000378:metabolism; D005838:Genotype; D006801:Humans; D008297:Male; D010447:Peptide Hydrolases / Q000378:metabolism; D010641:Phenotype; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D012720:Severity of Illness Index; D014006:Tinea Capitis / Q000382:microbiology* / Q000503:physiopathology*; D014249:Trichophyton / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*
D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D005656:Fungal Proteins; D010447:Peptide Hydrolases