Fungemia caused by Zygoascus hellenicus in an allogeneic stem cell transplant recipient

Pseudozyma and other non-Candida opportunistic yeast bloodstream infections in a large stem cell transplant center

Non-Candida opportunistic yeasts are emerging causes of bloodstream infection (BSI) in immunocompromised hosts. However, their clinical presentation, management, and outcomes in stem cell transplant (SCT) recipients are not well described. We report the first case to our knowledge of Pseudozyma BSI in a SCT recipient. He had evidence of cutaneous involvement, which has not been previously described in the literature. He became infected while neutropenic and receiving empiric micafungin, which is notable because Pseudozyma is reported to be resistant to echinocandins. He was successfully treated with the sequential use of liposomal amphotericin B and voriconazole. A review of the literature revealed nine reported instances of Pseudozyma fungemia. We performed a retrospective review of 3557 SCT recipients at our institution from January 2000 to June 2015 and identified four additional cases of non-Candida yeast BSIs. These include two with Cryptococcus, one with Trichosporon, and one with Saccharomyces. Pseudozyma and other non-Candida yeasts are emerging pathogens that can cause severe and disseminated infections in SCT recipients and other immunocompromised hosts. Clinicians should have a high degree of suspicion for echinocandin-resistant yeasts, if patients develop breakthrough yeast BSIs while receiving echinocandin therapy.

The Frequency, Antifungal Susceptibility and Enzymatic Profiles of Candida Species Isolated from Neutropenic Patients

BACKGROUND

Neutropenia, as a predisposing factor for invasive candidiasis, is defined as a reduction in neutrophil count to less than 1500/mm³. It is a common condition in patients with hematological malignancy and cytostatic chemotherapy. Extensive chemotherapy and prophylaxis with antifungals have increased the resistance of Candida isolates to antifungal drugs. Although, Candida albicans is the most common causative agent among neutropenic patients, there is an increasing rate of non-albicans species. Extracellular enzymes activity pattern and antifungal agent sensitivity profiles are two important factors for spreading resistant strains.

OBJECTIVES

The aim of the present study was to identify the Candida strains isolated from hospitalized neutropenic patients. The patterns of antifungal susceptibility of the causative agents to antifungals and the extracellular enzymes activity of the isolates were also evaluated.

PATIENTS AND METHODS

In the present study, 243 urine and 243 oral swab samples were collected from neutropenic patients and inoculated on CHROMagar Candida. In addition, 100 blood samples were also inoculated in biphasic Brain Heart Infusion medium. Several yeast isolates were isolated from samples and identified by classical and molecular techniques. The profiles of extracellular enzymes and the susceptibility of recovered agents to amphotericin B, fluconazole and caspofungin were also evaluated.

RESULTS

A total of 110 yeast strains isolated from urine and oral cavities were identified as C. albicans (51.8%), C. krusei (25.5%), C. glabrata (6.4%) and other yeasts (16.3%). No yeast species was isolated from blood samples. Our result showed that in 90% of the isolates, the range of secretion of extracellular enzymes was medium (2+) and high (3+), however only a few isolates were negative for this characteristic. All isolates were sensitive to caspofungin and fluconazole, whereas 54.7% of isolates were resistant to amphotericin B.

CONCLUSIONS

We found a marked increase in the incidence of non-albicans species (48.2%) among neutropenic patients. Only a few strains failed to produce extracellular enzymes. Finally, in addition to fluconazole, caspofungin can be considered as the first line treatment against Candida species among neutropenic patients.

Candida hellenica var. hellenica as a possible cause of respiratory infection in a child with acute myeloid leukemia

Candida hellenica var. hellenica (teleomorph Zygoascus meyerae) is a member of the genus Zygoascus that comprises species isolated from environmental sources such as damaged grapes. A case of a possible pneumonia due to this uncommon yeast in a pediatric oncology patient suffering from acute myeloid leukemia is described. To our knowledge, this is the first report concerning the isolation of the species from a pediatric patient and the second in humans.