Diagnosis of invasive fungal diseases in pediatric patients

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Novel Insights into Fungal Infections Prophylaxis and Treatment in Pediatric Patients with Cancer

Invasive fungal diseases (IFDs) are a relevant cause of morbidity and mortality in children with cancer. Their correct prevention and management impact patients’ outcomes. The aim of this review is to highlight the rationale and novel insights into antifungal prophylaxis and treatment in pediatric patients with oncological and hematological diseases. The literature analysis showed that IFDs represent a minority of cases in comparison to bacterial and viral infections, but their impact might be far more serious, especially when prolonged antifungal therapy or invasive surgical treatments are required to eradicate colonization. A personalized approach is recommended since pediatric patients with cancer often present with different complications and require tailored therapy. Moreover, while the Aspergillus infection rate does not seem to increase, in the near future, new therapeutic recommendations should be required in light of new epidemiological data on Candidemia due to resistant species. Finally, further studies on CAR-T treatment and other immunotherapies are needed in patients with unique needs and the risk of complications. Definitive guidelines on IFD treatment considering the evolving epidemiology of antifungal resistance, new therapeutic approaches in pediatric cancer, novel antifungal drugs and the importance of an appropriate antifungal stewardship are urgently needed.

Comparison of Direct Sequencing with Real-time PCR High Resolution Melt and PCR Restriction Fragment Length Polymorphism Analysis to Identify Clinically Important Candida Species

Background: Candida albicans is the predominant yeast reported from human infection. Non-albicans Candida species have been recently developed as medically vital fungi. Therefore, it is essential to detect and identify the pathogens at the species level to prescribe appropriate treatment. Methods: This study assessed two complementary methods, including real-time polymerase chain reaction-high resolution melt (PCR-HRM) and polymerase chain reaction-restriction fragment length morphism (PCR-RFLP) with standard PCR and Sanger sequencing as the benchmark. Results: In total, 66 samples were tested, and two newly-advanced assays were more effective and displayed comprehensive concordance (66/66, 100%) with Sanger sequencing outcomes. Moreover, accurate and economical tests were positively advanced by real-time PCR-HRM for C. albicans and C. parapsilosis complexes. Conclusions: Given the number of studies performed on the comparison of sensitivity and specificity of phenotypic and genotypic methods to diagnose and identify invasive fungal pathogens and the findings of this study, it could be stated that the correlative PCR-HRM and PCR-RFLP methods were effectively advanced as substitutes for conventional Sanger sequencing for the reasonable identification. However, supplementary evaluations and confirming studies should be carried out with a broad range of samples to standardize this method for routine application in medical laboratories.

The role of galactomannan test results in the diagnosis of pediatric invasive aspergillosis

BACKGROUND

Invasive aspergillosis (IA) is an important cause of morbidity and mortality in immunosuppressed children. Early detection of the infection can improve prognosis in this patient population.

OBJECTIVES

To investigate the utility of Aspergillus galactomannan antigen assay (GM-EIA) as a diagnostic tool for IA in at-risk paediatric patients.

PATIENTS/METHODS

For the study, 659 GM-EIA results from 59 patients diagnosed with IA and 3368 GM-EIA results from 351 subjects without evidence for IA (controls) were reviewed retrospectively. Three cut-off values (i.e. ≥0.5, ≥1, ≥1.5) were specified to determine GM-EIA positivity.

RESULTS

The median age was 6.3 years for boys and 14.5 years for girls. There was a significant difference between the girls and boys in terms of age (p < 0.01). For proven/probable/possible IA patients, sensitivity of 67.8% and specificity of 59.8% were detected when the ≥0.5 cut-off value was used for GM-EIA-positivity. The specificity increased to 80% at the cut-off of ≥1 and to 88% at the cut-off of ≥1.5. False positivity rates were 9.14, 3, and 1.45% at the ≥0.5, ≥1 and ≥1.5 cut-offs respectively. In the proven/probable IA group, sensitivity and negative predictive values were 86.9 and 97.2% at the ≥0.5 cut-off, 85.7 and 97.9%, at the ≥1 cut-off and 84.2 and 98.1% at ≥1.5 cut-off respectively. The positive likelihood ratio was 7.57 and the odds ratio was 42.67 at ≥1.5 cut-off.

CONCLUSION

The GM-EIA may be used for both screening and diagnostic purposes in paediatric patients using a cut-off value of ≥1.5 for GM-EIA positivity.

Invasive Fungal Infections in Immunocompromised Children: Novel Insight Following a National Study

OBJECTIVE

To obtain a national overview of the epidemiology and management of invasive fungal infections (IFIs) in France for severely immunocompromised children who were treated for acute leukemia or had undergone allogeneic hematopoietic stem cell transplantation (a-HSCT).

STUDY DESIGN

We performed a national multicenter retrospective study to collect epidemiologic data for proven and probable IFIs in children with acute leukemia under first- line or relapse treatment or who had undergone a-HSCT. We also conducted a prospective practice survey to provide a national overview of IFI management in pediatric hematology units.

RESULTS

From January 2014 to December 2017, 144 cases of IFI were diagnosed (5.3%) in 2721 patients, including 61 cases of candidiasis, 60 cases of aspergillosis, and 23 cases of infection with "emergent" fungi, including 10 cases of mucormycosis and 6 cases of fusariosis. The IFI rate was higher in patients with acute myelogenous leukemia (12.9%) (OR, 3.24; 95% CI, 2.15-4.81; P < .0001) compared with the rest of the cohort. Patients undergoing a-HSCT had an IFI rate of only 4.3%. In these patients, the use of primary antifungal prophylaxis (principally fluconazole) was associated with a lower IFI rate (OR, 0.28; 95% CI, 0.14-0.60; P = 4.90 ×10^-4) compared with a-HSCT recipients who did not receive antifungal prophylaxis. The main cause of IFI in children receiving prophylaxis was emergent pathogens (41%), such as mucormycosis and fusariosis, which were resistant to the prophylactic agents.

CONCLUSIONS

The emerging fungi and new antifungal resistance profiles uncovered in this study should be considered in IFI management in immunocompromised children.

Assessment of Serum Galactomannan Test Results of Pediatric Patients With Hematologic Malignancies According to Consecutive Positivity and Threshold Level in Terms of Invasive Aspergillosis Diagnosis: Cross-Sectional Research in a Tertiary Care Hospital

The aim of this study was to evaluate the diagnostic utility of serum galactomannan (GM) positivity for invasive aspergillosis (IA) in children. Positive GM results between January 2015 and August 2017 were reviewed retrospectively in children with hematologic malignancies. Single and consecutive positive GM results were evaluated according to the different galactomannan index (GMI) (>0.5, >0.7, >1.0 and >1.5) values. There were 104 positive GM results of 70 patients. IA was identified in 29 patients (41.4%) (2 proven and 27 probable). For a single positive GMI of >0.5, >0.7, >1.0, and >1.5, the numbers were 104, 76, 57, and 32 and the positive predictive values (PPVs) were 39.4%, 43.2%, 47.2%, and 50.0%, respectively. The single GM positivity at different thresholds showed no difference between the IA and non-IA group (P>0.05). For 2 consecutive positive GMI values of >0.5, >0.7, >1.0, and >1.5, the numbers were 34, 20, 13, and 4, and the PPVs were 58.8%, 65.0%, 84.6%, and 100.0%, respectively. In the IA group, positivity was higher at all thresholds (P<0.05). According to our findings, consecutive GM positivity has higher PPVs independently from the cutoff value chosen. In pediatric patients with high risk, consecutive sampling should be preferred.

Neonatal Antifungal Consumption Is Dominated by Prophylactic Use; Outcomes From The Pediatric Antifungal Stewardship: Optimizing Antifungal Prescription Study

BACKGROUND

Diagnostic challenges combined with the vulnerability of neonates to develop invasive candidiasis (IC) may lead to antifungal administration in the absence of IC. A modified point-prevalence study was performed to obtain an improved insight and understanding of antifungal prescribing in this specific patient population.

METHODS

Neonates and infants ≤90 days of age receiving systemic antifungals from 12 centers in England were included. Data were collected prospectively during 26 consecutive weeks and entered into an online REDCap database.

RESULTS

Two hundred eighty neonates and infants were included, the majority ≤1 month of age (68.2%). Prematurity was the commonest underlying condition (68.9%). Antifungals were prescribed for prophylactic reason in 79.6%; of those, 64.6% and 76.3% were extreme low birth weight infants and prematurely born neonates, respectively. Additional risk factors were present in almost all patients, but only 44.7% had ≥3 risk factors rendering them more susceptible to develop IC. Nonpremature and non extremely low birth weight premature infants only scored ≥3 risk factors in 32.6% and 15%, respectively. Fluconazole was the most common antifungal used (76.7% of all prescriptions), and commonly underdosed as treatment. The number of microbiologic proven IC was low, 5.4%.

CONCLUSIONS

Neonatal antifungal prophylaxis is commonly prescribed outside the recommendations based on known risk profiles. Fluconazole is the main antifungal prescribed in neonates and infants, with underdosing frequently observed when prescribed for treatment. Number of proven IC was very low. These observations should be taken into consideration to develop a national pediatric Antifungal Stewardship program aiming to guide rational prescribing.

Diagnosis of invasive fungal disease in children: a narrative review

Introduction: Invasive fungal diseases (IFD) represent important causes of morbidity and mortality in pediatrics. Early diagnosis and treatment of IFD is associated with better outcome and this entails the need to use fast and highly sensitive and specific methods that can support clinicians in the management of IFD.Areas covered: A narrative review was performed on conventional diagnostic methods such as culture, microscopy and histopathology are still gold standard but are burdened by a lack of sensitivity and specificity; on the other hand, imaging and noninvasive antigen-based such as beta-D-glucan, galactomannan and molecular biomarkers are the most convenient nonculture methods for diagnosis and monitoring effects of therapy. Aim of the present review is to summarize what is available in these fields at end of the second decade of the third millennium and look for future perspectives.Expert opinion: Promising and useful diagnostic methods have been applied in infectious disease diagnosis in clinical practice or in designing platforms. Unfortunately, most of them are not standardized or validated in pediatric population. However, clinicians should be aware of all innovative diagnostic tools to use in combination with conventional diagnostic methods for a better management of pathology and patient.

Voriconazole Antifungal Prophylaxis in Children With Malignancies: A Nationwide Study

BACKGROUND

Antifungal prophylaxis (AFP) is recommended in at-risk hematology-oncology patients. We evaluated the safety of AFP with voriconazole (VRC) in pediatric hematology/oncology patients.

MATERIALS AND METHODS

A retrospective study of VRC AFP in children with malignancies hospitalized in all 7 Greek pediatric hematology/oncology centers during 2008 to 2012 was conducted. Patients' demographics, outcome, and adverse event (AE) data were recorded.

RESULTS

Four hundred twenty-nine VRC AFP courses in 249 patients (median age 6 y, 55% boys) were studied. The most common underlying diseases were acute lymphoblastic leukemia (51%), non Hodgkin lymphoma (8.6%), and acute myeloid leukemia (7.7%). The median number of VRC courses per patient was 1.7, whereas the median VRC dose was 7 mg/kg (range, 5 to 7 mg/kg) every 12 hours. During the last 2 weeks before AFP, 51% of the patients had received corticosteroids, 43% suffered from severe neutropenia, and 17.3% from mucositis. The median duration of VRC AFP was 17 days (range, 1 to 31 d). A single breakthrough fungemia due to Candida glabrata was recorded. Only 1 patient died due to the underlying disease. The most common AEs reported in 70/429 (16.3%) courses with ≥1 AE were elevated liver enzymes (50%), hypokalemia (24.3%), and ophthalmological disorders (14.3%). The median time of AE onset was 5 days (range, 1 to 21 d). Among 70 AEs reported, 38.5%, 48.4%, and 12.8% were of grade I, II, and III, respectively.

CONCLUSIONS

VRC prophylaxis in pediatric hematology/oncology patients appears to be well tolerated.

Recent advances in the microbiological diagnosis of bloodstream infections

Rapid identification (ID) and antimicrobial susceptibility testing (AST) of the causative agent(s) of bloodstream infections (BSIs) are essential for the prompt administration of an effective antimicrobial therapy, which can result in clinical and financial benefits. Immediately after blood sampling, empirical antimicrobial therapy, chosen on clinical and epidemiological data, is administered. When ID and AST results are available, the clinician decides whether to continue or streamline the antimicrobial therapy, based on the results of the in vitro antimicrobial susceptibility profile of the pathogen. The aim of the present study is to review and discuss the experimental data, advantages, and drawbacks of recently developed technological advances of culture-based and molecular methods for the diagnosis of BSI (including mass spectrometry, magnetic resonance, PCR-based methods, direct inoculation methods, and peptide nucleic acid fluorescence in situ hybridization), the understanding of which could provide new perspectives to improve and fasten the diagnosis and treatment of septic patients. Although blood culture remains the gold standard to diagnose BSIs, newly developed methods can significantly shorten the turnaround time of reliable microbial ID and AST, thus substantially improving the diagnostic yield.

Epidemiology of Invasive Fungal Disease in Children

Considerable progress has been made in the prevention, diagnosis, and management of pediatric patients with invasive fungal disease (IFD). The reported decreasing trend in the incidence of invasive candidiasis (IC) over the past 15 years in both neonates and children has been encouraging. Nevertheless, due to the growing number of immunocompromised children at risk for IFD, this disease continues to be associated with significant morbidity and death and with increased financial burden to the health care system. Therefore, it is important to understand the contemporary epidemiology of IFD. Incidence rates of IFD in children are affected by geographical, population, and time variability. There is an ongoing effort to constantly document and update the incidence of IFD and species distribution among different pediatric populations as a means to direct preventative, diagnostic, and therapeutic resources to the most appropriate subset of patients. Children with a hematologic malignancy or a primary or secondary immunodeficiency, those undergoing solid organ or hematopoietic stem cell transplantation, and premature neonates are the major subsets of pediatric patients at risk of developing IFD. In this review, we focus on fungal disease epidemiology with a specific emphasis on the 2 most common pediatric IFDs, IC and invasive aspergillosis (IA).