Dermatophytes are widely distributed in the environment, with an estimated prevalence of 20–25% of the the global population yearly. These fungi are keratinophilic and keratinolytic and cause the infection of keratin-rich structures such as skin, hair, and nails. 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 even life-threatening symptoms. This review summarizes current information on the pathogenicity, virulence factors, and drug resistance mechanisms associated with dermatophytes. A greater number of virulence factors of these fungi are important for the occurrence of infection and the changes that occur, including those regarding adhesins, the sulfite efflux pump, and proteolytic enzymes. Other virulence factors include mechanisms of evading the host defense, while the development of resistance to antifungal drugs is increasing, resulting in treatment failure. The investigation of host-pathogen interactions is essential for developing a more complete understanding of the mechanisms underlying dermatophyte pathogenesis and host response to inform the use of diagnostics methods and antifungal therapeutics to minimize the high fungal burden caused by dermatophytes and to control the spread of resistance.

The aim of our study was to determine the susceptibility of 15 Candida albicans sputum isolates on fluconazole and caspofungin, as well as the antifungal potential of Lavandula angustifolia essential oil (LAEO). The commercial LAEO was analyzed using gas chromatography-mass spectrometry. The antifungal activity was evaluated using EUCAST protocol. A killing assay was performed to evaluate kinetics of 2% LAEO within 30 min treatment. LAEO with major constituents’ linalool (33.4%) and linalyl acetate (30.5%) effective inhibited grows of C. albicans in concentration range 0.5–2%. Fluconazole activity was noted in 67% of the isolates with MICs in range 0.06–1 µg/mL. Surprisingly, 40% of isolates were non-wild-type (non-WT), while MICs for WT ranged between 0.125–0.25 µg/mL. There were no significant differences in the LAEO MICs among fluconazole-resistant and fluconazole-susceptible sputum strains (p = 0.31) and neither among caspofungin non-WT and WT isolates (p = 0.79). The 2% LAEO rapidly achieved 50% growth reduction in all tested strains between 0.2 and 3.5 min. Within 30 min, the same LAEO concentration exhibited a 99.9% reduction in 27% isolates. This study demonstrated that 2% solution of LAEO showed a significant antifungal activity which is equally effective against fluconazole and caspofungin susceptible and less-susceptible strains.

Toxoplasma gondii is an obligate intracellular parasite existing in three infectious life stages—tachyzoites, bradyzoites, and sporozoites. Rupture of tissue cysts and re-conversion of bradyzoites to tachyzoites leads to reactivated toxoplasmosis (RT) in an immunocompromised host. The aim of this study was to apply ImageJ software for analysis of T. gondii brain cysts obtained from a newly established in vivo model of RT. Mice chronically infected with T. gondii (BGD1 and BGD26 strains) were treated with cyclophosphamide and hydrocortisone (experimental group—EG) or left untreated as infection controls (ICs). RT in mice was confirmed by qPCR (PCR+); mice remaining chronically infected were PCR−. A total of 90 images of cysts were analyzed for fractal dimension (FD), lacunarity (L), diameter (D), circularity (C), and packing density (PD). Circularity was significantly higher in PCR+ compared to IC mice (p < 0.05 for BGD1, p < 0.001 for the BGD26 strain). A significant negative correlation between D and PD was observed only in IC for the BGD1 strain (ρ = −0.384, p = 0.048), while fractal parameters were stable. Significantly higher D, C, and PD and lower lacunarity, L, were noticed in the BGD1 compared to the more aggressive BGD26 strain. In conclusion, these results demonstrate the complexity of structural alterations of T. gondii cysts in an immunocompromised host and emphasize the application potential of ImageJ in the experimental models of toxoplasmosis.

Toxoplasmosis is one of the most widespread zoonosis worldwide, since Toxoplasma gondii (T. gondii) is a ubiquitous obligate intracellular protozoan parasite that infects up to one third of the human population. Although infection is usually asymptomatic in immunocompetent individuals, in vulnerabile categories such as the fetus and immunocompromised patients, toxoplasmosis can lead to severe consequences, in particular congenital and reactivated toxoplasmosis (RT). Highly active antiretroviral therapy (HAART) and global increase in the number of immunocompromised patients undergoing organ and tissue transplantations, in which toxoplasmosis represents important opportunistic infection, shifted the focus of interest from HIV+ patients to transplant recipients. There is an urgent need for identifying novel potent and well-tolerated drugs, since available options for toxoplasmosis chemotherapy are limited, and associated with numerous side effects. Although potential chemotherapeutics are also investigated in vitro, results obtained in in vivo experimental models provide more valuable data. Iatrogenic immunosuppression in mice chronically infected with T. gondii is mostly based on administration of corticosteroids, such as dexamethasone in drinking water and hydrocortisone via subcutaneous injections. In addition, some models involve the use of cytostatics, mainly cyclophosphamide, which is among the most commonly used immunosuppressants in transplantation protocols. Large variations in dosing of immunosuppressants in models of RT call for their optimization. Cytostatics and corticosteroids, applied simultaneously in adequate doses and intervals would allow for simulation of the most frequently applied immunosuppressive regimens in human transplantation medicine. Although there is a variety of in vivo models of toxoplasmosis, a current trend of exponential increase in population of transplant recipients requires a better insight into possible ways of establishing a model of RT. Establishment of a sustainable model of RT would be of great importance in future studies focused on T. gondii infection, and above all, for conducting chemotherapy experiments oriented towards discovery of potential new candidates for the treatment of toxoplasmosis.