Diagnosis of invasive fungal diseases in haematology and oncology: 2018 update of the recommendations of the infectious diseases working party of the German society for hematology and medical oncology (AGIHO)

Detecting Azole-Antifungal Resistance in Aspergillus fumigatus by Pyrosequencing

Guidelines on the diagnosis and management of Aspergillus disease recommend a multi-test approach including CT scans, culture, fungal biomarker tests, microscopy and fungal PCR. The first-line treatment of confirmed invasive aspergillosis (IA) consists of drugs in the azole family; however, the emergence of azole-resistant isolates has negatively impacted the management of IA. Failure to detect azole-resistance dramatically increases the mortality rates of azole-treated patients. Despite drug susceptibility tests not being routinely performed currently, we suggest including resistance testing whilst diagnosing Aspergillus disease. Multiple tools, including DNA sequencing, are available to screen for drug-resistant Aspergillus in clinical samples. This is particularly beneficial as a large proportion of IA samples are culture negative, consequently impeding susceptibility testing through conventional methods. Pyrosequencing is a promising in-house DNA sequencing method that can rapidly screen for genetic hotspots associated with antifungal resistance. Pyrosequencing outperforms other susceptibility testing methods due to its fast turnaround time, accurate detection of polymorphisms within critical genes, including simultaneous detection of wild type and mutated sequences, and—most importantly—it is not limited to specific genes nor fungal species. Here we review current diagnostic methods and highlight the potential of pyrosequencing to aid in a diagnosis complete with a resistance profile to improve clinical outcomes.

Detection of the 'Big Five' mold killers of humans: Aspergillus, Fusarium, Lomentospora, Scedosporium and Mucormycetes

Fungi are an important but frequently overlooked cause of morbidity and mortality in humans. Life-threatening fungal infections mainly occur in immunocompromised patients, and are typically caused by environmental opportunists that take advantage of a weakened immune system. The filamentous fungus Aspergillus fumigatus is the most important and well-documented mold pathogen of humans, causing a number of complex respiratory diseases, including invasive pulmonary aspergillosis, an often fatal disease in patients with acute leukemia or in immunosuppressed bone marrow or solid organ transplant recipients. However, non-Aspergillus molds are increasingly reported as agents of disseminated diseases, with Fusarium, Scedosporium, Lomentospora and mucormycete species now firmly established as pathogens of immunosuppressed and immunocompetent individuals. Despite well-documented risk factors for invasive fungal diseases, and increased awareness of the risk factors for life-threatening infections, the number of deaths attributable to molds is likely to be severely underestimated driven, to a large extent, by the lack of readily accessible, cheap, and accurate tests that allow detection and differentiation of infecting species. Early diagnosis is critical to patient survival but, unlike Aspergillus diseases, where a number of CE-marked or FDA-approved biomarker tests are now available for clinical diagnosis, similar tests for fusariosis, scedosporiosis and mucormycosis remain experimental, with detection reliant on insensitive and slow culture of pathogens from invasive bronchoalveolar lavage fluid, tissue biopsy, or from blood. This review examines the ecology, epidemiology, and contemporary methods of detection of these mold pathogens, and the obstacles to diagnostic test development and translation of novel biomarkers to the clinical setting.

Interactions between immune response to fungal infection and microRNAs: The pioneer tuners

Due to their physiological and biological characteristics, numerous fungi are potentially emerging pathogens. Active dynamicity of fungal pathogens causes life-threatening infections annually impose high costs to the health systems. Although immune responses play crucial roles in controlling the fate of fungal infections, immunocompromised patients are at high risk with high mortality. Tuning the immune response against fungal infections might be an effective strategy for controlling and reducing the pathological damages. MicroRNAs (miRNAs) are known as the master regulators of immune response. These single-stranded tuners (18-23 bp non-coding RNAs) are endogenously expressed by all metazoan eukaryotes and have emerged as the master gene expression controllers of at least 30% human genes. In this review article, following the review of biology and physiology (biogenesis and mechanism of actions) of miRNAs and immune response against fungal infections, the interactions between them were scrutinised. In conclusion, miRNAs might be considered as one of the potential goals in immunotherapy for fungal infections. Undoubtedly, advanced studies in this field, further identifying of miRNA roles in governing the immune response, pave the way for inclusion of miRNA-related immunotherapeutic in the treatment of life-threatening fungal infections.

Comparison of procalcitonin and C-reactive protein as early diagnostic marker for the identification of transplant-related adverse events after allogeneic hematopoietic stem cell transplantation in pediatric patients

PURPOSE

To evaluate serum procalcitonin (PCT) and C-reactive protein (CRP) as diagnostic biomarkers of transplant-related adverse events (TRAE) in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT).

METHODS

This study analyzed PCT and CRP levels of 214 pediatric patients with a median age of 8.5 years (0.4-17.8 years) undergoing allogeneic HSCT with respect to major TRAE.

RESULTS

26 patients (12.1%) did not experience TRAE (control group), and 188 (87.9%) experienced median 2 (range 1-4) TRAE. Median CRP and PCT were highly and significantly increased during sepsis/SIRS and bacteremia (17.24 mg/dl | 6.30 ng/ml; p < 0.0001 vs. prior values), graft rejection (14.73 mg/dl | 3.20 ng/ml; p < 0.0001), and liver GvHD (6.88 mg/dl | 2.29 ng/ml; p < 0.01). Strong CRP increases and slight/minimal/no PCT increases occurred during fungemia (8.85 mg/dl | 0.72 ng/ml; p < 0.001), intestinal GvHD (8.73 mg/dl | 1.06 ng/ml; p < 0.0001), VOD (10.84 mg/dl | 0.59 ng/ml; p < 0.01), mucositis (8.84 mg/dl | 0.81 ng/ml; p < 0.0001), and viremia (3.62 mg/dl; p < 0.0001 | 0.43 ng/ml; below normal limit). During skin GvHD, CRP and PCT were slightly increased (2.03 mg/dl | 0.93 ng/ml; p < 0.0001).

CONCLUSIONS

CRP and PCT did not show congruent changes during TRAE. PCT was a clinically relevant marker for the early detection and differentiation of severe mucositis and sepsis/SIRS and bacteremia during the critical neutropenic period after HSCT. PCT helped to discriminate acute intestinal GvHD from adenovirus viremia and liver GvHD from hepatic VOD. Thus, PCT may be a valuable parameter to enable a prompt and appropriate treatment during these complications, improving patient outcomes.

[Fungal infections]

BACKGROUND

Invasive aspergillosis, mucormycosis, and cryptococcosis are severe opportunistic infections in patients with long phases of neutropenia and also after allogeneic stem cell and organ transplantation. Due to the late appearance of clinical signs and the often poor outcome, these diseases require special attention and proactive interventions.

MATERIAL AND METHODS

Published guidelines and selected current literature were reviewed for this article.

RESULTS

Invasive aspergillosis and mucormycosis are typically observed in the upper and lower airways of severely immunocompromized patients. When invasive fungal diseases are suspected, sectional imaging and, if possible, serological testing should be performed as soon as possible. If imaging or serological tests confirm the suspected diagnosis, pre-emptive antimycotic treatment should be started and further confirmation of the diagnosis sought via microbiological and/or histological investigations. Treatment depends on comedication, comorbidity and risk factors, primarily with voriconazole, isavuconazole and liposomal amphotericin B. With the advent of antiretroviral treatment, a decrease of cryptococcosis cases in people with human immunodeficiency virus was observed; however, increasing cases have been reported in patients with new forms of immunosuppression. Cryptococcus spp. predominantly cause central nervous system infections but also pneumonia and bloodstream infections. Diagnostics include blood and cerebrospinal fluid cultures and antigen tests. First line treatment consists of a combination therapy with amphotericin B and flucytosine.

CONCLUSION

An interdisciplinary approach with microbiologists, infectious diseases specialists and radiologists is needed for diagnostics and treatment of invasive fungal diseases.

Galactomannan and PCR in the Central Nervous System to Detect Invasive Mold Disease - A Retrospective Analysis in Immunocompromised Children

Invasive mold disease (IMD) of the central nervous system (CNS) is a severe infectious complication in immunocompromised patients, but early microbiological diagnosis is difficult. As data on the value of biomarkers in the CNS are scarce, in particular in children, we retrospectively analyzed the performance of galactomannan (GM) and PCR assays in CNS samples of 15 children with proven and probable CNS IMD and of 32 immunocompromised children without fungal infection. Galactomannan in the cerebrospinal fluid (CSF) was assessed in nine of the 15 pediatric patients and was positive in five of them. Polymerase chain reaction (PCR) was performed in eight of the 15 patients and detected nucleic acids from molds in six patients. Galactomannan and PCR in CNS samples were the only positive microbiologic parameter in the CNS in three and two patients, respectively. In four patients, PCR specified the pathogen detected in microscopy. Galactomannan and PCR results remained negative in the CSF of all immunocompromised children without evidence for CNS IMD. Our data suggest that GM and PCR in CNS specimens are valuable additional tools in diagnosing CNS IMD and should be included in the work up of all pediatric patients with suspected mold disease of the CNS.