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. 2022 Nov 14;8(11):1198.
doi: 10.3390/jof8111198.

Metagenomics of Toenail Onychomycosis in Three Victorian Regions of Australia

Steven Hainsworth  1   2 , Ann C Lawrie  1 , Thiru Vanniasinkam  2 , Danilla Grando  1
Affiliations

Metagenomics of Toenail Onychomycosis in Three Victorian Regions of Australia

Steven Hainsworth et al. J Fungi (Basel). .

Abstract

Onychomycosis is a fungal disease of the nail that is found worldwide and is difficult to diagnose accurately. This study used metagenomics to investigate the microbiology of 18 clinically diagnosed mycotic nails and two normal nails for fungi and bacteria using the ITS2 and 16S loci. Four mycotic nails were from Bass Coast, six from Melbourne Metropolitan and eight from Shepparton, Victoria, Australia. The mycotic nails were photographed and metagenomically analysed. The ITS2 sequences for T. rubrum and T. interdigitale/mentagrophytes averaged over 90% of hits in 14/18 nails. The high abundance of sequences of a single dermatophyte, compared to all other fungi in a single nail, made it the most likely infecting agents (MLIA). Trichophyton rubrum and T. interdigitale/mentagrophytes were found in Bass Coast and Shepparton while only T. interdigitale/mentagrophytes was found in Melbourne. Two nails with T. interdigitale/mentagrophytes mixed with high abundance non-dermatophyte moulds (NDMs) (Aspergillus versicolor, Acremonium sclerotigenum) were also observed. The two control nails contained chiefly Fusarium oxysporum and Malassezia slooffiae. For bacteria, Staphylococcus epidermidis was in every nail and was the most abundant, including the control nails, with an overall mean rate of 66.01%. Rothia koreensis, Corynebacterium tuberculostearicum, and Brevibacterium sediminis also featured.

Keywords: 16S onychomycosis; ITS2; Next generation sequencing; T. interdigitale/mentagrophytes; Trichophyton; dermatophyte; interdigitale; mentagrophytes; metagenomics; rubrum; tinea unguium.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Images of 18 toenails clinically diagnosed as mycotic. Numbers drawn on the toes were solely for the purpose of identification by the contributing podiatrist. Missing numbers 11 and 20 were normal control nails.
Figure 2
Figure 2
Main fungal species detected in mycotic and control nails. Stacked histograms show dominant species results of ITS2 for all nails. Normal control nails are boxed in black.
Figure 3
Figure 3
Main bacteria found in mycotic and normal control nails. Stacked histograms show dominant species results of 16S region analysis for all nails. Normal control nails are boxed in black.
Figure 4
Figure 4
Biplot from Principal Components analysis of combined ITS2 and 16S data.
See this image and copyright information in PMC

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References

    1. Ghannoum M.A., Salem I., Christensen L. Onychomycosis: Diagnosis and Effective Management. Wiley; New York, NY, USA: 2018. Epidemiology of onychomycosis; pp. 13–20.
    1. Kovitwanichkanont T., Chong A.H. Superficial fungal infections. Aust. J. Gen. Pract. 2019;48:706–711. - PubMed
    1. Eba M., Njunda A.L., Mouliom R.N., Kwenti E.T., Fuh A.N., Nchanji G.T., Atashili J. Onychomycosis in diabetic patients in Fako Division of Cameroon: Prevalence, causative agents, associated factors and antifungal sensitivity patterns. BMC Res. Notes. 2016;9:494. - PMC - PubMed
    1. Ilkit M., Durdu M. Tinea pedis: The etiology and global epidemiology of a common fungal infection. Crit. Rev. Microbiol. 2015;41:374–388. - PubMed
    1. Bickers D.R., Lim H.W., Margolis D., Weinstock M.A., Goodman C., Faulkner E., Gould C., Gemmen E., Dall T. The burden of skin diseases: 2004: A joint project of the American Academy of Dermatology Association and the Society for Investigative Dermatology. J. Am. Acad. Dermatol. 2006;55:490–500. - PubMed

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