Uncommon mold infections in hematological patients: epidemiology, diagnosis and treatment

Microascus cirrosus SZ 2021: A potentially new genotype of Microascus cirrosus, which can cause fatal pulmonary infection in patients with acute leukemia following haplo‑HSCT

Uncommon Microascus cirrosus (M. cirrosus) species have been reported to cause an increasing number of subcutaneous and invasive fungal infections worldwide; since the first human infection was reported in 1992, seven cases have been reported in PubMed. The present study reports a novel genotype named M. cirrosus SZ 2021 isolated from a patient undergoing hematopoietic stem cell transplantation, who exhibited extensive drug resistance and suffered a fatal pulmonary infection. This isolated M. cirrosus was cultured and determined by morphological observation, multi-locus sequence typing, matrix-assisted laser desorption and ionization time-of-flight mass spectrometry, and whole genome sequencing by next-generation sequencing. The whole nucleotide sequence (32.61 Mb) has been uploaded in the NCBI database (PRJNA835605). In addition, M. cirrosus SZ 2021 was not sensitive to the commonly used antifungal drugs, including fluconazole, amphotericin B, 5-flucytosine and caspofungin. The current literature on human infections by M. cirrosus was reviewed to closely define the comprehensive clinical characteristics and etiological identification. In brief, the present study identified a new M. cirrosus and summarized the clinical characteristics of fungal pneumonia by M. cirrosus species. Complete laboratory identification methods from morphology to gene sequencing were also established for an improved etiological identification and further investigation into the real prevalence of invasive pneumonia by M. cirrosus.

Invasive Fungal Infection in Febrile Patients with Hematologic Malignancies Undergoing Chemotherapy in Iran

BACKGROUND

Patients with hematological malignancies undergoing cytotoxic chemotherapy are susceptible to develop invasive fungal infections particularly Aspergillus and Candida spp. Early detection of these infections is required to start immediate antifungal therapy and increase the survival of these patients.

METHOD

Our study included consecutive patients of any age with hematologic malignancies who were hospitalized to receive chemotherapy and suffer from persistent fever (rectal temperature >38.5°C) for more than 5 days despite receiving broad-spectrum antibiotics. A whole blood sample was taken and sent for blood culture. PCR was also conducted for Aspergillus and Candida species.

RESULTS

One hundred and two patients were investigated according to the inclusion criteria. The most common hematologic malignancy was AML affecting 38 patients (37.2%). Six patients were diagnosed with invasive fungal infections (A. fumigatus n=3, C. albicans n=2, A. flavus n=1) by PCR (5.8%) while blood culture showed fungus only in 1 patient. Three more cases were known as probable IFI since they responded to antifungal therapy but the PCR result was negative for them. AML was the most prevalent malignancy in IFI patients (83.3%) and odds ratio for severing neutropenia was 21.5. Odds for each of the baseline characteristics of patients including gender, age>60, diabetes mellitus, previous IFI, history of using more than 3 antibiotics, antifungal prophylaxis, episodes of chemotherapy> 8 and chemotherapy regimen of daunarubicin+cytarabine were calculated.

CONCLUSION

We found that multiplex real-time PCR assay is more accurate than blood culture in detecting fungal species and the results are prepared sooner. Among all factors, the only type of cancer (AML) and severe neutropenia, were found to be risk factors for the development of fungal infections in all hematologic cancer patients and previous IFI was a risk factor only AML patients.

Evaluation of Mass Spectrometry-Based Detection of Panfungal Serum Disaccharide for Diagnosis of Invasive Fungal Infections: Results from a Collaborative Study Involving Six European Clinical Centers

A mass spectrometry (MS) method that detects a serum disaccharide (DS) (MS-DS) was recently described for the diagnosis of invasive fungal infections (IFI). We carried out a European collaborative study to evaluate this assay. Patients with the following IFI were selected according to the availability of sera obtained at about the time that IFI was documented: invasive candidiasis (IC; n = 26 patients), invasive aspergillosis (IA; n = 19), and mucormycosis (MM; n = 23). Control sera originated from 20 neutropenic patients and 20 patients with bacteremia. MS-DS was carried out in blind manner for the diagnosis of IFI. A diagnosis of IC or IA was confirmed by detection of mannan (Man) or galactomannan (GM), respectively, associated with detection of (1,3)-β-d-glucan (BDG) in both infections. MM was detected by quantitative real-time PCR (qPCR). All tests discriminated sera from patients with IC from sera from control subjects with bacteremia (P ≤ 0.0009). For IC, the MS-DS sensitivity and specificity were 51% and 87%, respectively. MS-DS complemented the high specificity of Man monitoring. All tests discriminated sera from IA patients from sera from neutropenic controls (P ≤ 0.0009). For IA, MS-DS sensitivity and specificity were 64% and 95%, respectively. Only 13/36 serum samples from patients with MM were concordant by MS-DS and qPCR (6 were positive, and 7 were negative); 14 were positive by MS-DS alone. qPCR and MS-DS made a similar contribution to the diagnosis of MM. In patients undergoing long-term monitoring, the persistent circulation of serum disaccharide was observed, whereas DNA was detected only for a short period after initiation of treatment. MS-DS has an important role to play in the early diagnosis of IFI. Its panfungal nature and complementarity with other tests may justify its use in the management of IFI.

Successful salvage chemotherapy and allogeneic transplantation of an acute myeloid leukemia patient with disseminated Fusarium solani infection

Disseminated Fusarium infection is associated with high mortality in immunocompromised patients. Patients with acute myeloid leukemia (AML) often have an extended duration of neutropenia during intensive induction chemotherapy, consolidation chemotherapy, and hematopoietic stem cell transplantation (SCT). There is no consensus regarding management of invasive disseminated Fusarium infections in the setting of prolonged neutropenia (Tortorano et al., 2014) [1]. We report a case of disseminated Fusarium in a patient with relapsed AML who underwent successful chemotherapy and haplo-identical allogeneic SCT with administration of granulocyte colony stimulating factor (G-CSF) and granulocyte infusions.

Fungal Pneumonia in Patients with Hematologic Malignancy and Hematopoietic Stem Cell Transplantation

Fungal pneumonias cause unacceptable morbidity among patients with hematologic malignancies (HM) and recipients of hematopoietic stem cell transplantation (HSCT). The high incidence of fungal pneumonias in HM/HSCT populations arises from their frequently severe, complex, and persistent immune dysfunction caused by the underlying disease and its treatment. The cytopenias, treatment toxicities, and other immune derangements that make patients susceptible to fungal pneumonia frequently complicate its diagnosis and increase the intensity and duration of antifungal therapy. This article addresses the host factors that contribute to susceptibility, summarizes diagnostic recommendations, and reviews current guidelines for management of fungal pneumonia in patients with HM/HSCT.

Cerebral Rhizomucor Infection Treated by Posaconazole Delayed-Release Tablets in an Allogeneic Stem Cell Transplant Recipient

Mucormycosis (zygomycosis) is an emerging fungal disease in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. A 30-year-old woman diagnosed with acute myelomonocytic leukemia and needing allo-HSCT presented pulmonary and cerebral infection due to Rhizomucor pusillus. This fungal infection was treated with surgical treatment and posaconazole delayed-release tablets. This strategy allowed reaching high drug levels that could not be obtained with the posaconazole solution.

Pre-chemotherapy risk factors for invasive fungal diseases: prospective analysis of 1,192 patients with newly diagnosed acute myeloid leukemia (SEIFEM 2010-a multicenter study)

Correct definition of the level of risk of invasive fungal infections is the first step in improving the targeting of preventive strategies. We investigated the potential relationship between pre-hospitalization exposure to sources of fungi and the development of invasive fungal infections in adult patients with newly diagnosed acute myeloid leukemia after their first course of chemotherapy. From January 2010 to April 2012, all consecutive acute myeloid leukemia patients in 33 Italian centers were prospectively registered. Upon first admission, information about possible pre-chemotherapy risk factors and environmental exposure was collected. We recorded data regarding comorbid conditions, employment, hygienic habits, working and living environment, personal habits, hobbies, and pets. All invasive fungal infections occurring within 30 days after the first course of chemotherapy were recorded. Of the 1,192 patients enrolled in this study, 881 received intensive chemotherapy and were included in the present analysis. Of these, 214 developed an invasive fungal infection, including 77 proven/probable cases (8.7%). Of these 77 cases, 54 were proven/probable invasive mold infections (6.1%) and 23 were proven yeast infections (2.6%). Upon univariate analysis, a significant association was found between invasive mold infections and age, performance status, diabetes, chronic obstructive pulmonary disease, smoking, cocaine use, job, hobbies, and a recent house renovation. Higher body weight resulted in a reduced risk of invasive mold infections. Multivariate analysis confirmed the role of performance status, job, body weight, chronic obstructive pulmonary disease, and house renovation. In conclusion, several hospital-independent variables could potentially influence the onset of invasive mold infections in patients with acute myeloid leukemia. Investigation of these factors upon first admission may help to define a patient's risk category and improve targeted prophylactic strategies. (Clinicaltrial.gov: NCT01315925)

Disseminated mucormycosis in a paediatric patient: Lichthemia corymbifera successfully treated with combination antifungal therapy

Mucormycosis is a severe fungal infection that largely affects immunocompromised individuals. It carries a high morbidity and mortality rate and is characterised by extensive angioinvasion and necrosis of host tissue. This case report details success in treating disseminated mucormycosis in a paediatric patient with an underlying haematological malignancy. Treatment included institution of combination antifungal therapy with liposomal amphotericin B and caspofungin, aggressive surgical debridement of infected tissue and reversal of underlying immunosuppression.