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

Simvastatin inhibits Candida albicans biofilm in vitro

By inhibiting the conversion of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) to mevalonate, statins impair cholesterol metabolism in humans. We reasoned that statins might similarly interfere with the biosynthesis of ergosterol, the major sterol of the yeast cell membrane. As assessed by spectrophotometric and microscopic analysis, significant inhibition of biofilm production was noted after 16-h incubation with 1, 2.5, and 5 muM simvastatin, concentrations that did not affect growth, adhesion, or hyphal formation by C. albicans in vitro. Higher concentrations (10, 20, and 25 muM simvastatin) inhibited biofilm by >90% but also impaired growth. Addition of exogenous ergosterol (90 muM) overcame the effects of 1 and 2.5 muM simvastatin, suggesting that at least one mechanism of inhibition is interference with ergosterol biosynthesis. Clinical isolates from blood, skin, and mucosal surfaces produced biofilms; biofilms from bloodstream isolates were similarly inhibited by simvastatin. In the absence of fungicidal activity, simvastatin's interruption of a critical step in an essential metabolic pathway, highly conserved from yeast to man, has unexpected effects on biofilm production by a eukaryotic pathogen.

Prospective monitoring for invasive aspergillosis using galactomannan and polymerase chain reaction in high risk pediatric patients

BACKGROUND

The diagnosis of invasive aspergillus remains a challenge in the care of high-risk patients. Outcomes are improved when invasive aspergillus is diagnosed early, prompting the initiation of appropriate antifungal therapy. We evaluated the utility of prospective monitoring for invasive aspergillosis (IA) using biomarkers such as serum galactomannan (GM) and/or blood polymerase chain reaction (PCR) in high-risk pediatric patients.

METHODS

Patients with high-risk leukemia (HRL) or allogenic hematopoietic cell transplant (HCT) recipients were prospectively monitored twice weekly for IA using GM and PCR for Aspergillus species.

RESULTS

Sixty-eight patients had collected >or=2 specimens. The 1086 specimens were collected; 627 from HRL (58%) and 459 (42%) from HCT recipients. Median specimens/patient was 11.0 (2 to 58), and median follow-up/patient was 98.5 days (14 to 437). Fifty-six percent of samples were obtained from patients receiving mold-active agents; 32% HRL and 89% HCT. There were no proven, 3 probable, and 20 possible episodes of IA. Thirteen specimens (1.2%) from 4 patients (5%) were GM+. None were positive by PCR.

CONCLUSIONS

The prospective use of GM and PCR in this high-risk pediatric population did not identify cases of proven IA. A high false positive rate was not detected. It is speculated that changes in clinical practice, such as early use of empiric and/or prophylactic mold-active agent and frequent imaging studies have impacted the epidemiology of IA. In a population with low incidence of IA, the use of these assays as a screening device on blood may not further enhance current outcomes.

Candidemia in patients with hematologic malignancies in the era of new antifungal agents (2001-2007): stable incidence but changing epidemiology of a still frequently lethal infection

BACKGROUND

The incidence, epidemiology, Candida species distribution, resistance patterns, and outcome of candidemia in high-risk hematologic malignancy and/or stem cell transplantation patients have not been extensively described since the introduction of new antifungal agents.

METHODS

In this retrospective study, the authors reviewed the medical records and microbiologic data of hematologic malignancy patients with candidemia at The University of Texas M. D. Anderson Cancer Center from March 2001 to February 2007.

RESULTS

The authors analyzed 173 episodes of candidemia (170 patients), 125 (72%) of which were breakthrough cases after prior antifungal agents, mainly fluconazole (28 [22%]), caspofungin (25 [20%]), and voriconazole (18 [14%]). The incidence of candidemia (per 100,000 inpatient days) remained relatively stable, from 13.9 in 2001 to 19.2 in 2006. However, compared with the findings of previous studies at the authors' institution, the frequency of Candida glabrata and C. krusei infection decreased (to 5% and 17%, respectively) and C. parapsilosis (24%) and C. tropicalis (21%) increased. C. parapsilosis fungemia was associated with prior caspofungin use (P<.001). The overall 30-day crude mortality rate was 38%, and the attributable mortality rate was 19%, similar to previous findings at the authors' institution. The Candida species associated with the highest mortality rate was C. glabrata.

CONCLUSIONS

Despite the widespread use of antifungal prophylaxis and the introduction of new antifungal agents, the incidence and associated mortality rates of candidemia remained stable in high-risk hematologic malignancy patients. However, its epidemiological characteristics have shifted, with C. parapsilosis and C. tropicalis becoming more common.

Treatment of candidemia and invasive candidiasis in the intensive care unit: post hoc analysis of a randomized, controlled trial comparing micafungin and liposomal amphotericin B

Introduction

Invasive candidiasis and candidemia are life-threatening nosocomial infections in intensive care patients.

Methods

A post hoc analysis of a phase 3 trial assessing micafungin (100 mg/day for subjects > 40 kg; 2 mg/kg/day for subjects ≤ 40 kg) versus liposomal amphotericin B (3 mg/kg/day). Subgroups were defined according to the type of ward on the first day of treatment: intensive care unit (ICU) or non-ICU. Multivariate regression was performed to identify factors associated with treatment success at end of therapy and all-cause mortality at days 8 and 30.

Results

In non-ICU subjects, treatment success was significantly higher for micafungin versus liposomal amphotericin B (85% (n = 108/127) versus 72.1% (n = 98/136); P = 0.0113). However, for ICU subjects, treatment success rates for micafungin versus liposomal amphotericin B were similar (62.5% (n = 75/120) versus 66.4% (n = 73/110); P = 0.5828). Overall, treatment success was significantly lower in ICU subjects compared with non-ICU subjects (64.3% (n = 148/230) versus 78.3% (n = 206/263); P = 0.0006). Multivariate regression analysis revealed a lower likelihood of treatment success for: ICU versus non-ICU subjects; persistent neutropenia; and high versus low Acute Physiology and Chronic Health Evaluation (APACHE) II scores. However, when interactions between potential explanatory factors were included in the analysis model, ICU status no longer emerged as a significant associated variable but the association between APACHE II score and treatment outcome remained. Further analyses indicated that the likelihood of mortality at day 8 and day 30 was lower for subjects with lower APACHE II scores. Renal function was significantly better in micafungin versus liposomal amphotericin B subjects: a difference (liposomal amphotericin B - micafungin in mean peak change in estimated glomerular filtration rate (ml/minute/1.73 m²) of -18.2 (P < 0.0001) and -17.7 (P = 0.0124) in non-ICU and ICU subjects, respectively.

Conclusions

Overall, ICU subjects had lower treatment success rates than non-ICU subjects for both liposomal amphotericin B and micafungin. Multivariate regression after controlling for potential confounding factors suggested the APACHE II score remained a potential explanatory factor associated with treatment success, mortality at day 8, and mortality at day 30.

Trial registration

Post hoc analysis - clinicaltrials.gov trial NCT00106288.

Invasive candidiasis in pediatric intensive care units

Candidemia and disseminated candidiasis are major causes of morbidity and mortality in hospitalized patients especially in the intensive care units (ICU). The incidence of invasive candidasis is on a steady rise because of increasing use of multiple antibiotics and invasive procedures carried out in the ICUs. Worldwide there is a shifting trend from C. albicans towards non albicans species, with an associated increase in mortality and antifungal resistance. In the ICU a predisposed host in one who is on broad spectrum antibiotics, parenteral nutrition, and central venous catheters. There are no pathognomonic signs or symptoms. The clinical clues are: unexplained fever or signs of severe sepsis or septic shock while on antibiotics, multiple, non-tender, nodular erythematous cutaneous lesions. The spectrum of infection with candida species range from superficial candidiasis of the skin and mucosa to more serious life threatening infections. Treatment of candidiasis involves removal of the most likely source of infection and drug therapy to speed up the clearance of infection. Amphotericin B remains the initial drug of first choice in hemodynamically unstable critically ill children in the wake of increasing resistance to azoles. Evaluation of newer antifungal agents and precise role of prophylactic therapy in ICU patients is needed.

Invasive candidiasis and candidemia: from current opinions to future perspectives

Candida spp. are the fourth most common cause of nosocomial bloodstream infections in the United States, as well as the single most important cause of opportunistic fungal infections worldwide. A delayed diagnosis of invasive candidiasis and/or inadequate treatment choice is associated with high mortality rates and prolonged hospital stays. Even though the antifungal armamentarium has been broadened significantly over the last years, the best options for diagnosing and treating invasive candidiasis still remain a matter of discussion. In this article we present and analyze current evidence on the epidemiology, diagnostic methods and treatment options of invasive candidiasis, with a focus on results from randomized clinical trials. Finally, the reader is provided with a brief overview on promising clinical trial designs and antifungals that might shape the treatment of invasive candidiasis in the years to come.

Excess mortality, length of stay and cost attributable to candidaemia

BACKGROUND

There were 1967 reports of Candida species isolated from blood specimens in 2007 in the UK (excluding Scotland). Such infections are particularly common in the intensive care unit (ICU). The impact of candidaemia on mortality, length of stay (LOS) and cost in a UK hospital was examined.

METHODS

A retrospective analysis of candidaemia episodes and appropriate matched controls was undertaken based on data from the ICU, high dependency units and hospital wards at Wythenshawe Hospital in Manchester. The study covered the period November 2003-February 2007.

RESULTS

In total, 48 case-patients of candidaemia and 81 control-patients were identified. The attributable mortality due to candidaemia varied from 21.5% to 34.7%. Candidaemia patients spend on average 5.6 days more in the ICU than matched patients and generate mean additional costs of at least 8252 UK pounds per patient, 16,595 pounds in adults only.

CONCLUSION

Candidaemia remains a severe disease associated with high attributable mortality in the UK. In addition, candidaemia leads to additional ICU length of stay and costs. The implication is an attributable cost of at least 16.2 million UK pounds with 683 deaths attributable to candidaemia per year in the UK.

Micafungin: a review of its use in the prophylaxis and treatment of invasive Candida infections in pediatric patients

Intravenous micafungin (Mycamine; Funguard) is an echinocandin indicated in Japan and the EU for the treatment of pediatric patients (including neonates) with invasive candidiasis and as prophylaxis against Candida infection in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). In the EU, micafungin is also indicated in pediatric patients who are expected to have neutropenia for >/=10 days. In Japan, children may also receive micafungin for the treatment of, or as prophylaxis against, invasive Aspergillus infection. Micafungin is not currently approved for use in pediatric patients in the US. Micafungin has very good antifungal activity against a wide range of Candida spp. in vitro. It has a favorable pharmacokinetic profile allowing for once-daily administration, has few drug-drug interactions, and reports of resistance are rare. The results of pediatric substudies indicate that intravenous micafungin is effective in a majority of patients for the treatment of candidemia and other types of invasive candidiasis, and provides effective prophylaxis against invasive fungal infections in pediatric patients undergoing HSCT. The tolerability profile of micafungin in pediatric patients was generally acceptable. In the EU, micafungin is indicated for use when other antifungal medications are not appropriate. Therefore, micafungin provides an alternative to other antifungal agents used in the management of candidemia and invasive candidiasis in pediatric patients, or as prophylaxis against fungal infections in pediatric patients undergoing HSCT.

Hsp90 governs echinocandin resistance in the pathogenic yeast Candida albicans via calcineurin

Candida albicans is the leading fungal pathogen of humans, causing life-threatening disease in immunocompromised individuals. Treatment of candidiasis is hampered by the limited number of antifungal drugs whose efficacy is compromised by host toxicity, fungistatic activity, and the emergence of drug resistance. We previously established that the molecular chaperone Hsp90, which regulates the form and function of diverse client proteins, potentiates resistance to the azoles in C. albicans and in the model yeast Saccharomyces cerevisiae. Genetic studies in S. cerevisiae revealed that Hsp90's role in azole resistance is to enable crucial cellular responses to the membrane stress exerted by azoles via the client protein calcineurin. Here, we demonstrate that Hsp90 governs cellular circuitry required for resistance to the only new class of antifungals to reach the clinic in decades, the echinocandins, which inhibit biosynthesis of a critical component of the fungal cell wall. Pharmacological or genetic impairment of Hsp90 function reduced tolerance of C. albicans laboratory strains and resistance of clinical isolates to the echinocandins and created a fungicidal combination. Compromising calcineurin function phenocopied compromising Hsp90 function. We established that calcineurin is an Hsp90 client protein in C. albicans: reciprocal co-immunoprecipitation validated physical interaction; Hsp90 inhibition blocked calcineurin activation; and calcineurin levels were depleted upon genetic reduction of Hsp90. The downstream effector of calcineurin, Crz1, played a partial role in mediating calcineurin-dependent stress responses activated by echinocandins. Hsp90's role in echinocandin resistance has therapeutic potential given that genetic compromise of C. albicans HSP90 expression enhanced the efficacy of an echinocandin in a murine model of disseminated candidiasis. Our results identify the first Hsp90 client protein in C. albicans, establish an entirely new role for Hsp90 in mediating resistance to echinocandins, and demonstrate that targeting Hsp90 provides a promising therapeutic strategy for the treatment of life-threatening fungal disease.

Fungal pathogens pose a serious threat to people with compromised immune systems. Chief among the opportunistic fungal pathogens is Candida albicans. Treatment of C. albicans infections remains challenging because there are very few effective drugs and the pathogen has evolved many strategies to survive drug exposure. The echinocandins are the only new class of antifungal drug to reach the clinic in decades and they block biosynthesis of an essential component of the fungal cell wall. We discovered that the molecular chaperone Hsp90, which is required for its client proteins in the cell to fold and function, governs the ability of C. albicans to survive exposure to echinocandins. Compromising Hsp90 function renders the echinocandins more effective at killing C. albicans laboratory strains and clinical isolates. Hsp90 orchestrates the crucial responses to cell wall stress exerted by the echinocandins by enabling the function of its client protein calcineurin, which allows the fungus to survive otherwise lethal conditions. Our results suggest that compromising Hsp90 function provides a powerful and much-needed strategy to render existing antifungal drugs more effective in the treatment of life-threatening fungal infections.

Candida in the ICU

Invasive Candida infections are becoming increasingly recognized in critically ill patients. These infections result in serious morbidity, can be life threatening, and are expensive to manage. Early suspicion of Candida infection and the use of timely and proper antifungal treatment can improve outcome. Although treatment of documented, deep-seated Candida infections in nonneutropenic patients has been studied extensively, guidelines for the management of suspected but undocumented cases of invasive Candida infections in critically ill patients have not been clearly established. Future work should focus on better delineation of the sector of critically ill patients who have suspected invasive Candida infection and who could benefit from the use of empiric antifungal therapy, and on the investigation of novel approaches for the potential salvage of devices infected with Candida species.

Candidaemia with uncommon Candida species: predisposing factors, outcome, antifungal susceptibility, and implications for management

The risk factors for and clinical features of bloodstream infection with uncommon Candida spp. (species other than C. albicans, C. glabrata, C. parapsilosis, C. tropicals and C. krusei) are incompletely defined. To identify clinical variables associated with these species that might guide management, 57 cases of candidaemia resulting from uncommon Candida spp. were analysed in comparison with 517 episodes of Candida albicans candidaemia (2001-2004). Infection with uncommon Candida spp. (5.3% of candidaemia cases), as compared with C. albicans candidaemia, was significantly more likely to be outpatient-acquired than inpatient-acquired (15 of 57 vs. 65 of 517 episodes, p 0.01). Prior exposure to fluconazole was uncommon (n=1). Candida dubliniensis was the commonest species (n=22, 39%), followed by Candida guilliermondii (n=11, 19%) and Candida lusitaniae (n=7, 12%).C. dubliniensis candidaemia was independently associated with recent intravenous drug use (p 0.01) and chronic liver disease (p 0.03), and infection with species other than C. dubliniensis was independently associated with age<65 years (p 0.02), male sex (p 0.03) and human immunodeficiency virus infection (p 0.05). Presence of sepsis at diagnosis and crude 30-day mortality rates were similar for C. dubliniensis-related, non-C. dubliniensis-related and C. albicans-related candidaemia. Haematological malignancy was the commonest predisposing factor in C. guilliermondii (n=3, 27%) and C. lusitaniae (n=3, 43%) candidaemia. The 30-day mortality rate of C. lusitaniae candidaemia was higher than the overall death rate for all uncommon Candida spp. (42.9% vs. 25%, p not significant). All isolates were susceptible to amphotericin B, voriconazole, posaconazole, and caspofungin; five strains (9%) had fluconazole MIC values of 16-32 mg/L. Candidaemia due to uncommon Candida spp. is emerging among hospital outpatients; certain clinical variables may assist in recognition of this entity.

Effect of beta-1,6-glucan inhibitors on the invasion process of Candida albicans: potential mechanism of their in vivo efficacy

Beta-1,6-glucan is a fungus-specific cell wall component that is essential for the retention of many cell wall proteins. We recently reported the discovery of a small molecule inhibitor of beta-1,6-glucan biosynthesis in yeasts. In the course of our study of its derivatives, we found a unique feature in their antifungal profile. D21-6076, one of these compounds, exhibited potent in vitro and in vivo antifungal activities against Candida glabrata. Interestingly, although it only weakly reduced the growth of Candida albicans in conventional media, it significantly prolonged the survival of mice infected by the pathogen. Biochemical evaluation of D21-6076 indicated that it inhibited beta-1,6-glucan synthesis of C. albicans, leading the cell wall proteins, which play a critical role in its virulence, to be released from the cell. Correspondingly, adhesion of C. albicans cells to mammalian cells and their hyphal elongation were strongly reduced by the drug treatment. The results of the experiment using an in vitro model of vaginal candidiasis showed that D21-6076 strongly inhibited the invasion process of C. albicans without a significant reduction in its growth in the medium. These evidences suggested that D21-6076 probably exhibited in vivo efficacy against C. albicans by inhibiting its invasion process.

Overview of the changing epidemiology of candidemia

Candida spp. are currently the fourth most common cause of bloodstream infections in US hospitals, and the third most common cause of bloodstream infections in the intensive care unit. Over the last 2 decades there has been a shift towards a greater involvement of non-Candida albicans spp. as the cause of candidemia. Several of these non-albicans spp. (e.g., C. glabrata and C. krusei ) exhibit resistance to traditional triazole antifungals like fluconazole, and cross-resistance with newer triazoles, focusing attention on the first-line use of antifungals such as the echinocandins, which possess improved activity against fluconazole-resistant strains. Recent treatment guidelines from the Infectious Diseases Society of America (IDSA) recommend an echinocandin as primary therapy for nonneutropenic or neutropenic patients with moderately severe to severe candidiasis and for patients at risk for infection with a triazole-resistant strain. However, further improvement in candidemia-associated mortality will only be attainable with the development and validation of new diagnostic tools that will allow earlier detection, discrimination, and treatment of invasive candidiasis. Clinicians should remain vigilant to wider emergence of Candida spp. with echinocandin resistance.

[Epidemiology of invasive candidiasis in pediatric and adult populations]

BACKGROUND

Invasive candidiasis (IC) is the most frequent fungal disease in children and adults.

AIMS

To critically review and update the current epidemiology of Candida spp. disease in neonates, children and adults (critically ill patients and in oncohematologic patients and in solid organ transplant recipients).

METHODS

We searched the PubMed/Medline, discussing the current data.

RESULTS AND CONCLUSIONS

IC is associated with high attributable morbimortality and increased healthcare costs. In the last decades the incidence of invasive Candida spp. disease has increased in critically ill patients, has decreased in oncohematologic patients, although currently the involvement of non-albicans Candida species in the etiology of this disease is increasing steadily.

Evolving role of early antifungals in the adult intensive care unit

BACKGROUND

Invasive candidiasis (IC) is associated with significant morbidity and mortality in critically ill patients. This, in conjunction with difficulties in diagnosis, underscores the need for novel treatment strategies based on the identification of significant risk factors for IC.

OBJECTIVE

To review the evidence surrounding the use of early antifungals in critically ill adult patients and to present concise and specific recommendations for different early treatment strategies for IC.

DATA SOURCES AND DATA EXTRACTION

Pubmed search from 1966 to July 2008 using the search terms "antifungals, critical care, prophylaxis, preemptive therapy, and empiric therapy." Examined all relevant peer-reviewed original articles, meta-analyses, guidelines, consensus statements, and review articles.

CONCLUSION

The use of early antifungal therapy should be reserved for patients with a high risk (10% to 15%) of developing IC. Despite a large number of articles published on this topic, there is no single predictive rule that can adequately forecast IC in critically ill patients. Until further prospective validation of existing data is completed, clinicians should assess patients on a case-by-case basis and determine the need for early antifungal treatment strategies based on frequent evaluations of risk factors and clinical status.

Not just little adults: candidemia epidemiology, molecular characterization, and antifungal susceptibility in neonatal and pediatric patients

OBJECTIVE

The purpose of this work was to identify differences in incidence, risk factors, microbiology, treatment, and clinical outcome of candidemia in neonates, children, and adults that might impact on management.

PATIENTS AND METHODS

Cases of candidemia in Australia were identified prospectively by blood culture surveillance over 3 years. Episodes of candidemia in neonatal, pediatric, and adult age groups were analyzed and compared.

RESULTS

Of 1005 incident cases, 33 occurred in neonates, 110 in children, and 862 in adults. The respective annual age-specific incidences were 4.4, 0.9, and 1.8 per 100,000 population. Prematurity and ICU admission were major risk factors in neonates. Hematologic malignancy and neutropenia were significantly more frequent in children than in neonates and adults. Diabetes, renal disease, hemodialysis, and recent surgery were more common in adults. Candidemia was attributed to a vascular access device in 58% of neonates, 70% of children, and 44% of adults. Candida albicans caused approximately 48% of cases in all of the age groups. Candida parapsilosis was significantly more common in neonates and children (42% and 38% vs 15%). Candida glabrata was infrequent in neonates and children (9% and 3% vs 17%). Significantly more isolates from children were susceptible to fluconazole compared with those from adults (95% vs 75%). Fluconazole-resistant candidal isolates were infrequent in all of the age groups. Neonates and children were more likely to receive amphotericin B compared with adults. Adults were more likely to receive fluconazole. Survival rates at 30 days were 78% in neonates, 90% in children, and 70% in adults.

CONCLUSIONS

This study identifies significant differences in candidemia in neonates, children, and adults. Neonatologists and pediatricians must consider age-specific differences when interpreting adult studies and developing treatment and prevention guidelines.

Candida albicans and non-albicans bloodstream infections in adult and pediatric patients: comparison of mortality and costs

We compared length of stay, inpatient costs, and mortality associated with Candida albicans and non-albicans bloodstream infections in adults and children. Compared with adults, children with Candida bloodstream infections had longer lengths of stay (36.7 vs. 20.7 days; P < 0.001) and higher inpatient costs ($133,871 vs. $56,725; P < 0.001) but lower mortality (28.3% vs. 43.5%; P < 0.001).

'Relation, association, attribution ...' - the multiple faces of death in critical care medicine

Mortality is one of the most important quality markers in critical care, and there have been many epidemiological studies trying to identify risk factors to better understand the mechanisms leading to death in this complex disease. One of the major problems is that there are multiple factors contributing to fatal outcome of septic patients, and it is difficult to distinguish between those that are independent from the acute disease (comorbidities and 'risk factors') and those that are directly involved in the pathomechanisms of sepsis, thus leading to the 'sepsis-attributable' mortality. In this short commentary, some examples of different approaches of how to analyze data on mortality are presented.

Saccharomyces cerevisiae: population divergence and resistance to oxidative stress in clinical, domesticated and wild isolates

BACKGROUND

Saccharomyces cerevisiae has been associated with human life for millennia in the brewery and bakery. Recently it has been recognized as an emerging opportunistic pathogen. To study the evolutionary history of S. cerevisiae, the origin of clinical isolates and the importance of a virulence-associated trait, population genetics and phenotypic assays have been applied to an ecologically diverse set of 103 strains isolated from clinics, breweries, vineyards, fruits, soil, commercial supplements and insect guts.

METHODOLOGY/PRINCIPAL FINDINGS

DNA sequence data from five nuclear DNA loci were analyzed for population structure and haplotype distribution. Additionally, all strains were tested for survival of oxidative stress, a trait associated with microbial pathogenicity. DNA sequence analyses identified three genetic subgroups within the recombining S. cerevisiae strains that are associated with ecology, geography and virulence. Shared alleles suggest that the clinical isolates contain genetic contribution from the fruit isolates. Clinical and fruit isolates exhibit high levels of recombination, unlike the genetically homogenous soil isolates in which no recombination was detected. However, clinical and soil isolates were more resistant to oxidative stress than any other population, suggesting a correlation between survival in oxidative stress and yeast pathogenicity.

CONCLUSIONS/SIGNIFICANCE

Population genetic analyses of S. cerevisiae delineated three distinct groups, comprising primarily the (i) human-associated brewery and vineyard strains, (ii) clinical and fruit isolates (iii) and wild soil isolates from eastern U.S. The interactions between S. cerevisiae and humans potentiate yeast evolution and the development of genetically, ecologically and geographically divergent groups.

[Epidemiology of candidemia: a one-year prospective observational study in the west of France]

OBJECTIVE

A one-year prospective, observational study was conducted in the west of France, to evaluate the epidemiology of candidemia.

METHOD

During the year 2004, each patient with at least one blood culture yielding Candida sp. was included. For each episode of candidemia, mycological, demographical, clinical, and therapeutic data, as well as outcome, were collected.

RESULTS

One hundred and ninety-three strains of Candida sp. were isolated in 186 patients, Candida albicans accounting for 54.9%, Candida glabrata for 18.7%, Candida parapsilosis for 12.9%, Candida tropicalis for 4.7% and Candida krusei for 4.1% of these isolates. A percentage of 84% of the Candida isolates were fully susceptible to fluconazole in vitro. Dose-dependent susceptibility or resistance to fluconazole was detected in more than one third of the Candida glabrata strains, of which 36% were also resistant to voriconazole. Two-thirds of the patients were males, and the mean age was 61.5 years. A percentage of 37% of patients were hospitalized in intensive care units. The main predisposing factors for candidemia were broad-spectrum antibiotics (75.8%), central venous catheter (72.6%), cancer or hematologic malignancy (47.3%), recent surgery (42.5%), total parenteral nutrition (37.6%). One hundred and fifty-four patients were treated with antifungal therapy, two-thirds of whom received fluconazole as first-line agent. Mortality was 49% overall, and was significantly higher in case of septic shock, advanced age, and absence of catheter removal.

Clinical practice guidelines for the management of candidiasis: 2009 update by the Infectious Diseases Society of America

Guidelines for the management of patients with invasive candidiasis and mucosal candidiasis were prepared by an Expert Panel of the Infectious Diseases Society of America. These updated guidelines replace the previous guidelines published in the 15 January 2004 issue of Clinical Infectious Diseases and are intended for use by health care providers who care for patients who either have or are at risk of these infections. Since 2004, several new antifungal agents have become available, and several new studies have been published relating to the treatment of candidemia, other forms of invasive candidiasis, and mucosal disease, including oropharyngeal and esophageal candidiasis. There are also recent prospective data on the prevention of invasive candidiasis in high-risk neonates and adults and on the empiric treatment of suspected invasive candidiasis in adults. This new information is incorporated into this revised document.

A prospective, multicenter study of caspofungin for the treatment of documented Candida or Aspergillus infections in pediatric patients

OBJECTIVE

We evaluated the safety, tolerability, and efficacy of caspofungin in pediatric patients with invasive aspergillosis, invasive candidiasis, or esophageal candidiasis.

METHODS

This was a multicenter, prospective, open-label study in children 3 months to 17 years of age with proven or probable invasive aspergillosis, proven invasive candidiasis, or proven esophageal candidiasis. All of the patients received caspofungin 70 mg/m(2) on day 1, followed by 50 mg/m(2) per day (maximum: 70 mg/day), as primary or salvage monotherapy. Favorable response was defined as complete resolution of clinical findings and microbiologic (or radiographic/endoscopic) eradication (complete response) or significant improvement in these parameters (partial response). Efficacy was assessed at the end of caspofungin therapy in patients with a confirmed diagnosis who received >/=1 dose of caspofungin. The primary safety evaluation was the proportion of patients with clinical or laboratory drug-related adverse events.

RESULTS

Of the 49 patients enrolled, 3 were <2 years of age, 30 were 2 to 11 years of age, and 16 were 12 to 17 years of age. Forty-eight patients had confirmed disease: invasive aspergillosis (10), invasive candidiasis (37), and esophageal candidiasis (1). Eight of 10 patients with invasive aspergillosis had pulmonary involvement; 34 of 37 patients with invasive candidiasis had candidemia. Caspofungin was given for 2 to 87 days. Success at end of therapy was achieved in 5 of 10 patients with invasive aspergillosis, 30 of 37 with invasive candidiasis, and 1 of 1 with esophageal candidiasis. One patient (invasive candidiasis) relapsed during the 28-day follow-up period. Drug-related clinical or laboratory adverse events occurred in 27% and 35% of patients, respectively. There were no serious drug-related adverse events or discontinuations of caspofungin because of toxicity.

CONCLUSIONS

Caspofungin was generally well tolerated in pediatric patients aged 6 months through 17 years. Efficacy outcomes in patients with invasive aspergillosis or invasive candidiasis were consistent with previous adult studies in these indications.

Anidulafungin in the treatment of patients with invasive candidiasis

Echinocandins have emerged as important agents for the treatment of invasive candidiasis. Forthcoming guidelines are expected to recommend an echinocandin agent as initial primary therapy in patients who are severely ill and/or have risk factors for azole resistance. Amphotericin B deoxycholate and fluconazole should be considered for initial therapy in specific populations. The echinocandin, anidulafungin, has been shown to have higher response rates compared with fluconazole in patients with invasive candidiasis. Additionally, patients treated with anidulafungin compared with patients receiving fluconazole have exhibited a trend toward improved survival. The three echinocandins (anidulafungin, caspofungin and micafungin) offer proven efficacy along with excellent side-effect profiles. While these three drugs have important differences, the empirical selection of an echinocandin should be based on the specific patient population, including clinical status, the suspected pathogen, and the susceptibility pattern at the institution. Once the Candida species is identified and its susceptibility is determined, clinicians should consider step-down therapy to either fluconazole or voriconazole, with possible conversion from intravenous to oral therapy.

The interaction of mannose binding lectin (MBL) with mannose containing glycopeptides and the resultant potential impact on invasive fungal infection

Mannnose-binding lectin (MBL) binds oligosaccharides on the surface of microorganisms to form complexes that activate the complement cascade and facilitate phagocytosis. Teicoplanin and dalbavancin glycopeptide antibiotics possess N-acetyl glucosamine and mannose oligosaccharides that may bind MBL. Pharmaceuticals capable of binding to MBL may decrease clearance of significant pathogens such as yeast. An invasive candidemia murine model was utilized to evaluate differences in survival between mannose- and teicoplanin-treated groups compared to a control group administered normal saline. Three groups of BALB/c mice were injected with Candida albicans ATCC 44858 (1.4 x 10(6) CFU). Pharmaceutical agents were administered 2 h pre-infection and 8 h post-infection. In vivo cumulative survival at 52 h revealed 10%, 30% and 90% survival rates for mice administered mannose, teicoplanin, and saline, respectively. There was 0% survival for mice given mannose or teicoplanin at 56 h, compared with 70% for the normal saline treated mice at the same time point (P < 0.05). This in vivo study shows 'accelerated progression of infection' for Candida-inoculated mice exposed to mannose or teicoplanin compared to those given normal saline. Further, protein polyacrylamide gel electrophoresis studies suggested a potential MBL-drug interaction which may attenuate complement activation, opsonization and phagocytosis.

Prediction of pediatric death in the year after hospitalization: a population-level retrospective cohort study

BACKGROUND

The study of how the quality of pediatric end-of-life care varies across systems of health care delivery and financing is hampered by lack of methods to adjust for the probability of death in populations of ill children.

OBJECTIVE

To develop a prognostication models using administratively available data to predict the probability of in-hospital and 1-year postdischarge death.

METHODS

Retrospective cohort study of 0-21 year old patients admitted to Pennsylvania hospitals from 1994-2001 and followed for 1-year postdischarge mortality, assessing logistic regression models ability to predict in-hospital and 1-year postdischarge deaths.

RESULTS

Among 678,365 subjects there were 2,202 deaths that occurred during the hospitalization (0.32% of cohort) and 860 deaths that occurred 365 days or less after hospital discharge (0.13% of cohort). The model predicting hospitalization deaths exhibited a C statistic of 0.91, with sensitivity of 65.9% and specificity of 92.9% at the 99th percentile cutpoint; while the model predicting 1-year postdischarge deaths exhibited a C statistic of 0.92, with sensitivity of 56.1% and specificity of 98.4% at the 99th percentile cutpoint.

CONCLUSIONS

Population-level mortality prognostication of hospitalized children using administratively available data is feasible, assisting the comparison of health care services delivered to children with the highest probability of dying during and after a hospital admission.

Candida bloodstream infections in hemodialysis recipients

Candidemia is a major cause of morbidity and mortality in patients undergoing hemodialysis but it has not been well defined in this patient population. We performed a retrospective case-control study to characterize the epidemiology, microbiology, and outcomes of hemodialysis-associated candidemia. All cases of candidemia at our institution were evaluated from 1 January 2000 until 1 September 2004. For each case, two non-candidemic dialysis patients served as controls. Among 350 cases of candidemia, 78 (22%) occurred in adult hemodialysis patients. Cases and controls were similar with respect to age, corticosteroid, antibiotics use, prevalence of diabetes mellitus, liver cirrhosis, surgical procedures, and cancer. Multivariate analysis found total parenteral nutrition (TPN) (19.5% vs. 1.3%; P<0.0001) and dialysis through a vascular catheter (74% vs. 46.8%; P=0.0001) to be independently associated with candidemia. Non-C.albicans Candida spp. particularly C. glabrata and C. krusei were more common in hemodialysis recipients than in candidemic patients not receiving hemodialysis (31% vs. 17% p = 0.009). In-hospital mortality was significantly elevated for candidemic vs. non-candidemic hemodialysis recipients (51.9% vs. 7.8%; P<0.0001). Candidemia in hemodialysis recipients is frequently caused by non-C. albicansCandida species, is associated with TPN and dialysis via a vascular catheter (vs. shunt or fistula) and carries a high mortality rate.

Pediatric antifungal utilization: new drugs, new trends

BACKGROUND

The frequency and severity of invasive fungal infections in immunocompromised patients has increased steadily over the last 2 decades. In response to the increased incidence and high mortality rates, novel antifungal agents have been developed to expand the breadth and effectiveness of treatment options available to clinicians. Despite these therapeutic advances, the impact of the availability of new antifungal agents on pediatric practice is unknown.

METHODS

A retrospective cohort study was conducted using the Pediatric Health Information System database to describe the changes in pediatric antifungal therapy at 25 freestanding United States children's hospitals from 2000 to 2006. All pediatric inpatients who received a charge for one or more of the following agents were included in the analysis: conventional amphotericin B (AMB), lipid amphotericin B, fluconazole, itraconazole, voriconazole, flucytosine, caspofungin, and micafungin. Underlying conditions and fungal infection status were ascertained.

RESULTS

A total of 62,842 patients received antifungal therapy, with prescriptions significantly increasing during the 7-year study period (P = 0.03). The most commonly prescribed antifungal agent was fluconazole (76%), followed by amphotericin preparations (26%). Prescription of AMB steadily decreased from 2000 to 2006 (P = 0.02). Prescription of voriconazole steadily increased during the study period and replaced AMB for the treatment of aspergillosis. The echinocandins steadily increased in prescription for treatment of fungal infections, particularly in disseminated/systemic candidiasis.

CONCLUSIONS

We found that the number of pediatric inpatients requiring antifungal therapy has increased significantly and the choice of treatment has changed dramatically with the introduction of newer antifungal agents.

The role of the cell wall in fungal pathogenesis

Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections.

Results from the ARTEMIS DISK Global Antifungal Surveillance Study, 1997 to 2007: 10.5-year analysis of susceptibilities of noncandidal yeast species to fluconazole and voriconazole determined by CLSI standardized disk diffusion testing

Fluconazole in vitro susceptibility test results determined by the CLSI M44-A disk diffusion method for 11,240 isolates of noncandidal yeasts were collected from 134 study sites in 40 countries from June 1997 through December 2007. Data were collected for 8,717 yeast isolates tested with voriconazole from 2001 through 2007. A total of 22 different species/organism groups were isolated, of which Cryptococcus neoformans was the most common (31.2% of all isolates). Overall, Cryptococcus (32.9%), Saccharomyces (11.7%), Trichosporon (10.6%), and Rhodotorula (4.1%) were the most commonly identified genera. The overall percentages of isolates in each category (susceptible, susceptible dose dependent, and resistant) were 78.0%, 9.5%, and 12.5% and 92.7%, 2.3%, and 5.0% for fluconazole and voriconazole, respectively. Less than 30% of fluconazole-resistant isolates of Cryptococcus spp., Cryptococcus albidus, Cryptococcus laurentii, Trichosporon beigelii/Trichosporon cutaneum, Rhodotorula spp., Rhodotorula rubra/Rhodotorula mucilaginosa, and Rhodotorula glutinis remained susceptible to voriconazole. Emerging resistance to fluconazole was documented among isolates of C. neoformans from the Asia-Pacific, Africa/Middle East, and Latin American regions but not among isolates from Europe or North America. This survey documents the continuing broad spectrum of activity of voriconazole against opportunistic yeast pathogens but identifies several of the less common species with decreased azole susceptibility. These organisms may pose a future threat to optimal antifungal therapy and emphasize the importance of prompt and accurate species identification.

Invasive candidiasis in the ICU: prophylaxis versus preemptive treatment

Candidemia/invasive candidiasis has increased in incidence over the past 15 years. Because of numerous risk factors, intensive care unit patients have a predilection for this type of infection. Most of these infections are acquired endogenously, but occasionally may result from an exogenous source. Antifungal prophylaxis and preemptive antifungal therapy have been developed to prevent candidemia/invasive candidiasis. Antifungal prophylaxis with azoles has been demonstrated to reduce candidemia, overall mortality, and attributable mortality. This strategy is also effective for the prevention of invasive fungal infection in liver transplant recipients. Preemptive treatment appears to be a more focused intervention that uses markers (eg, the presence of colonization) and serologic testing to trigger the initiation of antifungal therapy. Further developments in serologic testing are necessary to enhance the precision of selecting the patients at risk for candidemia/invasive candidiasis. The optimum agent to be used prophylactically and for preemptive therapy requires further clinical investigation.

Candidemia in the 21st century

The 21st century has brought forth vast innovations in the healthcare field. The availability and use of aggressive chemotherapeutic and immunosuppressive agents as well as broad-spectrum antibacterial agents has created a large population of patients who are at increased risk of acquiring infections with fungal organisms, especially Candida species. This review will focus on the changing epidemiology of candidal bloodstream infections, its impact on healthcare and new advances in the diagnosis and treatment of candidemia.

Antifungal therapies in the intensive care unit

Fungal infections are increasing nationwide, paralleling increases in the number of immunosuppressed hosts. Most of the candida infections seen in the intensive care unit are likely due to iatrogenic factors such as hyperalimentation, catheters, broad-spectrum antibiotics, and postprocedure complications that are prevalent in intensive care unit patients. Delays in appropriate therapy are common and may compromise care. Fortunately, the recognition of several clinical syndromes in the intensive care unit that require specialized treatment can improve outcomes. The issue of antifungal prophylaxis has to be balanced against issues of resistance, and current guidelines are reviewed here for prophylactic use of fluconazole only in selected intensive care unit patients. Finally, several new antifungal agents are available to treat the emerging resistant fungi, with better toxic/therapeutic ratios than in the past. Thus, there are an increasing number of safer and more effective options for treating fungal infections in the intensive care unit.

Molecular epidemiology of candidemia: evidence of clusters of smoldering nosocomial infections

BACKGROUND

Invasive fungal infections pose a serious threat to hospitalized patients worldwide. In particular, the prevalence of clusters of nosocomial infection among patients with candidemia remains unknown. The aim of this study was to investigate the molecular epidemiology of candidemia in a nationwide setting in Iceland during a 16-year period.

METHODS

The genotypes of all available fungal bloodstream isolates during 1991-2006 (n = 219) were determined by polymerase chain reaction fingerprinting with use of 4 separate primers. Clusters were defined as isolation of > or =2 strains with genotypes that had > or =90% relatedness in the same hospital within a period of 90 days.

RESULTS

Candida albicans represented 61.6% of isolates, followed by Candida glabrata (13.7%), Candida tropicalis (9.1%), and Candida parapsilosis (8.7%). Polymerase chain reaction fingerprinting revealed 35 clones of C. albicans, 10 clones of C. glabrata, 7 clones of C. tropicalis, 4 clones of C. parapsilosis, and 5 clones of Candida dubliniensis. Overall, 18.7%-39.9% of all infections were part of nosocomial clusters, most commonly caused by C. albicans, C. parapsilosis, and C. tropicalis. Most clusters involved 2 cases and disproportionately affected patients in adult and neonatal intensive care units (P = .045). The 7-day (16%) and 30-day (32%) case-fatality rates among cluster-associated cases did not differ statistically significantly from those for sporadic nosocomial infections. None of the clusters were identified by the hospital surveillance team.

CONCLUSIONS

In an unselected patient population, as many as one-third of all cases of candidemia may be attributable to nosocomial clusters. The risk is dependent on hospital wards and patient populations; it is highest in intensive care units. Small clusters are not identified by routine hospital surveillance.

Treatment of invasive candidal infections: systematic review and meta-analysis

OBJECTIVE

To compare available antifungal treatments for invasive candidiasis, a leading cause of nosocomial bloodstream infections.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials that compared different antifungal agents for the treatment of candidemia and other forms of invasive candidiasis. Two reviewers independently appraised the quality of trials and extracted data. The primary outcome was all-cause mortality, and secondary outcomes were microbiological failure, treatment failure, and adverse events. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled.

RESULTS

Of the 15 included trials, 9 compared fluconazole with other drugs (amphotericin B, itraconazole, or a combination of fluconazole and amphotericin B), 4 compared echinocandins with other drugs (fluconazole, amphotericin B, liposomal amphotericin B), 1 compared micafungin and caspofungin, and 1 compared amphotericin B plus fluconazole and voriconazole. No difference in mortality was observed with fluconazole vs amphotericin B (RR, 0.92; 95% CI, 0.72-1.17); however, the rate of microbiological failure increased in the fluconazole arm (RR, 1.52; 95% CI, 1.12-2.07). Anidulafungin decreased the rate of microbiological failure compared with fluconazole (RR, 0.50; 95% CI, 0.29-0.86) with fewer adverse events. Caspofungin was comparable to amphotericin B in mortality and efficacy, with fewer adverse events requiring discontinuation (RR, 0.11; 95% CI, 0.04-0.36). Micafungin was comparable to liposomal amphotericin B in mortality.

CONCLUSION

All assessed antifungal agents showed similar efficacy, but the rate of microbiological failure increased with fluconazole vs amphotericin B or anidulafungin. Amphotericin B is associated with a higher rate of adverse events than fluconazole and echinocandins.

Structure of protein geranylgeranyltransferase-I from the human pathogen Candida albicans complexed with a lipid substrate

Protein geranylgeranyltransferase-I (GGTase-I) catalyzes the transfer of a 20-carbon isoprenoid lipid to the sulfur of a cysteine residue located near the C terminus of numerous cellular proteins, including members of the Rho superfamily of small GTPases and other essential signal transduction proteins. In humans, GGTase-I and the homologous protein farnesyltransferase (FTase) are targets of anticancer therapeutics because of the role small GTPases play in oncogenesis. Protein prenyltransferases are also essential for many fungal and protozoan pathogens that infect humans, and have therefore become important targets for treating infectious diseases. Candida albicans, a causative agent of systemic fungal infections in immunocompromised individuals, is one pathogen for which protein prenylation is essential for survival. Here we present the crystal structure of GGTase-I from C. albicans (CaGGTase-I) in complex with its cognate lipid substrate, geranylgeranylpyrophosphate. This structure provides a high-resolution picture of a non-mammalian protein prenyltransferase. There are significant variations between species in critical areas of the active site, including the isoprenoid-binding pocket, as well as the putative product exit groove. These differences indicate the regions where specific protein prenyltransferase inhibitors with antifungal activity can be designed.

Cell density and cell aging as factors modulating antifungal resistance of Candida albicans biofilms

Biofilm formation is a major virulence attribute of Candida pathogenicity which contributes to higher antifungal resistance. We investigated the roles of cell density and cellular aging on the relative antifungal susceptibility of planktonic, biofilm, and biofilm-derived planktonic modes of Candida. A reference and a wild-type strain of Candida albicans were used to evaluate the MICs of caspofungin (CAS), amphotericin B (AMB), nystatin (NYT), ketoconazole (KTC), and flucytosine (5FC). Standard, NCCLS, and European Committee on Antibiotic Susceptibility Testing methods were used for planktonic MIC determination. Candida biofilms were then developed on polystyrene wells, and MICs were determined with a standard 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide assay. Subsequently, antifungal susceptibility testing was performed for greater inoculum concentrations and 24- and 48-h-old cultures of planktonic Candida. Furthermore, Candida biofilm-derived planktonic cells (BDPC) were also subjected to antifungal susceptibility testing. The MICs for both C. albicans strains in the planktonic mode were low, although on increasing the inoculum concentration (up to 1 x 10(8) cells/ml), a variable MIC was noted. On the contrary, for Candida biofilms, the MICs of antifungals were 15- to >1,000-fold higher. Interestingly, the MICs for BDPC were lower and were similar to those for planktonic-mode cells, particularly those of CAS and AMB. Our data indicate that higher antifungal resistance of Candida biofilms is an intrinsic feature possibly related to the biofilm architecture rather than cellular density or cellular aging.