Asymptomatic dermatophyte scalp carriage in school children in Adana, Turkey

Trichophyton species isolated from asymptomatic patients of the pet-owner pair in Mexico

Background and Purpose:

Superficial mycoses are the fourth most common cause of disease worldwide. It is not surprising that zoonotic transmission occurs to humans due to close contact with different animals, be it companion or farm animals. Therefore, the objective of this study was to determine the presence of asymptomatic dermatophyte carriers in the owner-pet pairs, identify the most common etiologic agents, and find the likely connection between the carrier status of an owner and the presence of dermatophytes in their pets.

Materials and Methods:

From May 2019 to January 2020, 21 cats and 115 dogs with their respective owners were selected for dermatophyte culture. All the dogs and cats included in the study were from the communities of southeastern Mexico. The samples were taken with a cotton swab, which was vigorously rubbed and twisted on the scalp or body of the pet four times and grown on Mycosel Agar. The isolates were identified based on macroscopic and microscopic characteristics. The prevalence of the binomial ranged from 0.73% in pet skin and human hands to 2.2% in human scalp. In humans, the agents were Trichophyton tonsurans and Trichophyton verrucosum, while in pets, a strain of Trichophyton sp was found.

Conclusion:

Different species of dermatophytes were found in the owner/pet pairs, which denotes that coexistence is not related in asymptomatic cases.

Asymptomatic Scalp Carriage among Household Contacts of Children Affected by Tinea Capitis: A Prospective Study in the Metropolitan Area of Brussels, Belgium

<b><i>Introduction:</i></b> Tinea capitis (TC) is a superficial fungal infection affecting the scalp. The existence of asymptomatic carriers (ACs) could represent a potential reservoir responsible of (re)contamination and failure of treatment. No prospective studies on ACs in household contacts of TC patients in Europe have been published to date. <b><i>Objectives:</i></b> The aim of this study was to assess the prevalence of ACs in a cohort of household contacts of children who were diagnosed with TC in the metropolitan area of Bruxelles, Belgium. <b><i>Methods:</i></b> This prospective observational study was conducted from October 2015 to April 2016 at the Dermatology Department of the University Hospitals Brugmann, Saint-Pierre, Queen Fabiola Children Hospital. <b><i>Results:</i></b> Ninety-nine cases of TC from 95 different family circles were included. The main infectious agent identified was <i>Microsporum audouinii</i> in 53 cases. The mean age of TC patients was 5.8 years. Male/female ratio was 2.8. Eighty-one household contacts of TC patients were enrolled in the study. Two cases of ACs (5%) were identified. <b><i>Conclusions:</i></b> <i>M. audouinii</i> was the most common pathogen identified. The prevalence of ACs we report is on average higher compared to other European large cities. Larger prospective studies including all close contacts of affected patients are required in order to establish guidelines regarding identification and management of ACs.

Molecular characterization and antifungal susceptibility profile of dermatophytes isolated from scalp dermatophyte carriage in primary school children in Arak city, Center of Iran

OBJECTIVE

Asymptomatic carriage is a condition of positive dermatophyte scalp culture without signs and symptoms of tinea capitis. Carriers are the source of dermatophytes that are able to transfer fungal agents to other people. The aim of this study was evaluating asymptomatic dermatophyte scalp carriage among students of primary schools in Arak city.

MATERIALS AND METHODS

Sampling by a sterilized hairbrush from scalp was performed among 3174 students. Hairbrush was inoculated onto Mycosel agar plates. Dermatophyte isolates were identified by PCR-RFLP using MvaI enzyme. In vitro antifungal susceptibility test was done according to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 protocol. The antifungal drugs used included griseofulvin (GRZ), terbinafine (TER), itraconazole (ITC) and fluconazole (FLU).

RESULTS

A total of 3174 schoolchildren were screened, 15 cases (0.48%) had a positive culture for dermatophytes. Asymptomatic carriers including 11 (73.3%) boys and 4 (26.7%) girls and their age range were between 7-12 years. Trichophyton tonsurans (80%), T. interdigitale (13.3%) and T. rubrum (6.7%) were the most common isolated dermatophyte. Based on the obtained antifungal susceptibility results, terbinafine had the lowest and fluconazole had the highest MIC values for all of the tested dermatophyte isolates.

CONCLUSION

In the study, T. tonsurans was the most common species isolated from asymptomatic carriers and of the four antifungals tested, terbinafine had the most active antifungal in vitro against all isolates. Identifying and treating scalp dermatophyte carriers can prevent the spread of tinea capitis in the community.

Dermatophytes and transmission risks to family: a retrospective study of a cohort of 256 adopted children from 1998 to 2012

In this 14-year retrospective study we analyzed samples collected from 101 adopted children originating from developing countries in search of dermatophytosis; a dermatophyte was isolated in 44 children. We demonstrated that dermatophytoses often have a silent clinical presentation (16%) and in approximately 20% of cases cause family member contamination. This study highlights the importance of the clinical examination of children and families as well as systematic sampling of children to avoid dermatophyte transmission to other family members.

Screening for asymptomatic scalp carriage in household contacts of patients with tinea capitis during 1997-2011: a retrospective hospital-based study

For anthropophilic tinea capitis (TC), household spread and asymptomatic scalp carriage (ASC) is considered an important route of transmission and incomplete clearance. To investigate ASC in household contacts of patients diagnosed with TC in a tertiary hospital in Athens, Greece, we retrospectively reviewed the medical files of household contacts that were screened for ASC from 1997 to 2011. Only 34 household contacts of 15 index cases agreed to come for screening. Thirty-three (97%) household contacts were asymptomatic scalp carriers. The most commonly isolated species was Trichophyton violaceum (59%). There was a statistically significant association of ASC with the isolated dermatophyte species (T. violaceum, P-value: 0.029), and with the age of younger than 16 years old (P-value: 0.005), while there was no association with gender (P-value: 0.672). A small number of household contacts accepted to proceed for screening. ASC was found in nearly all screened household contacts and was associated with T. violaceum and younger age. The low number of household contacts that accepted screening may reflect the ignorance of the general population about the possibility of ASC among household contacts in case of a patient with TC.

Comparison of hairbrush, toothbrush and cotton swab methods for diagnosing asymptomatic dermatophyte scalp carriage

BACKGROUND

Tinea capitis may also present as a minimal infection, termed carrier state. Anthropophilic dermatophytes (i.e. Trichophyton tonsurans and Trichophyton violaceum) have been generally associated with high rates of asymptomatic carriage.

OBJECTIVES

The aim of this study was to compare the efficacy of the hairbrush, toothbrush and cotton swab methods for diagnosing scalp carriage as well as to determine the prevalence and related dermatophyte species for both asymptomatic and symptomatic tinea capitis in Adana Province, Turkey.

PATIENTS AND METHODS

A screening study was carried out between February 2006 and May 2006, covering three schools and a total of 1560 children with 857 (54.9%) boys and 703 (45.1%) girls, aged between 7 and 17 years (10.6 +/- 2.3 years). The diagnosis was made by using three of the methods mentioned above with inoculation onto Sabouraud glucose agar.

RESULTS

Symptomatic tinea capitis was not detected in the study; however, 21 (1.3%) asymptomatic carriers, with 9 (42.9%) boys and 12 (57.1%) girls, aged 7 to 13 years (9.7 +/- 1.9 years) were detected. The diagnosis was made via hairbrush in 13, via cotton swab in 4 and via toothbrush in 4. The mean age (P = 0.075) and gender differences were found to be statistically insignificant (P = 0.26). The most common isolated species was Trichophyton mentagrophytes var. mentagrophytes (90.4%) followed by Trichophyton audouinii (4.8%) and Microsporum gypseum (4.8%). Nine children had Arab origin (P = 0.005), and 12 had immigrated from the south-eastern region of Anatolia, Turkey. The screening of 32 households of 21 children with asymptomatic carriage enabled the researchers to detect the carrier state in three mothers and one sister, resulting in a total of four households (12.5%), with T. mentagrophytes var. mentagrophytes isolated, by hairbrush method in three cases and cotton swab in one case. If the methods were to be used alone, the prevalence of asymptomatic carriage would be found as 1.0% (16 of 1592) in the hairbrush, 0.3% (4 of 1592) in the toothbrush and 0.3% (5 of 1592) in the cotton swab methods; whereas the combined use of these three methods could reveal a total prevalence of 1.6% (25 of 1592). The hairbrush method was significantly found to be more effective in detecting dermatophyte fungi than the toothbrush (P < 0.01) and the cotton swab methods (P < 0.05). There was also a statistically significant difference between the use of a single method and the combination of all other three methods (P < 0.005).

CONCLUSIONS

In summary, it was found that the prevalence of asymptomatic carriage did not cover symptomatic tinea capitis prevalence (1.6% vs. 0%), and the dominant species was zoophilic T. mentagrophytes (92%, 23 of 25). Asymptomatic carriage was not found to be related to age, gender and the coexistence of other dermatophytoses; however, race (Arab origin) was found to be the only risk factor. For laboratory diagnosis, no method was found to be nominated as a gold standard; hence, a combined use of diagnosing methods was suggested.

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.