The epidemiology and attributable outcomes of candidemia in adults and children hospitalized in the United States: a propensity analysis

Efficacy of micafungin in invasive candidiasis caused by common Candida species with special emphasis on non-albicans Candida species

The incidence of invasive candidiasis caused by non-albicans Candida (NAC) spp. is increasing. The aim of this analysis was to evaluate the efficacy of micafungin, caspofungin and liposomal amphotericin B in patients with invasive candidiasis and candidaemia caused by different Candida spp. This post hoc analysis used data obtained from two randomised phase III trials was conducted to evaluate the efficacy and safety of micafungin vs. caspofungin and micafungin vs. liposomal amphotericin B. Treatment success, clinical response, mycological response and mortality were evaluated in patients infected with C. albicans and NAC spp. Treatment success rates in patients with either C. albicans or NAC infections were similar. Outcomes were similar for micafungin, caspofungin and liposomal amphotericin B. Candida albicans was the most prevalent pathogen recovered (41.0%), followed by C. tropicalis (17.9%), C. parapsilosis (14.4%), C. glabrata (10.4%), multiple Candida spp. (7.3%) and C. krusei (3.2%). Age, primary diagnosis (i.e. candidaemia or invasive candidiasis), previous corticosteroid therapy and Acute Physiology and Chronic Health Evaluation II score were identified as potential predictors of treatment success and mortality. Micafungin, caspofungin and liposomal amphotericin B exhibit favourable treatment response rates that are comparable for patients infected with different Candida spp.

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'.

[Épico project: Development of educational recommendations using the DELPHI technique on invasive candidiasis in non-neutropenic critically ill adult patients. Grupo Proyecto Épico]

BACKGROUND

Although there has been an improved management of invasive candidiasis in the last decade, controversial issues still remain, especially in the diagnostic and therapeutic approaches.

AIMS

We sought to identify the core clinical knowledge and to achieve high level agreement recommendations required to care for critically ill adult patients with invasive candidiasis.

METHODS

A prospective Spanish survey reaching consensus by the DELPHI technique was made. It was anonymously conducted by electronic mail in a first term to 25 national multidisciplinary experts in invasive fungal infections from five national scientific societies, including intensivists, anesthesiologists, microbiologists, pharmacologists and infectious diseases specialists, who answered to 47 questions prepared by a coordination group after a strict review of the literature in the last five years. The educational objectives spanned five categories, including epidemiology, diagnostic tools, prediction rules, and treatment and de-escalation approaches. The level of agreement achieved among the panel experts in each item should exceed 75% to be selected. In a second term, after extracting recommendations from the selected items, a face to face meeting was performed where more than 80 specialists in a second round were invited to validate the preselected recommendations.

RESULTS

In the first term, 20 recommendations were preselected (Epidemiology 4, Scores 3, Diagnostic tools 4, Treatment 6 and De-escalation approaches 3). After the second round, the following 12 were validated: (1) Epidemiology (2 recommendations): think about candidiasis in your Intensive Care Unit (ICU) and do not forget that non-Candida albicans-Candida species also exist. (2) Diagnostic tools (4 recommendations): blood cultures should be performed under suspicion every 2-3 days and, if positive, every 3 days until obtaining the first negative result. Obtain sterile fluid and tissue, if possible (direct examination of the sample is important). Use non-culture based methods as microbiological tools, whenever possible. Determination of antifungal susceptibility is mandatory. (3) Scores (1 recommendation): as screening tool, use the Candida Score and determine multicolonization in high risk patients. (4) Treatment (4 recommendations): start early. Choose echinocandins. Withdraw any central venous catheter. Fundoscopy is needed. (5) De-escalation (1 recommendation): only applied when knowing susceptibility determinations and after 3 days of clinical stability. The higher rate of agreement was achieved in the optimization of microbiological tools and the withdrawal of the catheter, whereas the lower rate corresponded to de-escalation therapy and the use of scores.

CONCLUSIONS

The management of invasive candidiasis in ICU patients requires the application of a broad range of knowledge and skills that we summarize in our recommendations. These recommendations may help to identify the potential patients, standardize their global management and improve their outcomes, based on the DELPHI methodology.

Candidiasis drug discovery and development: new approaches targeting virulence for discovering and identifying new drugs

INTRODUCTION

Targeting pathogenetic mechanisms, rather than essential processes, represents a very attractive alternative for the development of new antibiotics. This may be particularly important in the case of antimycotics, due to the urgent need for novel antifungal drugs and the paucity of selective fungal targets. The opportunistic pathogenic fungus Candida albicans is the main etiological agent of candidiasis, the most common human fungal infection. These infections carry unacceptably high mortality rates, a clear reflection of the many shortcomings of current antifungal therapy, including the limited armamentarium of antifungal agents, their toxicity and the emergence of resistance. Moreover, the antifungal pipeline is mostly dry.

AREAS COVERED

This review covers some of the most recent progress toward understanding C. albicans pathogenetic processes and how to harness this information for the development of anti-virulence agents. The two principal areas covered are filamentation and biofilm formation, as C. albicans pathogenicity is intimately linked to its ability to undergo morphogenetic conversions between yeast and filamentous morphologies and to its ability to form biofilms.

EXPERT OPINION

Filamentation and biofilm formation represent high value targets, yet are clinically unexploited, for the development of novel anti-virulence approaches against candidiasis. Although this has proved a difficult task despite increasing understanding at the molecular level of C. albicans virulence, there are some opportunities and prospects for antifungal drug development targeting these two important biological processes.

Lipolytic enzymes involved in the virulence of human pathogenic fungi

Pathogenic microbes secrete various enzymes with lipolytic activities to facilitate their survival within the host. Lipolytic enzymes include extracellular lipases and phospholipases, and several lines of evidence have suggested that these enzymes contribute to the virulence of pathogenic fungi. Candida albicans and Cryptococcus neoformans are the most commonly isolated human fungal pathogens, and several biochemical and molecular approaches have identified their extracellular lipolytic enzymes. The role of lipases and phospholipases in the virulence of C. albicans has been extensively studied, and these enzymes have been shown to contribute to C. albicans morphological transition, colonization, cytotoxicity, and penetration to the host. While not much is known about the lipases in C. neoformans, the roles of phospholipases in the dissemination of fungal cells in the host and in signaling pathways have been described. Lipolytic enzymes may also influence the survival of the lipophilic cutaneous pathogenic yeast Malassezia species within the host, and an unusually high number of lipase-coding genes may complement the lipid dependency of this fungus. This review briefly describes the current understanding of the lipolytic enzymes in major human fungal pathogens, namely C. albicans, C. neoformans, and Malassezia spp.

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.

Infecciones nosocomiales en pediatría

Numerosas son las particularidades de la población pediátrica que deben intervenir, en nuestra opinión, en el control de las infecciones nosocomiales. Los riesgos y los agentes patógenos responsables son diferentes en función del tipo de población (prematuros, recién nacidos, otros). Además, esta población, que comparte los mismos factores de riesgo de infecciones nosocomiales que la población adulta (hospitalización en reanimación, cateterismos, etc.), se distingue no sólo por la inmadurez del sistema inmunitario de los recién nacidos, sino también por la multiplicidad de los participantes, desde los sanitarios hasta los padres, pasando por los educadores y los acompañantes (visitantes de todo tipo, etc.) necesarios para el desarrollo conductual y emocional del niño. Además, es importante subrayar el aumento del riesgo ligado a los contactos frecuentes, cercanos e íntimos que están parcial e incluso totalmente ausentes en el ámbito hospitalario «adulto». Así como existen riesgos de transmisión cruzada a través del principal vector constituido por los sanitarios, el control del riesgo no puede excluir a los educadores, a los acompañantes, a los padres y a los mismos niños. Si el riesgo en la esfera adulta está limitado a las actividades médicas, en la esfera pediátrica se comparte con las demás actividades (juegos, enseñanza, etc.), que con frecuencia son comunes. Todos estos riesgos son todavía mayores debido a la prevalencia de los agentes patógenos como los virus (respiratorios y digestivos), la frecuencia de las antibioticoterapias y la dificultad de los diagnósticos etiológicos, dada la inespecificidad de los signos clínicos y la actitud diagnóstica poco o nada invasiva. De esta manera, el control del riesgo infeccioso nosocomial se resume en los siguientes elementos: un reservorio importante y difícilmente identificable, numerosos vectores potenciales, una población expuesta de manera variable al riesgo, todo ello sin olvidar las necesidades emocionales de los niños y los comportamientos «culturales».

Épico Project. Development of educational recommendations using the DELPHI technique on invasive candidiasis in non-neutropenic critically ill adult patients

BACKGROUND

Although there has been an improved management of invasive candidiasis in the last decade, controversial issues still remain, especially in the diagnostic and therapeutic approaches.

AIMS

We sought to identify the core clinical knowledge and to achieve high level agreement recommendations required to care for critically ill adult patients with invasive candidiasis.

METHODS

A prospective Spanish survey reaching consensus by the DELPHI technique was made. It was anonymously conducted by electronic mail in a first term to 25 national multidisciplinary experts in invasive fungal infections from five national scientific societies, including intensivists, anesthesiologists, microbiologists, pharmacologists and infectious diseases specialists, who answered to 47 questions prepared by a coordination group after a strict review of the literature in the last five years. The educational objectives spanned five categories, including epidemiology, diagnostic tools, prediction rules, and treatment and de-escalation approaches. The level of agreement achieved among the panel experts in each item should exceed 75% to be selected. In a second term, after extracting recommendations from the selected items, a face to face meeting was performed where more than 80 specialists in a second round were invited to validate the preselected recommendations.

RESULTS

In the first term, 20 recommendations were preselected (Epidemiology 4, Scores 3, Diagnostic tools 4, Treatment 6 and De-escalation approaches 3). After the second round, the following 12 were validated: (1) Epidemiology (2 recommendations): think about candidiasis in your Intensive Care Unit (ICU) and do not forget that non-Candida albicans-Candida species also exist. (2) Diagnostic tools (4 recommendations): blood cultures should be performed under suspicion every 2-3 days and, if positive, every 3 days until obtaining the first negative result. Obtain sterile fluid and tissue, if possible (direct examination of the sample is important). Use non-culture based methods as microbiological tools, whenever possible. Determination of antifungal susceptibility is mandatory. (3) Scores (1 recommendation): as screening tool, use the Candida Score and determine multicolonization in high risk patients. (4) Treatment (4 recommendations): start early. Choose echinocandins. Withdraw any central venous catheter. Fundoscopy is needed. (5) De-escalation (1 recommendation): only applied when knowing susceptibility determinations and after 3 days of clinical stability. The higher rate of agreement was achieved in the optimization of microbiological tools and the withdrawal of the catheter, whereas the lower rate corresponded to de-escalation therapy and the use of scores.

CONCLUSIONS

The management of invasive candidiasis in ICU patients requires the application of a broad range of knowledge and skills that we summarize in our recommendations. These recommendations may help to identify the potential patients, standardize their global management and improve their outcomes, based on the DELPHI methodology.

Management of candidaemia and invasive candidiasis in critically ill patients

Critically ill patients in the intensive care unit (ICU) are at increased risk of encountering bloodstream infections (BSIs) with Candida spp., associated with an elevated crude mortality rate. This supports the significance of early detection of infection and identification of the most effective management approach. A review of the various antifungal treatments and an evaluation of the diverse management approaches for invasive candidiasis in critically ill patients is necessary for guiding evidence-based decision-making. Different early detection schemes for invasive candidiasis are well documented in the literature. Other than the common use of blood cultures, new methods entail the use of risk prediction scores and biomarker tests. Regarding management strategies, different options are currently supported. These include prophylaxis, empirical therapy, pre-emptive therapy, and treatment of culture-documented infections. The choice of treatment is greatly dependent on several factors related to the patient and/or to the surrounding environment. Attention needs to be given to previous exposure to azoles, epidemiological data on dominant Candida spp. in local ICUs, severity of illness and associated morbidities. This paper summarises the most recent literature as well as the guidelines issued by the Infectious Diseases Society of America. The objective is to identify the best diagnosis and management approaches for serious Candida infections in critically ill patients. In addition, this article addresses an important aspect associated with managing candidaemia in critically ill patients pertaining to the decision for intravenous catheter removal.

Occurrence, presentation and treatment of candidemia

Candida is one of the most common causes of nosocomial bloodstream infections. Candidemia is not confined to hematological patients, intensive care units or abdominal surgery wards, but it is remarkably frequent in the internal medicine setting. High mortality associated with candidemia can be reduced by prompt, appropriate antifungal therapy. The epidemiology of species has been shifting toward non-albicans strains. Significant improvements in nonculture-based diagnostic methods, such as serological markers, have been made in recent years, and novel diagnostic techniques should be further studied to enable early pre-emptive therapy. Treatment guidelines indicate that echinocandins are at present the best choice for patients who are severely ill or possibly infected with fluconazole-resistant strains.

Evaluation of efficacy of probiotics in prevention of candida colonization in a PICU-a randomized controlled trial

OBJECTIVE

To evaluate the efficacy of probiotics in prevention of Candida colonization in a PICU.

DESIGN

Prospective double blinded, randomized controlled trial.

SETTING

PICU of a tertiary care teaching hospital in north India.

SUBJECTS

One hundred fifty children (106 boys, 44 girls), 3 months to 12 yrs old, on broad spectrum antibiotics for at least 48 hrs were randomized using computer-generated random numbers to receive probiotic mix (EUGI) (n = 75) or placebo (n = 75).

INTERVENTION

Patients received one sachet twice a day of either probiotics or placebo for 7 days. Probiotics contained Lactobacillus acidophillus, Lactobacillus rhamnosum, Bifidobacterium longum, Bifidobacterium bifidum, Saccharomyces boulardi, Saccharomyces thermophilus, fructo-oligosaccharides; and placebo-contained lactose packed in similar-looking sachets. Rectal swabs for fungal culture were taken at day 0, 7, and 14 of enrollment. Primary outcome measure was prevalence of rectal colonization with Candida on day 14 postenrollment; secondary outcomes were growth of Candida in urine (candiduria) and blood (candidemia). Patients were followed until completion of 14 days study period or death of patient.

RESULTS

Demographic and clinical variables were comparable in two groups. Prevalence of Candida colonization on day 0 was similar (15 of 75) in both the groups. On day 7, 27.9% (19 of 68) patients in the probiotic group and 42.6% (29 of 68) patients in the placebo group were colonized (relative risk 0.65; 95% confidence interval 0.41-1.05; p = 0.07), whereas, on day 14, colonization was observed in 31.3% (21 of 67) patients in the probiotic group and 50% (34 of 68) in the placebo group (relative risk 0.63; 95% confidence interval 0.41-0.96; p = 0.02). Thus, the relative reduction in prevalence of Candida colonization on day 7 and 14 in the probiotic group was 34.5% and 37.2%, respectively. The increase in number of colonized patients from day 0 to 7 and day 0 to 14 was significant in the placebo group (p = 0.004 and 0.001, respectively) but not in the probiotic group (p = 0.30 and 0.19, respectively; McNemar test). Candiduria was significantly less common in the probiotic group than in the placebo group (17.3% vs. 37.3%; relative risk 0.46; 95% confidence interval 0.26-0.82; p = 0.006). However, prevalence of candidemia did not differ significantly in two groups (1.6% in the probiotic group vs. 6.35% in placebo group; relative risk 0.46; 95% confidence interval 0.08-2.74; p = 0.39).

CONCLUSIONS

Supplementation with probiotics could be a potential strategy to reduce gastrointestinal Candida colonization and candiduria in critically ill children receiving broad spectrum antibiotics.

Cap1p attenuates the apoptosis of Candida albicans

Candida albicans is the most common opportunistic fungal pathogen and its apoptosis is inducible by environmental stress. Based on our previous finding that transcription factor Cap1p was involved in baicalein-induced apoptosis, the present study aimed to further clarify the role of Cap1p in apoptosis by observing the impact of CAP1 deletion on cell fate. It was found that apoptotic stimulation with amphotericin B, acetic acid and hydrogen peroxide increased the number of apoptotic and necrotic cells, caspase activity and the accumulation of reactive oxygen species, whereas it decreased the mitochondrial membrane potential and intracellular ATP level in the cap1Δ/Δ mutant. The cell fate was, at least partly, caused by glutathione depletion and attenuation of the expression of the glutathione reductase gene in the cap1Δ/Δ mutant. Collectively, our data suggest that Cap1p participated in the apoptosis of C. albicans by regulating the expression of the glutathione reductase gene and glutathione content.

Fungal diagnosis: how do we do it and can we do better?

BACKGROUND

Morbidity and mortality remain high for patients with invasive fungal infections (IFIs) despite an increasing number of antifungals and other treatments. Many studies indicate that delayed or inaccurate diagnosis and treatment are major causes of poor outcomes in patients with IFIs.

OBJECTIVE

The aim of the current paper is to provide a review of traditional and newer approaches to the diagnosis of IFIs, with a particular focus on invasive candidiasis (IC) and aspergillosis (IA). Recent studies from the author's institution are highlighted, along with an advancement in cryptococcal meningitis diagnosis that should improve the care of AIDS and its opportunistic infection in many developing countries.

FINDINGS

Currently available tools for the diagnosis of IFIs include traditional methods like histopathology, culture, and radiology, and newer antigen- and PCR-based diagnostic assays. Attempts have also been made to predict IFIs based on colonization or other factors, including genetic polymorphisms impacting IFI susceptibility in high-risk patients. Biopsy with histopathologic analysis is often not possible in patients suspected of pulmonary aspergillosis due to increased bleeding risk, and blood cultures for IC, IA, or other IFIs are hindered by poor sensitivity and slow turnaround time which delays diagnosis. Radiology is often used to predict IFI but suffers from inability to differentiate certain pathogens and does not generally provide certainty of IFI diagnosis. Newer antigen-based diagnostics for early diagnosis include the β-glucan assay for IFIs, galactomannan assay for IA, and a recent variation on the traditional cryptococcal antigen (CRAG) test with a Lateral Flow Assay for invasive cryptococcosis. PCR-based diagnostics represent additional tools with high sensitivity for the rapid diagnosis of IFIs, although better standardization of these methods is still required for their routine clinical use.

CONCLUSION

Better understanding of the strengths and weaknesses of currently available diagnostic tools, and further devising linked strategies to best implement them either alone or in combination, would greatly improve early and accurate diagnosis of IFIs and improve their successful management.

Time to initiation of antifungal therapy for neonatal candidiasis

The effect of delayed antifungal therapy in critically ill infants with invasive candidiasis has not been studied. Our objective was to evaluate the effect of time to initiation of antifungal therapy (TIA) on mortality, disseminated disease, and postinfection hospital stay. We conducted a cohort study of critically ill infants with cultures positive for Candida from 1990 to 2008. TIA was defined as the number of hours from the collection of the first positive culture until the start of antifungal therapy. Of 96 infants, 57% were male, the median gestational age was 27 weeks (range, 23 to 41 weeks), and the median birth weight was 956 g (range, 415 to 6,191 g). Most subjects received amphotericin B deoxycholate. TIA was ≤ 24 h for 35% of infants, between 25 and 48 h for 42%, and >48 h for 23%. Eleven subjects died during hospitalization, and 22% had disseminated candidiasis. The median duration of hospital stay postinfection was 53 days (range, 6 to 217 days). Both univariate and multivariate analyses demonstrated that TIA was not associated with mortality, disseminated disease, or hospital stay postinfection. However, ventilator use for >60 days significantly increased the risk of death (odds ratio [OR], 9.5; 95% confidence interval [CI], 2.2 to 66.7; P = 0.002). Prolonged candidemia increased the risk of disseminated disease by 10% per day of positive culture (OR, 1.1; 95% CI, 1.08 to 1.2; P = 0.007), and low gestational age was associated with increased neonatal intensive care unit (NICU) stay after the first positive Candida culture by 0.94 weeks (95% CI, 0.70 to 0.98; P < 0.001). The TIA was not associated with all-cause mortality, disseminated candidiasis, and postinfection length of hospital stay.

Risk factors for invasive candidiasis in infants >1500 g birth weight

BACKGROUND

We describe the incidence, risk factors and outcomes of invasive candidiasis in infants >1500 g birth weight.

METHODS

We conducted a retrospective cohort study of infants >1500 g birth weight discharged from 305 neonatal intensive care units in the Pediatrix Medical Group from 2001 to 2010. Using multivariable logistic regression, we identified risk factors for invasive candidiasis.

RESULTS

Invasive candidiasis occurred in 330 of the 530,162 (0.06%) infants. These were documented from positive cultures from ≥1 of these sources: blood (n = 323), cerebrospinal fluid (n = 6) or urine from catheterization (n = 19). Risk factors included day of life >7 (odds ratio [OR]: 25.2; 95% confidence interval: 14.6-43.3), vaginal birth (OR: 1.6 [1.2-2.3]), exposure to broad-spectrum antibiotics (OR: 1.6 [1.1-2.4]), central venous line (OR: 1.8 [1.3-2.6]) and platelet count <50,000/mm (OR: 3.7 [2.1-6.7]). All risk factors had poor sensitivities, low positive likelihood ratios and low positive predictive values. The combination of broad-spectrum antibiotics and low platelet count had the highest positive likelihood ratio (46.2), but the sensitivity of this combination was only 4%. Infants with invasive candidiasis had increased mortality (OR: 2.2 [1.3-3.6]).

CONCLUSIONS

Invasive candidiasis is uncommon in infants >1500 g birth weight. Infants at greatest risk are those exposed to broad-spectrum antibiotics and with platelet counts of <50,000/mm(3).

Shuttle vectors for facile gap repair cloning and integration into a neutral locus in Candida albicans

Candida albicans is the most prevalent fungal pathogen of humans. The current techniques used to construct C. albicans strains require integration of exogenous DNA at ectopic locations, which can exert position effects on gene expression that can confound the interpretation of data from critical experiments such as virulence assays. We have identified a large intergenic region, NEUT5L, which facilitates the integration and expression of ectopic genes. To construct and integrate inserts into this novel locus, we re-engineered yeast/bacterial shuttle vectors by incorporating 550 bp of homology to NEUT5L. These vectors allow rapid, facile cloning through in vivo recombination (gap repair) in Saccharomyces cerevisiae and efficient integration of the construct into the NEUT5L locus. Other useful features of these vectors include a choice of three selectable markers (URA3, the recyclable URA3-dpl200 or NAT1), and rare restriction enzyme recognition sites for releasing the insert from the vector prior to transformation into C. albicans, thereby reducing the insert size and preventing integration of non-C. albicans DNA. Importantly, unlike the commonly used RPS1/RP10 locus, integration at NEUT5L has no negative effect on growth rates and allows native-locus expression levels, making it an ideal genomic locus for the integration of exogenous DNA in C. albicans.

A review of Candida species causing blood stream infection

The incidence of candidemia has been on a rise worldwide. The epidemiology of invasive fungal infections in general and of candidemia in particular has changed in the past three decades because of a variety of factors like the AIDS epidemic, increased number of patients receiving immunosuppressive therapy for transplantation and the increasing use of antimicrobials in the hospital setups and even in the community. The important risk factors for candidemia include use of broad-spectrum antimicrobials, cancer chemotherapy, mucosal colonization by Candida species, indwelling vascular catheters like central venous catheters, etc. More than 90% of the invasive infections due to Candida species are attributed to five species-Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis and Candida krusei. However, the list of new species of Candida isolated from clinical specimens continues to grow every year. Early diagnosis and proper treatment is the key for management of candidemia cases.

The epidemiology of neonatal and pediatric candidemia in England and Wales, 2000-2009

BACKGROUND

There are few population-based studies on the epidemiology of neonatal and pediatric invasive Candida infections, despite their significant clinical impact on patients. This study aimed to describe the epidemiology of pediatric candidemia in England and Wales during a 10-year period as a means of quantifying the changing burden of infection and identifying emerging trends.

METHODS

National Health Service hospital microbiology laboratories in England and Wales routinely report clinically significant invasive infections electronically to the Health Protection Agency. Records of all positive blood cultures for Candida species in children aged <15 years between 2000 and 2009 inclusive were extracted for analysis.

RESULTS

During 2000 to 2009, 1473 childhood candidemia cases were reported in England and Wales (annual incidence, 1.52/100,000 person-years), with the highest rate in <1 year olds (n = 706; 11.0/100,000), followed by 1-4 year olds (n = 440; 1.77/100,000), 5-9 year olds (n = 168; 0.53/100,000) and 10-14 year olds (n = 159; 0.47/100,000). Incidence increased from 1.04 per 100,000 in 2000 to 2.09 per 100,000 in 2007 (P < 0.001) before falling to 1.53 per 100,000 in 2009 (P < 0.001). Candida species was reported in 89.6% (1320/1473) cases, with Candida albicans and Candida parapsilosis accounting for most infections in all age groups. There were no significant differences in species distribution by season or year of study and the proportion of non-albicans cases did not increase with time.

CONCLUSIONS

Pediatric candidemia rates are beginning to fall in England and Wales. C. albicans continues to account for most Candida bloodstream infections in all age groups with no evidence of increases in non-albicans species.

Mortality in patients with early- or late-onset candidaemia

OBJECTIVES

Although candidaemia is a well-known complication of hospital stay and has a crude mortality of ∼40%, few data are available for episodes diagnosed within 10 days after hospital admission. In this paper, we compared the risk factors for mortality according to the onset of candidaemia.

METHODS

This was a retrospective study of hospitalized patients with early-onset candidaemia (EOC; ≤ 10 days) or late-onset candidaemia (LOC; >10 days) to identify any distinct clinical characteristics and risk factors for 30 day mortality in two Italian academic centres.

RESULTS

A total of 779 patients were included in the study: 183 EOC and 596 LOC. Mortality was significantly lower in EOC (71/183, 38.8% versus 283/596, 47.5%, P=0.03). In EOC, multivariate analysis showed that inadequate initial antifungal therapy (IIAT) (P=0.005, OR 3.02, 95% CI 1.40-6.51), Candida albicans aetiology (P=0.02, OR 2.17, 95% CI 1.11-4.26) and older age (P<0.001, OR 1.05, 95% CI 1.02-1.07) were independent risk factors for mortality. In LOC, liver disease (P=0.003, OR 2.46, 95% CI 1.36-4.43), IIAT (P=0.002, OR 2.01, 95% CI 1.28-3.15) and older age (P<0.001, OR 1.03, 95% CI 1.02-1.04) were independently associated with a fatal outcome, while treatment with caspofungin was associated with survival (P<0.001, OR 0.42, 95% CI 0.26-0.67).

CONCLUSIONS

EOC has different clinical characteristics and risk factors for mortality compared with LOC. Although EOC mortality is significantly lower, the rate of inappropriate antifungal treatment is higher. Treatment with caspofungin is significantly associated with survival in patients with LOC. Efforts are needed to improve the diagnosis and treatment of EOC.

Results from a prospective, international, epidemiologic study of invasive candidiasis in children and neonates

BACKGROUND

Candida species are the third most common cause of pediatric health care-associated bloodstream infection in the United States and Europe. To our knowledge, this report from the International Pediatric Fungal Network is the largest prospective, multicenter observational study dedicated to pediatric and neonatal invasive candidiasis.

METHODS

From 2007 to 2011, we enrolled 196 pediatric and 25 neonatal patients with invasive candidiasis.

RESULTS

Non-albicans Candida species predominated in pediatric (56%) and neonatal (52%) age groups, yet Candida albicans was the most common species in both groups. Successful treatment responses were observed in pediatric (76%) and neonatal patients (92%). Infection with Candida parapsilosis led to successful responses in pediatric (92%) and neonatal (100%) patients, whereas infection with Candida glabrata was associated with a lower successful outcome in pediatric patients (55%). The most commonly used primary antifungal therapies for pediatric invasive candidiasis were fluconazole (21%), liposomal amphotericin B (20%) and micafungin (18%). Outcome of pediatric invasive candidiasis was similar in response to polyenes (73%), triazoles (67%) and echinocandins (73%). The most commonly used primary antifungal therapies for neonatal invasive candidiasis were fluconazole (32%), caspofungin (24%) and liposomal amphotericin B (16%) and micafungin (8%). Outcomes of neonatal candidiasis by antifungal class again revealed similar response rates among the classes.

CONCLUSIONS

We found a predominance of non-albicans Candida infection in children and similar outcomes based on antifungal class used. This international collaborative study sets the foundation for large epidemiologic studies focusing on the unique features of neonatal and pediatric candidiasis and comparative studies of therapeutic interventions in these populations.

The PATH (Prospective Antifungal Therapy) Alliance® registry and invasive fungal infections: update 2012

The Prospective Antifungal Therapy Alliance (PATH Alliance®) performed prospective surveillance of invasive fungal infections (IFIs) among patients hospitalized at 25 medical centers in North America between 2004 and 2008, collecting information on the epidemiology, diagnosis, treatment, and mortality rates of IFIs. In total, 7526 IFIs were identified in 6845 patients. Candida spp. (73.4%) were the most common pathogens, followed by Aspergillus spp. (13.3%), and other yeasts (6.2%). Culture was the most frequently used diagnostic test in the majority of IFI categories. Most patients with invasive candidiasis were treated with fluconazole (48.3%) and the echinocandins (34.0%), while voriconazole (45.5%) was the main antifungal agent for invasive aspergillosis. The 12-week survival rate ranged from 37.5% for hematopoietic stem cell transplant recipients to ~75.0% for those with HIV/AIDS. In summary, the findings of the PATH Alliance® registry provide a better understanding of the epidemiology of a vast variety and large numbers of IFIs.

Design of a Candida albicans disaccharide conjugate vaccine by reverse engineering a protective monoclonal antibody

A disaccharide-chicken serum albumin conjugate vaccine against Candida albicans infections has been developed by reverse engineering a protective monoclonal antibody, C3.1. The binding site of C3.1 binds short oligosaccharides of β1,2-linked mannopyranose residues present in the fungal cell wall phosphomannan. By delineating the fine detail of the molecular recognition of the cell wall β-mannan antigen, a disaccharide epitope was deduced to be the minimum size epitope that should induce the formation of protective antibody. Sequential functional group replacement of disaccharide hydroxyl groups to yield a series of monodeoxy and mono-O-methyl β1,2-linked mannobioside congeners established that three hydroxyl groups are essential for binding. Two of these, O-3 and O-4, are located on the internal mannose residue of the disaccharide, and a third, O-3', is located on the terminal mannose. Synthesis of a series of trisaccharides that mandate binding of either the reducing or nonreducing disaccharide epitopes provided the final indication that a disaccharide protein conjugate should have the potential to induce protective antibody. When disaccharide was conjugated to chicken serum albumin this vaccine produced antibodies in rabbits that recognized the native cell wall phosphomannan. In proof of concept protection experiments, three immunized rabbits showed a reduction in fungal burden when challenged with live C. albicans.

Infections occurring in adult patients receiving mechanical circulatory support: the two-year experience of an Italian National Referral Tertiary Care Center

OBJECTIVE

Infection during mechanical circulatory support is a frequent adverse complication. We analyzed infections occurring in this population in a national tertiary care center, and assessed the differences existing between the setting of extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs).

DESIGN, SETTING, AND PARTICIPANTS

An observational study was made of patients treated with ECMO or VAD in the San Raffaele Scientific Institute (Italy) between 2009 and 2011.

INTERVENTIONS

None.

RESULTS

Thirty-nine percent of the 46 patients with ECMO and 69% of the 15 patients with VAD developed infection. We observed a mortality rate of 36.1% during mechanical circulatory support and of 55.7% during the global hospitalization period. Although Gram-negative infections were predominant overall, patients with ECMO were more prone to develop Candida infection (29%), and patients with VAD tended to suffer Staphylococcus infection (18%). Patients with infection had longer ECMO support (p=0.03), VAD support (p=0.01), stay in the intensive care unit (p=0.002), and hospital admission (p=0.03) than patients without infection. Infection (regression coefficient=3.99, 95% CI 0.93-7.05, p=0.02), body mass index (regression coefficient=0.46, 95% CI 0.09-0.83, p=0.02), fungal infection (regression coefficient=4.96, 95% CI 1.42-8.44, p=0.009) and obesity (regression coefficient=10.47, 95% CI 1.77-19.17, p=0.02) were predictors of the duration of ECMO support. Stepwise logistic regression analysis showed the SOFA score at the time of implant (OR=12.33, 95% CI 1.15-132.36, p=0.04) and VAD (OR=1.27, 95% CI 1.04-1.56, p=0.02) to be associated with infection.

CONCLUSIONS

Infection is a major challenge during ECMO and VAD support. Each mechanical circulatory support configuration is associated with specific pathogens; fungal infections play a major role.

Clinical characteristics of candidaemia in adults with haematological malignancy, and antimicrobial susceptibilities of the isolates at a medical centre in Taiwan, 2001-2010

During the period 2001-2010, a total of 154 episodes of candidaemia were noted in 111 of 2574 patients with haematological malignancies at the National Taiwan University Hospital (Taipei, Taiwan). Patients with acute lymphoblastic leukaemia had a significantly higher rate of candidaemia than patients with other haematological malignancies (odds ratio=2.69; P<0.001). Candida tropicalis was the most common Candida species (n=51; 46%), followed by Candida albicans (n=35; 32%), Candida parapsilosis (n=13; 12%), Candida glabrata (n=8; 7%) and Candida krusei (n=4; 4%). Persistent candidaemia was initially identified in 21 patients (18.9%) and was frequently associated with central venous catheter-related infection (52% vs. 24%; P=0.017). Multivariate analysis revealed that shock (P<0.001), allogeneic transplantation (P=0.033) and elderly age (≥60 years) (P=0.041) were independent prognostic factors of 30-day overall survival in patients with haematological malignancy and candidaemia. Minimum inhibitory concentrations (MICs) of a total of 103 non-duplicate blood isolates of Candida spp., including 82 isolates from 82 patients without persistent candidaemia and 21 isolates causing first episodes among 21 patients with persistent candidaemia, to nine antifungal agents were determined using the broth microdilution method. Among the 103 Candida isolates, 53 (51.5%), 94 (91.3%) and 102 (99.0%) were susceptible to itraconazole, fluconazole and voriconazole, respectively. All Candida isolates were susceptible to caspofungin, and 2 (15%) of the 13 C. parapsilosis isolates were not susceptible to micafungin or anidulafungin. The MIC(90) (MIC for 90% of the organisms) of posaconazole was 0.03 mg/L for C. albicans, 0.5 mg/L for C. tropicalis, 0.12 mg/L for C. parapsilosis and 2 mg/L for C. glabrata.

Hsp90 is involved in apoptosis of Candida albicans by regulating the calcineurin-caspase apoptotic pathway

Candida albicans is the most common human fungal pathogen. Recent evidence has revealed the occurrence of apoptosis in C. albicans that is inducible by environmental stresses such as hydrogen peroxide, acetic acid, and amphotericin B. Apoptosis is regulated by the calcineurin-caspase pathway in C. albicans, and calcineurin is under the control of Hsp90 in echinocandin resistance. However, the role of Hsp90 in apoptosis of C. albicans remains unclear. In this study, we investigated the role of Hsp90 in apoptosis of C. albicans by using an Hsp90-compromised strain tetO-HSP90/hsp90 and found that upon apoptotic stimuli, including hydrogen peroxide, acetic acid or amphotericin B treatment, less apoptosis occurred, less ROS was produced, and more cells survived in the Hsp90-compromised strain compared with the Hsp90/Hsp90 wild-type strain. In addition, Hsp90-compromised cells were defective in up-regulating caspase-encoding gene CaMCA1 expression and activating caspase activity upon the apoptotic stimuli. Investigations on the relationship between Hsp90 and calcineurin revealed that activation of calcineurin could up-regulate apoptosis but could not further down-regulate apoptosis in Hsp90-compromised cells, indicating that calcineurin was downstream of Hsp90. Hsp90 inhibitor geldanamycin (GdA) could further decrease the apoptosis in calcineurin-pathway-defect strains, indicating that compromising Hsp90 function had a stronger effect than compromising calcineurin function on apoptosis. Collectively, this study demonstrated that compromised Hsp90 reduced apoptosis in C. albicans, partially through downregulating the calcineurin-caspase pathway.

Dectin-1 is not required for controlling Candida albicans colonization of the gastrointestinal tract

Candida albicans is normally found as a commensal microbe, commonly colonizing the gastrointestinal tract in humans. However, this fungus can also cause mucosal and systemic infections once immune function is compromised. Dectin-1 is an innate pattern recognition receptor essential for the control of fungal infections in both mice and humans; however, its role in the control of C. albicans colonization of the gastrointestinal tract has not been defined. Here, we demonstrate that in mice dectin-1 is essential for the control of gastrointestinal invasion during systemic infection, with dectin-1 deficiency associating with impaired fungal clearance and dysregulated cytokine production. Surprisingly, however, following oral infection, dectin-1 was not required for the control of mucosal colonization of the gastrointestinal tract, in terms of either fungal burdens or cytokine response. Thus, in mice, dectin-1 is essential for controlling systemic infection with C. albicans but appears to be redundant for the control of gastrointestinal colonization.

Chemokine receptor Ccr1 drives neutrophil-mediated kidney immunopathology and mortality in invasive candidiasis

Invasive candidiasis is the 4^th leading cause of nosocomial bloodstream infection in the US with mortality that exceeds 40% despite administration of antifungal therapy; neutropenia is a major risk factor for poor outcome after invasive candidiasis. In a fatal mouse model of invasive candidiasis that mimics human bloodstream-derived invasive candidiasis, the most highly infected organ is the kidney and neutrophils are the major cellular mediators of host defense; however, factors regulating neutrophil recruitment have not been previously defined. Here we show that mice lacking chemokine receptor Ccr1, which is widely expressed on leukocytes, had selectively impaired accumulation of neutrophils in the kidney limited to the late phase of the time course of the model; surprisingly, this was associated with improved renal function and survival without affecting tissue fungal burden. Consistent with this, neutrophils from wild-type mice in blood and kidney switched from Ccr1^lo to Ccr1^high at late time-points post-infection, when Ccr1 ligands were produced at high levels in the kidney and were chemotactic for kidney neutrophils ex vivo. Further, when a 1∶1 mixture of Ccr1^+/+ and Ccr1^−/− donor neutrophils was adoptively transferred intravenously into Candida-infected Ccr1^+/+ recipient mice, neutrophil trafficking into the kidney was significantly skewed toward Ccr1^+/+ cells. Thus, neutrophil Ccr1 amplifies late renal immunopathology and increases mortality in invasive candidiasis by mediating excessive recruitment of neutrophils from the blood to the target organ.

Invasive infection by the yeast Candida represents a significant cause of morbidity and mortality in patients in the intensive care unit. Neutrophils, which are recruited to sites of Candida infection by chemokines and their receptors, are important immune cells in host defense against invasive candidiasis. Consistent with that, lack of neutrophils is a well-established risk factor for adverse outcome after infection. In this study, we performed a broad survey of the chemokine system in a mouse model of invasive candidiasis with an aim to determine factors that regulate neutrophil trafficking to sites of infection. We used that survey to identify Ccr1 as a mediator of mortality in the model via excessive recruitment of neutrophils from the blood to the kidney that results in kidney tissue injury. Strikingly, the effect of Ccr1 on neutrophil accumulation in the kidney was not seen until the late phase of the infection, when the receptor was up-regulated on the neutrophil surface. Together these data demonstrate that neutrophils, besides their recognized protective roles in antifungal host defense, may also exert detrimental effects by causing uncontrolled tissue damage, and identify Ccr1 as a mediator of neutrophil tissue injury in a mouse model of invasive candidiasis.

Changes in incidence and antifungal drug resistance in candidemia: results from population-based laboratory surveillance in Atlanta and Baltimore, 2008-2011

BACKGROUND

Candidemia is common and associated with high morbidity and mortality; changes in population-based incidence rates have not been reported.

METHODS

We conducted active, population-based surveillance in metropolitan Atlanta, Georgia, and Baltimore City/County, Maryland (combined population 5.2 million), during 2008-2011. We calculated candidemia incidence and antifungal drug resistance compared with prior surveillance (Atlanta, 1992-1993; Baltimore, 1998-2000).

RESULTS

We identified 2675 cases of candidemia with 2329 isolates during 3 years of surveillance. Mean annual crude incidence per 100 000 person-years was 13.3 in Atlanta and 26.2 in Baltimore. Rates were highest among adults aged ≥65 years (Atlanta, 59.1; Baltimore, 72.4) and infants (aged <1 year; Atlanta, 34.3; Baltimore, 46.2). In both locations compared with prior surveillance, adjusted incidence significantly declined for infants of both black and white race (Atlanta: black risk ratio [RR], 0.26 [95% confidence interval {CI}, .17-.38]; white RR: 0.19 [95% CI, .12-.29]; Baltimore: black RR, 0.38 [95% CI, .22-.64]; white RR: 0.51 [95% CI: .29-.90]). Prevalence of fluconazole resistance (7%) was unchanged compared with prior surveillance; 32 (1%) isolates were echinocandin-resistant, and 9 (8 Candida glabrata) were multidrug resistant to both fluconazole and an echinocandin.

CONCLUSIONS

We describe marked shifts in candidemia epidemiology over the past 2 decades. Adults aged ≥65 years replaced infants as the highest incidence group; adjusted incidence has declined significantly in infants. Use of antifungal prophylaxis, improvements in infection control, or changes in catheter insertion practices may be contributing to these declines. Further surveillance for antifungal resistance and efforts to determine effective prevention strategies are needed.

β-D-glucan surveillance with preemptive anidulafungin for invasive candidiasis in intensive care unit patients: a randomized pilot study

BACKGROUND

Invasive candidiasis (IC) is a devastating disease. While prompt antifungal therapy improves outcomes, empiric treatment based on the presence of fever has little clinical impact. Β-D-Glucan (BDG) is a fungal cell wall component detectable in the serum of patients with early invasive fungal infection (IFI). We evaluated the utility of BDG surveillance as a guide for preemptive antifungal therapy in at-risk intensive care unit (ICU) patients.

METHODS

Patients admitted to the ICU for ≥ 3 days and expected to require at least 2 additional days of intensive care were enrolled. Subjects were randomized in 3:1 fashion to receive twice weekly BDG surveillance with preemptive anidulafungin in response to a positive test or empiric antifungal treatment based on physician preference.

RESULTS

Sixty-four subjects were enrolled, with 1 proven and 5 probable cases of IC identified over a 2.5 year period. BDG levels were higher in subjects with proven/probable IC as compared to those without an IFI (117 pg/ml vs. 28 pg/ml; p<0.001). Optimal assay performance required 2 sequential BDG determinations of ≥ 80 pg/ml to define a positive test (sensitivity 100%, specificity 75%, positive predictive value 30%, negative predictive value 100%). In all, 21 preemptive and 5 empiric subjects received systemic antifungal therapy. Receipt of preemptive antifungal treatment had a significant effect on BDG concentrations (p< 0.001). Preemptive anidulafungin was safe and generally well tolerated with excellent outcome.

CONCLUSIONS

BDG monitoring may be useful for identifying ICU patients at highest risk to develop an IFI as well as for monitoring treatment response. Preemptive strategies based on fungal biomarkers warrant further study.

TRIAL REGISTRATION

Clinical Trials.gov NCT00672841.

Caspofungin as antifungal prophylaxis in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation: a retrospective analysis

Background

Pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) often receive intravenous liposomal amphotericin B (L-AmB) as antifungal prophylaxis. There are no guidelines for antifungal prophylaxis in children in this situation. Caspofungin (CAS), a broad-spectrum echinocandin, could be an effective alternative with lower nephrotoxicity than L-AmB.

Methods

We retrospectively analyzed the safety, feasibility, and efficacy of CAS in our center, and compared the results with L-AmB as antifungal monoprophylaxis in pediatric patients undergoing HSCT. 60 pediatric patients received L-AmB (1 or 3 mg/kg bw/day) and another 60 patients received CAS (50 mg/m²/day) as antifungal monoprophylaxis starting on day one after HSCT. The median ages of patients receiving L-AmB and CAS were 7.5 years and 9.5 years, respectively.

Results

No proven breakthrough fungal infection occurred in either group during the median treatment period of 23 days in the L-AmB group and 24 days in the CAS group. One patient receiving CAS developed probable invasive aspergillosis. During L-AmB treatment, potassium levels significantly decreased below normal values. Patients treated with L-AmB had more drug-related side effects and an increased need for oral supplementation with potassium, sodium bicarbonate and calcium upon discharge as compared with the CAS group. CAS was well-tolerated and safe in this cohort of immunocompromised pediatric patients, who underwent high-dose chemotherapy and HSCT.

Conclusion

Prophylactic CAS and L-AmB showed similar efficacy in this biggest cohort of pediatric patients after allogeneic HSCT reported, so far. A prospective randomized trial in children is warranted to allow for standardized guidelines.

Echinocandin Resistance in Candida Species: Mechanisms of Reduced Susceptibility and Therapeutic Approaches

OBJECTIVE:

To summarize published data regarding mechanisms of reduced echinocandin susceptibility in Candida spp., the impact of echinocandin resistance on the fitness and virulence of Candida isolates, and current and future treatment approaches.

DATA SOURCES:

A search of MEDLINE databases (1966-September 2011) was conducted.

STUDY SELECTION AND DATA EXTRACTION:

Databases were searched using the terms echinocandin, resistance, and Candida. Citations from publications were reviewed for additional references.

DATA SYNTHESIS:

Echinocandins have in vitro activity against most Candida spp. and are first-line agents in the treatment of candidemia. However, case reports describing echinocandin treatment failure due to resistant isolates have been published. Reduced echinocandin susceptibility has been shown to occur via 3 main mechanisms: (1) adaptive stress responses, which result in elevated cell wall chitin content and paradoxical growth in vitro at supra minimum inhibitory concentrations (MICs); (2) acquired FKS mutations, which confer reduced glucan synthase sensitivity, elevated MICs, and are associated with clinical failure; and (3) intrinsic FKS mutations, which are naturally occurring mutations in C. parapsilosis and C. guilliermondii, which confer elevated MIC levels but a lower level of reduced glucan synthase sensitivity compared with acquired FKS mutations. Some FKS mutants have been shown to have significantly reduced fitness and virulence versus wild type isolates and may contribute to the low incidence of echinocandin resistance reported in large surveillance studies. Treatment strategies evaluated for FKS mutants include echinocandin dose escalation and combination with agents such as calcineurin inhibitors, HSP90 inhibitors, and chitin synthase inhibitors.

CONCLUSIONS:

While the incidence of echinocandin resistance in Candida spp. is low, it can present a significant therapeutic challenge, especially in multidrug-resistant Candida isolates. Dose escalation is unlikely to be effective in treating FKS mutant isolates, and significant adverse effects limit the clinical use of agents evaluated as combination therapy. Patients with infections failing to respond to echinocandin therapy should undergo susceptibility testing and be treated with an alternative antifungal agent if possible.

Caspofungin for the treatment of immunocompromised and severely ill children and neonates with invasive fungal infections

Caspofungin is the first member of the echinocandin class of antifungals to receive an indication for the use in infants, children, and adolescents from the United States Food and Drug Administration. Daily doses of 50 mg/m(2) result in pharmacokinetic parameters that are similar to those observed in adults. Although fewer data are available, the response rates in pediatric patients who received caspofungin either as treatment or empiric therapy in clinical trials are similar to those reported in adults. In addition, caspofungin appears to be generally safe and well tolerated in this population. This represents a significant step forward in the treatment of invasive fungal infections within this population, as caspofungin is associated with few clinically significant drug-interactions and toxicities compared to other antifungals, such as the azoles and amphotericin B.

Population dynamics and the evolution of antifungal drug resistance in Candida albicans

Candida albicans is an important human fungal pathogen. Resistance to all major antifungal agents has been observed in clinical isolates of Candida spp. and is a major clinical challenge. The rise and expansion of drug-resistant mutants during exposure to antifungal agents occurs through a process of adaptive evolution, with potentially complex population dynamics. Understanding the population dynamics during the emergence of drug resistance is important for determining the fundamental principles of how fungal pathogens evolve for resistance. While few detailed reports that focus on the population dynamics of C. albicans currently exist, several important features on the population structure and adaptive landscape can be elucidated from existing evolutionary studies in in vivo and in vitro systems.

Global analysis of the evolution and mechanism of echinocandin resistance in Candida glabrata

The evolution of drug resistance has a profound impact on human health. Candida glabrata is a leading human fungal pathogen that can rapidly evolve resistance to echinocandins, which target cell wall biosynthesis and are front-line therapeutics for Candida infections. Here, we provide the first global analysis of mutations accompanying the evolution of fungal drug resistance in a human host utilizing a series of C. glabrata isolates that evolved echinocandin resistance in a patient treated with the echinocandin caspofungin for recurring bloodstream candidemia. Whole genome sequencing identified a mutation in the drug target, FKS2, accompanying a major resistance increase, and 8 additional non-synonymous mutations. The FKS2-T1987C mutation was sufficient for echinocandin resistance, and associated with a fitness cost that was mitigated with further evolution, observed in vitro and in a murine model of systemic candidemia. A CDC6-A511G(K171E) mutation acquired before FKS2-T1987C(S663P), conferred a small resistance increase. Elevated dosage of CDC55, which acquired a C463T(P155S) mutation after FKS2-T1987C(S663P), ameliorated fitness. To discover strategies to abrogate echinocandin resistance, we focused on the molecular chaperone Hsp90 and downstream effector calcineurin. Genetic or pharmacological compromise of Hsp90 or calcineurin function reduced basal tolerance and resistance. Hsp90 and calcineurin were required for caspofungin-dependent FKS2 induction, providing a mechanism governing echinocandin resistance. A mitochondrial respiration-defective petite mutant in the series revealed that the petite phenotype does not confer echinocandin resistance, but renders strains refractory to synergy between echinocandins and Hsp90 or calcineurin inhibitors. The kidneys of mice infected with the petite mutant were sterile, while those infected with the HSP90-repressible strain had reduced fungal burden. We provide the first global view of mutations accompanying the evolution of fungal drug resistance in a human host, implicate the premier compensatory mutation mitigating the cost of echinocandin resistance, and suggest a new mechanism of echinocandin resistance with broad therapeutic potential.

The evolution of drug resistance poses a severe threat to human health. Candida glabrata is a leading cause of mortality due to fungal infections worldwide. It can rapidly evolve resistance to drugs such as echinocandins, which target the fungal cell wall and are front-line therapeutics for Candida infections. We harness whole genome sequencing to provide a global view of mutations that accumulate in C. glabrata during the evolution of echinocandin resistance in a human host. Nine non-synonymous mutations were identified, including one in the echinocandin target. A mutation in an additional gene conferred a small resistance increase and another was in a gene whose dosage mitigated the fitness cost of resistance. We further discovered that compromising function of the molecular chaperone Hsp90 abrogates drug resistance and reduces kidney fungal burden in a mouse model of infection. Hsp90 and its downstream effector calcineurin are required for induction of the drug target in response to drug. Thus, we reveal the first global portrait of antifungal resistance mutations that evolve in a human host, identify the first compensatory mutation that mitigates the cost of echinocandin resistance, and suggest a new mechanism of echinocandin resistance that can be exploited to treat life-threatening fungal infections.

Importance of pharmacokinetic considerations for selecting therapy in the treatment of invasive fungal infections

Invasive fungal infections continue to be a significant cause of morbidity and mortality among at-risk patients. Over the last decade, the epidemiology of invasive mycoses has been defined by increasing rates of infection caused by azole-resistant yeast (Candida glabrata, Candida krusei), Aspergillus, and in some centers, non-Aspergillus moulds, such as Fusarium species, Scedosporium species, and Mucorales. Early and appropriate antifungal therapy is crucial for a favorable clinical outcome. When selecting antifungal therapy--especially during the initial acute phases of treatment--spectrum of activity and pharmacokinetic characteristics are key treatment considerations. Important pharmacokinetic considerations for selecting antifungal therapy in the treatment of invasive fungal infections include drug-drug interactions and variability in adsorption that may limit efficacy during the early phase of treatment, poor oral availability, and variable tissue distribution. A patient's underlying condition and pharmacogenetics also may affect the pharmacokinetics of antifungal drugs, resulting in interpatient pharmacokinetic differences.