Tracking Trichophyton tonsurans through a large urban child care center: defining infection prevalence and transmission patterns by molecular strain typing

Molecular typing of a collection of Iranian clinical Trichophyton tonsurans isolates based on the non-transcribed spacer region of rDNA and antifungal susceptibility testing of the species

INTRODUCTION

Wrestling, considered the national sport of Iran, has gained immense popularity among Iranians. Wrestlers frequently encounter skin conditions, with dermatophyte fungal infections, particularly tinea gladiatorum (TG), being a common issue. TG, caused by the Trichophyton genus, has emerged as a major health concern for wrestlers and other contact sport athletes worldwide. This study aimed to assess the genotypic diversity and antifungal susceptibility of Trichophyton tonsurans isolates responsible for TG in Iranian wrestlers from Mazandaran province, northern Iran.

MATERIALS AND METHODS

A total of 60 clinical T. tonsurans isolates collected from various cities in Mazandaran, were included in the study. The isolates were identified through PCR-restriction fragment length polymorphism and sequencing methods. Genomic DNA was extracted from these isolates, and the non-transcribed spacer (NTS) region of ribosomal RNA (rRNA) was targeted for genotyping using newly designed primers. Haplotype analysis was performed to explore genetic diversity, and antifungal susceptibility to terbinafine (TRB) and itraconazole (ITC) was assessed.

RESULTS

The results revealed five distinct NTS types: NTS-I, NTS-II, NTS-III, NTS-IV and NTS-V, with NTS-IV being the most prevalent. The distribution of NTS types varied across different cities, suggesting potential transmission patterns among wrestlers. Antifungal susceptibility testing showed that all isolates were susceptible to TRB, while one isolate demonstrated resistance to ITC. Genotypic diversity was not correlated with antifungal susceptibility, emphasising the importance of monitoring susceptibility to ensure effective treatment. Haplotype analysis highlighted significant genetic diversity among the T. tonsurans isolates. This diversity may be attributed to factors such as human-to-human transmission, geographic location and lifestyle changes. The study's findings underscore the need for comprehensive genotypic analysis to understand the epidemiology and evolution of T. tonsurans infections in athletes.

CONCLUSION

In conclusion, this study provides valuable insights into the genotypic diversity and antifungal susceptibility of T. tonsurans isolates causing TG in Iranian wrestlers. The presence of multiple NTS types and varying susceptibility patterns highlights the complexity of T. tonsurans infections in this population. Further research is warranted to track the transmission routes and genetic evolution of T. tonsurans strains among wrestlers and develop effective control measures.

Genetic Predisposition and its Heredity in the Context of Increased Prevalence of Dermatophytoses

Dermatophytosis is a widespread disease with high prevalence and a substantial economic burden associated with costs of treatment. The pattern of this infectious disease covers a wide spectrum from exposed individuals without symptoms to those with acutely inflammatory or non-inflammatory, chronic to invasive, and life-threatening symptoms. Moreover, the prevalence of cutaneous fungal infections is not as high as might be expected. This curious disparity in the dermatophyte infection patterns may suggest that there are individual factors that predispose to infection, with genetics as an increasingly well-known determinant. In this review, we describe recent findings about the genetic predisposition to dermatophyte infections, with focus on inheritance in families with a high frequency of dermatophyte infections and specific host-pathogen interactions. The results of studies indicating a hereditary predisposition to dermatophytoses have been challenged by many skeptics suggesting that the varied degree of pathogenicity and the ecological diversity of this group of fungi are more important in increasing sensitivity. Nonetheless, a retrospective analysis of the hereditary propensity to dermatophytoses revealed at least several proven genetic relationships such as races, CARD9 deficiency, HLA-DR4 and HLA-DR8 type and responsible genes encoding interleukin-22, β-defensin 2 and 4 as well as genetic defects in dectin-1, which increased the prevalence of the disease in families and were involved in the inheritance of the proneness in their members. In future, the Human Genome Diversity Project can contribute to elucidation of the genetic predisposition to dermatophytoses and provide more information.

Molecular epidemiology of Tinea gladiatorum in contact sports in northern Iran

BACKGROUND

Tinea gladiatorum as the major health concern among combat athletes and the most common cause of a decrease in the quality of their sports activities.

OBJECTIVES

This study aimed to determine the molecular epidemiology of tinea gladiatorum in contact sports in Mazandaran Province, Northern Iran.

MATERIALS/METHODS

In total, 631 suspected athletes out of 4240 ones were screened for tinea gladiatorum in this cross-sectional study from May 2018 to February 2019. The infection was confirmed by direct microscopy and culture tests. The causative agents were identified by polymerase chain reaction-restriction fragment length polymorphism method on ITS rDNA region. The indoor environmental factors were evaluated in 81 sports halls in terms of temperature (°C), humidity (%), density (m² /athletes) and the number of ventilators.

RESULTS

Tinea gladiatorum was confirmed in 6.5% (278/4240) of the athletes. Tinea corporis was the most common type of tinea (192/278; 69.0%), and 175 cases (27.7%) had more than one type of tinea. Moreover, Trichophyton tonsurans (192/203; 94.5%) was the most aetiological agent in all athletes followed by Microsporum canis (6/203; 2.9%), Trichophyton rubrum (2/203; 0.9%) and Trichophyton interdigitale (1/203; 0.4%). There was no significant association between the prevalence of tinea gladiatorum and the indoor environmental factors.

CONCLUSION

T. tonsurans is the most common agent of tinea gladiatorum in Northern Iran. Since no positive culture of dermatophyte was obtained from mats, it seems that skin-to-skin contact would be the most probable mode of transmission among wrestlers. Accordingly, periodical checkups should be considered by health care providers.

Advances in Understanding Human Genetic Variations That Influence Innate Immunity to Fungi

Fungi are ubiquitous. Yet, despite our frequent exposure to commensal fungi of the normal mammalian microbiota and environmental fungi, serious, systemic fungal infections are rare in the general population. Few, if any, fungi are obligate pathogens that rely on infection of mammalian hosts to complete their lifecycle; however, many fungal species are able to cause disease under select conditions. The distinction between fungal saprophyte, commensal, and pathogen is artificial and heavily determined by the ability of an individual host's immune system to limit infection. Dramatic examples of commensal fungi acting as opportunistic pathogens are seen in hosts that are immune compromised due to congenital or acquired immune deficiency. Genetic variants that lead to immunological susceptibility to fungi have long been sought and recognized. Decreased myeloperoxidase activity in neutrophils was first reported as a mechanism for susceptibility to Candida infection in 1969. The ability to detect genetic variants and mutations that lead to rare or subtle susceptibilities has improved with techniques such as single nucleotide polymorphism (SNP) microarrays, whole exome sequencing (WES), and whole genome sequencing (WGS). Still, these approaches have been limited by logistical considerations and cost, and they have been applied primarily to Mendelian impairments in anti-fungal responses. For example, loss-of-function mutations in CARD9 were discovered by studying an extended family with a history of fungal infection. While discovery of such mutations furthers the understanding of human antifungal immunity, major Mendelian susceptibility loci are unlikely to explain genetic disparities in the rate or severity of fungal infection on the population level. Recent work using unbiased techniques has revealed, for example, polygenic mechanisms contributing to candidiasis. Understanding the genetic underpinnings of susceptibility to fungal infections will be a powerful tool in the age of personalized medicine. Future application of this knowledge may enable targeted health interventions for susceptible individuals, and guide clinical decision making based on a patient's individual susceptibility profile.

Major challenges and perspectives in the diagnostics and treatment of dermatophyte infections

Dermatophytes are the aetiological factors of a majority of superficial fungal infections. What distinguishes them from other pathogenic filamentous fungi is their unique ability to degrade keratin. The remarkable ability of this group of fungi to survive in different ecosystems results from their morphological and ecological diversity as well as high adaptability to changing environmental conditions. Paradoxically, despite the progress in medicine, the prevalence of dermatophyte infections is increasing from year to year. At the beginning of the third millennium, practical diagnostic and therapeutic options are still very limited. This review focuses on understanding the major problems in this aspect of dermatophyte infections and indicates future strategies and perspectives for novel approaches to identification and drugs for elimination of dermatophytes. Particular importance is placed on development of a strategy for a diagnostic pathway and implementation of rapid and reliable diagnostics methods designed by international teams. Furthermore, among compounds that currently arouse great interest, representatives of terpenoids, alkaloids, saponins, flavonoids and essential oils deserve attention. Many of these compounds are undergoing clinical trials as potential antifungal agents, and future research should focus on attempts at determination of the applicability of tested substances. Finally, the advantages and disadvantages in implementation of new diagnostic paths and medicinal substances for routine use are indicated.

Host- and pathogen-dependent susceptibility and predisposition to dermatophytosis

Dermatophytes are a highly specialized group of keratinophilic and keratinolytic filamentous fungi causing a ringworm disease called dermatophytosis or superficial mycoses. Although dermatophyte infections do not threaten the host's life, they lower its quality in humans by causing discomfort related to cosmetic problems and through their epidemiological significance, whereas in farm animals they are responsible for economic losses and constitute a source of the spread of spores. Evidence from countless observational studies that have been conducted over the last 90 years indicates that dermatophytes infect humans of every age, race, gender and socioeconomic status with strikingly high rates, as well as both farmed and wild animals in various health conditions and with various epidemiological statuses. However, the prevalence of superficial fungal infections is highly variable, since it depends on several parameters associated with the infected individual and the dermatophyte, their mutual interactions, and epidemiological and geographical factors. The curious disparity in dermatophyte infection patterns has prompted many investigators to search for a link between the host, the host's predispositions and susceptibility to the disease, and the dermatophyte species and virulence. Thus, the question arises as to whether, in addition to the generally recognized factors predisposing hosts to diseases, there are some other predispositions to dermatophyte infections in a species-specific host. In this review, we describe recent findings about the mechanism of dermatophyte infections, focusing on the adaptation of the fungi to the host and conditions predisposing each side to the disease.

Antidermatophytic Activity of the Fruticose Lichen Usnea orientalis

In the present study, the new biological sources in the form of lichen Usnea orientalis Motyka was screened for its antidermatophytic potential. Six species of dermatophytes were chosen on the basis of their prevalence for antidermatophytic assays, and the Clinical Laboratory Standard Institute (CLSI)-recommended broth microdilution procedure was used to detect the efficacy of extract against dermatophytes. Thin layer chromatography of lichen extracts reveals the presence of two secondary metabolites viz. salazinic acid and usnic acid. U. orientalis extract exhibited promising antidermatophytic activity against all tested pathogens. Amongst all tested pathogens, Epidermophyton floccosum exhibited most susceptibility towards extract, whereas Trichophyton mentagrophytes exhibited the least susceptibility. Topical application of U. orientalis extract might be helpful in the cure of dermal infections.

Genetic Predictors of Susceptibility to Dermatophytoses

Countless observational studies conducted over the last century reveal that dermatophytes infect humans of every age, race, gender, and socioeconomic status with strikingly high rates. The curious disparity in dermatophyte infection patterns observed within and between populations has led countless investigators to explore whether genetics underlie a susceptibility to, or confer protection against, dermatophyte infections. This paper examines the data that offer a link between genetics and dermatophytoses and discusses the underlying mechanisms that support these observations.

Molecular Markers Useful for Intraspecies Subtyping and Strain Differentiation of Dermatophytes

Dermatophytosis is a very common skin disorder and the most frequent infection encountered by practicing dermatologists. The identification, pathogenicity, biology, and epidemiology of dermatophytes, the causative agents of dermatophytosis, are of interest for both dermatologists and medical mycologists. Recent advances in molecular methods have provided new techniques for identifying dermatophytes, including intraspecies variations. Intraspecies subtyping and strain differentiation have made possible the tracking of infections, the identification of common sources of infections, recurrence or reinfection after treatment, and analysis of strain virulence and drug resistance. This review describes molecular methods of intraspecies subtyping and strain differentiation, including analyses of mitochondrial DNA and non-transcribed spacer regions of ribosomal RNA genes, random amplification of polymorphic DNA, and microsatellite markers, along with their advantages and limitations.

Development and Application of a High-Throughput Screening Method to Evaluate Antifungal Activity against Trichophyton tonsurans

There exist relatively few drug classes on the market to treat dermatophyte infections. This investigation was designed to develop and validate high-throughput methodology for screening and confirmation of chemicals for activity against Trichophyton tonsurans. Growth characteristics were examined on two platforms (96- and 384-well) in three media at eight spore concentrations over a period of up to 120 h. Microspectrophotometry was used to automate plate reads. The 384-well platform was used to screen more than 7000 compounds from six chemical libraries. Z-scores for optical density relative to positive growth controls were used to flag compounds of interest and activity confirmed in separate assays. The final conditions selected for both screening and confirmation with minimum inhibitory concentration (MIC) determination were growth for 48 h at 32 °C in SabDex with 1 × 10(4) spores per reaction. Sensitivity and specificity averaged 99.2% (range, 95.2%-100%) and 99.8% (range, 99.1%-100%), respectively. MICs for known antifungals were similar to those reported by others using Clinical and Laboratory Standards Institute methods. Several novel compound classes were identified to have activity against T. tonsurans with potency comparable to known antifungals. A robust, reproducible assay is described that permits high-throughput screening in T. tonsurans.

Tinea faciei in a newborn due to Trichophyton tonsurans

We report here the first case of neonatal tinea faciei caused by Trichophyton tonsurans in mainland China. The mother of the infant had tinea corpris and tinea capitis while the father had tinea incongnito. The infections in the parents were mycologically confirmed to be due to Trichophyton tonsurans. Ttinea faciei in the infant was cured after two-week topical use of amorolfine cream. The mother ceased breastfeeding and took oral terbinafine for 4 weeks. No recurrence was observed in the infant during 12 months of follow-up.

Back to the future for dermatophyte genomics

Dermatophytes are a uniquely pathogenic group of fungi that cause most common fungal infections globally. The major cause of athlete’s foot is Trichophyton rubrum, a pathogen of human skin. A recent paper in this journal reported the sequencing and analysis of five additional genome sequences, including that of Trichophyton rubrum. These five join the existing two additional genome sequences to bring the total to seven dermatophyte genome sequences, a notable milestone in the study of these fungi. These additional genomes set the stage for future genome-supported studies on the biology, pathogenicity, and host specificity of this important group of pathogens. To predict how this future might play out, we review the history of Aspergillus genomics since the initial publication of the first three Aspergillus genome sequences in 2005, an event that stimulated important studies of the pathogenic Aspergillus species. From these 7 years of Aspergillus history, we offer some speculation on the future of dermatophyte studies supported by the genome sequences given the similarities, differences, and relative levels of support for studies in these two groups of fungi and the diseases they cause.

Griseofulvin Only Modestly Diminishes Persistence of Trichophyton tonsurans on the Scalp of Carriers

OBJECTIVES

Using genetic strain typing, we previously identified a high rate of T. tonsurans carriage among preschool-aged children attending an urban daycare center. No treatment was provided as part of the observational study; however, children when symptomatic were treated in accordance with daycare policies. This retrospective investigation examines antifungal drug therapy received during the previous investigation and characterizes the impact of treatment on persistence of the fungus on the scalp.

METHODS

Children in whom serial typeable isolates of T. tonsurans were recovered were eligible for evaluation. Clinic charts were reviewed and dispensing records obtained from the primary pharmacies serving the daycare. Infection patterns were examined before and after treatment.

RESULTS

We identified 72 dispensing records for 53 children, all of whom received griseofulvin. Nine children could not be evaluated because treatment was coincident with their last study visit. Thus, 63 treatment events in 44 children with 331 discrete infection events remained. After a single course of griseofulvin, 22.7% of children became culture negative, 6.8% acquired another strain of T. tonsurans and, 70.5% remained persistently positive with the same strain carried prior to treatment. Among those receiving a second course of therapy, 54% remained positive and the cumulative percent of children that became culture negative increased to 36.4%. If children subsequently acquiring a different strain are considered together with those that became culture negative, cumulative strain clearance was observed in 43% of children. Neither the griseofulvin dose nor the duration of time over which children were infected prior to treatment differed between those that remained positive and those that became negative.

CONCLUSIONS

Griseofulvin eradicates dermatophyte scalp carriage in less than one-half of preschool-aged children receiving between one and four 4-week courses of the drug.

Genetic predictors of susceptibility to cutaneous fungal infections: a pilot genome wide association study to refine a candidate gene search

BACKGROUND

Trichophyton tonsurans is the foremost fungal pathogen of minority children in the U.S. Despite overwhelming infection rates, it does not appear that this fungus infects children in a non-specific manner.

OBJECTIVE

This study was designed to identify genes that may predispose or protect a child from T. tonsurans infection.

METHODS

Children participating in an earlier longitudinal study wherein infection rates could be reliably determined were eligible for inclusion. DNA from a subset (n=40) of these children at the population extremes underwent whole genome genotyping (WGG). Allele frequencies between cases and controls were examined and significant SNPs were used to develop a candidate gene list for which the remainder of the cohort (n=115) were genotyped. Cumulative infection rate was examined by genotype and the ability of selected genotypes to predict the likelihood of infection explored by multivariable analysis.

RESULTS

23 genes with a putative mechanistic role in cutaneous infection were selected for evaluation. Of these, 21 demonstrated significant differences in infection rate between genotypes. A risk index assigned to genotypes in the 21 genes accounted for over 60% of the variability observed in infection rate (adjusted r(2)=0.665, p<0.001). Among these, 8 appeared to account for the majority of variability that was observed (r(2)=0.603, p<0.001). These included genes involved in: leukocyte activation and migration, extracellular matrix integrity and remodeling, epidermal maintenance and wound repair, and cutaneous permeability.

CONCLUSIONS

Applying WGG to individuals at the extremes of phenotype can help to guide the selection of candidate genes in populations of small cohorts where disease etiology is likely polygenic in nature.

Epidemiology of dermatophytosis in junior combat and non-combat sports participants

Participation in competitive sports is popular and widely encouraged worldwide. Herein, we investigated 252 male and 67 female sports players, aged 16.4 ± 1.3 years, active in 15 different types of combat (n = 143) and non-combat (n = 176) sports. Of the 319 participants in this study, 11 (3.5%) players, including six wrestlers, four football players and one handball player, all of whom were men, harboured dermatophytic fungi. Briefly, Trichophyton tonsurans was present in three athletes, who were scalp carriers of the fungus. Furthermore, T. rubrum (4), T. interdigitale (3) and Arthroderma simii (1) were recovered from eight participants with tinea inguinalis (4), tinea pedis (2) or both (1). One patient was a trunk carrier of concomitant tinea pedis. All dermatophytic fungi were identified using both direction sequence of the rDNA regions spanning the internal transcribed spacers (ITS1 and ITS2) and 5.8 rRNA gene. Although sports-active individuals are active and sweat more, we observed a low prevalence of dermatophytosis, both in combat (5.2%) and non-combat sports participants (3.4%) (P > 0.05). However, dermatophyte infections require more attention and appropriate management to eradicate the infection and to prevent possible outbreaks. This study also documents the first case of zoophilic A. simii in Turkey.

Dermatophytes: host-pathogen interaction and antifungal resistance

Cutaneous mycoses are among the most common infections in humans and have become an important public health issue because they cause invasive infections in immunocompromised patients. During the infectious process, dermatophyte-host interactions trigger specific metabolic adaptations that allow the pathogen to adhere to and penetrate the host tissue, scavenge nutrients, and overcome the host defense mechanisms. This metabolic shift and the interplay between metabolism, morphogenesis and stress response are important factors that have been extensively studied in several pathogens. Host cells also respond to the pathogen stimuli by activating intracellular signaling pathways that trigger the immune response against the infectious agent. The comprehension of the molecular aspects of these responses may help to establish new therapeutical strategies. In this review, different aspects of the biology of dermatophytes are addressed, with emphasis on the dermatophyte-host interaction and the mechanisms of antifungal resistance.

Trichophyton tonsurans scalp carriage among wrestlers in a national competition in Turkey

Trichophyton tonsurans tinea gladiatorum is an emerging epidemic among combat-sport athletes across the globe. In the present study, we investigated the prevalence of symptomatic and asymptomatic dermatophytic infections among wrestlers in the National Greco-Roman Championship in Turkey. In total, 194 wrestlers from 32 provinces and 72 clubs were examined for scalp, trunk, groin, and toe web dermatophytic infections. We also administered a questionnaire to obtain information on the participants' lifestyles, wrestling characteristics, and risk factors for dermatophytic infections. The hairbrush method was used for scalp and trunk sampling, whereas a cotton swab was used for groin, toe web, and mat sampling. Three wrestling mats in the gymnasium were surveyed for dermatophytes using the touch preparation method. A total of 17 (8.8%) wrestlers harbored dermatophytes, and 22 strains were isolated: 13 (59.1%) T. tonsurans and 9 (40.9%) T. rubrum. These isolates were found on the scalp (8), trunk (2), forearm (1), hand (1), groin (3), and feet (7). In addition, we recovered 8 dermatophyte strains from the 150 mat samples (5.3%): T. rubrum in 6 samples (75%) and T. tonsurans in two samples (25%). T. tonsurans was only recovered from 11 out of 194 (5.7%) wrestlers. Scalp carriage represents the predominant (72.7%) clinical picture of a T. tonsurans infection in these Greco-Roman wrestlers in Turkey.

Medical management of Trichophyton dermatophytosis using a novel treatment regimen in L'Hoest's monkeys (Cercopithecus lhoesti)

An outbreak of Trichophyton dermatophytosis was diagnosed in a group of four L'Hoest's monkeys (Cercopithecus lhoesti) housed in the primate section at a zoological collection. The affected animals presented with areas of non-pruritic alopecia, scaling and crusting. The diagnosis was based on culture and direct microscopy of hair plucks. Treatment was commenced with oral terbinafine at a dose of 8.25 mg/kg bodyweight, topical enilconazole washes and disinfectant fogging of the enclosure. Control measures were designed to limit the spread of infection and reduce the zoonotic risk. Treatment was successful, with no further clinical cases being diagnosed and with resolution of the clinical signs after four weeks and mycological cure after eight weeks.

The prevalence of infections with Trichophyton tonsurans in schoolchildren: the CAPITIS study

BACKGROUND

Although Trichophyton tonsurans has become the leading cause of tinea capitis in the United States, reported infection rates vary widely, and prevalence estimates for the pediatric population at large remain poorly characterized.

METHODS

A prospective, cross-sectional, surveillance study of children attending kindergarten through fifth grade in 44 schools across the bi-state (Kansas/Missouri), Kansas City metropolitan area was conducted. Fungal cultures were collected from all participants, and molecular analyses were used to characterize the patterns of infection within the population.

RESULTS

Of 10,514 children (age: 8.3 +/- 1.9 years) examined for the presence of T tonsurans on their scalps, 6.6% exhibited positive cultures. Infection rates at participating schools ranged from 0% to 19.4%, exceeding 30% at a given grade level in some schools. Black children demonstrated the highest rates of infection (12.9%), with prevalence estimates for the youngest members of this racial group approaching 18%. Infection rates for Hispanic (1.6%) and white (1.1%) children were markedly lower. A single genetic strain of T tonsurans was identified in only 16.6% of classrooms, whereas each child harbored a unique genetic strain in 51.4%.

CONCLUSIONS

We report a large-scale, citywide, surveillance study of T tonsurans infection rates among children in primary school in a metropolitan area. The striking prevalence rates and genetic heterogeneity among the fungal isolates confirm the relatively large degree to which this pathogen has become integrated into metropolitan communities.

Comparative analysis of secreted enzymes between the anthropophilic-zoophilic sister species Trichophyton tonsurans and Trichophyton equinum

Trichophyton tonsurans (TT) and Trichophyton equinum (TE) are two closely related dermatophytes with very different host preferences. This study was designed to examine the genetic and transcript level variations of secreted enzymes between TT and TE. Thirty-one genes representing 10 gene families were selected for comparison and complete genomic and cDNA sequences were elucidated. Sequence analyses of the selected genes identified 104 polymorphisms between the two dermatophytes, 37 of which are expected to encode changes in their polypeptide sequence. Quantitative RT-PCR was used to examine the differences in levels of transcript between TT and TE grown over 14d in aqueous keratin medium. Differences in transcript expression between TT and TE were gene specific and ranged from 1.1-fold to 33-fold. Intra-specific variability across all genes ranged from 41% to 250%. Despite their overall genetic similarity, TT and TE exhibit a moderate degree of variability in the genomic make-up of their secreted enzymes and the extent to which they are transcribed when grown in an aqueous keratin medium. Such differences may contribute to how these genetically similar organisms have adapted to infect divergent host organisms.

Tinea capitis: predictive value of symptoms and time to cure with griseofulvin treatment

OBJECTIVES

To describe (a) the predictive value of symptoms for diagnosis of tinea capitis and (b) the rate and timing of cure with high-dose griseofulvin treatment.

METHODS

This prospective open-label study enrolled children aged 1 to 12 years with clinical tinea capitis. Participants with a positive dermatophyte culture received oral griseofulvin (20-25 mg/kg/day) and topical selenium sulfide shampoo for 6 weeks. Main outcome measures. The rate of symptoms of tinea capitis, and rates of mycologic and clinical cure.

RESULTS

The positive predictive values of any 1, 2, 3, or 4 symptoms for a positive culture were 88%, 82%, 78%, and 77%, respectively. The observed rates of mycologic, clinical, and complete cure were 89%, 66%, and 49%, respectively. conclusion: In a high-risk population it is reasonable to diagnose tinea capitis using one or more cardinal symptoms. Oral griseofulvin at 20 to 25 mg/ kg/day with adjunctive shampooing for 6 weeks is moderately successful as treatment.

Trichophyton tonsurans-Ringworm in an NICU

Ringworm is very rarely found in the neonate, especially infants who have been confined from birth to an intensive care unit. We report an infection with the dermatophyte Trichophyton tonsurans, the most common cause of tinea capitis in children but not yet described in a premature baby who has never left the nursery. Our case illustrates the need to consider this diagnosis among the causes of dermatitis in the newborn, especially in at-risk populations such as indigenous Australians. Though our infant's presentation was the classic "ring" shape, a literature review revealed varied presentations. In contrast to the usual need for long-term antifungal medication, our case responded rapidly to a topical azole preparation. Although we did not screen visiting family members, screening would have been appropriate, and those found positive might have benefited from at least antifungal shampoo.

A large outbreak of Trichophyton tonsurans among health care workers in a pediatric hospital

BACKGROUND

Although Trichophyton tonsurans remains a major cause of dermataophytoses in US children, nosocomial spread may go unrecognized in health care settings. We describe a staff outbreak of T tonsurans infection among health care workers in a freestanding pediatric hospital.

METHODS

Epidemiologic evaluation (retrospective and prospective) was performed in the health care providers and ancillary staff assigned to a 27-bed inpatient medical unit in which the suspected outbreak occurred.

RESULTS

Twenty-one individuals, including staff, a hospital volunteer, and a patient, developed tinea corporis during a 5-month period. All infections coincided with multiple admissions of a 2-year-old suspected index patient who demonstrated persistent infections of the scalp and arm. Fungal isolates obtained from the index patient and affected staff (when available) were subjected to multilocus strain typing, which revealed an identical genetic match between the index case and infected hospital personnel.

CONCLUSION

T tonsurans can spread widely among staff members caring for children with recalcitrant dermatophyte infections. Recognition that workplace transmission may be the etiology of a succession of infections occurring in a single inpatient unit is necessary to limit the number of infected individuals.

Single-step PCR using (GACA)4 primer: utility for rapid identification of dermatophyte species and strains

Dermatophytes are fungi that belong to three genera: Epidermophyton, Microsporum, and Trichophyton. Identification of dermatophyte species is essential for appropriate diagnosis and treatment of dermatophytosis. Routine identification depends on macroscopic and microscopic morphology, which is time-consuming and does not identify dermatophyte strains. In this study, two PCR-based methods were compared for their abilities to identify 21 dermatophyte isolates obtained from Egyptian patients to the species and strain levels. The first method employed a two-step method: PCR amplification, using ITS1 and ITS4 as primers, followed by restriction enzyme digestion using the endonuclease MvaI. The second method employed a one-step approach employing the repetitive oligonucleotide (GACA)(4) as a primer. Dermatophyte strains were also identified using a conventional culture method. Our results showed that the conventional culture method identified four species: Microsporum canis, Trichophyton mentagrophytes, Trichophyton rubrum, and Trichophyton violaceum. Moreover, both PCR methods agreed with the diagnosis made using the conventional approach. Furthermore, ITS1/ITS4-based PCR provided no strain differentiation, while (GACA)(4)-based PCR identified different varieties among the T. mentagrophytes isolates. Taken together, our results suggest that (GACA)(4)-based PCR has utility as a simple and rapid method for identification of dermatophyte species as well as utility for differentiation of T. mentagrophytes variants.

Asymptomatic dermatophyte scalp carriage: laboratory diagnosis, epidemiology and management

Asymptomatic carrier is defined as an individual who has dermatophyte-positive scalp culture without signs or symptoms of tinea capitis. The prevalence of asymptomatic carriage differs from region to region with a rate of 0.1-49%. Anthropophilic dermatophytes, Trichophyton tonsurans and Trichophyton violaceum, have been generally associated with high rates of asymptomatic carriage. Hence, the presence of dermatophytes on healthy scalp hairs of children may be a potential source of infection for schoolmates, playmates and/or households. Although it was also reported in adults, most carriage has been observed in children especially among those between 4 and 8 years of age, while male to female ratios vary between studies. It is still unclear, whether carriers should be treated with topical antifungal shampoos or oral antifungals or both, as some studies indicate that some untreated cases become culture-negative after 2-12 months. This review provides details on related dermatophyte fungi, laboratory diagnosis, epidemiology, ways of spreading as well as treatment and follow-up results of asymptomatic carriage. An integration into the school health programs is proposed, which will render the possible dealing of the subject in a comprehensive and reasonable manner.

Multilocus genotyping identifies infections by multiple strains of Trichophyton tonsurans

Acquisition of multiple genetic strains of a single dermatophyte species should not be unexpected in areas of high endemicity, and yet multistrain infections are infrequently reported. This communication details mixed Trichophyton tonsurans infections and highlights the need to confirm the presence of multiple strains in a clinical single isolate by use of a multilocus approach.