Investigations upon the Improvement of Dermatophyte Identification Using an Online Mass Spectrometry Application

Online MALDI-TOF mass spectrometry applications, such as MSI-2, have been shown to help identify dermatophytes, but recurrent errors are still observed between phylogenetically close species. The objective of this study was to assess different approaches to reduce the occurrence of such errors by adding new reference spectra to the MSI-2 application. Nine libraries were set up, comprising an increasing number of spectra obtained from reference strains that were submitted to various culture durations on two distinct culture media: Sabouraud gentamicin chloramphenicol medium and IDFP Conidia medium. The final library included spectra from 111 strains of 20 species obtained from cultures on both media collected every three days after the appearance of the colony. The performance of each library was then analyzed using a cross-validation approach. The spectra acquisitions were carried out using a Microflex Bruker spectrometer. Diversifying the references and adding spectra from various culture media and culture durations improved identification performance. The percentage of correct identification at the species level rose from 63.4 to 91.7% when combining all approaches. Nevertheless, residual confusion between close species, such as Trichophyton rubrum, Trichophyton violaceum and Trichophyton soudanense, remained. To distinguish between these species, mass spectrometry identification should take into account basic morphological and/or clinico-epidemiological features.

Antioxidant, antiradical power of Syzygium aromaticum essential oil, and its antidermatophytic activity against Epidermophyton floccosum and Trichophyton soudanense

In order to provide an effective alternative for efficient management of dermatophytosis, we evaluate in vitro the antioxidant and antiradical potentials of the essential oil of the dry flower buds of Syzygium aromaticum and its antidermatophytic activity against Epidermophyton floccosum and Trichophyton soudanense, For this purpose, the essential oil was obtained by hydrodistillation through a Clevenger apparatus and the antioxidant and antiradical potentials were evaluated by the ferric reducing antioxidant power (FRAP) and the trapping of the ABTS•+ radical methods, respectively. The evaluation of the antidermatophytic activity was made by the agar incorporation method. The results showed that the essential oil reduced ferric iron (Fe3+) to ferrous iron (Fe2+) in a more significant manner than BHT (reference antioxidant). Moreover, the antiradical power of the essential oil was twice greater than that of BHT. Furthermore, the essential oil inhibited the mycelial growth of the two dermatophytes, with 500 ppm and 1000 ppm of minimal inhibitory concentrations against Epidermophyton floccosum and Trichophyton soudanense, respectively. This activity was greater than that of griseofulvin whose minimal inhibitory concentration was greater than 4000 ppm against both studied germs. These findings show that, withon the framework of safeguarding human lives and protecting the environment, the essential oil from the dry flower buds of Syzygium aromaticum appeared as reliable alternative for the treatment of dermatophytosis caused by Epidermophyton floccosum and Trichophyton soudanense. Our results lay scientific foundation toward the promotion and development of Cameroonian biodiversity in treatments of dermatophytosis.

Phytochemical analysis and antifungal property of Mallotus oppositifolius (Geiseler) Müll.Arg. (Euphorbiaceae)

The emergence of resistant fungi to available drugs highlights the need for new antifungal drugs. The present study aimed to evaluate the antifungal activity of the isolated compounds, fractions and crude extract from the leaf of Mallotus oppositifolius (Geiseler) Müll. Arg. Three pure compounds labelled 1-3 were isolated from the methylene chloride / methanol (1/1) extract of the leaf of this plant using chromatography techniques. These compounds were identified using analytical spectroscopic methods as betulinic acid (1), quercetine (2) and quercitin (3). The crude extract, fractions and compounds were tested against pathogenic yeasts (Candida albicans, Candida glabrata, Candida krusei) and dermatophytes (Trichophyton rubrum, Trichophyton soudanense, Microsporum audouinii, Microsporum langeronii) using agar well diffusion and dilution methods. The safety of the crude extract was studied on Wistar rats according to the WHO guidelines. The minimal inhibitory concentration (MIC) values ranged from 48 to 781 μg/ml against yeasts for crude extract and fractions, and 1.86 to 25000 μg/ml against dermatophytes for pure compounds, fractions and crude extract. The antifungal activity of pure compounds was not determined against yeasts. The crude extract of leaf was found to be safe in rat at up to 12 g/kg. The results achieved supported the traditional use of Mallotus oppositifolius leaf for the treatment of fungal infections.Keywords: Mallotus oppositifolius, antifungal activity, safety, phytochemical screening.

Is the Antimicrobial Activity of Hydrolates Lower than That of Essential Oils?

Among the top five human infections requiring medical treatment is dermatitis. Treatment of bacterial and fungal skin infections is usually based on antibiotic therapy, which is often ineffective due to the involvement of antibiotic-resistant microbial strains. The aim of this study was to compare the antimicrobial activity of essential oils (EOs) and hydrolates (Hys) extracted from six aromatic plants grown in Italy (Lavandula angustifolia, Lavandula intermedia, Origanum hirtum, Satureja montana, Monarda didyma, and Monarda fistulosa) towards fungal (Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis; Trichophyton soudanense, Trichophyton tonsurans, Trichophyton rubrum, Trichophyton violaceum and Microsporum canis) and bacterial strains (Staphylococcus aureus MRSA, Staphylococcus aureus MSSA, Streptococcus pyogenes, E. faecalis, Enterococcus faecalis VRE, and Enterococcus faecium) potentially pathogenic for human skin. The composition and antimicrobial activity of EOs and Hys were evaluated using the Gas-chromatography mass spectrometry and micro dilution-broth test, respectively. The volatiles’ conversion factors (CFs) were calculated to compare the activity of Hys with that of the corresponding EOs. Data show that, although the minimum inhibitory concentration values of EOs are lower than the corresponding Hys, the volatiles contained in Hys are more effective at inhibiting microbial growth because they are active at lower concentrations.

Epidemiology of Superficial Fungal Infections in Hospital Settings in Togo and Senegal from 2019 to 2020

Background: Superficial fungal diseases are cosmopolitan affections caused by yeast and filamentous microscopic fungi (dermatophytes and moulds). Their very high prevalence and worldwide distribution make them one of the most common dermatological diseases. Our study aims to describe the profile of superficial fungal diseases diagnosed in Senegal and Togo and to identify the causative agents circulating in both countries. Material and Methods: This is a descriptive study carried out in Senegal and Togo, involving 602 and 135 patients respectively. The patients presenting clinical signs were screened in the Parasitology-Mycology laboratories of the Fann University Hospital in Dakar (from February 2019 to February 2020) and Sylvanus Olympio University Hospital in Lomé (from October 2019 to March 2020). Samples collected were examined using routine mycological techniques (Direct examination and culture). Results: In Senegal 293 (48.67%) out of 602 patients enrolled were diagnosed with superficial fungal diseases. Patients under 10 old years and female, most affected, represented 23.42% and 61.39% of cases respectively. The patients were seen mostly in September with 27 positives cases out of 42. Trichophyton soudanense and Candida albicans complex were the most common species, with a prevalence rate of 30.37% and 26.96% respectively. In Togo, 67.41% (91) of the 135 patients presented superficial mycosis. The female (58.76%) and the patients aged 31-40 year old (21.65%) were the most affected. Highest prevalence is recorded in October with 11 positive cases out of 13. Malassezia furfur was the most common species with a prevalence of 28.57%. The same species of fungi were found in both countries with the exception of three fungi Trichophyton violaceum, Aspergillus candidus (respectively 3 cases and 1 case in Senegal) and Trichophyton tonsurans (3 cases in Togo). Conclusion: Superficial mycoses are a frequent reason for consultation in Senegal and Togo. Dermatophytes and yeasts of the genus Candida and Malassezia are the most common agents involved. The use of innovative diagnostic techniques could allow a more precise identification of species for a better therapeutic management.