Antifungal susceptibility of Candida spp. isolated from pediatric patients: A survey of 4 children's hospitals

Relationship between posaconazole concentrations and clinical outcomes in paediatric cancer and haematopoietic stem cell transplant recipients

BACKGROUND

Posaconazole is used to prevent and treat invasive fungal infections (IFIs) in immunocompromised children, including those undergoing cancer treatment or HSCT. Despite differences in pharmacokinetics and IFI epidemiology between children and adults, therapeutic targets established in adult studies are often applied to children.

OBJECTIVES

This systematic review evaluated the correlation between serum posaconazole concentrations and clinical outcomes of IFI prophylaxis and treatment in children with malignancies or HSCT recipients.

METHODS

Four databases (Cochrane, Embase, MEDLINE and PubMed) were searched for studies involving children (≤18 years old) receiving cancer treatment or HSCT that reported posaconazole serum concentrations and treatment outcomes. Animal studies, those primarily in adult (>18 years old) populations, non-malignant conditions (excluding HSCT), case reports, letters, editorials, conference abstracts and narrative reviews were excluded. Bias was assessed using the Newcastle-Ottawa scale.

RESULTS

Nineteen studies were included: 12 reported outcomes of posaconazole prophylaxis; two of treatment; and five of both. For prophylaxis, breakthrough IFIs occurred in 1%-12% of children. All but one occurred with serum concentrations of ≤0.7 mg/L. For treatment, no clear association was observed between a trough concentration of >1.0 mg/L and treatment efficacy, with poor outcomes reported for serum concentrations ranging between 0.2 and 4.8 mg/L. Overall, quality of evidence was poor (medium to high risk of bias for 18 papers, low risk for 1 paper) and there was variation in IFI definitions across studies.

CONCLUSIONS

This review supports current recommendations for posaconazole prophylaxis in paediatric oncology and HSCT recipients. The absence of a clear correlation found between serum trough concentrations and treatment efficacy highlights the need for further studies to determine optimal therapeutic targets for treatment.

Emerging trends in pediatric candidemia: mapping the rise in Candida parapsilosis incidence and antifungal resistance in Turkey

Candidemia is emerging as a significant concern in children, particularly among those with underlying conditions like malignancies or prematurity. The interpretation of epidemiological data on candidemias and their antifungal resistance plays a vital role in aiding diagnosis and guiding clinicians in treatment decisions. From 2014 to 2021, a retrospective analysis was conducted in İstanbul, Turkey; comparing Candida albicans and non-albicans (NAC) spp in both surviving and deceased groups. Furthermore, an examination of Candida parapsilosis and other species was performed, assessing various clinical and laboratory parameters. Among 93 patients, with a median age of 17 months, C. parapsilosis emerged as the predominant isolated species (44%), followed by C. albicans (34.4%). Resistance to fluconazole, voricanozole, and echinocandins, along with a history of broad-spectrum antibiotic use were found to be significantly higher in the non-albicans Candida group compared to C. albicans group. In the C. parapsilosis group, statistically lower age was identified in comparison to the other groups (P = .018). In addition, high fluconazole and voriconazole resistance was detected in Candida parapsilosis spp. Our study highlights a notable prevalence of C. parapsilosis, particularly in younger children, which is different from similar studies in childhood. This trend may be attributed to the common use of total parenteral nutrition and central venous catheter in gastrointestinal disorders and metabolic diseases. Furthermore, as anticipated, high azole resistance is noted in C. parapsilosis and other non-albicans Candida species. Interestingly, resistance to both amphotericin B and echinocandins within this group has been notably high. It is crucial to emphasize the considerable antifungal resistance seen in C. parapsilosis isolates.

Genetic Analysis of Candida glabrata from Candiduric Patients Using Microsatellite Length Polymorphism, Antifungal Susceptibility, and Enzymatic Profiles

Background: Candida glabrata is the second agent of candiduria with increased resistance to antifungals. Microsatellite length polymorphism (MLP) is one of the genotyping techniques used in the epidemiological investigation to improve clinical management. Objectives: We aimed to detect different genotypes of C. glabrata isolates using six microsatellite markers and the MLP technique. Moreover, our genotypes' association with other countries' genotypes was illustrated using a minimum spanning tree. We investigated in vitro antifungal susceptibility and enzymatic activity profiles of the isolates. Methods: Six microsatellite markers were amplified using multiplex-PCR for 22 C. glabrata strains isolated from urine in pediatric patients admitted to the Abuzar Children's Hospital in Ahvaz, Iran. The PCR products were presented for fragment analysis, and the size of the alleles was determined. Antifungal susceptibility tests and extracellular enzyme activities were also performed. Results: Nineteen multilocus genotypes were detected so that 22.7% of the strains had identical genotypes. The isolates were wild-type for amphotericin B (0.0625 - 2 µg/mL), itraconazole (0.125 - 2 µg/mL), and voriconazole (0.0078 - 0.00625 µg/mL). All the isolates were sensitive to fluconazole at the minimum inhibitory concentration (MIC) range (0.0312 - 16 μg/mL), and three of them were resistant to caspofungin (MIC ≥ 0.5 μg/mL). Moreover, 72.7 and 68.2% of the isolates had no phospholipase and esterase activities. The highest potency of enzymatic activity was obtained in hemolysin and proteinase enzymes. A high genetic diversity (19 genotypes of the 22 isolates) existed among the urinary C. glabrata isolates. Based on the minimum spanning tree, two clusters of our genotypes were related to C. glabrata genotypes in a previous study in Iran, and the third cluster was entirely connected with Chinese genotypes. Conclusions: Most of the isolates were the non-wild type for posaconazole but were rarely resistant to other antifungals. Hemolysin and proteinase secreted as the main virulence factors among the urinary C. glabrata isolates.

Health care-associated invasive Candida infections in children

The aims of the study were to examine the distribution of Candida spp. isolated from sterile body sites, the antifungal susceptibility of the isolates to amphotericin B, and fluconazole, risk factors and clinical outcomes associated with invasive health care-associated Candida infections in neonates and children. Between January 2007 and January 2012, the patients with invasive candidiasis were detected from microbiology laboratary records and medical records were examined retrospectively. Candida spp. were isolated from sterile body sites in 94 patients. The most common underlying diseases were prematurity in neonates and surgery in children. Parenteral nutrition, stay in intensive care unit (ICU), and mechanical ventilation (MV) were major risk factors in neonates. Hospitalization before infection and immunosuppressant therapy were significantly more frequent in children. Of Candida infection episodes, 29.8% was due to C. albicans and 70.2% was due to non-albicans Candida spp. The most common isolated species was C. parapsilosis. Of the Candida species, 90.8% were sensitive, and 9.2% were resistant to fluconazole. The rate of amphotericin B resistant was 1.3%; 23.4% of the patients died in the first 30 days. The main variables associated with mortality were neonates, prematurity, stay in the ICU, parenteral nutrition, MV, length of stay, amphotericin B susceptibility, and high levels of C-reactive protein.

Use of Micafungin for the Prevention and Treatment of Invasive Fungal Infections in Everyday Pediatric Care in France: Results of the MYRIADE Study

BACKGROUND

Invasive fungal infections are responsible for significant morbidity and mortality. Safety and effectiveness of antifungal agents is a particular concern in pediatric populations, where data are often limited. Micafungin is an echinocandin with demonstrated antifungal activity against a wide spectrum of Candida spp.; this subanalysis of data from the MYRIADE study describes the use of micafungin and its therapeutic outcomes in pediatric patients, in normal clinical practice.

METHODS

MYRIADE was an observational, multicenter, national, prospective, longitudinal study conducted from January 2010 to December 2012, in patients treated with micafungin using a prophylactic or curative strategy, across 17 sites [oncohematology (n = 8), neonatal intensive care units (ICUs) (n = 5) and pediatric ICUs (n = 4)]. The treatment regimen, the achievement of the therapeutic objective and the tolerance were reported.

RESULTS

The study population consisted of 110 pediatric patients (31 neonates, 24 children <2 years old and 55 children ≥2 to <16 years old). The therapeutic objective was achieved in 49/64 (76.6%) oncohematology patients, 28/29 (96.6%) neonatal ICU patients and 12/14 (85.7%) pediatric ICU patients. Twenty-four (21.8%) children developed an adverse event (AE); more AEs were observed in oncohematology patients compared with ICU patients [17 (26.1%) vs. 7 (15.6%)]. Only one serious AE, reported in an oncohematology patient, was considered related to micafungin.

CONCLUSIONS

In the first large observational study of micafungin treatment or prophylaxis conducted under real-world conditions in France, micafungin was effective and well tolerated for prophylaxis of invasive fungal infections in pediatric oncohematology patients and for curative purposes in pediatric and neonatal ICU patients.

Epidemiological and mycological characteristics of candidemia in Iran: A systematic review and meta-analysis

To date, there has been no comprehensive review of the epidemiology, risk factors, species distribution, and outcomes of candidemia in Iran. This study aimed to perform a systematic review and meta-analysis of all reported candidemia cases in Iran until December 2015. The review process occurred in three steps, namely a literature search, data extraction and statistical analyses. After a comprehensive literature search, we identified 55 cases. The mean age of patients was 46.80±24.30 years (range 1-81 years). The main risk factors for candidemia were surgery and burns (23.6%), followed by malignancies (20%), use of broad-spectrum antibiotics (18.2%), and diabetes (7.3%). Candida parapsilosis (n=17, 30.8%) was the leading agent, followed by Candida albicans (n=15, 27.3%), Candida glabrata (n=10, 18.2%), and Candida tropicalis (n=8, 14.5%). The frequencies of candidemia cases due to C. glabrata, C. parapsilosis, and C. albicans were significantly higher among patients aged>60, 21-40, and 41-60 years, respectively. Comparison of risk factors for candidemia by multiple logistic regression showed that one of the most important risk factors was surgery (OR: 4.245; 95% CI: 1.141-15.789; P=0.031). The outcome was recorded in only 19 cases and 13 of those patients (68.4%) expired. This study confirms that knowledge of the local epidemiology is important when conducting surveillance studies to prevent and control candidemia and will be of interest for antifungal stewardship.

Candida glabrata Biofilms: How Far Have We Come?

Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata's biofilms are emerging. In this article, the knowledge available on C. glabrata's resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them.

Investigation of ERG11 gene expression among fluconazole-resistant Candida albicans: first report from an Iranian referral paediatric hospital

The multiplicity of mechanisms of resistance to azole antifungal agents has been described. As fluconazole-resistant clinical Candida albicans isolates that constitutively over-express ERG11 have been identified in previous studies, the aim of this study is to investigate this molecular mechanism involved in fluconazole resistance of C. albicans clinical isolates. Fluconazole susceptibility testing was carried out on clinical isolates of Candida spp. obtained from hospitalised children in an Iranian referral children's hospital. A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique was used to differentiate Candida spp. The resistant C. albicans isolates were subjected to RT-qPCR using primers that identify ERG11 gene expression. Of the 142 Candida spp. isolates studied, C. albicans was the most predominant isolate, occurring in 68.3% (97/142) of the patients. According to the CLSI method, the majority of the C. albicans isolates (91.7%, 89/97), categorised as susceptible (minimum inhibitory concentration [MIC] ≤8 μg/mL), five isolates were considered resistant (MIC ≤64 μg/mL) and three had dose-dependent susceptibility (MIC = 8.16-32 μg/mL). The ERG11 gene in the five fluconazole-resistant C. albicans isolates was upregulated 4.15-5.84-fold relative to the ATCC 10231 control strain. In this study, the expression of ERG11 was upregulated in all the fluconazole-resistant C. albicans isolates. There are limited data on the antifungal susceptibility of Candida spp. as well as the molecular mechanism of azole resistance in Iran, especially for isolates causing infections in children. Therefore, the surveillance of antifungal resistance patterns and investigation of other mechanisms of azole resistance in all Candida spp. isolates is recommended.

Micafungin in premature and non-premature infants: a systematic review of 9 clinical trials

BACKGROUND

Invasive fungal infections cause excessive morbidity and mortality in premature neonates and severely ill infants.

METHODS

Safety and efficacy outcomes of micafungin were compared between prematurely and non-prematurely born infants <2 years of age. Data were obtained from all completed phase I-III clinical trials with micafungin that had enrolled infants (<2 years of age) that were listed in the Astellas Clinical Study Database. Demographics, adverse events, hepatic function tests and treatment success data were extracted and validated by the Astellas biostatistical group for all micafungin-treated patients, <2 years of age, using the unique patient identifier.

RESULTS

One-hundred and sixteen patients included in 9 clinical trials, 48% premature [birth weight (BW) <2500 g and/or gestational age <37 weeks], 52% non-premature, received ≥ 1 dose of micafungin. Among premature patients, 14.5% were low BW (1500-2499 g), 36.4% very low BW (1000-1499 g) and 49.1% extremely low BW (<1000 g). Ninety patients (78%) completed the studies; 13 [11% (4 premature)] died. Significantly more non-premature than premature patients discontinued treatment (P = 0.003). Treatment-related adverse events were recorded in 23% of patients with no difference between groups. More extremely low BW (n = 4, 15%) and very low BW (n = 8, 40%) infants experienced treatment-related adverse events than low BW (n = 0) and there was no relation to micafungin dose or duration. For a subgroup of 30 patients with invasive candidiasis, treatment success was achieved in 73% in both premature and non-premature groups. Prophylaxis was successful in 4/5 non-premature hematopoietic stem cell transplant patients.

CONCLUSION

Micafungin has a safe profile in premature and non-premature infants with substantial efficacy.

Invasive candidiasis and candidaemia in neonates and children: update on current guidelines

Invasive candidiasis (IC) and candidaemia are leading causes of infectious morbidity and mortality among immunocompromised paediatric patients and those admitted to intensive care units. Despite improvements in diagnosis, prevention and treatment, both mortality rates and the economic burden of disease still remain high. To address this issue, several international societies and organisations have proposed guidelines for the management of IC/candidaemia in both neonates and children. In this article, we review current recommendations of the Infectious Diseases Society of America, the European Conference on Infection in Leukaemia, the European Society of Clinical Microbiology and Infectious Diseases and the German Speaking Mycological Society/Paul-Ehrlich Society for Chemotherapy for the management and prevention of IC/candidaemia in children and neonates.

Yeast colonization and drug susceptibility pattern in the pediatric patients with neutropenia

BACKGROUND

Pediatric patients with neutropenia are vulnerable to invasive Candida infections. Candida is the primary cause of fungal infections, particularly in immunosuppressed patients. Candida albicans has been the most common etiologic agent of these infections, affecting 48% of patients.

OBJECTIVES

The aim of this study was to identify Candida spp. isolated from children with neutropenia and determine the antifungal susceptibility pattern of the isolated yeasts.

PATIENTS AND METHODS

In this study 188 children with neutropenia were recruited, fungal surveillance cultures were carried out on nose, oropharynx, stool, and urine samples. Identification of Candida strains was performed using germ tube and chlamydospore production tests on an API 20 C AUX system. Susceptibility testing on seven antifungal agents was performed using the agar-based E-test method.

RESULTS

A total of 229 yeasts were isolated. Among those, C. albicans was the most common species followed by C. krusei, C. parapsilosis, C. glabrata, C. tropicalis, C. famata, C. dubliniensis, C. kefyr, and other Candida species. C. glabrata was the most resistant isolated yeasts, which was 70% resistant to fluconazole and 50% to itraconazole, 7.5% to amphotericin B and 14% to ketoconazole. All the tested species were mostly sensitive to caspofungin.

CONCLUSIONS

Knowledge about the susceptibility patterns of colonized Candida spp. can be helpful for clinicians to manage pediatric patients with neutropenia. In this study, caspofungin was the most effective antifungal agent against the colonized Candida spp. followed by conventional amphotericin B.

Invasive candidiasis: update on current pharmacotherapy options and future perspectives

INTRODUCTION

Invasive candidiasis (IC), mainly candidemia, is a leading cause of morbidity and mortality among immunocompromised patients and those admitted to intensive care units. Despite the recognition of risk factors and advances in disease prevention, Candida-related hospitalizations and mortality continue to rise. For treatment, four classes of older and newer antifungal agents are currently available. Adjunctive immunotherapies and a monoclonal antibody against heat shock protein 90 (efungumab) are promising novel therapeutic approaches.

AREAS COVERED

In this article, approaches and therapeutic agents for candidemia and other forms of IC are reviewed.

EXPERT OPINION

The thorough understanding of the available antifungal agents in combination with the increasing knowledge of the mechanisms that underlie the pathogenesis of Candida infections and the development of newer approaches such as efungumab and immunotherapy with adjunctive cytokines may improve the prognosis of patients with life-threatening invasive Candida infections.

Candida parapsilosis and the neonate: epidemiology, virulence and host defense in a unique patient setting

Invasive candidiasis is a common problem in premature infants that leads to high morbidity and mortality. Although Candida albicans has historically been the most prominent species involved in these infections and has therefore been the subject of the most study, Candida parapsilosis is increasing in frequency, and neonates are disproportionately affected. This article reviews unique aspects of the epidemiology of this organism as well as strategies for prophylaxis against invasive candidiasis in general. Additionally, important differences between C. parapsilosis and C. albicans are coming to light related to virulence determinants and interactions with components of host immunity. These developments are reviewed while highlighting the significant gaps in our understanding that remain to be elucidated.

Strategies for the prevention of neonatal candidiasis

Invasive fungal infections represent the third-leading cause of late-onset sepsis in very-low-birth-weight infants (VLBWI) and have a high rate of infection-associated mortality. The infants at high risk for fungal sepsis are VLBWI with presence of additional risk factors that contribute to increased colonization and concentration of fungal organisms. Colonization with Candida spp. in neonates is secondary to either maternal vertical transmission or nosocomial acquisition in the nursery. Multiple sites may become colonized and a direct correlation between fungal colonization and subsequent progression to invasive candidemia was determined. Randomized, single and multiple-center, placebo-controlled trials found intravenous fluconazole prophylaxis to be effective in decreasing fungal colonization and sepsis for at-risk preterm infants <1500 g birth weight. The prophylactic use of fluconazole was found to be safe with no significant development of fungal resistance. Fluconazole prophylaxis administered to preterm neonates with birth weight <1000 g and/or 27 weeks' gestation or less has the potential of reducing and potentially eliminating invasive fungal infections and Candida-related mortality.

Diagnosis and therapy of Candida infections: joint recommendations of the German Speaking Mycological Society and the Paul-Ehrlich-Society for Chemotherapy

Invasive Candida infections are important causes of morbidity and mortality in immunocompromised and hospitalised patients. This article provides the joint recommendations of the German-speaking Mycological Society (Deutschsprachige Mykologische Gesellschaft, DMyKG) and the Paul-Ehrlich-Society for Chemotherapy (PEG) for diagnosis and treatment of invasive and superficial Candida infections. The recommendations are based on published results of clinical trials, case-series and expert opinion using the evidence criteria set forth by the Infectious Diseases Society of America (IDSA). Key recommendations are summarised here: The cornerstone of diagnosis remains the detection of the organism by culture with identification of the isolate at the species level; in vitro susceptibility testing is mandatory for invasive isolates. Options for initial therapy of candidaemia and other invasive Candida infections in non-granulocytopenic patients include fluconazole or one of the three approved echinocandin compounds; liposomal amphotericin B and voriconazole are secondary alternatives because of their less favourable pharmacological properties. In granulocytopenic patients, an echinocandin or liposomal amphotericin B is recommended as initial therapy based on the fungicidal mode of action. Indwelling central venous catheters serve as a main source of infection independent of the pathogenesis of candidaemia in the individual patients and should be removed whenever feasible. Pre-existing immunosuppressive treatment, particularly by glucocorticosteroids, ought to be discontinued, if feasible, or reduced. The duration of treatment for uncomplicated candidaemia is 14 days following the first negative blood culture and resolution of all associated symptoms and findings. Ophthalmoscopy is recommended prior to the discontinuation of antifungal chemotherapy to rule out endophthalmitis or chorioretinitis. Beyond these key recommendations, this article provides detailed recommendations for specific disease entities, for antifungal treatment in paediatric patients as well as a comprehensive discussion of epidemiology, clinical presentation and emerging diagnostic options of invasive and superficial Candida infections.

Prospective multicenter study of the epidemiology, molecular identification, and antifungal susceptibility of Candida parapsilosis, Candida orthopsilosis, and Candida metapsilosis isolated from patients with candidemia

A 13-month prospective multicenter study including 44 hospitals was carried out to evaluate the epidemiology of Candida parapsilosis complex candidemia in Spain. Susceptibility to amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, caspofungin, and micafungin was tested by the microdilution colorimetric method. A total of 364 C. parapsilosis complex isolates were identified by molecular methods: C. parapsilosis (90.7%), Candida orthopsilosis (8.2%), and Candida metapsilosis (1.1%). Most candidemias (C. parapsilosis, 76.4%; C. orthopsilosis, 70.0%; C. metapsilosis, 100%) were observed in adults. No C. orthopsilosis or C. metapsilosis candidemias occurred in neonates. C. parapsilosis was most frequent in adult intensive care unit (28.8%), surgery (20.9%), and internal medicine (19.7%) departments; and C. orthopsilosis was most frequent in hematology (28.6%), pediatrics (12.0%), and neonatology (11.5%) departments. The geographic distribution of C. orthopsilosis and C. metapsilosis was not uniform. According to CLSI clinical breakpoints, all C. orthopsilosis and C. metapsilosis isolates were susceptible to the nine agents tested. Resistance (MICs > 1 mg/liter) was observed only in C. parapsilosis: amphotericin B, posaconazole, itraconazole, and caspofungin (0.3% each), anidulafungin (1.9%), and micafungin (2.5%). Applying the new species-specific fluconazole and echinocandin breakpoints, the rates of resistance to fluconazole for C. parapsilosis and C. orthopsilosis increased to 4.8% and 0.3%, respectively; conversely, for C. parapsilosis they shifted from 1.9 to 0.6% (anidulafungin) and from 2.5 to 0.6% (micafungin). Our study confirms the different prevalence of C. parapsilosis complex candidemia among age groups: neither C. orthopsilosis nor C. metapsilosis was isolated from neonates; interestingly, C. metapsilosis was isolated only from adults and the elderly. The disparity in antifungal susceptibility among species could be important for therapy.

Epidemiology and microbiology of nosocomial pediatric candidemia at a northern Indian tertiary care hospital

The availability and aggressive use of chemotherapeutic and immunosuppressive agents as well as broad-spectrum antibacterial agents have created a large population of patients who are at increased risk of acquiring infections with fungal organisms, especially Candida species. Present work was undertaken to study the epidemiology and microbiology of candidemia and Candida colonization in hospitalized children. A total of 323 suspected cases of septicemia were enrolled, of which blood culture from 7.4% subjects was positive for Candida species. In total, 57.3% subjects were colonized by Candida species at least at one of the tested sites. Of 337 isolates, 24.3, 71.5, 2.9, 0.59, and 0.59% were Candida albicans, Candida tropicalis, Candida krusei, Candida kefyr, and Candida lusitaniae, respectively. Antifungal susceptibility results show that fluconazole, itraconazole, and amphotericin B resistance is prevalent in 18.2, 2.4, and 3.6% of C. albicans isolates, and 21.1, 4.6, and 0.04% of C. tropicalis isolates, respectively. In a large number of cases, source of blood infection was patient's own colonizers, as shown by genetic matching. It was also noted that some strain types are circulating within the ward. High prevalence of non-albicans candidemia with high resistance to fluconazole is prevalent in North Indian hospitalized children.

Screening for drug-resistant Candida yeasts with chromogenic agar

We examined the utility of agar dilution to screen yeasts for reduced susceptibility to several newer antifungal drugs including echinocandins and azoles. We compared agar dilution susceptibility screening with the Clinical and Laboratory Standards Institute (CLSI) method for Candida isolates. We added echinocandins and azoles to CHROMagar Candida medium prior to its solidification. Assessment of resistance was based on growth characteristics, wherein decreased colony size in the presence of antifungal drugs was used as an indicator of susceptibility. Clinical Candida isolates of C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. guilliermondii, C. lusitaniae, C. rugosa and C. dubliniensis were screened for drug susceptibility. Overall, antifungal susceptibility of the yeasts to anidulafungin, caspofungin, micafungin, posaconazole and voriconazole, determined using CHROMagar agar dilution, were shown to be 96, 80, 94, 90 and 97% as accurate, respectively, as those determined by the CLSI method, i.e., within one tube dilution of CLSI MICs. Categorical errors by percentage had a broader range. Major errors noted with anidulafungin, caspofungin and micafungin were 3, 6 and 0%, respectively, while very major errors were 15, 55 and 38%, respectively. Major errors with posaconazole and voriconazole were 12 and 0%, respectively, while very major errors were 0 and 22%, respectively, compared to CLSI standards. Most of the assessment errors were found with C. glabrata and C. parapsilosis. Agar dilution screening for drug susceptibility with the current panel of antifungal drugs is rapid, accurate and effective. However, the determination of resistance or non-susceptibility in yeasts may be more problematic, and may be species dependent.

Candidemia in children

Seriously ill or immunocompromised children are at increased risk of invasive fungal infections, particularly candidemia. Candida albicans and Candida parapsilosis are the two most frequent causes of candidemia in pediatric patients. Candidemia in children is associated with high morbidity and mortality, increased length of hospital stays, and higher healthcare costs. Early effective antifungal therapy is the key to improved outcomes. Risk factors for candidemia may be used to identify patients suitable for empiric therapy. Such risk factors include prolonged stay in an intensive care unit, immunosuppression, prior bacterial infection, and recent surgery, as well as the use of a central venous catheter, mechanical ventilation, and/or total parenteral nutrition. Recent guidelines from the Infectious Diseases Society of America recommend consideration of fluconazole or an echinocandin for empiric therapy in suitable candidates, with a preference for an echinocandin in patients with moderate-to-severe disease, recent azole exposure, or high risk of Candida glabrata or Candida krusei infection. Fluconazole or an echinocandin is also preferred initial therapy for non-neutropenic candidemia, depending on disease severity and other characteristics. The guidelines recommend treatment with an echinocandin or lipid formulation of amphotericin B for most patients with neutropenic candidemia, although fluconazole is identified as an alternative for less critically ill patients without recent azole exposure. Risk factors for candidemia - and, hence, criteria for prophylaxis - are less well established in older children than in neonates. Further research is needed to better establish criteria for antifungal prophylaxis in children at high risk for candidemia.

Caspofungin: in pediatric patients with fungal infections

Caspofungin is the first echinocandin to be approved for the treatment of fungal infections in pediatric patients. The antifungal properties of caspofungin result from interference with fungal cell-wall integrity. In vitro, caspofungin is fungicidal against Candida spp. and fungistatic against Aspergillus spp., but has little or no fungicidal or fungistatic activity against Cryptococcus neoformans, the Zygomycetes, Fusarium spp., or Trichosporon beigelii. Caspofungin was effective as empirical antifungal therapy in pediatric patients with persistent fever and neutropenia. Almost half (46%) of caspofungin recipients and one-third (32%) of liposomal amphotericin B recipients achieved an overall favorable response in a randomized, double-blind trial. Caspofungin was also effective in pediatric patients with fungal infections (invasive candidiasis, invasive aspergillosis refractory to or intolerant of standard antifungal agents, or esophageal candidiasis). Positive responses to treatment were seen in 30 of 37 patients with invasive candidiasis, 5 of 10 patients with invasive aspergillosis, and in the one patient with esophageal candidiasis, in a noncomparative, open-label trial. Caspofungin was generally well tolerated in the clinical trials in pediatric patients with febrile neutropenia requiring empirical antifungal treatment, or with fungal infections. Few caspofungin recipients reported serious drug-related adverse events or discontinued treatment as a result of drug-related adverse events.

Infections in pediatric patients with hematologic malignancies

Despite significant advances in supportive care, infection remains second only to malignancy as a cause of death in pediatric oncology patients, and infection accounts for a large fraction of treatment-related costs. Multiple risk factors contribute to infection-related morbidity, chief among them the immunosuppressive effects of leukemia itself and of cytotoxic chemotherapy, prolonged hospitalization and antibiotic use, and loss of barrier integrity associated with mucositis and the need for indwelling central access. While viruses are the most common causes of infection, bacteria are responsible for most life-threatening complications. Gram-negative bacilli are a concern for all patients undergoing treatment, while a subset of gram-positive organisms, particularly viridans streptococci, become significant pathogens in children receiving profoundly immunosuppressive therapy. Invasive fungal infections are also a serious risk for morbidity and mortality in this population. Availability of new antimicrobial agents has made it possible to treat infectious complications more effectively, but their availability is also leading to an increased prevalence of highly resistant pathogens. Future work in pediatric oncology will need to include measures to reduce the immunosuppressive effects of anti-cancer therapy, provide targeted treatment for infections, and better identify groups of patients at high risk for infectious complications, who may benefit from antimicrobial prophylaxis or more aggressive empirical therapy.

[In vitro antifungal activity of voriconazole: New data after the first years of clinical experience]

Voriconazole has been developed to meet the increasing need for new and useful antifungal agents for the treatment of invasive mycoses. This review describes the spectrum of voriconazole antifungal activity based on data from in vitro studies published during the last three years. This survey demonstrates that voriconazole has a broad antifungal spectrum against the most common fungal pathogens being its action fungistatic for Candida and fungicidal for Aspergillus and other filamentous fungi. Overall, more than 95% of all Candida isolates tested are susceptible to voriconazole and less than 3% are resistant. Similar or even better activity rates have been described for Aspergillus, Cryptococcus and most of yeasts and moulds of medical importance. We also discuss the limitations related to the azole cross-resistance observed in some Candida glabrata isolates, the poor activity of voriconazole against Scedosporium prolificans, its activity against fungal biofilms and the great potential usefulness of combination of voriconazole with other antifungal drugs.

Posaconazole: a new broad-spectrum antifungal agent

The rising incidence of invasive fungal infections and the emergence of broader fungal resistance have led to the need for novel antifungal agents. Posaconazole is a new member of the triazole class of antifungals. It is available as an oral suspension and has a favorable toxicity profile, has demonstrated clinical efficacy in the treatment of oropharyngeal candidiasis and has shown promise as salvage therapy for invasive aspergillosis, zygomycosis, cryptococcal meningitis and a variety of other fungal infections. In addition, data from randomized controlled studies support its efficacy for use in prophylaxis of invasive fungal infections in patients who are severely immunocompromised. The wide spectrum activity of posaconazole in in vitro studies, animal models and preliminary clinical studies suggest that posaconazole represents an important addition to the antifungal armamentarium.

Invasive candidiasis in pediatric intensive care patients: epidemiology, risk factors, management, and outcome

BACKGROUND

The incidence of candidemia in pediatric patients follows the same pattern of increase as in adults, but the rate of increase is greater. Pediatric patients in critical condition, particularly young infants, are especially vulnerable to invasive Candida infections (ICI), partly because of their age and severe underlying disease and partly because of the invasive procedures used.

DISCUSSION

Central venous catheters and arterial lines, parenteral nutrition, mechanical ventilation and extended use of antimicrobials enhance the risk of ICI. C. albicans continues to be the most prevalent isolate. However, an increasing role of non-C. albicans (NAC) spp., some of which are intrinsically or potentially resistant to antifungal agents, has been observed. NAC spp., particularly C. parapsilosis and C. tropicalis, account for almost half of ICI. The increased use of antifungals in immunocompromised patients, mainly prophylactically, is considered the strongest contributory factor to the changes in species distribution, which have subsequently affected the mortality and choice of empirical treatment.

CONCLUSIONS

Prompt removal of lines and initiation of antifungal treatment are the milestones of management. Conventional amphotericin B remains a commonly used antifungal agent, but its lipid formulations and fluconazole are also used frequently. Novel antifungal agents such as second-generation triazoles and echinocandins exhibit potential as alternative agents in critically ill children with ICI. Although response rates are still far from satisfactory, improved understanding of risk factors, preventive strategies and new treatment options promise a better future outcome.

Caspofungin for the treatment of fungal infections: a systematic review of randomized controlled trials

During the last decade, owing to the low effectiveness and high toxicity of older antifungals, new antifungal agents have been released to the market for the treatment of patients with fungal infections. Several randomized controlled trials (RCTs) have been designed to evaluate the effectiveness of caspofungin in comparison with other antifungal agents. This review was conducted to examine further the role of caspofungin in the treatment of patients with fungal, mainly Candida, infections. Two reviewers independently performed the literature search, study selection and data extraction from relevant RCTs. A total of six RCTs comparing caspofungin with amphotericin B (deoxycholate in four and liposomal in one RCT) or fluconazole (in one RCT), which studied a total of 1974 patients, were included in our review. Success of the applied treatment in the clinically evaluable patients was achieved in 496/943 (52.6%) of the caspofungin-treated patients and in 381/852 (44.7%) of the amphotericin B- and lipid amphotericin B-treated patients. Discontinuation due to drug toxicity was significantly less common in patients receiving caspofungin than amphotericin B (odds ratio (OR) 0.25, 95% confidence interval (CI) 0.07-0.85, random effects model). Development of nephrotoxicity, hypokalaemia and fever also occurred significantly less often with caspofungin than amphotericin B (OR 0.23, 95% CI 0.14-0.36, fixed effects model; OR 0.3, 95% CI 0.12-0.76, random effects model; and OR 0.26, 95% CI 0.08-0.79, random effects model, respectively). No difference in mortality was noted. Caspofungin was associated with better clinical outcomes (higher cure and fewer adverse effects) than amphotericin B in the treatment of patients with fungal infections.

Identification of Candida species isolated from patients in intensive care unit and in vitro susceptibility to fluconazole for a 3-year period

Species level identification of Candida and antifungal susceptibility testing is not generally performed in routine laboratory practice. There is limited information about the distribution of Candida species and antifungal susceptibility in Turkey. In this study, we aimed at identifying Candida isolates to species level from various samples obtained from patients treated in an intensive care unit between 2002 and 2005 and to evaluate fluconazole susceptibilities of the isolates. A total of 320 Candida isolates obtained from 270 patients were identified by conventional methods and using API (Candida and/or 20C AUX) system. Antifungal susceptibility testing was performed by broth microdilution method. Candida albicans was isolated with the highest frequency (65.6%) followed by C. parapsilosis (11.3%), C. glabrata (8.8%) and C. tropicalis (7.8%). Of all the isolates, 92.9% revealed susceptibility to fluconazole. Susceptibility to fluconazole was highest for C. albicans followed by C. parapsilosis and C. glabrata. The MIC(90) values for C. albicans, C. parapsilosis, C. glabrata and C. tropicalis were 1, 2, 8 and 4 mug ml(-1) respectively. Fluconazole remains effective against both C. albicans and the majority of non-albicans Candida species. In this study, we determine the distribution of Candida species and evaluate the susceptibilities of the isolates, particularly for the azoles.

Antifungal resistance in Candida spp. isolated in Italy between 2002 and 2005 from children and adults

The activity of amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole was tested in vitro against 618 clinical Candida spp. isolates, using the broth microdilution or the disk diffusion method (voriconazole). Amphotericin B and voriconazole were the most potent antifungal agents assayed (100% of susceptible strains). Resistance to fluconazole and itraconazole was detected in three (0.7%) and 11 (2.7%) isolates of Candida albicans and in four (3.7%) isolates of Candida glabrata. Flucytosine intermediate, resistant strains, or both, were observed in C. albicans (0.3% and 0.7%), C. glabrata (2.8% intermediate) and C. tropicalis (15.2% and 15.2%). C. krusei was the least susceptible species to azoles. No statistically significant differences in the rates of resistant isolates depending on site of infection and age of the patient were observed, with the exception of C. albicans and itraconazole (higher percentage of resistance in children). At present, acquired antifungal resistance represents an uncommon finding in most Candida spp. circulating in Northern Italy.

Developments in the treatment of candidiasis: more choices and new challenges

The incidence of oesophageal candidiasis, candidaemia and disseminated candidiasis has increased dramatically. In addition to the amphotericin B formulations and fluconazole, the echinocandins anidulafungin, caspofungin and micafungin and the newer triazoles posaconazole and voriconazole are in the last stages of development and are becoming available for the management of candidiasis. This review presents these new agents and addresses their role in the treatment of candidiasis. All new antifungal agents exhibit potent activity against Candida spp. and echinocandins are fungicidal against most Candida spp. but appear to be less potent against certain species, such as Candida parapsilosis and C. guilliermondii. Systemic antifungal therapy can now be individualised based on the severity of the infection, comorbid conditions and the Candida spp. causing the infection. Studies are needed to investigate the possible development of resistance and the efficacy of these antifungal agents against the more resistant Candida spp.

CNS-manifestation of aspergillosis in an extremely low-birth-weight infant

Invasive aspergillosis is a rare condition in term and preterm infants. We present here the fatal case of a 28-week gestational age preterm baby who developed pulmonary, hepatic and central nervous system aspergillosis during the first days of life. A hyperechogenic lesion adjacent to the lateral ventricle was diagnosed by ultrasound and initially considered to represent periventricular leukomalacia. Within several days the lesion increased in size and was then falsely considered to be an intraventricular haemorrhage. Aspergillus fumigatus was ultimately isolated in the tracheal aspirates, ascites and in material recovered by open brain biopsy. Despite treatment with conventional and liposomal amphotericin B the infant patient died.

CONCLUSION

Invasive aspergillosis has to be considered in the differential diagnosis of an unusual hyperechogenic brain lesion in very low-birth-weight infants with persistent symptoms and signs of systemic infection despite broad-spectrum antibacterial therapy. Consideration of this diagnosis should result in an aggressive diagnostic work-up to allow early initiation of an appropriate treatment.

Newer triazole antifungal agents: pharmacology, spectrum, clinical efficacy and limitations

New triazole antifungals (voriconazole, posaconazole, ravuconazole and albaconazole) have been developed to meet the increasing need for new antifungals, and address the rising incidence of invasive fungal infections and the emergence of fungal resistance. This report describes the spectrum of activity of the newer-generation triazoles based on data from in vitro, animal and clinical studies. The authors discuss the use of these agents in combination with other antifungals, the extent of cross-resistance, their toxicity profile and pharmacokinetic properties. A total of two agents are currently available: voriconazole (which is becoming a primary treatment for the management of invasive aspergillosis) and posaconazole (which demonstrates a broad antifungal spectrum). A further two agents, albaconazole and ravuconazole, are undergoing early clinical evaluation and their future is uncertain. For all newer triazoles, concerns about emerging drug-resistant fungi and the incidence and management of breakthrough infections will dictate their role in antifungal prophylaxis and treatment.

Current treatment strategies for disseminated candidiasis

The incidence of disseminated candidiasis has increased dramatically over the past several decades. Fortunately, in recent years, a variety of new antifungal agents have become available to treat these infections. On the basis of efficacy, safety, and cost considerations, fluconazole is the agent of choice for the empirical treatment of disseminated candidiasis in nonneutropenic, hemodynamically stable patients, unless a patient is suspected to be infected with an azole-resistant species (i.e., Candida glabrata or Candida krusei). For hemodynamically unstable or neutropenic patients, agents with broader species coverage, such as polyenes, echinocandins, or, possibly, voriconazole, are preferred for empirical treatment of candidemia. Modification of the initial, empirical regimen depends on the response to therapy and the subsequent identification of the species of the offending pathogen. Echinocandins or high-dose polyenes are preferred for the treatment of infections with C. glabrata or C. krusei. Central venous catheters should be removed from all patients who have disseminated candidiasis, if feasible, and antifungal therapy should be administered to all patients who have candidemia or proven candidiasis.