Update on the management of Candida infections in preterm neonates

Autopsy-related histomorphological findings in neonatal sepsis: a narrative review

Neonatal sepsis is an important concern in the field of neonatology, contributing significantly to morbidity and mortality among newborns worldwide. Despite progress in medical care, the accurate diagnosis and comprehension of the pathological underpinnings of neonatal sepsis continue to present challenges. Conventional diagnostic autopsy (CDA) provides unique opportunities to gain insights into the histomorphological alterations associated with neonatal sepsis. There is a paucity of literature regarding autopsy-related histomorphological features in neonatal sepsis in various organs. This narrative review aims to glean data from published literature concerning autopsy-related histomorphological findings in neonatal sepsis, which would aid in understanding organ-related pathological changes and assisting pathologists in determining the exact cause of death.

Recent Challenges in Diagnosis and Treatment of Invasive Candidiasis in Neonates

Invasive Candida infections represent a significant cause of morbidity and mortality in the neonatal intensive care unit (NICU), particularly among preterm and low birth weight neonates. The nonspecific clinical presentation of invasive candidiasis, resembling that of bacterial sepsis with multiorgan involvement, makes the diagnosis challenging. Given the atypical clinical presentation and the potential detrimental effects of delayed treatment, empirical treatment is often initiated in cases with high clinical suspicion. This underscores the need to develop alternative laboratory methods other than cultures, which are known to have low sensitivity and a prolonged detection time, to optimize therapeutic strategies. Serum biomarkers, including mannan antigen/anti-mannan antibody and 1,3-β-D-glucan (BDG), both components of the yeast cell wall, a nano-diagnostic method utilizing T2 magnetic resonance, and Candida DNA detection by PCR-based techniques have been investigated as adjuncts to body fluid cultures and have shown promising results in improving diagnostic efficacy and shortening detection time in neonatal populations. This review aims to provide an overview of the diagnostic tools and the current management strategies for invasive candidiasis in neonates. Timely and accurate diagnosis followed by targeted antifungal treatment can significantly improve the survival and outcome of neonates affected by Candida species.

The gut microbiome, resistome, and mycobiome in preterm newborn infants and mouse pups: lack of lasting effects by antimicrobial therapy or probiotic prophylaxis

BACKGROUND

Enhancing our understanding of the underlying influences of medical interventions on the microbiome, resistome and mycobiome of preterm born infants holds significant potential for advancing infection prevention and treatment strategies. We conducted a prospective quasi-intervention study to better understand how antibiotics, and probiotics, and other medical factors influence the gut development of preterm infants. A controlled neonatal mice model was conducted in parallel, designed to closely reflect and predict exposures. Preterm infants and neonatal mice were stratified into four groups: antibiotics only, probiotics only, antibiotics followed by probiotics, and none of these interventions. Stool samples from both preterm infants and neonatal mice were collected at varying time points and analyzed by 16 S rRNA amplicon sequencing, ITS amplicon sequencing and whole genome shotgun sequencing.

RESULTS

The human infant microbiomes showed an unexpectedly high degree of heterogeneity. Little impact from medical exposure (antibiotics/probiotics) was observed on the strain patterns, however, Bifidobacterium bifidum was found more abundant after exposure to probiotics, regardless of prior antibiotic administration. Twenty-seven antibiotic resistant genes were identified in the resistome. High intra-variability was evident within the different treatment groups. Lastly, we found significant effects of antibiotics and probiotics on the mycobiome but not on the microbiome and resistome of preterm infants.

CONCLUSIONS

Although our analyses showed transient effects, these results provide positive motivation to continue the research on the effects of medical interventions on the microbiome, resistome and mycobiome of preterm infants.

The Nonbacterial Microbiome: Fungal and Viral Contributions to the Preterm Infant Gut in Health and Disease

The intestinal microbiome is frequently implicated in necrotizing enterocolitis (NEC) pathogenesis. While no particular organism has been associated with NEC development, a general reduction in bacterial diversity and increase in pathobiont abundance has been noted preceding disease onset. However, nearly all evaluations of the preterm infant microbiome focus exclusively on the bacterial constituents, completely ignoring any fungi, protozoa, archaea, and viruses present. The abundance, diversity, and function of these nonbacterial microbes within the preterm intestinal ecosystem are largely unknown. Here, we review findings on the role of fungi and viruses, including bacteriophages, in preterm intestinal development and neonatal intestinal inflammation, with potential roles in NEC pathogenesis yet to be determined. In addition, we highlight the importance of host and environmental influences, interkingdom interactions, and the role of human milk in shaping fungal and viral abundance, diversity, and function within the preterm intestinal ecosystem.

Antibiotic Resistance and Biofilm Infections in the NICUs and Methods to Combat It

Neonatal sepsis is an important cause of neonatal morbidity and mortality. A significant proportion of bacteria causing neonatal sepsis is resistant to multiple antibiotics, not only to the usual empirical first-line regimens, but also to second- and third-line antibiotics in many neonatal intensive care units (NICUs). NICUs have unique antimicrobial stewardship goals. Apart from antimicrobial resistance, NICUs have to deal with another problem, namely biofilm infections, since neonates often have central and peripheral lines, tracheal tubes and other foreign bodies for a prolonged duration. The aim of this review is to describe traditional and novel ways to fight antibiotic-resistant bacteria and biofilm infections in NICUs. The topics discussed will include prevention and control of the spread of infection in NICUs, as well as the wise use of antimicrobial therapy and ways to fight biofilm infections.

Epidemiology and Drug Resistance of Neonatal Bloodstream Infection Pathogens in East China Children's Medical Center From 2016 to 2020

Introduction

To analyze the pathogen distribution and drug resistance of newborns with bloodstream infection (BSI) to help clinicians choose the appropriate empirical antibiotic therapy for clinical infection control.

Methods

A total of 707 neonatal BSI cases were retrospectively analyzed. The bacteria in blood culture-positive samples were cultured, identified, and analyzed for drug sensitivity by routine methods. Statistical software was used to compare and analyze the basic data, pathogenic information, and drug resistance of the main bacteria.

Results

The 5-year average positive rate of neonatal blood culture was 2.50%. The number of specimens submitted for inspection in 2020 significantly decreased. The top five infectious pathogens with the highest proportion were coagulase-negative Staphylococcus (67.35%), of which Staphylococcus epidermidis had the highest proportion (31.26%), followed by Escherichia coli (12.87%), Klebsiella pneumoniae (9.05%), Streptococcus agalactiae (8.63%), and Staphylococcus aureus (3.25%). Gram-positive (G+) bacteria were dominant, accounting for 69.45%. The main G+ bacteria had a higher rate of resistance to erythromycin and penicillin G. The main Gram-negative (G-) bacteria had a high resistance rate to a variety of antibacterial drugs, especially cephalosporin antibiotics. The overall resistance of K. pneumoniae was higher than that of E. coli. The top two fungi detected were Candida parapsilosis and Candida albicans. C. parapsilosis did not appear to be resistant to antibiotics, while C. albicans was resistant to multiple antibiotics. The type of microbial infection had a statistically significant difference in the positive rate among the age at delivery and wards (p < 0.05). There were significant differences in the detection of fungi among these groups (p < 0.05). The positive rate of G+ bacteria in the term newborns was significantly higher than that in the preterm newborns (p < 0.05). Preterm newborns are more susceptible to pneumonia.

Conclusion

G+ bacteria are the main pathogens of neonatal BSI. Preterm newborns are more likely to be infected with G- bacteria. E. coli and K. pneumoniae are the most common G- bacteria, and both have a high resistance rate to a variety of antibacterial drugs. According to the distribution characteristics and drug resistance, it is very important to select antibiotics reasonably.

Successful fluconazole combined with caspofungin treatment of candida bloodstream infection in preterm infant: A case report

RATIONALE

Candida bloodstream infection continues to be a significant cause of mortality in premature infants. Amphotericin B has been recommended as the primary treatment; however, its use is limited due to drug-induced nephrotoxicity and amphotericin B-resistant candidemia.

PATIENT CONCERNS

The gestational age was 29 (+6) weeks, and birth weight was 1760 g.

DIAGNOSIS

The infant was diagnosed with Candida parapsilosis bloodstream infection.

INTERVENTIONS

Fluconazole, 12 mg/kg/day, combined with caspofungin (loading dose 3 mg/kg, at a maintenance dose of 2 mg/kg every 24 h) therapy was administered to premature infant with Candida bloodstream infection. When fluconazole or caspofungin was used to treat Candida bloodstream infection in preterm infants, the blood cultures of the infant remained positive for Candida parapsilosis.

OUTCOMES

All persistent candidemia resolved on fluconazole combined with caspofungin therapy. There were no adverse effects, hepatotoxicity, nephrotoxicity, anemia, or thrombocytopenia.

LESSONS

Fluconazole combined with caspofungin successfully treated Candida bloodstream infection in premature infants at 29 + 6 weeks' gestational age, but large-scale clinical trials are required.

New Insights Into Microbiota Modulation-Based Nutritional Interventions for Neurodevelopmental Outcomes in Preterm Infants

Gut microbiota and the central nervous system have parallel developmental windows during pre and post-natal life. Increasing evidences suggest that intestinal dysbiosis in preterm infants predisposes the neonate to adverse neurological outcomes later in life. Understanding the link between gut microbiota colonization and brain development to tailor therapies aimed at optimizing initial colonization and microbiota development are promising strategies to warrant adequate brain development and enhance neurological outcomes in preterm infants. Breast-feeding has been associated with both adequate cognitive development and healthy microbiota in preterms. Infant formula are industrially produced substitutes for infant nutrition that do not completely recapitulate breast-feeding benefices and could be largely improved by the understanding of the role of breast milk components upon gut microbiota. In this review, we will first discuss the nutritional and bioactive component information on breast milk composition and its contribution to the assembly of the neonatal gut microbiota in preterms. We will then discuss the emerging pathways connecting the gut microbiota and brain development. Finally, we will discuss the promising microbiota modulation-based nutritional interventions (including probiotic and prebiotic supplementation of infant formula and maternal nutrition) for improving neurodevelopmental outcomes.

Prophylactic Use of Fluconazole in Very Premature Infants

Objective: To evaluate the efficacy, safety, and fungal sensitivity of prophylactic fluconazole use in very premature infants. Methods: We performed a retrospective historical comparative analysis of 196 very premature infants (113 in the prophylaxis group and 83 in the rescue group). The incidence of nosocomial fungal infection (NCFI) and pathogenic fungi, their drug sensitivity, and the minimum inhibitory concentration (MIC) of fluconazole were compared between the two groups. We also analyzed differences in short-term adverse outcomes, such as drug-induced liver or renal function disruption, fungal-attributable death, bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), and necrotizing enterocolitis (NEC), between the groups. The effects of the prophylactic fluconazole strategy on NCFI and short-term adverse outcomes were assessed by multivariate logistic regression. Results: Candida albicans (46.7%) and Candida glabrata (43.3%) were the main culprit pathogens causing NCFI. The incidence of NCFI was significantly lower in the prophylaxis group than in the rescue group (15.9 vs. 45.8%, P < 0.001). However, fewer fungi were completely sensitive to fluconazole (40 vs. 85%, P < 0.05) and the MIC of fluconazole was higher [16.0 (3.5 ~ 16.0) vs. 3.0 (1.0 ~ 8.0) μg/ml, P < 0.001] in the prophylaxis group than in the rescue group. Compared with the rescue group, the prophylaxis group had a lower risk of NCFI (adjusted OR 0.25; 95% CI 0.11, 0.55). Additionally, the prophylaxis group had significantly lower risks of combined outcomes (one or more complications, such as BPD, ROP needing interventions, PVL/IVH (grade > 2), NEC stage ≥2, and fungal-attributable death) (adjusted OR 0.44; 95% CI 0.21, 0.92). There was no significant difference in serum alanine transferase (ALT), aspartate transaminase (AST), creatinine (Cr), or direct bilirubin (DBIL) levels between the two groups. Conclusions: Fluconazole prophylaxis reduced NCFI and improved combined clinical outcomes in very premature infants, with no increased risks of serious short-term adverse side effects; however, the MIC of fluconazole showed significant increases. Therefore, further optimization of preventive strategies is necessary to maintain the sensitivity of fluconazole against fungal isolates.

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.

CoERG11 A395T mutation confers azole resistance in Candida orthopsilosis clinical isolates

Background

Candida orthopsilosis is a human fungal pathogen responsible for a wide spectrum of symptomatic infections. Evidence suggests that C. orthopsilosis is mainly susceptible to azoles, the most extensively used antifungals for treatment of these infections. However, fluconazole-resistant clinical isolates are reported.

Objectives

This study evaluated the contribution of a single amino acid substitution in the azole target CoErg11 to the development of azole resistance in C. orthopsilosis.

Methods

C. orthopsilosis clinical isolates (n = 40) were tested for their susceptibility to azoles and their CoERG11 genes were sequenced. We used a SAT1 flipper-driven transformation to integrate a mutated CoERG11 allele in the genetic background of a fluconazole-susceptible isolate.

Results

Susceptibility testing revealed that 16 of 40 C. orthopsilosis clinical isolates were resistant to fluconazole and to at least one other azole. We identified an A395T mutation in the CoERG11 coding sequence of azole-resistant isolates only that resulted in the non-synonymous amino acid substitution Y132F. The SAT1 flipper cassette strategy led to the creation of C. orthopsilosis mutants that carried the A395T mutation in one or both CoERG11 alleles (heterozygous or homozygous mutant, respectively) in an azole-susceptible genetic background. We tested mutant strains for azole susceptibility and for hot-spot locus heterozygosity. Both the heterozygous and the homozygous mutant strains exhibited an azole-resistant phenotype.

Conclusions

To the best of our knowledge, these findings provide the first evidence that the CoErg11 Y132F substitution confers multi-azole resistance in C. orthopsilosis.

Antifungal Drugs for Invasive Candida Infections (ICI) in Neonates: Future Perspectives

Fungal infections may complicate the neonatal clinical course, and the spectrum of therapies for their treatment in the perinatal period is limited. Polyenes, Azoles and Echinocandins represent the three classes of antifungal drugs commonly used in the neonatal period. The present review provides an overview about the most recent therapeutic strategies for the treatment of fungal infections in neonates.

Genome-resolved metagenomics of eukaryotic populations during early colonization of premature infants and in hospital rooms

BACKGROUND

Fungal infections are a significant cause of mortality and morbidity in hospitalized preterm infants, yet little is known about eukaryotic colonization of infants and of the neonatal intensive care unit as a possible source of colonizing strains. This is partly because microbiome studies often utilize bacterial 16S rRNA marker gene sequencing, a technique that is blind to eukaryotic organisms. Knowledge gaps exist regarding the phylogeny and microdiversity of eukaryotes that colonize hospitalized infants, as well as potential reservoirs of eukaryotes in the hospital room built environment.

RESULTS

Genome-resolved analysis of 1174 time-series fecal metagenomes from 161 premature infants revealed fungal colonization of 10 infants. Relative abundance levels reached as high as 97% and were significantly higher in the first weeks of life (p = 0.004). When fungal colonization occurred, multiple species were present more often than expected by random chance (p = 0.008). Twenty-four metagenomic samples were analyzed from hospital rooms of six different infants. Compared to floor and surface samples, hospital sinks hosted diverse and highly variable communities containing genomically novel species, including from Diptera (fly) and Rhabditida (worm) for which genomes were assembled. With the exception of Diptera and two other organisms, zygosity of the newly assembled diploid eukaryote genomes was low. Interestingly, Malassezia and Candida species were present in both room and infant gut samples.

CONCLUSIONS

Increased levels of fungal co-colonization may reflect synergistic interactions or differences in infant susceptibility to fungal colonization. Discovery of eukaryotic organisms that have not been sequenced previously highlights the benefit of genome-resolved analyses, and low zygosity of assembled genomes could reflect inbreeding or strong selection imposed by room conditions.

Pathology of Neonatal Non- albicans Candidiasis: Autopsy Study and Literature Review

INTRODUCTION/OBJECTIVES

Non- albicans Candida species such as Candida parapsilosis and Candida glabrata have emerged as prevalent pathogens in premature infants. The aim of this study was to systematically delineate the histopathologic findings in neonatal non- albicans candidiasis.

METHODS

We performed a retrospective clinicopathologic analysis of extremely premature (23-28 weeks' gestation) infants diagnosed with invasive candidiasis. Archival autopsy tissues were subjected to periodic acid-Schiff, methenamine-silver and anti- Candida (immuno)histochemical stains, as well as dual anti- Candida and anti-cytokeratin or anti-CD31 immunofluorescence assays. In addition, we studied the prevalence of intestinal Candida colonization in a consecutive autopsy series of extremely premature infants.

RESULTS

Based on positive postmortem blood and/or lung cultures, invasive candidiasis (3 non- albicans and 11 Candida albicans) was diagnosed in 14 of the 187 extremely premature infants examined between 1995 and 2017. In contrast to the well-known inflammatory and tissue-destructive phenotype of congenital C. albicans infection, invasive non- albicans candidiasis/candidemia caused by C. parapsilosis and C. glabrata was inconspicuous by routine hematoxylin-eosin-based histopathologic analysis despite a heavy fungal presence detected in intestines, lungs, and blood by targeted (immuno)histochemical assays. Intestinal colonization by Candida species was identified in 16 of the 26 (61%) extremely premature neonates who had lived for at least 1 week, as assessed by anti- Candida immunostaining.

CONCLUSION

Invasive neonatal non- albicans candidiasis/candidemia appears to have no distinct histopathologic signature. Based on the notoriously low sensitivity of fungal blood cultures and the observed high frequency of Candida intestinal colonization (>50%), it is likely that non- albicans candidiasis/candidemia may be underdiagnosed in (deceased) preterm infants. Routine inclusion of targeted (immuno)histochemical fungal detection strategies in the perinatal autopsy may lead to deeper insight into the prevalence and clinical relevance of neonatal non- albicans candidiasis.

Antifungal Treatment and Outcome in Very Low Birth Weight Infants: A Population-based Observational Study of the German Neonatal Network

BACKGROUND

The diagnostic proof of fungal infection in preterm infants is difficult. Antifungal treatment (AFT) is often initiated empirically when infants with suspected infection do not improve despite broad-spectrum antibiotic therapy. It was the aim of our study to determine the rate of exposure to empirical AFT in a large cohort of very low birth weight infants (VLBWI) of the German Neonatal Network and to address associated risks and outcomes.

METHODS

The epidemiologic database consisted of n = 13,343 VLBWI born in 54 German Neonatal Network centers between 2009 and 2015. AFT was defined as number of neonates who got any dose of at least one of the following antifungal drugs: fluconazole, amphotericin B, voriconazole and caspofungin (denominator: number of infants enrolled in German Neonatal Network) for treatment (not prophylaxis) of (suspected) fungal infection. Univariate and logistic regression analyses were used to identify risk factors for exposure to AFT and associated short-term morbidities and long-term outcomes at 5-year follow-up.

RESULTS

In our cohort, 724 out of 13,343 (5.4%) VLBWI were exposed to empiric AFT and had a mean gestational age of 25.7 (±2.1) weeks. Forty-four out of 13,343 (0.3%) had proven bloodstream infection with Candida spp. The main risk factors for exposure to AFT were gestational age, postnatal steroid treatment, need for abdominal surgery and use of carbapenems. Notably, AFT was associated with adverse outcomes such as bronchopulmonary dysplasia [adjusted odds ratio (OR): 1.9; 95% confidence interval (CI): 1.6-2.3; P < 0.001) and retinopathy of prematurity requiring intervention (adjusted OR: 1.69; 95% CI: 1.3-2.3; P <0.001) but not mortality. In the subgroup of infants available for 5-year follow-up (n = 895), exposure to AFT was associated with a risk for cerebral palsy (adjusted OR: 2.79; 95% CI: 1.11-7.04; P = 0.04) and intelligence quotient < 85 (adjusted OR: 2.07; 95% CI: 1.01-4.28; P = 0.049).

CONCLUSIONS

A significant proportion of VLBWI is exposed to AFT, specifically those born <26 weeks. Exposed infants were found to have a higher risk for adverse outcomes, which may reflect their significant vulnerability in general. Given the observational design of our study, it remains unclear whether potential side effects of empirical or target AFT itself contribute to adverse outcome. Future studies need to include risk-based strategies and stewardship programs to restrict the use of antifungal management in VLBWI.

A Phase 3 Study of Micafungin Versus Amphotericin B Deoxycholate in Infants With Invasive Candidiasis

BACKGROUND

Amphotericin B deoxycholate (AmB-D) is standard of care treatment for neonatal invasive candidiasis (IC). Micafungin (MCA) has broad-spectrum fungicidal activity against Candida spp. We compared the efficacy and safety of intravenous MCA with intravenous AmB-D and assessed the pharmacokinetics of MCA in infants >2-120 days of age with proven IC in a phase 3, randomized, double-blind, multicenter, parallel-group, noninferiority study (NCT00815516).

METHODS

Infants were randomized 2:1 to MCA (10 mg/kg/d) or AmB-D (1 mg/kg/d) for ≥21 days. Primary efficacy endpoint was fungal-free survival (FFS) 1 week after last study drug dose. MCA population pharmacokinetics included simulated area under the curve (AUC) at steady state and maximum plasma concentration after 2-hour infusion. AUC pharmacodynamic target exposure was 170 µg·h/mL.

RESULTS

Thirty infants received MCA (n = 20) or AmB-D (n = 10). The trial was terminated early because of slow recruitment. FFS was observed in 12 of 20 [60%; 95% confidence interval (CI): 36%-81%] MCA-group infants and in 7 of 10 (70%; 95% CI: 35%-93%) AmB-D-group infants. The most common treatment-emergent adverse events were anemia [MCA: n = 9 (45%); AmB-D: n = 3 (30%)] and thrombocytopenia [n = 2 (10%) and n = 3 (30%), respectively]. Model-derived mean AUC at steady state for MCA was 399.3 ± 163.9 µg·h/mL (95% prediction interval: 190.3-742.3 µg/mL); steady state and maximum plasma concentration after 2-hour infusion was 31.1 ± 10.5 µg/mL (95% prediction interval: 17.0-49.7 µg/mL). MCA exposures were above the AUC pharmacodynamic target exposure.

CONCLUSIONS

Within the study limitations, infants with IC treated with MCA achieved similar FFS compared with AmB-D. Both agents were safe and well tolerated.

Pharmacokinetics and safety of fluconazole and micafungin in neonates with systemic candidiasis: a randomized, open-label clinical trial

AIMS

The pharmacokinetics (PK) of fluconazole and micafungin differ in neonates compared with children and adults. Dosing instructions in product labels appear to be inconsistent with the emerging scientific evidence. Limited information is available on the safety profile of these agents in neonates. Our objective was to study the population PK and safety of both drugs, randomly administered in neonates with suspected or confirmed systemic candidiasis.

METHODS

Neonates were randomized 1:1 to fluconazole (loading dose 25 mg kg^-1 ; maintenance dose 12 mg kg^-1 day^-1 or 20 mg kg^-1 day^-1 , respectively, for infants <30 weeks or ≥30 weeks' corrected gestational age) or micafungin (loading dose 15 mg kg^-1 day^-1 ; maintenance dose 10 mg kg^-1 day^-1 ). PK samples were taken on treatment days 1 and 5. Population parameters were determined using NONMEM and Monte Carlo simulations performed to reach predefined targets. Clinical and laboratory data, and adverse events were collected up to 36 weeks' corrected gestational age or hospital discharge.

RESULTS

Thirty-six neonates were enrolled. The median (range) gestational age was 28.2 (24.1-40.1) and 26.8 (23.5-40.0) weeks for fluconazole and micafungin, respectively. Based on 163 PK samples, the median population clearance (l h^-1 kg^-1 ) and volume of distribution (l kg^-1 ) for fluconazole were: 0.015 [95% confidence interval (CI) 0.008, 0.039] and 0.913, and for micafungin were: 0.020 (95% CI 0.010, 0.023) and 0.354 (95% CI 0.225, 0.482), respectively. The loading dose was well tolerated. No adverse events associated with micafungin or fluconazole were reported.

CONCLUSION

Based on Monte Carlo simulations, a loading dose for fluconazole and dosing higher than recommended for both drugs are required to increase the area under the plasma drug concentration-time curve target attainment rate in neonates.

Exposure-Response Analysis of Micafungin in Neonatal Candidiasis: Pooled Analysis of Two Clinical Trials

BACKGROUND

Neonatal candidiasis causes significant morbidity and mortality in high risk infants. The micafungin dosage regimen of 10 mg/kg established for the treatment of neonatal candidiasis is based on a laboratory animal model of neonatal hematogenous Candida meningoencephalitis and pharmacokinetic (PK)-pharmacodynamic (PD) bridging studies. However, little is known about the how these PK-PD data translate clinically.

METHODS

Micafungin plasma concentrations from infants were used to construct a population PK model using Pmetrics software. Bayesian posterior estimates for infants with invasive candidiasis were used to evaluate the relationship between drug exposure and mycologic response using logistic regression.

RESULTS

Sixty-four infants 3-119 days of age were included, of which 29 (45%) infants had invasive candidiasis. A 2-compartment PK model fits the data well. Allometric scaling was applied to clearance and volume normalized to the mean population weight (kg). The mean (standard deviation) estimates for clearance and volume in the central compartment were 0.07 (0.05) L/h/1.8 kg and 0.61 (0.53) L/1.8 kg, respectively. No relationship between average daily area under concentration-time curve or average daily area under concentration-time curve:minimum inhibitory concentration ratio and mycologic response was demonstrated (P > 0.05). Although not statistically significant, mycologic response was numerically higher when area under concentration-time curves were at or above the PD target.

CONCLUSIONS

While a significant exposure-response relationship was not found, PK-PD experiments support higher exposures of micafungin in infants with invasive candidiasis. More patients would clarify this relationship; however, low incidence deters the feasibility of these studies.

Lactoferrin, chitosan and Melaleuca alternifolia-natural products that show promise in candidiasis treatment

The evolution of microorganisms resistant to many medicines has become a major challenge for the scientific community around the world. Motivated by the gravity of such a situation, the World Health Organization released a report in 2014 with the aim of providing updated information on this critical scenario. Among the most worrying microorganisms, species from the genus Candida have exhibited a high rate of resistance to antifungal drugs. Therefore, the objective of this review is to show that the use of natural products (extracts or isolated biomolecules), along with conventional antifungal therapy, can be a very promising strategy to overcome microbial multiresistance. Some promising alternatives are essential oils of Melaleuca alternifolia (mainly composed of terpinen-4-ol, a type of monoterpene), lactoferrin (a peptide isolated from milk) and chitosan (a copolymer from chitin). Such products have great potential to increase antifungal therapy efficacy, mitigate side effects and provide a wide range of action in antifungal therapy.

Fluconazole Doses Used for Prophylaxis of Invasive Fungal Infection in Neonatal Intensive Care Units: A Network Meta-Analysis

OBJECTIVES

To evaluate the safety and efficacy of different doses of fluconazole used for invasive prophylaxis of fungal infection in neonates.

STUDY DESIGN

A systematic search was conducted with PubMed, Scopus, and Web of Science. A manual search was performed as well. Only randomized controlled trials of neonates in a neonatal intensive care unit (NICU) who received fluconazole prophylaxis for invasive fungal infection, regardless of the dose or therapeutic regimen, were included in this review. Data on baseline characteristics, outcomes incidence of proven invasive Candida infection, overall mortality, and invasive Candida infection-related mortality were extracted.

RESULTS

Eleven studies were included in the review, with fluconazole doses of 3, 4, or 6?mg/kg. When the incidence of invasive Candida and invasive Candida-related mortality were considered as outcomes, the 3 and 6?mg/kg fluconazole doses were found to be statistically superior to placebo (OR, 5.48 [95% credible interval, 1.81-18.94] and 2.63 [1.18-7.02], respectively, and 15.32 [1.54-54.31] and 9.14 [1.26-142.7], respectively), but data for the 3 doses were not statistically significantly different.

CONCLUSIONS

Use of the lowest fluconazole dose (3?mg/kg) should be recommended for Candida prophylaxis in neonates, given that increasing the fluconazole dose is not associated with higher efficacy and has greater potential for toxicity and increased cost.

Antifungal Immunological Defenses in Newborns

Newborns are prone to fungal infections, largely due to Candida species. The immunological basis for this vulnerability is not yet fully understood. However, useful insights can be gained from the knowledge of the maturation of immune pathways during ontogeny, particularly when placed in context with how rare genetic mutations in humans predispose to fungal diseases. In this article, we review these most current data on immune functions in human newborns, highlighting pathways most relevant to the response to Candida. While discussing these data, we propose a framework of why deficiencies in these pathways make newborns particularly vulnerable to this opportunistic pathogen.

Infant fungal communities: current knowledge and research opportunities

The microbes colonizing the infant gastrointestinal tract have been implicated in later-life disease states such as allergies and obesity. Recently, the medical research community has begun to realize that very early colonization events may be most impactful on future health, with the presence of key taxa required for proper immune and metabolic development. However, most studies to date have focused on bacterial colonization events and have left out fungi, a clinically important sub-population of the microbiota. A number of recent findings indicate the importance of host-associated fungi (the mycobiota) in adult and infant disease states, including acute infections, allergies, and metabolism, making characterization of early human mycobiota an important frontier of medical research. This review summarizes the current state of knowledge with a focus on factors influencing infant mycobiota development and associations between early fungal exposures and health outcomes. We also propose next steps for infant fungal mycobiome research, including longitudinal studies of mother-infant pairs while monitoring long-term health outcomes, further exploration of bacterium-fungus interactions, and improved methods and databases for mycobiome quantitation.

Reduced PICD in Monocytes Mounts Altered Neonate Immune Response to Candida albicans

Background

Invasive fungal infections with Candida albicans (C. albicans) occur frequently in extremely low birthweight (ELBW) infants and are associated with poor outcome. Phagocytosis of C.albicans initializes apoptosis in monocytes (phagocytosis induced cell death, PICD). PICD is reduced in neonatal cord blood monocytes (CBMO).

Hypothesis

Phagocytosis of C. albicans causes PICD which differs between neonatal monocytes (CBMO) and adult peripheral blood monocytes (PBMO) due to lower stimulation of TLR-mediated immune responses.

Methods

The ability to phagocytose C. albicans, expression of TLRs, the induction of apoptosis (assessment of sub-G1 and nick-strand breaks) were analyzed by FACS. TLR signalling was induced by agonists such as lipopolysaccharide (LPS), Pam3Cys, FSL-1 and Zymosan and blocked (neutralizing TLR2 antibodies and MYD88 inhibitor).

Results

Phagocytic indices of PBMO and CBMO were similar. Following stimulation with agonists and C. albicans induced up-regulation of TLR2 and consecutive phosphorylation of MAP kinase P38 and expression of TNF-α, which were stronger on PBMO compared to CBMO (p < 0.005). Downstream, TLR2 signalling initiated caspase-3-dependent PICD which was found reduced in CBMO (p < 0.05 vs PBMO).

Conclusion

Our data suggest direct involvement of TLR2-signalling in C. albicans-induced PICD in monocytes and an alteration of this pathway in CBMO.

Fungal infections in children in the early postoperative period after cardiac surgery for congenital heart disease: a single-centre experience

OBJECTIVES

Postoperative infections are still an important problem in cardiac surgery, especially in the paediatric population, and may influence the final outcome of congenital heart disease treatment. Postoperative infections with fungi are uncommon. The aetiology is poorly understood, and the proper diagnosis and treatment is unclear. In this single-centre study, the frequency of invasive fungal disease in children who underwent surgical management of congenital heart diseases was determined along with the risk factors for infection, treatment options and outcomes.

METHODS

All consecutive paediatric patients (<18 years of age) who underwent cardiac surgery for congenital heart disease between September 2008 and December 2015 in a paediatric cardiac centre in Poland were identified. Those who developed invasive fungal disease in the early postoperative period (30 days) were identified.

RESULTS

Of the 1540 cardiosurgical procedures for congenital heart disease, 6 were complicated by fungal infection (0.39%). One patient had a high probability of fungal infection, but the diagnosis was unproved. Nevertheless, the patient was successfully treated with antifungal treatment. Five had proven invasive fungal disease. Of these, 3 were diagnosed with candidaemia. All had undergone cardiopulmonary bypass. Of the remaining 2 patients, 1 was a preterm newborn with complete atrioventricular septal defect who developed rib fungal invasion. The remaining patient had pulmonary atresia with ventricular septal defect and developed Fournier's gangrene after surgery. None of the patients died due to infection in the early postoperative period. However, the child with rib fungal invasion died 39 days after surgery as a result of multiorgan failure.

CONCLUSIONS

Fungal infections in paediatric patients after cardiac surgery may markedly influence morbidity and mortality. Fungal infection prophylaxis in this specific group of children may reduce morbidity, whereas early empirical treatment followed by a targeted approach may improve outcomes. The 'hit fast, hit hard' treatment strategy may be the best rescue option for children who develop invasive fungal disease after cardiac surgery.

Severe neonatal infection secondary to prenatal transmembranous ascending vaginal candidiasis

Fungal neonatal infection with Candida is rare, despite a prevalence of vaginal mycosis of up to 30% during pregnancy. Although there are no recommendations to treat asymptomatic vaginal colonization with candida in healthy pregnant women, this case report highlights that asymptomatic colonization with Candida can lead to chorioamnionitis and systemic neonatal infection with leukemoid reaction. Treatment of asymptomatic candida colonization in women at risk of preterm delivery should be considered.