Dermatophytes and skin dermatophytoses in Southeast Asia-First epidemiological survey from Cambodia.

BACKGROUND: Dermatomycoses count to the most frequent dermatoses in Cambodia. OBJECTIVES: The aim of this survey was to investigate the occurrence of dermatophytes in this Southeast Asian country. METHODS: From June 2017 to July 2018, skin scrapings were taken from 67 patients with superficial dermatophytosis for mycological diagnostics. Identification of dermatophytes was confirmed by sequencing of the 'internal transcribed spacer'-(ITS) region of the rDNA, and the gene of the Translation Elongation Factor (TEF)-1α. RESULTS: Patients were suffering from tinea corporis and tinea inguinalis/cruris 42/67 (63%), tinea capitis/faciei 14/67 (21%), tinea corporis/capitis/faciei 6/67 (9%), tinea manuum/pedis 2/67 (3%), tinea pedis 2/67 (3%) and tinea manuum 1/67 (1%). Both, by culture and/or PCR, a dermatophyte was detected in 52 (78%) out of 67 samples. Culture positive were 42 (81%) of 52, PCR positive were 50 (96%). The following dermatophytes were found: Trichophyton (T.) rubrum, 36/52 strains (69%, 29 by culture), T. mentagrophytes/T. interdigitale (TM/TI) 9/52 (17%, six by culture) and Microsporum (M.) canis 5/52 strains (10%, by culture). One strain of Nannizzia (N.) incurvata 1/52 (2%) and N. nana 1/52 (2%) was isolated. Based on sequencing, we demonstrated that two T. mentagrophytes strains out of the nine TM/TI represented the new ITS genotype XXV Cambodia. We found one T. mentagrophytes strain genotype VIII (now, reclassified as T. indotineae). This isolate was terbinafine resistant, and it exhibited the amino acid substitution Phe397Leu in the squalene epoxidase. Three strains of T. interdigitale genotype II* were isolated. CONCLUSION: This is the first survey on epidemiology of dermatophytes in Cambodia. Currently, T. rubrum represents the most frequent species in Cambodia. One Indian strain genotype VIII T. mentagrophytes was found. A highlight was the first description of the new T. mentagrophytes genotype XXV Cambodia.

Nannizzia incurvata as a rare cause of favus and tinea corporis in Cambodia and Vietnam.

Nannizzia (N.) incurvata (formerly Microsporum incurvatum) represents a geophilic dermatophyte which has been previously classified as belonging to the species complex of N. gypsea (formerly Microsporum gypseum). A 42-year-old Vietnamese female from Saxony, Germany, suffered from tinea corporis of the right buttock after she returned from a 2-week-visit to her homeland Vietnam. From skin scrapings of lesions, N. incurvata grew on Sabouraud's dextrose agar. Treatment by ciclopirox olamine cream twice daily for 4 weeks was successful. A 6-year-old Cambodian boy living near river Mekong with contact history to chicken, dogs and cattle suffered from tinea faciei and capitis. Symptoms of the favus-like tinea capitis and tinea faciei were erythema and scaly patches with areas of alopecia. N. incurvata grew on Sabouraud's dextrose agar. The boy was treated with oral terbinafine 125 mg daily, topical miconazole cream and ketoconazole shampoo. The symptoms healed within 4 weeks of treatment. Cultivation of the samples revealed growth of N. incurvata. For confirmation of species identification, the isolates were subject to sequencing of ITS (internal transcribed spacer) region of the rDNA, and addition of the "translation elongation factor 1 α" (TEF 1 α) gene. Sequencing of the ITS region showed 100% accordance with the sequence of N. incurvata deposited at the NCBI database under the accession number MF415405. N. incurvata is a rare, or might be underdiagnosed geophilic dermatophyte described in Sri Lanka and Vietnam until now. This is the first isolation of N. incurvata in Cambodia, and the first description of favus in a child due to this dermatophyte.

Palmoplantar keratoderma, oral involvement, and homozygous CTSC mutation in two brothers from Cambodia.

Haim-Munk syndrome (HMS) and Papillon-Lefevre syndrome (PLS) are phenotypic variants of palmoplantar keratoderma (PPK) with progressive early-onset periodontitis and dental caries. HMS and PLS have been associated with homozygous or compound heterozygous mutations in the lysosomal protease gene Cathepsin C (CTSC). There have been only a few documented cases of CTSC mutations in patients from South-East Asia. We report the clinical findings of two Cambodian brothers who presented with diffuse, demarcated PPK with transgrediens extending to the elbows and knees, as well as pachyonychia and dental caries. Arachnodactyly and periodontitis were also found in the older brother. Next-generation sequencing unveiled a homozygous missense variant in CTSC (NM_001814.5: c.1337AC: p.(Asp446Ala)) in both brothers. Both parents were heterozygous for the variant, while an unaffected older brother was homozygous for the wild-type allele. Our study adds to the spectrum of mutations and associated clinical presentations for this rare genodermatosis.