Анализ на наличие патогенных и паразитарных грибов, соскоб

Fungal culture (Candida spp., Aspergillus spp., Cryptococcus spp.) is used to isolate and identify pathogenic yeasts and molds when invasive fungal disease is suspected. The assay confirms infection by growing organisms from clinical material and, for Candida spp., provides antifungal susceptibility results that can guide targeted therapy. It is typically performed alongside faster screening methods (eg, cryptococcal antigen, potassium hydroxide preparation, or PCR) and histopathology to improve diagnostic yield.

Mycoses encompass infections caused by yeasts, molds, and dimorphic fungi. They range from superficial disease confined to skin and mucous membranes (eg, candidal stomatitis) to invasive infections that can involve virtually any organ, including the lungs, central nervous system, cardiac valves, kidneys, and joints. Among invasive fungal pathogens, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus are encountered most often. Invasive infections due to Candida spp., Cryptococcus spp., and Aspergillus spp. frequently arise in the setting of immunosuppression, such as HIV infection, solid-organ or hematopoietic transplantation, or hematologic malignancy. Presentations overlap and are frequently nonspecific (eg, fever, malaise, cough, chest pain, headache), so laboratory methods are central to diagnosis. Culture remains the confirmatory (“gold standard”) approach, whereas preliminary evaluation often relies on faster but less definitive assays, including cryptococcal antigen testing, potassium hydroxide (KOH) preparation for suspected candidiasis, and PCR-based methods for suspected aspergillosis. Growth characteristics vary: Aspergillus spp. may be evident by approximately 48 hours, Cryptococcus spp. by 48–72 hours, and Candida albicans may require up to 1 week or longer. Culture sensitivity depends on specimen type; isolation from blood is uncommon even in disseminated disease, particularly for Aspergillus spp. and sometimes for Candida spp. Prior antifungal therapy (azoles, amphotericin, echinocandins) before sampling can suppress growth and yield false-negative results. Consequently, a negative culture does not exclude invasive mycosis. Interpretation of positive cultures also requires attention to specimen source. Nonsterile sites such as sputum, urine, or bronchial washings can harbor fungi; Candida spp. and Aspergillus spp. may be recovered from respiratory samples in colonized but otherwise healthy individuals. Cryptococcus spp. are not typical human flora but can appear transiently on mucosal surfaces. In contrast, recovery of fungi from normally sterile sites (eg, blood or tissue), particularly in immunosuppressed patients, is pathologic and supports invasive infection. Culture is best integrated with other modalities, especially histopathologic examination of involved tissue.