Prevalence of Dermatophytosis and Antifungal Activity of Ethanolic Crude Leaf Extract of Tetradenia riparia against Dermatophytes Isolated from Patients Attending Kampala International University Teaching Hospital, Uganda

Activity of essential oils from leaves, flower buds and stems of Tetradenia riparia on Rhipicephalus (Boophilus) microplus larvae

Around the world, the main problems of livestock are caused by ectoparasites, however, commercial acaracide are toxic to the environment and detrimental to One Health. Therefore, research has increasingly focused on development of natural products as alternatives for tick control. The purpose of this study was to evaluate the larvicidal effect on Rhipicephalus (Boophilus) microplus, through use of essential oils (EOs) extracted from the leaves, flower buds and stems of Tetradenia riparia. The chemical composition of these EOs was determined through gas chromatography coupled to mass spectrometry (GC-MS). They were tested on larvae at concentrations of 100.000 to 40 µg/mL, using the larval packet test and under semi-natural conditions. The main class of compounds in the chemical composition was sesquiterpenes (both oxygenates and hydrocarbons), whereas the predominant compounds in the leaves, flower buds and stems were 14-hydroxy-9-epi-caryophyllene, T-cadinol and 6-7-dehydroroyleanone, respectively. The leaves proved to be the most effective, with highest larvicidal activity (LC99.9 = 83.53 µg/mL). When tested under semi-natural conditions, the oils obtained efficiency above 98% in all compound tests. The results indicated that these EOs were effective against R. (B.) microplus larvae in vitro and ex-situ, proving that this plant has bioactive molecules with significant larvicidal activity.

In situ facile green synthesis of Ag-ZnO nanocomposites using Tetradenia riperia leaf extract and its antimicrobial efficacy on water disinfection

In this work, Ag–ZnO nanocomposites were prepared by a green synthesis route using aqueous leaf extract of Tetradenia riperia and investigated for antibacterial activity against Escherichia coli and Staphylococcus aureus. To optimize the synthesis of the Ag–ZnO, the effects of precursor concentrations, pH, and temperatures were studied. The Ag–ZnO nanocomposites were characterized by XRD, ATR-FTIR, FESEM, and TEM. Results show that the concentration of 8% Ag, the temperature of 80 °C, and a pH of 7–8 were optimal for the synthesis of Ag–ZnO nanocomposites. The XRD analysis showed the decrease in particle size of Ag–ZnO from 23.6 to 14.8 nm with an increase in Ag concentrations, which was further supported by FESEM analysis. TEM image of 8% Ag provides more information on the coexistence of Ag on ZnO where an average particle size of 14.8 nm was determined. The ATR-FTIR analysis confirmed the presence of phenolic compounds, which work as reducing and stabilizing agents. The antimicrobial activity results show that Ag–ZnO nanocomposite demonstrated a higher antimicrobial potency on E. coli than on S. aureus. Therefore, Tetradenia riperia leaf extract is a viable route for the synthesis of Ag–ZnO nanocomposites to be used for various applications, including water disinfection.

Ethnomedicinal, Phytochemical and Pharmacological Investigations of Tetradenia riparia (Hochst.) Codd (Lamiaceae)

Tetradenia riparia Hochsteter codd. (Lamiaceae) in its native African continent, is considered one of the most popular aromatic medicinal plants. In folk medicine it may be used as an infusion to treat respiratory problems, cough, headache, stomach pain, diarrhea, fever, malaria, and dengue; and in the form of compresses it is applied for the relief of headaches and toothaches. The species T. riparia has been researched for decades to isolate and identify chemical constituents present in extracts or essential oil obtained from the leaves, floral buds, or stems of this plant. The present study reviews the scientific literature on ethnomedicinal, phytochemical, and pharmacological aspects of T. riparia. We discuss issues related to the botanical and geographical description of the species, ethnobotanical uses, phytochemical studies on its essential oil and extracts, and biological activities of T. riparia. Several compounds have already been isolated from leaves, such as ibozol, 7α-hydroxyroileanone, 1',2'-dideacetylboronolide, 8(14),15-sandaracopimaradiene-7α,18-diol; 5,6-dihydro-α-pyrone and α-pyrone. Terpenes predominated in the essential oil, comprising monoterpenes, sesquiterpenes, diterpenes, hydrocarbons, and oxygenates. Most phytocompounds were isolated from the leaves and flower buds, namely fenchone, 14-hydroxy-9-epi (E)-caryophyllene, 9β, 13β-epoxy-7-abietene, and 6,7-dehydroroileanone. These compounds provide the species a high pharmacological potential, with antimicrobial, antioxidant, antitumor, analgesic, anti-leishmania, anti-tuberculosis, and anti-parasitic activities. Therefore, this species is a promising herbal medicine.

Trends in the epidemiology of dermatophytosis in the Middle East and North Africa region

Dermatophytosis corresponds to a broad series of infections, mostly superficial, caused by a group of keratinophilic and keratinolytic filamentous fungi called dermatophytes. These mycoses are currently considered to be a major public health concern worldwide, particularly in developing countries such as those in the Middle East and North Africa (MENA) region. Here we compiled and discussed existing epidemiologic data on these infections in the MENA region. Most of the available studies were based on conventional diagnostic strategies and were published before the last taxonomic revision of dermatophytes. This has led to misidentifications, which might have resulted in the underestimation of the real burden of these infections in the MENA countries. Our analysis of the available literature highlights an urgent need for further studies based on reliable diagnostic tools and standard susceptibility testing methods for dermatophytosis, which represents a major challenge for these countries. This is crucial for guiding appropriate interventions and activating antifungal stewardship programs in the future.

An Insight into Biomolecules for the Treatment of Skin Infectious Diseases

In assigning priorities, skin infectious diseases are frequently classified as minor when compared to infectious diseases of high mortality rates, such as tuberculosis or HIV. However, skin infections are amongst the most common and prevalent diseases worldwide. Elderly individuals present an increased susceptibility to skin infections, which may develop atypical signs and symptoms or even complicate pre-existing chronic disorders. When the skin fails to correct or inhibit the action of certain pathogenic microorganisms, biomolecules endowed with antimicrobial features are frequently administered topically or systemically to assist or treat such conditions. (1) Antibiotics, (2) antimicrobial peptides, or (3) natural extracts display important features that can actively inhibit the propagation of these pathogens and prevent the evolution of infectious diseases. This review highlights the properties and mechanisms of action of these biomolecules, emphasizing their effects on the most prevalent and difficult to treat skin infections caused by pathogenic bacteria, fungi, and viruses. The versatility of biomolecules’ actions, their symbiotic effects with skin cells and other inherent antimicrobial components, and their target-directed signatures are also explored here.

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.

Epidemiological Characterization of Dermatomycosis in Ethiopia

Background

Superficial mycosis is common worldwide and their epidemiological characteristics are different in different geographical areas and have shown variations in the last decades. The aim of this study was to analyze and characterize the epidemiology of dermatomycosis and their causative fungi species in Ethiopia between 2015 and 2019.

Methods

A laboratory-based cross-sectional study was conducted using the data of mycological examination and culture findings from all patients who visited the Dermatology Department of Arsho Advanced Medical Laboratory, Addis Ababa, Ethiopia. The direct wet mount microscopy and culture data of the isolates were collected from the database of the dermatology unit from 2015 to 2019 after permission was obtained from the laboratory head. The data were double-entered into Microsoft Excel, exported and analyzed using SPSS version 20.

Results

The total prevalence of fungi causing dermatomycosis was 67.7% (760/1122 cases) using direct wet mount microscopy and from these 489/1122 (43.5%) were culture positive. Dermatomycosis was found to be higher among females 694/1122 (61.9%) than male participants. Age group 25–44 years was the most affected 442/1122 (39.4%) followed by 1–14 years old 291/1122 (25.94%). Tinea unguium (50.8%) is the most common type of dermatomycosis followed by tinea capitis (24.1%) and tinea corporis (13.9%). Trichophyton spp. (32%) was the most highly distributed causative agent, followed by Epidermophyton spp. (20.2%) and Aspergillus fumigatus (8.3%).

Conclusion

The retrospective analysis of epidemiological data collected at Arsho Advanced Medical Laboratory since 2015 showed a gradual increase in the frequency of tinea unguium and tinea pedis. However, during the past years, there was a gradual decline in the frequency of tinea corporis. In parallel with this variable pattern, the rate of isolation of non-dermatophytes especially Aspergillus fumigates and Candida species has shown a gradual increment during the past five years.

Phenotypic Characterization of Enzymatic and Non-enzymatic Virulence Factors in Etiopathogenesis and Evolution of Drug Resistance among Dermatophytes

The virulence factors of dermatophytes play a vital role in the etio-pathogenesis and emergence of drug resistance. Regular surveillance is essential for constant monitoring of association of virulence factors in the emergence of drug resistant isolates and to guide proper therapeutic strategies to combat infections due to drug resistant isolates of dermatophytes. The aim of this study is to isolate and identify various enzymatic and non-enzymatic virulence factors of dermatophytes isolated from clinically suspected cases of dermatophytosis attending the dermatology outpatient clinic. From 30 clinical samples received from department of Dermatology to the department of Microbiology during the study period July to December 2019, KOH mount and fungal culture was done and only the isolates which grew dermatophytes were used for detecting virulence factors using standard methods. Among 30 affected patients, 13 were male (43.3%) and 17 were female (56.7%) with age range of 13 to 60 years. Skin sample yielded positive growth in 96.6% of the cases. Out of 30 samples, 6 samples were positive for Trichophyton mentagrophytes. Tinea corporis was the common manifestation which yielded positive growth. Female predominance was seen. Male predominance was seen in younger age group while females were more commonly affected in older age group. Adolescents were commonly affected age group (40%). Then people between age 41-50 (middle age group) were mostly affected. The six Trichophyton mentagrophytes were found to have enzymatic and non- enzymatic virulence factors. All the virulence factors included in the study were present in Trichophyton mentagrophytes.

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.