Особенности антифунгальной терапии при длительном инфекционном процессе: клинический случай грибкового кератита и анализ профиля противогрибковой чувствительности с учетом формирования биопленок

Among infectious diseases, opportunistic mycoses occupy a special place. There is a lot of information in the literature about the clinical and epidemiological aspects of infection caused by Fusarium spp. The frequency of occurrence of this infection among microbial keratitis in the world varies from 2 to 40% depending on the geographical location of the country. Colonizing mucous membranes, fungi can exist not only in the form of plankton, but, attaching to the surface, form biofilms, which leads to an increase in resistance to many antifungal agents. The article presents the case of fungal keratitis formed by Fusarium solani with the determination of the profile of the antifungal sensitivity of the selected cultures, taking into account their ability to biofilm formation. The study used a culture of F. solani isolated from the patient and a test culture of F. solani obtained from the Museum collection. When determining the sensitivity of planktonic cultures of fungi to antifungal agents of the azole group (fluconazole, voriconazole), amphotericin B and terbinafine, it was revealed that antimycotics had a pronounced antifungal activity in relation to the clinical culture: amphotericin B and voriconazole, whereas the plankton test culture F.solani had a more pronounced sensitivity to all groups of antifungal agents. In connection with the long progressive course of the infectious process and the high biofilm-forming ability of the clinical strain F. solani , the activity of antifungal agents on cells in biofilms modeled in vitro was studied. It was shown that in relation to biofilms indicators of minimally inhibitory concentrations exceed 100 times the values of planktonic cultures. The analysis of the mechanisms of action of antifungal agents on the vital activity of cell structures using confocal laser scanning microscopy. Stained with propidium iodide and acridine orange for 15 min to reveal the difference between the intact and damaged cell surface of the fungus. It was found that as part of the biofilm cells retained vitality under the influence of high concentrations of substances. In addition, despite the fungicidal activity of the drug in significant concentrations on the cell membrane of the biofilm, the cell nuclei remained viable. In connection with the mechanism of resistance in mycelial fungi shown in the study, it is necessary to take into account and study the characteristics of biofilms in relation to sensitivity to drugs, which will optimize the choice of antimicrobial therapy.