Mentagrophytes Strains Research Articles

Optimization of an Infected Shoe Model for the Evaluation of an Ultraviolet Shoe Sanitizer Device

Onychomycosis and tinea pedis (athlete's foot) are infections of the nails and skin caused by pathogenic fungi collectively known as dermatophytes. These infections are difficult to treat, and patients often relapse; it is thought that a patient's footwear becomes infected with these fungal organisms and, thus, is an important reservoir for reinfection. Therefore, it is important to find an effective means for killing the dermatophytes that may have colonized the inner surface of the shoes of patients with superficial fungal infections. In this study, we developed an in vitro model for culturing dermatophytes in footwear and used this model to evaluate the effectiveness of a commercial ultraviolet shoe sanitizer in eradicating the fungal elements residing in shoes. Leather and athletic shoes (24 pairs) were inoculated with either Trichophyton rubrum or Trichophyton mentagrophytes (10(7) colony-forming units/mL) strains and were placed at 35°C for 4 to 5 days. Next, we compared the ability of swabbing versus scraping to collect microorganisms from infected shoes. Following the optimized method, shoes were infected and were irradiated with one to three cycles of radiation. The inner surfaces of the shoes were swabbed or scraped, and the specimens were cultured for dermatophyte colony-forming units. Leather and canvas shoes were infected to the same extent. Moreover, scraping with a scalpel was overall more effective than was swabbing with a cotton-tipped applicator in recovering viable fungal elements. Irradiation of shoes with one, two, or three cycles resulted in reduction of fungal colonization to the same extent. The developed infected shoe model is useful for assessing the effectiveness of ultraviolet shoe sanitizers. Also, ultraviolet treatment of shoes with a commercial ultraviolet C sanitizing device was effective in reducing the fungal burden in shoes. These findings have implications regarding breaking foot infection cycles.

Inhibitory effect of nicotinamide on enzymatic activity of selected fungal strains causing skin infection

Pathogenicity of fungi is connected with their ability to easily penetrate the host tissues, survive in the infected host organism and use the elements of the host tissues as nutrients. Hence, the co-occurrence of pathogenic properties with the high enzymatic activity, which is manifested through the production of various enzymes including extracellular enzymes, was observed. It can be expected that it is possible to decrease fungal pathogenicity by lowering their enzymatic activity. The aim of the study was to determine the effect of nicotinamide on enzymatic activity of the fungi, which are most frequently isolated in cases of skin infection. Enzymatic activity was analysed using 15 Candida albicans, 15 Trichophyton rubrum and 15 Trichophyton mentagrophytes strains. The strains used for the study were collected from the current diagnostic material. API ZYM tests were used in diagnostic analysis. MICs of nicotinamide were determined by the macrodilution method in liquid medium. In the case of Candida strains, the presence of nicotinamide in the broth had a significant effect on the decrease of enzymatic activity (P < 0.05) of esterase (C4), esterase lipase (C-8), valin-arylamidase, acid phosphatase and alpha-glycosydase. A considerably stronger effect of nicotinamide was observed in the case of dermatophytes (P < 0.005). Its action led to a decrease in the activity of all the enzymes under study except alpha-glucosidase produced by T. rubrum strains. Thus, nicotinamide exhibited biological activity towards C. albicans, T. rubrum and Trichophyton mentagrophytes, which resulted in a decrease in the activity of enzymes produced by the fungi.

Liquid Sabouraud's medium for the differentiation of Trichophyton rubrum and Trichophyton mentagrophytes

A practical and reliable method of differentiating T. rubrum and T. mentagrophytes, var. interdigitale, is described and compared with the methods of Edgecombe (5) (dextrose-potato-agar medium) and of Bocobo and Benham (4) (dextrose-corn flour-agar medium). The method is based on differences of specific density between T. rubrum and T. mentagrophytes. After incubation of 2 to 3 days in a test tube containing a 4% dextrose and 1% pepton solution (liquid Sabouraud's solution), 92.5% (211) of the 228 T. rubrum strains examined grew at the bottom of the tube while 96.5% (56) of 58 T. mentagrophytes strains developed at the surface of the solution. This represents a modification of the original method described by Götz (2) who utilized a 10% pepton water solution as selective medium. Our method has been found to be of a higher degree of reliability than that carried out by Götz and yet easy to perform and obtaining the results within 2–3 days.

Glucose improves the in vitro viability of Microsporum canis and Trichophyton mentagrophytes var. mentagrophytes

We describe simple and cost-effective methods using carbohydrates to improve the in vitro viability of dermatophytes. Glucose and sucrose in different concentrations (3, 6, 9 and 12%) were used to maintain fifteen strains of M. canis and T. mentagrophytes var. mentagrophytes at 4 and − 20 °C. The strains were phenotypically analyzed before storage and reevaluated at 1, 3, 6 and 9 months. At 1 and 3 months, any alterations in the viability or phenotype pattern of the stored strains were noted. At 6 months, both dermatophytes were 100% viable, when preserved in glucose (3, 6, 9 and 12%) at − 20 °C. All T. mentagrophytes strains were also viable in sucrose (12%), at 4 °C and − 20 °C. However, sucrose failed to improve the viability of M. canis at both temperatures. At 9 months, the higher viabilities without pleomorphism were seen for both dermatophytes preserved in glucose (9 and 12%) at − 20 °C.

Susceptibility to fungal infections of nails in patients with primary antibody deficiency

Primary antibody deficiencies are rare diseases, which require early treatment with intravenous immunoglobulins to prevent fatal infections. The cell mediated immunity in patients with those immunodeficiencies remains unimpaired and usually they do not develop fungal infections. The aim of the study was to determine the susceptibility to fungal infections of nails in children with X-linked agammaglobulinaemia (XLA) and common variable immunedeficiency (CVID). Nail plate fragments collected from five patients with XLA and five with CVID were experimentally infected with a Candida albicans and Trichophyton mentagrophytes strains. The same procedures were carried out with the nails from a control group of 10 healthy volunteers. The intensity of the infection was evaluated on the basis of hyphe ingrown into the nail fragments. The main finding of the study was the increased susceptibility of antibody deficient patients to experimental nail infection with C. albicans and T. mentagrophytes.

Comparative efficacies of commonly used disinfectants and antifungal pharmaceutical spray preparations against dermatophytic fungi

Arthroconidia from five fungal strains belonging to three Trichophyton species, Trichophyton mentagrophytes, T. raubitschekii and T. tonsurans, were tested against commercial chemical disinfectants and pharmaceutical antifungal agents. The chemical disinfectants included chlorine, phenol, sodium dodecyl sulphate and several quaternary ammonium salts, while the two pharmaceutical preparations contained bifonazole and terbinafine as active agents. Arthroconidia were exposed to the antifungal agent either in a suspension solution for a given period of time and assayed for kill rate, or on a sprayed agar plate and monitored for surviving colonies over a period of 14 days. Chlorine (1%) and terbinafine (0·01%) were found to be high level disinfectants bringing about a rapid inactivation of conidia in all five strains. Phenol was equally effective against T. raubitschekii and T. tonsurans; however, T. mentagrophytes cells were able to survive for up to 1 h in 5% phenol. Quaternary ammonium compounds were less rapid in their action against dermatophytes and were needed at a level of about 0·5% to be completely fungicidal. Three commercial spray formulations with a range of 0·1 to 0·3% quaternary ammonium salts were fungistatic against T. mentagrophytes strains. Bifonazole (1%) was also fungistatic in its action against T. mentagrophytes. Sodium dodecyl sulphate (0·5%) was largely ineffective against Trichophyton arthroconidia.

Identification and subtyping of Trichophyton mentagrophytes by random amplified polymorphic DNA.

Trichophyton mentagrophytes is one of the most common pathogens for human and animal dermatophytoses and known as a complex species with variable morphology, and ecologic and genetic backgrounds. We performed random amplified polymorphic DNA (RAPD) analysis on 43 human and 18 animal isolates of T. mentagrophytes along with other 10 anamorphic species of dermatophytes and three teleomorphic species of T. mentagrophytes. Using RAPD analysis with primer 5'-ATGGATC(G,C)(G,C)C-3' (ATGS), all T. mentagrophytes strains produced identical band patterns with those of Arthroderma vanbreuseghemii, one of the teleomorphs of T. mentagrophytes, regardless of their phenotypes. Therefore, T. mentagrophytes could be identified by RAPD analysis with primer ATGS. Using RAPD analysis with primer 5'-ATGGATCGGC-3' (ATG) on T. mentagrophytes, human isolates yielded two distinct subgroups related by their colony morphologies at the time of primary isolation from patients. Three morphologic types--cottony, powdery and persicolor--revealed identical bands whereas the granular type lacked one minor band (0.74 kbp). Animal isolates of T. mentagrophytes produced five band patterns and some of them were identical with those of human isolates. With primer 5'-GAAGGCTCCC-3' (OPAO-15), animal isolates of T. mentagrophytes showed diverse band patterns in contrast to the uniform band pattern of human isolates. These results suggest that RAPD analysis may be a useful tool to identify and subtype T. mentagrophytes complex.

Results of German multicenter study of antimicrobial susceptibilities of Trichophyton rubrum and Trichophyton mentagrophytes strains causing tinea unguium. German Collaborative Dermatophyte Drug Susceptibility Study Group.

Thirty-two strains of Trichophyton rubrum and 16 strains of Trichophyton mentagrophytes isolated from patients with tinea unguium in various parts of Germany were subjected to a microdilution test with six systemic or topical antimycotic agents. Apart from griseofulvin, there were no species-specific differences between the two species. Terbinafine was the most active antimycotic agent, with a MIC not exceeding 0.05 micrograms/ml.

Adherence of arthroconidia and germlings of anthropophilic and zoophilic varieties of Trichophyton mentagrophytes to human corneocytes as an early event in the pathogenesis of dermatophytosis

The association (adherence) between human corneocytes and arthroconidia of Trichophyton mentagrophytes strains 121 and 126, and T. interdigitale strain 4 was studied in vitro. Adherence of arthroconidia to corneocytes from either the palm and sole occurred and increased with time up to 6 h, by which time germination of arthroconidia had started. Significant differences were seen between the T. mentagrophytes strains and T. interdigitale in their adherence to corneocytes from the palm. When adherence values for plantar corneocytes were compared, significant differences were found between T. mentagrophytes and T. interdigitale. Not all corneocytes from either site had adherent arthroconidia, although there was a time-dependent increase in the numbers of corneocytes with adherent fungal cells. By scanning and transmission electron microscopy it was seen that there was a loose association between arthroconidia and corneocytes with no apparent damage to the corneocyte membrane. Adherence of germlings of T. interdigitale to corneocytes from the palm appeared to be mediated by germling outer cell wall fibrils. Hyphal branches and secondary germlings were observed to enhance the attachment of the parent hypha to adjacent corneocytes.

Cross-Immunity in Calves after Vaccination against Trichophytosis

Rybnikar A.: Cross-Imunity in Calves after Vaccination against Trichophytosis. Acta vet. Bmo, 61, 1992: 189-194. Calves vaccinated against Trichophyton verrucosum were resistant to experimental infection with T. verrucosum strain and T. mentagrophytes strain. Immunization with a vaccine containing T. mentagrophytes produced reliable immunity against the homologous strain but failed to confer a satisfactory degree of protection against the heterologous dermatophyte T. verrucosum. Four out of 12 calves of this group reacted to challenge by development of mycotic changes persisting throughout the observation period. All non-vaccinated controls inoculated with one or the other of the two challenge cultures showed a similar clinical picture of trichophytosis. Trichophyton mentagrophytes, Trichophyton verrucosum, immunization, challenge Immune cross-reactions in dermatophytes have been studied both in vitro and in vivo with frequently conflicting results. The differences have been explained particularly by different pre­ paration and composition of antigens and by the use of qualitatively and quantitatively different methods (Kaaman and Wasserman 1981). In in-vivo experiments the immune response was stu­ died in animals and humans sensibilized, infected or immunized with dermatophytic antigens. Foals injected i. m. with living Trichophyton equinum antigen developed immunity not only to the homologous species but also to Trichophyton mentagrophytes (petrovich and Sarkisov 1981). However, from the observations reported by Petrovich (1985) it appears that horses that recovered from trichophytosis lacked cross-immunity to subsequent infection with the causative agent-of microsporidia and vice versa. Woloszyn (1987) reported that cattle infected with T. ver­ rucosum cross-reacted with trichophytin prepared from T. mentagrophytes. Wawrzkiewicz and Rzechowski (1983) who vaccinated guinea-pigs with living and inactivated vaccine against trichophytosis found immune cross-reactions between T. verrucosum and T. mentagrophytes strains. Petrovich et a!. (1972) and Rasulev and Turdiev (1975), on the other hand, found no cross­ -immunity between T. verrucosum and T. mentagrophytes in calves. The present study was designed to assess the development of post-vaccination immunity against homologous and heterologous dermatophyte species in 69 calves on the basis of challenge ex­ periments.

Screening the keratinolytic activity of dermatophytes in vitro

Sixteen strains out of 12 species dermatophytes were examined in respect to their ability of utilizing keratin substrates as the only sources of C and N. The employed keratin substrates included a solubilized preparation of feather keratin (KS) and native keratin, guinea pig hair and chicken feathers. It has been shown that the preparation KS constitutes a convenient model for a preliminary estimation of fungal keratinolytic activity and it can be a source of information about the localization of these enzymes. It has been found that, among the 16 fungal strains, 13 strains synthesize mainly intracellular keratinases while 3 strains of T. verrucosum release enzymes mainly to the medium. Native keratin from hair and feathers was degraded only by some of the examined strains which, under the experimental conditions, developed characteristic spore forms. Keratin of guinea pigs hair was attacked only by the T. mentagrophytes strains, T. verrucosum and K. ajelloi, and only T. gallinae grew on native keratin from chicken feathers.

Differentiation between Trichophyton mentagrophytes and T. rubrum by sorbitol assimilation

Trichophyton rubrum was easily differentiated from T. mentagrophytes by its ability to assimilate sorbitol with an API 20C AUX strip. One hundred percent of 36 T. rubrum strains and none of 147 T. mentagrophytes strains assimilated sorbitol.

High‐performance liquid chromatographic identification of beta‐lactam antibiotics produced by dermatophytes

Thirteen of 48 dermatophyte isolates were found by bioassay to produce beta-lactam antibiotics and seven produced other antibiotics. Estimation and detection of specific beta-lactams in culture broths by derivatization and HPLC was only possible following concentration and extraction procedures. Analysis of the concentrated broths demonstrated the production of penicillin X and penicillin G by two Trichophyton mentagrophytes strains and by one Microsporum canis strain; one further T. mentagrophytes strain produced only penicillin X. Additions of the beta-lactam side-chain precursors, phenylacetic acid and phenoxyacetic acid, to fermentation media failed to increase the antibiotic titres.

Mating reactions ofTrichophyton simiiandT. mentagrophytesstrains from poultry farm soil in India

Seven strains of T. simii and 16 of T. mentagrophytes were isolated from soil and shed feathers at 4 Poona chicken farms. Six of the T. simii strains formed fertile cleistothecia with Stockdale's plus strain of Arthroderma simii, the other was not tested. Twelve of the T. mentagrophytes strains formed fertile cleistothecia with Ajello's a strain of A. benhamiae, one with his A strain, and 3 with neither.