Management of a Trichophyton tonsurans outbreak in a day-care center

Pediatric Tinea Capitis: A Retrospective Cohort Study from 2010 to 2021

Pediatric tinea capitis displays a wide range of prevalence, with significant variability among populations. We retrospectively extracted the medical records of 456 pediatric patients diagnosed with tinea capitis during the years 2010–2021, from the dermatology outpatient clinics in two tertiary medical centers. Three species were isolated in 90% of patients: T. tonsurans, M. canis, and T. violaceum. While T. tonsurans presented a six-fold increase in incidence during the years 2019–2021, M. canis maintained stable incidence rates. Furthermore, terbinafine was the most efficient antifungal agent against T. tonsurans, achieving complete clinical clearance in 95% of patients, as compared to fluconazole (68%) and griseofulvin (38%) (p < 0.001). The mycological cure was recorded in 61/90 (68%) of patients with available data, at an average of 10 weeks. For patients with M. canis, griseofulvin and fluconazole were equally efficient (73% and 66%, respectively) (p = 0.44). Kerion was described in 36% and 14% of patients with T. tonsurans and M. canis, respectively, (p < 0.001). In conclusion, since 2019, there has been a significant increase in the prevalence of T. tonsurans, establishing this pathogen as the most common cause for tinea capitis in our population. Our data suggest that terbinafine is effective and presents high cure rates for tinea capitis in the pediatric population.

Molecular identification and antifungal susceptibility of 75 clinical isolates of Trichophyton spp. from southern Brazil

BACKGROUND

Dermatophytoses affect more than 20% of the world's population and is caused by filamentous fungi, mainly of the genus Trichophyton. The species identification through microscopic direct examination and culture methods is challenging, with molecular presenting high sensitivity and specificity. Although there are several therapy options for dermatophyte infections, treatment failures and antifungal resistance are growing concerns.

OBJECTIVE

This study aimed to identify clinical isolates of Trichophyton spp. from southern Brazil using molecular methods and determine their in-vitro antifungal susceptibility.

MATERIAL AND METHODS

Seventy-five isolates were identified through sequencing of the ITS region. The exposure to seven antifungals drugs was performed according to protocol M28-A2 of the Clinical and Laboratory Standards Institute (CLSI).

RESULTS

Sixty-one isolates (81%) were identified as T. interdigitale, which differs from the epidemiological data present in the literature. Thirteen isolates were identified as T. rubrum and one as T. tonsurans. Terbinafine was the most effective antifungal, followed by itraconazole and voriconazole, which is in accordance with the results reported in previous studies.

CONCLUSIONS

The use of molecular methods to identify Trichophyton spp. clinical isolates and the performance of susceptibility tests are relevant to epidemiological data, identification of the emergence of antifungal resistance, and to help to translate the in-vitro antifungal susceptibility results into clinical practice.

Clinical clues and trends in epidemiology and pathogens in paediatric tinea capitis: a retrospective cohort study

BACKGROUND

Tinea capitis is the most common dermatophyte infection in children. Pathogens differ between populations. During the past few decades pathogen shifts have been reported in many countries around the world. This study aimed to characterize the pathogens involved in tinea capitis in a large tertiary paediatric medical centre in Israel.

METHODS

The electronic medical records of the dermatology unit were searched for patients diagnosed with tinea capitis from 2010 to 2019, and demographic, clinical and mycological data were retrieved. A stepwise logistic regression was performed to determine the variables most significantly associated with positive cultures.

RESULTS

The prevalence of Trichophyton tonsurans isolates was found to be significantly increased during 2019. In the logistic regression analysis, alopecia was most significantly associated with a positive culture (OR = 8.72, 95% CI 4.29-17.7, P < 0.001) while positive culture was also associated with age (OR = 1.11 per year of age, 95% CI 1.02-1.22, P = 0.01) and Ethiopian ethnicity (OR = 3.67, 95% CI 1.42-9.45, P = 0.01). The presentation of alopecia was significantly related to having a positive culture. This symptom was more prevalent in boys than in girls, and the diagnosis of tinea capitis was delayed by an average of 2 months in girls.

CONCLUSION

The results of this study may herald a pathogen shift in Israel. Physicians should be aware that rates of alopecia are lower in girls and this can result in delayed diagnosis and the development of complications, including chronicity, scarring alopecia and kerion formation.

The prevalence of dermatophytoses in Brazil: a systematic review

Dermatophytosis is a common cutaneous mycosis worldwide whose prevalence in Brazil is still unknown. This systematic review has estimated the burden of dermatophytoses from updated literature data reported in the general Brazilian population. We used the following databases: Web of Science, Medline/PubMed, Embase, The Cochrane Library and Scopus for studies published between 2011 and 2020. Original articles with an emphasis on prevalence data for dermatophytosis in the Brazilian population, and diagnosed by culture exam or molecular biology were eligible. We also assessed the methodological quality of the studies. A total of 24 articles met the inclusion criteria and were reviewed. The occurrence of dermatophytoses found in the studies ranged from 4-88.50 %. The pooled prevalence of dermatophytosis for the population studies was 25 % (95 % CI: 24.7-25.3 %). The size of the samples used in the studies ranged from 45 to 36 446 participants, and ages ranged up to 98 years old. The populations studied involved mostly women. The presence of tinea unguium (toenail and fingernail) and tinea pedis were the most frequent dermatophytosis, and we observed a predominance of Trichophyton rubrum, T. interdigitale and T. mentagrophytes. The studies were primarily conducted in patient groups with suspected mycoses and were not entirely representative of the general population. Yet we believe that in the future, more collaborative strategies would improve both diagnostic capacity and epidemiological methodologies, associating the prevalence of dermatophytosis with social and environmental risk factors. This review helps to better understand future epidemiological trends in Brazil and the world.

Polyphasic Discrimination of Trichophyton tonsurans and T. equinum from Humans and Horses

The anthropophilic dermatophyte Trichophyton tonsurans and its zoophilic counterpart T. equinum are phylogenetically closely related. The barcoding marker rDNA internal transcribed spacer (ITS) shows limited variation between these two species. In the current study, we combined molecular approaches with phenotypic data to determine the species boundaries between T. tonsurans (n = 52) and T. equinum (n = 15) strains originating from humans (n = 40), horses (n = 26), and a mouse (n = 1). Culture characteristics and physiology on Trichophyton agar media 1 and 5 were evaluated. Multi-locus sequencing involving ITS, partial large rDNA subunit (LSU), β-tubulin (TUB), 60S ribosomal protein (RPB), and translation elongation factor-3 (TEF3) genes, and the mating-type (MAT) locus was performed. Amplified fragment length polymorphism data were added. None of the test results showed complete mutual correspondence. With the exception of strains from New Zealand, strains of equine origin required niacin for growth, whereas most strains from human origin did not show this dependence. It is concluded that T. tonsurans and T. equinum incompletely diverged from a common lineage relatively recently. MAT1-1 and MAT1-2 are the main distinguishing genes between the two species.

[Sports-associated dermatophytoses : An overview]

Because of high exposure (e. g. swimmers and athletes competing on mats) and disposition (e. g. microtraumata of the skin in runners) athletes are prone to a higher risk for mycotic infections by dermatophytes. In disciplines with close contact during competition-especially wrestlers and judoists-infections by the anthropophilic Trichophyton (T.) tonsurans are most important (tinea gladiatorum). These infections are highly contagious and often cause small epidemics especially if the primary source of infection is not promptly recognized. The environment of the athletes (e. g. mats) and asymptomatic carriers may be sources of further spread. Tinea pedis with its clinical manifestations seems to be often underdiagnosed and insufficiently treated. Environmental contamination by fungal spores may be responsible for the significantly higher level of mycotic infections of the feet in children and adolescents active in sports. There is a higher risk for spread of the infection to the toe nails (onychomycosis) and for consecutive infections by bacteria (e. g. erysipelas). More rarely infections by zoophilic or geophilic dermatophytes are seen in athletes (e.g. equestrians). Education and more intensive measures of prevention and environmental decontamination are essential for all dermatophytoses associated with sports.

The Changing Face of Dermatophytic Infections Worldwide

Dermatophytes evolve along with the geography and socioeconomic conditions. Epidermophyton floccosum, Microsporum audouinii and Trichophyton schoenleinii acted as the major pathogens of superficial fungal diseases 100 years ago, but their frequency decreased dramatically since the middle of the twentieth century and they are limited to some less-developed countries nowadays; meanwhile, frequency of Trichophyton rubrum, Trichophyton interdigitale, Trichophyton tonsurans and Microsporum canis increased gradually, and these fungi have become the major species globally. Some other dermatophytes, i.e., Trichophyton violaceum, Trichophyton verrucosum and Microsporum ferrugineum, are mainly endemic in some parts of Africa, Asia and Europe. At present, T. rubrum is the leading pathogen for skin and nail fungal infections, whereas M. canis, T. tonsurans and T. violaceum present as the predominant dermatophytes involved in tinea capitis. Population mobility, changes in human lifestyle and advents of antifungal drugs will continually drive the dermatophyte evolution in the skin microenvironment. Comprehensive observation is needed to better understand this kind of organisms and prospect the trends of their changes in future.

A 9-Month-Old Girl from Iran with Extensive Erythematous Plaques Due to Trichophyton simii, a Zoophilic Dermatophyte

The incidence of dermatophytosis due to Trichophyton simii is generally considered to be limited to endemic areas, particularly one area of India. However, the high similarity between the morphological features of atypical T. simii isolates and those of other dermatophytes such as Trichophyton interdigitale and Arthroderma benhamiae may lead to misidentification of the cause of dermatophytosis in many instances. We investigated a rare case of tinea corporis in a 9-month-old female with extensive erythematous lesions. Morphological features of the recovered isolate from the culture resulted in the identification of Trichophyton interdigitale. For accurate identification, the internal transcribed spacer regions (ITS1 and ITS2) of the ribosomal DNA (rDNA) gene were sequenced and the isolate was ultimately identified as T. simii. In conclusion, T. simii, which has been formerly known to be restricted to specific endemic regions, appears to be not infrequent in non-endemic areas but instead simply less well-known and consequently underestimated. To determine its actual prevalence of infection, the application of DNA-based molecular methodologies is required.