Exposure of Toxocara canis eggs to Purpureocillium lilacinum as a biocontrol strategy: an experimental model evaluation

Purpureocillium lilacinum an emergent pathogen: antifungal susceptibility of environmental and clinical strains

Purpureocillium lilacinum is a filamentous and hyaline fungus cosmopolitan, saprophytic, largely used in the biological control of plant-parasitic nematodes and insects, also considered an emerging and opportunistic human pathogen. The standard treatment for hyalohyphomycosis caused by P. lilacinum is not yet defined, since this fungus is resistant to different antifungals, in vitro and in vivo. The aim of this study was to evaluate and compare in vitro antifungal activity against environmental and clinical P. lilacinum isolates and our results demonstrated that these isolates can be resistant to newer generation triazoles, such as voriconazole, and to caspofungin, a drug of the echinocandin class. In summary, we highlight the importance of knowing the different susceptibility profiles of P. lilacinum isolates, and besides that, the emergence of uncommon human and animal opportunistic fungi, such P. lilacinum, especially during COVID-19, highlight the need for antifungal susceptibility testing of isolates since empirical therapy with different treatment schedules failed in great number of patients.

The Use of Pythium oligandrum in the Biological Control of Roundworm Infection in Dogs and Cats

Pythium oligandrum is an oomycete used in veterinary medicine to treat dermatophytosis in animals. The ovicidal potential against various types of parasite eggs has not been investigated. Ascarids are very common in young animals and the resistance of eggs in the external environment is very high. A commercial product containing P. oligandrum was used in the present study. Its ovicidal action against Toxocara spp. eggs was investigated. Thus, two categories of media (soil and sandstone) were used, on which the ascarid eggs were dispersed. The commercial product was prepared as a solution and was applied according to the manufacturer. The treatment scheme indicated in case of animals with dermatophytosis was used. Thus, the external natural conditions were recreated in the laboratory, in order to establish whether there is any applicability for this oomycete in the biological control of some parasitic diseases. The results indicated an ovicidal action of Pythium oligandrum, supporting the prospects of its use in the decontamination methods of various surfaces or environments where ascarid eggs from carnivores are found.

Purpureocillium lilacinum and Trichoderma virens for biological control of trichostrongylid parasites of sheep: an in vitro evaluation

The study evaluated the ovicidal activity of enzymatic extracts of Purpureocillium lilacinum and Trichoderma virens against trichostrongylid eggs from sheep. Filtered extract (FE) and macerated crude extract (MCE) were prepared from fungal cultures in minimal broth. In the experiment, 100 trichostrongylid eggs, obtained from the feces of naturally infected sheep, were exposed to fungal extracts for 24 and 48 hours/25°C. In the control group, eggs were incubated in minimal broth. The number of L1 larvae was ascertained. Each treatment consisted of four repetitions and the experiment was repeated five times. It was observed that the effect of FE and MCE of P. lilacinum and T. virens on egg hatchability differed from that of the control group. MCE of T. virens and P. lilacinum showed higher ovicidal activity than FE over both periods and at 48 hours of exposure, respectively. From the percentage reductions in hatchability of the eggs, MCE was shown to be superior to FE for both fungi. This study demonstrated the ovicidal potential of these fungi against trichostrongylid eggs. However, further studies are needed in order to identify the molecules responsible for the ovicidal effects, and to evaluate the behavior of fungal extracts in biotic and abiotic interactions.