Molecular epidemiology of dermatophytes in Iraq and Cambodia
Part 1 Iraq – Objectives: From Iraq, few data on the occurrence of dermatophytes are available. A study on prevalence of dermatophytes in Baghdad, Iraq, was done.
Patients and methods: From April to December 2019, skin scrapings were taken from 92 out-patients in Baghdad under the suspicion of superficial dermatophytoses. Mycological diagnostics and sequencing were performed.
Results: Both, by culture and/or PCR, a dermatophyte was detected in 63 (68 %) out of 92 samples. Culture positive were 43 (81 %) of 63 samples, PCR positive were 57 (90 %). The following dermatophytes (out of 63 positive samples, 43 by culture, 20 by PCR) were found: Trichophyton (T.) mentagrophytes/ T. interdigitale (TM/TI), 40 (63 %, 26 by culture, 14 by PCR), Microsporum (M.) canis, 7 (11 %, 6 by culture, 1 by PCR), Epidermophyton floccosum, 6 (10 %, each 3 by culture and PCR, respectively), T. rubrum, 5 (8 %, 3 by culture, 2 by PCR), T. violaceum, 2 (3 %, 2 by culture). Each, one strain of Nannizzia incurvata (2 %), T. benhamiae (2 %), and M. ferrugineum (2 %) was isolated. Based on results of sequencing, we were able to demonstrate that among 26 cultural isolated T. mentagrophytes strains, surprisingly, 18 were T. mentagrophytes ITS Type VIII India, 5 were T. mentagrophytes ITS Type V Iran, and 2 were belonging to anthropophilic T. interdigitale ITS Type II*. Seven (39 %) out of 18 Indian T. mentagrophytes ITS Type VIII were terbinafine resistant. The resistant strains exhibited the amino acid substitution Phe397Leu of squalene epoxidase gene.
Conclusion: For 20 years, this is the first survey on epidemiology of dermatophyte species in Iraq. Surprisingly, T. mentagrophytes represented the most frequent dermatophyte in Baghdad, it has replaced T. rubrum. The new genotype VIII India of T. mentagrophytes counted for the biggest part of all dermatophytes. The percentage of terbinafine resistance is high in the strains isolated in Baghdad, Iraq, treatment failures of terbinafine are to be expected.
Part 2 Cambodia – Objectives: Dermatomycoses count to the most frequent dermatoses in Cambodia. The aim of this survey was to investigate the occurrence of dermatophytes in this Southeast Asian country.
Patients and methods: From June 2017 to July 2018, skin scrapings were taken from altogether 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 of 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 samples, PCR positive were 50 (96%). The following dermatophytes were found: Trichophyton (T.) rubrum, 36/52 strains (69%, 29 by culture, 7 by PCR), T. mentagrophytes/ T. interdigitale (TM/TI) 9/52 (17%, 6 by culture, 3 by PCR), and Microsporum (M.) canis 5/52 strains (10%, all by culture). Both, one strain of Nannizzia (N.) incurvata 1/52 (2%) and N. nana 1/52 (2%) was isolated. Based on results of sequencing, we were able to demonstrate that 2 T. mentagrophytes strains out of the 9 TM/TI strains represented the new ITS Type XXV Cambodia. We found one T. mentagrophytes strain Type VIII India. This isolate was terbinafine resistant, and it exhibited the amino acid substitution Phe397Leu in the squalene epoxidase. Three strains of T. interdigitale Type 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 Type VIII T. mentagrophytes was found. A highlight was the first description of the new T. mentagrophytes Type XXV Cambodia.