Taxonomy of Candida parapsilosis complex isolated from neonates and the role of Hsp90 inhibitors to enhanced the antifungal activity of micafungin.

Species from Candida parapsilosis complex are frequently found in neonatal candidemia. The antifungal agents to treat this infection are limited and the occurrence of low in vitro susceptibility to echinocandins such as micafungin has been observed. In this context, the chaperone Hsp90 could be a target to reduce resistance. Thus, the objective of this research was to identify isolates from the C. parapsilosis complex and verify the action of Hsp90 inhibitors associated with micafungin. The fungal identification was based on genetic sequencing and mass spectrometry. Minimal inhibitory concentrations were determined by broth microdilution method according to Clinical Laboratory and Standards Institute. The evaluation of the interaction between micafungin with Hsp90 inhibitors was realized using the checkerboard methodology. According to the polyphasic taxonomy, C. parapsilosis sensu stricto was the most frequently identified, followed by C. orthopsilosis and C. metapsilosis, and one isolate of Lodderomyces elongisporus was identified by genetic sequencing. The Hsp90 inhibitor geladanamycin associated with micafungin showed a synergic effect in 31.25% of the isolates, a better result was observed with radicicol, which shows synergic effect in 56.25% tested yeasts. The results obtained demonstrate that blocking Hsp90 could be effective to reduce antifungal resistance to echinocandins.

Multiparametric Flow Cytometry for Determination of Viability, Caspase 3 and 7 Activity, and Lipid Peroxidation Adduct (4-Hydroxynonenal) in Equine Spermatozoa.

Flow cytometry is a powerful tool for the analysis of cell samples formed of multipopulations, such as spermatozoa. In recent years, multiparametric cytometers have evolved, allowing the study of different cellular characteristics, such as protein expression, DNA analysis, or mitochondrial activity. Whether using traditional fluorescent dyes or fluorophore-conjugated antibodies, each cell or cellular component is individually stained, the sample is analyzed at high velocities, and then is displayed and interpreted in a dot-plot. We hereby describe the procedure to perform a multiparametric flow cytometry analysis in equine spermatozoa using three sources of excitation and polychromatic flow cytometry for the detection of 4HNE, a lipid peroxidation adduct (by anti-4HNE antibody), apoptotic markers (by caspases 3 and 7 activity), and live/dead spermatozoa (by ethidium-homodimer) excluding the debris with Hoechst 33342 staining and gating. This multiparametric analysis allows the simultaneous detection of different spermatic parameters, providing useful information for the characterization of a seminal sample and fertility estimation. © 2023 Wiley Periodicals LLC. Basic Protocol: Determination of viability, caspase 3 and 7 activity, and 4-hydroxynonenal in equine spermatozoa by flow cytometry.

Candidemia in Brazilian neonatal intensive care units: risk factors, epidemiology, and antifungal resistance.

Candidemia is responsible for substantial morbidity and mortality in neonatal intensive care units and represents a challenge due to the complexity of hospitalized neonates, the deficiency in approved and precise diagnostic techniques, and the increasing number of species resistant to antifungal agents. Thus, the objective of this study was to detect candidemia among neonates evaluating the risk factors, epidemiology, and antifungal susceptibility. Blood samples were obtained from neonates with suspected septicemia, and the mycological diagnosis was based on yeast growth in culture. The fungal taxonomy was based on classic identification, automated system, and proteomic, when necessary molecular tools were used. The in vitro susceptibility tests were performed according to the broth microdilution method from Clinical and Laboratory Standards Institute. Statistical analysis was performed using the R software version R-4.2.2. The prevalence of neonatal candidemia was 10.97%. The major risk factors involved were previous use of parenteral nutrition, exposure to broad-spectrum antibiotics, prematurity, and prior use central venous catheter, but only this last was statistically associated with mortality risk. Species from Candida parapsilosis complex and C. albicans were the most frequent. All isolates were susceptible to amphotericin B, except C. haemulonii that also exhibited elevated MICs to fluconazole. C. parapsilosis complex and C. glabrata exhibit the highest MICs to echinocandins. Considering these data, we emphasize that an effective management strategy to reduce the impact of neonatal candidemia should involve the knowledge of risk factors, rapid and precise mycological diagnostic, and tests of antifungal susceptibility to help in the selection of an appropriate treatment.

Invasive infection due to Saprochaete capitata in a young patient with hematological malignancies.

We report a case of invasive infection due to Saprochaete capitata in a patient with hematological malignancies after chemotherapy treatment and empiric antifungal therapy with caspofungin. Although severely immunocompromised the patient survived been treated with amphotericin B lipid complex associated with voriconazole.

Fungemia by Candida pelliculosa (Pichia anomala) in a neonatal intensive care unit: a possible clonal origin.

Neonatal candidemia can occur, however, infections caused by Candida pelliculosa are rare. Here, we describe an outbreak of candidemia caused by C. pelliculosa among babies hospitalized in a neonatal intensive care unit.

Pulmonary infection due to Pseudozyma aphidis in a patient with Burkitt lymphoma: first case report.

Fungal infections are being increasingly reported in patients with malignancies. Pseudozyma aphidis is an opportunistic yeast usually isolated from plants and rarely from human samples. In this study, we report the first case of pulmonary infection due to P. aphidis in a Burkitt lymphoma patient.

The mitochondria of stallion spermatozoa are more sensitive than the plasmalemma to osmotic-induced stress: role of c-Jun N-terminal kinase (JNK) pathway.

Cryopreservation introduces extreme temperature and osmolality changes that impart lethal and sublethal effects on spermatozoa. Additionally, there is evidence that the osmotic stress induced by cryopreservation causes oxidative stress to spermatozoa. The main sources of reactive oxygen species in mammalian sperm are the mitochondria. In view of this, the aim of our study was to test whether or not osmotic stress was able to induce mitochondrial damage and to explore the osmotic tolerance of the mitochondria of stallion spermatozoa. Ejaculates from 7 stallions were subjected to osmolalities ranging from 75 to 1500 mOsm/kg, and the effect on sperm membrane integrity and mitochondrial membrane potential was studied. Additionally, the effects of changes in osmolality from hyposmotic to isosmotic and from hyperosmotic to isosmotic solutions were studied (osmotic excursions). The cellular volume of stallion spermatozoa under isosmotic conditions was 20.4 ± 0.33 µm(3). When exposed to low osmolality, the stallion spermatozoa behaved like a linear osmometer, whereas exposure to high osmolalities up to 900 mOsm/kg resulted in decreased sperm volume. Although sperm membranes were relatively resistant to changes in osmolality, mitochondrial membrane potential decreased when osmolalities were low or very high (10.7 ± 1.74 and 16.5 ± 1.70 at 75 and 150 mOsm/kg, respectively, and 13.1 ± 1.83 at 1500 mOsm/kg), whereas in isosmolar controls the percentage of stallion sperm mitochondria with a high membrane potential was 41.1 ± 1.69 (P < .01). Osmotic excursions induced greater damage than exposure of spermatozoa to a given nonphysiologic osmolality, and again the mitochondria were more prone to damage induced by osmotic excursions than was the sperm plasma membrane. In search of intracellular components that could mediate these changes, we have detected for the first time the c-Jun N-terminal kinase 1/2 in stallion spermatozoa, which are apparently involved in the regulation of the viability of these cells.

Invasive infection in an acute myeloblastic leukemia patient due to triazole-resistant Candida tropicalis.

Non-albicans Candida species are being increasingly reported as causes of nosocomial fungal infections. For example, invasive candidiasis caused by C. tropicalis has been associated with hematologic malignancies. In this study, we report a fatal case of fungemia and a possible urinary and pulmonary infection in a leukemia patient that was due to a strain of C. tropicalis resistant to 2 triazole antifungals.