The aim of this review is to present the increased frequency of influenza-associated invasive pulmonary aspergillosis (IPA) cases reported from several countries. Classic risk factors or additional immunosuppression may not be observed in affected patients. Therefore, influenza-associated IPA might be diagnosed with a delay and consequently result in worse patient outcomes.

The yeast C. auris was first described as a new species in 2009. Since then, this species was recognized as an emerging multi-drug-resistant (MDR) yeast that can cause a wide spectrum of infections, ranging from fungemia to deep-seated infections, especially in intensive care settings. It can be not- or misidentified by commercial identification systems. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has recently been considered as a convenient, rapid and accurate technology in the identification of yeast isolates to species level. A total of 132 clinical isolates, collected from 2015 to 2021 in the National Reference Laboratory of Mycology and Sexually Transmitted Infections were included in the study. The isolates were mainly from patients with candidemia and other specimens from invasive Candida infections. The isolates were identified by standard mycological procedures, the assimilation profile was done by commercially available strips and with the automated VITEK2 Compact system. All the strains were identified with MALDI-TOF MS. Antifungal susceptibility testing was conducted to some of the strains by agar disk-diffusion (according to CLSI M44-A2), E-test and VITEK2. Some of the strains which could not be identified or were misidentified by standard mycological procedures were correctly determined by MALDI-TOF MS. None of them was identified as C. auris. There were no large deviations in the antifungal susceptibility profiles of the tested strains. We assess MALDI-TOF MS as convenient, rapid, cost- effective and accurate technology in the identification of fungal strains which are difficult to determine with the traditional procedures. Up to now, isolation of C. auris has not been reported in Bulgaria.

The incidence of infections caused by Cryptococcus neoformans has increased significantly in recent years, especially in the settings of immune deficiency  (HIV infection transplantation, etc.). Most often after inhalation of spores   dissemination of yeast to the brain parenchyma   occurs, leading to meningitis (meningo-encephalitis). Our clinical case,  is a patient with cryptococcal meningitis after liver   transplantation  , who died despite the onset of antifungal therapy. This is further evidence of the severe prognosis of CNS cryptococcosis, especially in immunocompromised patients.

The review presents common laboratory methods for the diagnosis of the majority of invasive fungal diseases, i. e. candidosis, aspergillosis and cryptococcosis. Some studies reveal an increasing range of the infectious agents such as Trichosporon and endemic fungal pathogens like Histoplasma, Blastomyces and Coccidioides. The most common serological tests for antigen and antibody-detection in body fluids (serum, plasma, bronchoalveolar lavage) are: indirect immunofluorescense, ELISA – Platelia (enzyme linked immunosorbent assay), latex-agglutination, immunodiffusion and molecular techniques like PCR and Real Time PCR. Not only current data on invasive fungal disease diagnostic methods are reviewed, but also studies on new biomarkers and recent discoveries in molecular diagnostics. New molecular approaches are needed to provide faster results.

Nocardia microorganisms are saprophytes, either non-pathogenic or pathogenic, causing nocardiosis. The clinically significant disease  occurs in immunocompromised people, most often as pneumonia with cough, dyspnea, and fever. Antibiotic therapy, which is longer in time, is necessary. The main treatment is with sulfonamides, but the sensitivity of these bacteria varies. Therefore, the antibiotic susceptibility of the respective strain is important to apply combined therapy if needed. The risk of death without treatment is high, especially if the infection disseminates and the brain is involved. Antibacterial prophylaxis is therefore recommended in patients at high risk of nocardiosis. Our clinical case concerns an immunocompromised patient with isolated Nocardia from bronchoalveolar lavage (BAL).