Recent Advances in the Detection of Neonatal Candidiasis

Updates in Laboratory Identification of Invasive Fungal Infection in Neonates

Invasive fungal infection (IFI) in immunocompromised neonates is significantly associated with high morbidity and mortality and has become the third most common infection in Neonatal Intensive Care Units. The early diagnosis of IFI for neonatal patients is difficult because of the lack of specific symptoms. The traditional blood culture remains the gold standard in clinical diagnosis for neonatal patients but it requires a long duration, which delays treatment initiation. Detections of fungal cell-wall components are developed for early diagnosis but the diagnostic accuracy in neonates needs to be improved. PCR-based laboratory methods, such as real-time PCR, droplet digital PCR, and the cationic conjugated polymer fluorescence resonance energy transfer (CCP-FRET) system, distinguish the infected fungal species by their specific nucleic acids and show a high sensitivity and specificity. Particularly, the CCP-FRET system, which contains a cationic conjugated polymer (CCP) fluorescent probe and pathogen-specific DNA labeled with fluorescent dyes, could identify multiple infections simultaneously. In the CCP-FRET system, the CCP and fungal DNA fragments can self-assemble into a complex with an electrostatic interaction and the CCP triggers the FRET effect under ultraviolet light to make the infection visible. Here, we summarize the recent laboratory methods for neonatal IFI identification and provide a new perspective for early clinical fungal diagnosis.

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.

Candidemia and invasive candidiasis among hospitalized neonates and pediatric patients

OBJECTIVE

To investigate the epidemiology, treatment, length of stay (LOS) and costs for neonatal and pediatric inpatients with invasive candidiasis (IC).

METHODS

The Cerner Health Facts Database was used to assess inpatients (2005-2014) identified by positive blood or cerebrospinal fluid (CSF) Candida cultures. Log-transformed LOS and cost were examined in candidemia-only patients (n = 191) using multivariable linear regression.

RESULTS

A total of 202 patients had a positive culture (blood: n = 192; CSF: n = 10; both: n = 2). The most prevalent species were C. parapsilosis (n = 70, 34.7%), and C. albicans (n = 66, 32.7%). Mean (SD) age was 5 (5.5) years; 30 (14.9%) patients were <4 months. Comorbidities included sepsis (n = 85, 42.1%), coagulation disorders (n = 57, 28.2%), cancer (n = 64, 31.7%), and low birthweight (n = 26, 12.9%). Antifungals (AFs) included azoles (57.4%), polyenes (28.7%), and echinocandins (35.1%); 20.8% of patients received no AF during their encounter. The mean (SD) cost per encounter was $97,392 ($149,253), with a mean (SD) LOS of 45.6 (59.5) days and 9.9% mortality at discharge. Results were similar across Candida species. In regression analysis, intensive care unit (ICU) exposure, central catheter, sepsis, AF >48 hours prior to index culture, and age <4 months were associated with increased LOS; treatment at a non-teaching hospital was associated with reduced LOS (p < .05). AF use >48 hours before index, in-hospital mortality, Midwest region and ventricular shunt were associated with increased cost (p ≤ .05).

CONCLUSIONS

This analysis confirms the association between pediatric candidemia and increased resource utilization and LOS. Given high observed rates of potential under-treatment, an opportunity may exist to improve AF therapy in this population.

Invasive fungal infection in neonatal intensive care units: a multicenter survey

This study assesses the epidemiology of invasive fungal infection (IFI) in Portuguese Neonatal Intensive Care Units (NICUs) and compares the effectiveness and safety of antifungal therapies. A survey concerning the period 2005-2010 was carried out in NICUs of Greater Lisbon. Among 10 473 admitted neonates, 44 cases were identified, 29 among extreme low birth weight neonates (65.9%). Cumulative incidence rate was 0.42% (95%CI 0.309-0.559). A central vascular catheter was present before IFI in all cases. Candida albicans and Candida parapsilosis were the most frequent isolates. The initial antifungic was fluconazole in 22 cases and liposomal amphotericin B (L-AmB) in 18. Therapy was switched in 10 patients on fluconazole and 3 on L-AmB. Case fatality rate was 11.4% (95%CI 4.39-23.91). No serious adverse drugs reactions (SADRs) or clinical side effects were observed. The knowledge of the local epidemiology helps to identify adequate prophylactic and treatment strategies.

Diagnosis of invasive fungal diseases in pediatric patients

INTRODUCTION

The optimal management of invasive fungal infections (IFIs) in children requires prompt and precise diagnosis that enables timely implementation of appropriate antifungal therapy and decreased use of unnecessary toxic antifungals. Areas covered: Traditional approaches such as culture, microscopy and histopathology remain the gold standard but are often not sufficiently sensitive and specific. These limitations have led to the development of alternative non-invasive diagnostic methods that in most cases detect fungal components, such as antigens or nucleic acids. To date, galactomannan and 1,3 β-D-glucan assays are the most efficient non-culture methods for diagnosis and monitoring of antifungal therapy. New technologies from nano-sciences are applied, like T2Candida assay. However, these are not standardized or validated in children. Herein, we focus on IFI diagnosis emphasizing current perspectives, interpretation difficulties, and need for further evaluation in pediatrics. Expert commentary: The new diagnostic tools may enhance diagnostic capacity in combination with traditional methods.

Use of Fungal Diagnostics and Therapy in Pediatric Cancer Patients in Resource-Limited Settings

Fungal diseases are an important cause of mortality in immunocompromised hosts, and their incidence in pediatric cancer patients in low- to middle-income countries is underestimated. In this review, we present relevant, up-to-date information about the most common opportunistic and endemic fungal diseases among children with cancer, their geographic distribution, and recommended diagnostics and treatment. Efforts to improve the care of children with cancer and fungal disease must address the urgent need for sustainable and cost-effective solutions that improve training, fungal disease testing capability, and the use of available resources. We hope that the collective information presented here will be used to advise healthcare providers, regional and country health leaders, and policymakers of the current challenges in diagnosing and treating fungal infections in children with cancer in low- to middle-income countries.

Recommendations for the management of candidemia in neonates in Latin America. Latin America Invasive Mycosis Network

Candidemia is one of the most frequent opportunistic mycoses worldwide. Limited epidemiological studies in Latin America indicate that incidence rates are higher in this region than in the Northern Hemisphere. Diagnosis is often made late in the infection, affecting the initiation of antifungal therapy. A more scientific approach, based on specific parameters, for diagnosis and management of candidemia in Latin America is warranted. 'Recommendations for the diagnosis and management of candidemia' are a series of manuscripts that have been developed by members of the Latin America Invasive Mycosis Network. They aim to provide a set of best-evidence recommendations for the diagnosis and management of candidemia. This publication, 'Recommendations for the management of candidemia in neonates in Latin America', was written to provide guidance to healthcare professionals on the management of neonates who have, or who are at risk of, candidemia. Computerized searches of existing literature were performed by PubMed. The data were extensively reviewed and analyzed by members of the group. The group also met on two occasions to pose questions, discuss conflicting views, and deliberate on a series of management recommendations. 'Recommendations for the management of candidemia in neonates in Latin America' includes prophylaxis, empirical therapy, therapy for proven candidemia, patient work-up following diagnosis of candidemia, central venous catheter management, and management of complications. This manuscript is the fourth of this series that deals with diagnosis and treatment of invasive candidiasis. Other publications in this series include: 'Recommendations for the diagnosis of candidemia in Latin America', 'Recommendations for the management of candidemia in adults in Latin America', and 'Recommendations for the management of candidemia in children in Latin America'.

[Recommendations for the management of candidemia in neonates in Latin America. Grupo Proyecto Épico]

Candidemia is one of the most frequent opportunistic mycoses worldwide. Limited epidemiological studies in Latin America indicate that incidence rates are higher in this region than in the Northern Hemisphere. Diagnosis is often made late in the infection, affecting the initiation of antifungal therapy. A more scientific approach, based on specific parameters, for diagnosis and management of candidemia in Latin America is warranted. 'Recommendations for the diagnosis and management of candidemia' are a series of manuscripts that have been developed by members of the Latin America Invasive Mycosis Network. They aim to provide a set of best-evidence recommendations for the diagnosis and management of candidemia. This publication, 'Recommendations for the management of candidemia in neonates in Latin America', was written to provide guidance to healthcare professionals on the management of neonates who have, or who are at risk of, candidemia. Computerized searches of existing literature were performed by PubMed. The data were extensively reviewed and analyzed by members of the group. The group also met on two occasions to pose questions, discuss conflicting views, and deliberate on a series of management recommendations. 'Recommendations for the management of candidemia in neonates in Latin America' includes prophylaxis, empirical therapy, therapy for proven candidemia, patient work-up following diagnosis of candidemia, central venous catheter management, and management of complications. This manuscript is the fourth of this series that deals with diagnosis and treatment of invasive candidiasis. Other publications in this series include: 'Recommendations for the diagnosis of candidemia in Latin America', 'Recommendations for the management of candidemia in adults in Latin America', and 'Recommendations for the management of candidemia in children in Latin America'.

Fungal diagnostics: review of commercially available methods

Fungi and yeasts are critical causes of acute infection. As such, the detection and identification of these organisms are crucial in the diagnosis of affected patient populations. There is a vast array of commercial tests currently available for diagnostic purposes. These vary from traditional culture and biochemical methods to advanced multiparameter molecular tests. Recent technological advances have driven the development of rapid tests which are complementing and in some cases replacing the more traditional methods of detection. Irrespective of the method used the ultimate goal is timely detection of the infectious agent allowing appropriate treatment and improved outcome for the patient.

Neonatal invasive candidiasis in Tunisian hospital: incidence, risk factors, distribution of species and antifungal susceptibility

The aim of our study was to assess epidemiological features of neonatal invasive candidiasis in Farhat Hached hospital of Sousse, Tunisia, including incidence, risk factors, mortality, species distribution and antifungal susceptibility. Laboratory data from 1995 to 2010 and medical records of 127 invasive candidiasis cases were reviewed. We tested the susceptibility of 100 Candida sp isolates by using ATB fungus(®) 3 and to fluconazole by using E-test(®) strips. A total of 252 cases of neonatal invasive candidiasis occurred over the study period. The incidence increased 1.8-fold from 1995 to 2006 and decreased fourfold from 2007 to 2010. Candida albicans was the predominant species up to 2006 and a shift in the species spectrum was observed with increase of the non-albicans species mainly C. parapsilosis. The agreement between the ATB Fungus(®) and the E-test(®) for determining fluconazole susceptibility was high. All tested isolates were susceptible to fluconazole, flucytosine, amphotéricine B and voriconazole and the itraconazole resistance rate was 5%. The mortality rate was 63%. The invasive candidiasis incidence increased from 1995 to 2006 and decreased from 2007 to 2010. The spectrum of Candida species and the lack of fluconazole-resistant strains argue for the usefulness of fluconazole as an empiric treatment.

Evaluation of a digital microfluidic real-time PCR platform to detect DNA of Candida albicans in blood

Species of Candida frequently cause life-threatening infections in neonates, transplant and intensive care unit (ICU) patients, and others with compromised host defenses. The successful management of systemic candidiasis depends upon early, rapid diagnosis. Blood cultures are the standard diagnostic method, but identification requires days and less than half of the patients are positive. These limitations may be eliminated by using real-time polymerase chain reaction (PCR) to detect Candida DNA in the blood specimens of patients at risk. Here, we optimized a PCR protocol to detect 5-10 yeasts in low volumes of simulated and clinical specimens. We also used a mouse model of systemic candidiasis and determined that candidemia is optimally detectable during the first few days after infection. However, PCR tests are often costly, labor-intensive, and inconvenient for routine use. To address these obstacles, we evaluated the innovative microfluidic real-time PCR platform (Advanced Liquid Logic, Inc.), which has the potential for full automation and rapid turnaround. Eleven and nine of 16 specimens from individual patients with culture-proven candidemia tested positive for C. albicans DNA by conventional and microfluidic real-time PCR, respectively, for a combined sensitivity of 94%. The microfluidic platform offers a significant technical advance in the detection of microbial DNA in clinical specimens.

Clinical practice: Obstructive renal candidiasis in infancy

Renal candidiasis is an increasingly common condition affecting predominantly premature infants receiving neonatal intensive care or term infants with urogenital tract anomalies. Multiple risk factors are usually present. Although rare, some infants develop an obstructive uropathy due to fungal balls, and this requires prompt detection and intervention to preserve kidney function. The management of obstructive renal bezoars is challenging and not well summarised in the past. This is mainly due to scarce literature confined to case reports or case series only. This review clarifies various definitions used in relation to renal candidiasis and identifies infants particularly at risk of obstruction. Clinical presentation, diagnosis and the role of imaging are discussed. A summary of the recent literature is provided to outline the range of existing treatment options available with published drug dosages and mode of delivery used. No single approach is successful in all cases and clinicians need to be aware of the different options available: apart from adequate urinary drainage and use of systemic +/- local antifungal agents, additional treatment with fibrinolytic agents and/or endoscopic or open surgical removal may be required. A new simplified algorithm for use in management is proposed. We hope this review will help clinicians in their management of patients presenting with this complex and challenging diagnosis.