Studies in the differentiation between Microsporum ferrugineum Ota and Trichophyton soudanense Joyeux

A study, conducted with 20 isolates of Microsporum ferrugineum and 12 isolates of Trichophyton soudanense, revealed that some of the discrepancies in the literature regarding their characteristics and differentiation were due to methodology, strain variation and the use of an insufficient number of isolates. We found all isolates of T. soudanense to be urease negative and gelatinase positive (usually by the first week); to produce brown to black colonies on Lowenstein-Jensen medium; to rapidly decompose casein and more slowly tyrosine; to grow well or better at 37°C as compared to room temperature; to produce reflexive branching on cornmeal Tween agar and abundant microconidia on casero medium and to exhibit no sexual reaction with either mating type of Arthroderma simii. All but one isolate demonstrated restricted growth on lactose agar and only three isolates perforated hair.In contrast, we found 18 of 20 isolates of M. ferrugineum to be urease positive in urea broth (most isolates were negative on urea agar); all produced light-colored colonies on Lowenstein-Jensen medium; spreading colonies on lactose agar and failed to perforate hair in vitro or to produce reflexive branching. Most isolates manifested poorer to no growth at 37°C compared to room temperature and all but one failed to decompose casein and tyrosine. A few strains produced macroconidia and/ or microconidia on casero medium and some reacted sexually with A. simii (a) or (–) mating type. Gelatin hydrolysis was variable.We suggest the following key tests to differentiate M. ferrugineum from T. soudanense: urease activity in urea broth; colony color on Lowenstein-Jensen medium; growth on lactose agar; growth at 37° C compared to room temperature; presence of reflexive branching on cornmeal Tween agar.     

Mating experiment of Microsporum canis and M. equinum isolated from animals with Nannizzia otae

In an attempt to study the influence of iron overload on deep mycotic infection, experimental candidiasis was induced in mice. One group received intravenous injections of colloidal iron (60 mg/kg weight) for three consecutive days before intravenous inoculation of Candida albicans spores (1×10⁷). The other received the same number of Candida spores without iron overload. The animals in both groups were observed for 28 days.The Candida lesions, regardless of iron administration, were located mainly in the kidney. There was a marked difference in mortality between the two groups, i.e., 40% in the group without iron administration and 80% in the group with it. The higher mortality rate in the latter group may be explained by following reasons: (1) increased serum iron and iron saturation (iron is essential to the growth of Candida), (2) decreased phagocytic activity against intravenously inoculated Candida because of the saturation of the phagocytic cells by the preceding colloidal iron administration and (3) enhanced proliferation of Candida, which tends to involve the kidney, exposed to abundant iron in the kidney due to increased excretion.The current experiment showed that excessive iron clearly promoted the proliferation of intravenously inoculated Candida in vivo.     

Immunological Studies on Dermatophytes IV. Chemical Structures and Serological Reactivities of Polysaccharides from Microsporum praecox, Trichophyton ferrugineum, Trichophyton sabouraudii, and Trichophyton tonsurans

The chemical structures and serological specificities of polysaccharides isolated from four species of dermatophytes, Microsporum praecox, Trichophyton ferrugineum, T. sabouraudii, and T. tonsurans, were investigated. Each of these species yielded a mixture of crude polysaccharides which could be separated into three water-soluble, neutral polysaccharides free of nitrogen. These were grouped as galactomannan I, galactomannan II, and glucan. The galactomannans I were quite similar in chemical structure. When measured by complement fixation, their serological cross-reactivities were similar with rabbit antisera to each of these species except T. sabouraudii. The differences in their relative reactivities with this antiserum could be correlated with differences in structure and specificity of this antiserum for galactofuranose end groups. The galactomannans II differed both in chemical structure and in their serological reactivities with antisera to each of these species. The galactomannan II from T. ferrugineum differed most in chemical structure and was the least reactive serologically. The glucans also differed in both structure and serological reactivities.     

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 degrees 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 degrees C. All T. mentagrophytes strains were also viable in sucrose (12%), at 4 degrees C and -20 degrees 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 degrees C.     

Enzymatic activities of Microsporum canis and Microsporum gypseum strains.

The presence of 11 enzymatic activities, detected by qualitative methods, and 19 enzymes, semi-quantitatively detected by API ZYM system, in strains belonging to Microsporum canis and Microsporum gypseum has been studied. No pronounced differences were noted between Microsporum canis and Microsporum gypseum, although Microsporum gypseum presented in some cases more intense enzymatic activities than Microsporum canis.     

Extensive dermatophytoses caused by Trichophyton mentagrophytes and Microsporum canis in a patient with AIDS

Retrospective studies have shown the occurrence of episodes of deep or superficial fungal infections in 58 to 81% of HIV/AIDS patients as a result of impairment of cell immunity. We describe a case of disseminated cutaneous dermatophytoses caused by Trichophyton mentagrophytes and Microsporum canis in a patients with AIDS. Diagnostic and therapeutic problems in relation to this unsual presentation are emphasized as well as the importance of an early mycologic diagnosis to prescribe antifungal therapy.     

Partial characterization of the extracellular keratinase from Microsporum canis

The extracellular keratinase of Microsporum canis released peptides from alpha-type fibrous protein and the membranous fraction isolated from human stratum corneum. Inhibition of the enzyme by phenylmethyl-sulfonylfluoride and its weak inhibition by N-ethylmaleimide and etheneglycol tetra-acetic acid indicated that it is probably a serine proteinase.     

Phenotypical and molecular characterization of Microsporum canis strains in north-east Brazil

AIMS: This study investigated the possible correlation between the phenotypical and genotypical characteristics of Microsporum canis isolated from cats and dogs in north-east Brazil. METHODS AND RESULTS: The mycological study was conducted by direct microscopic examination and by fungal culture. Polymerase chain reaction-restriction enzyme analysis and random amplification of polymorphic DNA techniques were used for the genotypical analysis. The morphological analysis showed a considerable diversity of colonies as well as different morphologies of conidia, despite the M. canis strains having been isolated under the same conditions. However, the molecular analysis showed that all analysed strains are genetically similar. CONCLUSIONS: This study, based on phenotypical and molecular analysis, evidences the wide spectrum of phenotypical variations in M. canis in contrast to the stable genotypes of such dermatophytes. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of this study indicate that M. canis isolated from cats and dogs with dermatophytosis in north-east Brazil may be clones, well adapted to the conditions of this region, despite M. canis showing different morphological features.     

Antifungal activity of Lactobacillus against Microsporum canis, Microsporum gypseum and Epidermophyton floccosum

A total of 220 lactic acid bacteria isolates were screened for antifungal activity using Aspergillus fumigatus and Aspergillus niger as the target strains. Four Lactobacillus strains exhibited strong inhibitory activity on agar surfaces. All four were also identified as having strong inhibitory activity against the human pathogenic fungi Microsporum canis, Microsporum gypseum and Epidermophyton floccosum. One of the four lactobacilli, namely Lb. reuteri ee1p exhibited the most inhibition against dermatophytes. Cell-free culture supernatants of Lb. reuteri ee1p and of the non-antifungal Lb. reuteri M13 were freeze-dried and used to access and compare antifungal activity in agar plate assays and microtiter plate assays. Addition of the Lb. reuteri ee1p freeze-dried cell-free supernatant powder into the agar medium at concentrations greater than 2% inhibited all fungal colony growth. Addition of the powder at 5% to liquid cultures caused complete inhibition of fungal growth on the basis of turbidity. Freeze-dried supernatant of the non-antifungal Lb. reuteri M13 at the same concentrations had a much lesser effect. As Lb. reuteri M13 is very similar to the antifungal strain ee1p in terms of growth rate and final pH in liquid culture, and as it has little antifungal activity, it is clear that other antifungal compounds must be specifically produced (or produced at higher levels) by the anti-dermatophyte strain Lb. reuteri ee1p. Reuterin was undetectable in all four antifungal strains. The cell free supernatant of Lb. reuteri ee1p was analyzed by LC-FTMS using an Accela LC coupled to an LTQ Orbitrap XL mass spectrometer. The high mass accuracy spectrum produced by compounds in the Lb. reuteri ee1p strain was compared with both a multianalyte chromatogram and individual spectra of standard anti-fungal compounds, which are known to be produced by lactic acid bacteria. Ten antifungal metabolites were detected.     

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

Mycopathologia - The anthropophilic dermatophyte Trichophyton tonsurans and its zoophilic counterpart T. equinum are phylogenetically closely related. The barcoding marker rDNA internal transcribed...     

Antimicrobial effects of aqueous plant extracts on the fungi Microsporum canis and Trichophyton rubrum and on three bacterial species

Aqueous extracts of 10 plants were tested for their ability to inhibit Trichophyton rubrum and Microsporum canis, the aetiological agents of dermal fungal infections in humans. These extracts were also evaluated for their activity against some bacteria. Aqueous extracts from the leaves of Inula viscosa produced detectable antifungal activity against these dermatophytes.     

Immunological Studies on Dermatophytes III. Further Analyses of the Reactivities of Neutral Polysaccharides with Rabbit Antisera to Microsporum quinckeanum, Trichophyton schoenleinii, Trichophyton rubrum, Trichophyton interdigitale, and Trichophyton granulosum

The serological reactivities of polysaccharides isolated from five species of dermatophytes, Microsporum quinckeanum, Trichophyton granulosum, T. interdigitale, T. rubrum, and T. schoenleinii, with rabbit antisera to these species were studied qualitatively by precipitation in gel and quantitatively by complement-fixation analyses. Significant differences in the serological reactivities of the galactomannans I were detected with antisera to T. schoenleinii and T. interdigitale. The differences appeared to be related to the specificity of these antisera for the galactofuranose residues in the polysaccharides. Antisera to M. quinckeanum, T. granulosum, or T. rubrum did not detect differences between the galactomannans I. The serological reactivities of the galactomannans II were different with each of the five antisera. The reactivities of the glucans could be correlated with the amount of alpha 1 --> 6 linked glucopyranose residues when antisera to T. schoenleinii and M. quinckeanum were used.     

Antifungal susceptibility and genotypical pattern of Microsporum canis strains

Dermatophytes are a group of fungi that are capable of invading keratinized tissues of humans and other animals. Antifungal susceptibility analysis and genetic studies by random amplification of polymorphic DNA (RAPD), have been used to detect polymorphism as well as determining the possible resistance of dermatophytes to antifungals. The aim of this study was to evaluate the possible correlation between the antifungal susceptibility and genotypical pattern of Microsporum canis strains isolated in dogs and cats with dermatophytosis in Northeast Brazil. The antifungal susceptibility study was conducted using the broth microdilution test with griseofulvine, ketoconazole, itraconazole, and fluconazole. The genotypical analysis was performed using the RAPD method. The antifungal susceptibility analysis showed that all the strains of M. canis analyzed (n = 22) were sensitive to griseofulvine (0.25 microg/mL < or minimum inhibitory concentration (MIC) < or = 1 microg/mL), ketoconazole (0.25 microg/mL < or = MIC < or = 2 microg/mL), itraconazole (0.25 microg/mL < or = MIC < or = 1 microg/mL), and fluconazole (1 microg/mL < or = MIC < or = 16 microg/mL). The RAPD results showed that all analyzed strains are genetically similar. Thus, based on antifungal susceptibility analysis and RAPD data, a possible correlation can be shown between the antifungal susceptibility and the genotypical pattern of the strains of M. canis from Northeast Brazil.     

Antigenic and genomic relatedness among Ehrlichia risticii, Ehrlichia sennetsu, and Ehrlichia canis.

Antigenic and genomic relatedness among Ehrlichia risticii, E. sennetsu, and E. canis was analyzed by enzyme-linked immunosorbent assay, Western blotting (immunoblotting) and DNA-DNA hybridization. E. risticii and E. sennetsu were serologically related, and their Western blot antigen profiles were nearly identical. Two antigens of E. sennetsu corresponding to the 28- and 51-kDa antigens of E. risticii were apparently larger than the E. risticii antigens, and the 55-kDa antigen of E. risticii appeared to be unique to this species. The 110-, 70-, and 44-kDa antigens of these two species were identical, as determined by the use of monospecific antibodies. DNA homology between these two species was high. On the other hand, E. canis was antigenically least reactive with the antisera to E. risticii and E. sennetsu. However, a dog convalescent-stage E. canis antiserum recognized antigens in the other two species which were different from those recognized by their homologous antisera. Similarly, homology between the DNA of E. canis and the DNAs of the other two species was very minimal. These results indicate that E. risticii and E. sennetsu are closely related both at the genomic and antigenic levels and that the relationship of these two species with E. canis is minimal.     

Observations of Microsporum canis with cryoscanning and scanning electron microscopy

The observations of Microsporum canis with cryoscanning and scanning electron microscopy without fixation and dehydration were reported. In the former an almost native state was observed through showing some fuzzy outlines due to frost; in the latter it was shown that marked shrinkage and distortion had occured. There were many granules on the surface of the macroconidia though their function is uncertain.     

Antigenic relationship between downy and granular forms of Trichophyton mentagrophytes and Trichophyton rubrum

One strain each of granular and downy varieties of Trichophyton mentagrophytes and two strains each of granular and floccose colonial types Trichophyton rubrum were used for preparation of antigens. The antigens were analyzed by double diffusion against homologous and heterologous antisera raised in rabbits. A total of 17 distinct antigens were recognized, seven of which were common to two dermatophytes. Granular and downy varieties of the Trichophyton species produced on additional line of nonidentity. Cross reactions failed to establish any relationship between similar morphologic forms of different dermatophytes. One isolate of T. rubrum, which was originally the floccose culture type but changed into the granular form after artificial infection, showed an antigenic relationship to the floccose culture.     

耐极端环境真菌对犬小孢子菌及孢子丝菌的拮抗研究

目的 检测极端环境分离出的真菌拮抗临床病原真菌的活性.方法 选用极端环境分离出的24株真菌菌株上清液及菌丝体的提取液,来进行临床病原真菌（孢子丝菌和犬小孢子菌）的拮抗试验,采用M38-A2产孢丝状真菌抗真菌药物敏感性试验方案和E-test纸片扩散法.结果 抑菌圈直径≥1.0 cm,具有较强拮抗孢子丝菌活性的极端环境真菌有8株;抑菌圈直径≥2.0 cm,具有极强拮抗犬小孢子菌的活性的极端环境真菌有1株.两种临床菌株的拮抗试验,90％的拮抗结果相一致.结论 70％极端环境真菌菌株上清液及菌丝体提取液具有拮抗临床病原真菌孢子丝菌和犬小孢子菌的活性.     

Flurbiprofen,a unique non-steroidal anti-inflammatory drug with antimicrobial activity against Trichophyton,Microsporum and Epidermophyton species

AIMS: The objective of this study was to determine the antifungal activity of flurbiprofen against dermatophytes like Trichophyton, Microsporum and Epidermophyton species. METHODS AND RESULTS: Susceptibility tests were performed against dermatophytes like Trichophyton, Microsporum and Epidermophyton species by the microbroth dilution method. Among the dermatophytes tested, Trichophyton, Microsporum and Epidermophyton species are remarkably susceptible to this compound (MIC(50): 8-16 microg ml(-1)). A yeast pathogen, Candida albicans, and a bacterium, Staphylococcus aureus, are also susceptible to flurbiprofen. CONCLUSIONS: Flurbiprofen is a non-steroidal anti-inflammatory compound with strong antifungal activity, which is not found in two well known and medically used antifungal organic acids like benzoic and salicylic acids. SIGNIFICANCE AND IMPACT OF THE STUDY: The present action of flurbiprofen on microbes indicates its future prospects as an antimicrobial agent against dermatophytes and yeast pathogens. However, in view of the anti-inflammatory property of flurbiprofen, its antifungal action may provide an additional advantage for use as a skin ointment.