Candidemia in the in-patient setting: treatment options and economics

Polymerase Chain Reaction Versus Blood Culture to Detect Candida Species in High-Risk Patients with Suspected Invasive Candidiasis: The MICAFEM Study

Introduction

We evaluated the diagnostic reliability of serum polymerase chain reaction (PCR) versus blood culture, abdominal fluid or both (composite measure) in patients receiving empirical antifungal treatment for suspected invasive candidiasis.

Methods

This observational, prospective, non-interventional, multicentre study in Spain enrolled 176 critically ill patients admitted to the intensive care unit. Separate blood samples for culture and serum PCR were taken before the start of antifungal therapy. Patient assessment was performed according to each site’s usual clinical practice. The primary end point was concordance between serum PCR and blood culture. Secondary end points were concordance between serum PCR and a positive abdominal fluid sample or the composite measure. Quality indices included sensitivity, specificity, positive/negative predictive values (PPV/NPV) and kappa indices.

Results

Among 175 evaluable patients, rates of Candida detection were similar for serum PCR (n = 16/175, 9.1%) versus blood culture (n = 14/175, 8.0%). Quality indices for serum PCR relative to blood culture were: sensitivity 21.4%; specificity 91.9%; PPV 18.8%; NPV 93.1%; kappa index 0.125. Thirty-two abdominal fluid samples were positive. Quality indices for serum PCR versus abdominal fluid were: sensitivity 31.3%; specificity 83.0%; PPV 15.6%; NPV 92.3%; kappa index 0.100. Quality indices for serum PCR versus the composite measure were: sensitivity 15.8%; specificity 92.7%; PPV 37.5%; NPV 79.9%; kappa index 0.107.

Conclusion

The sensitivity of serum PCR for Candida detection was low and the rate of concordance was low between serum PCR and the other diagnostic techniques used to identify Candida infections. Hospital-based diagnostic tests need optimising to improve outcomes in patients with suspected invasive candidiasis.

Funding

Astellas Pharma Inc.

Electronic supplementary material

The online version of this article (10.1007/s40121-019-0248-z) contains supplementary material, which is available to authorized users.

Design of a mimotope-peptide based double epitope vaccine against disseminated candidiasis

Hematogenously disseminated candidiasis in humans is the third leading cause of nosocomial bloodstream infections in the US. There is no FDA approved antifungal vaccine or prophylactic/therapeutic antibody for use in humans. We first reported novel synthetic peptide and glycopeptide vaccines against Candida albicans cell surface epitopes that protect mice against disseminated candidiasis. We showed that antibodies specific for the peptide Fba (derived from C. albicans cell surface protein fructose bisphosphate aldolase) or for C. albicans cell surface glycan epitope β-1, 2-mannotriose [β-(Man)₃]) are both protective. This is an important step forward in vaccine design against disseminated candidiasis in humans. However, given the complexity of oligosaccharide synthesis, in this study we performed a new strategy for use of peptide mimotopes that structurally mimic the protective glycan epitope β-(Man)₃ as surrogate immunogens that substitute for the glycan part of glycopeptide [β-(Man)₃-Fba] vaccine. All five selected mimotopes are immunogenic in mice and three mimotopes were able to induce protection in mice against disseminated candidiasis. Furthermore, immunization with three mimotope-peptide conjugate vaccines was also able to induce specific antibody responses, and importantly, protection against disseminated candidiasis in mice. Therefore, our new design of a mimotope-peptide based double epitope vaccine against candidiasis is a potential vaccine candidate that is economical to produce, highly efficacious and safe for use in humans.

Invasive candidiasis in critical care setting, updated recommendations from “Invasive Fungal Infections-Clinical Forum”, Iran

Invasive candidiasis (IC) bears a high risk of morbidity and mortality in the intensive care units (ICU). With the current advances in critical care and the use of wide-spectrum antibiotics, invasive fungal infections (IFIs) and IC in particular, have turned into a growing concern in the ICU. Further to blood cultures, some auxiliary laboratory tests and biomarkers are developed to enable an earlier detection of infection, however these test are neither consistently available nor validated in our setting. On the other hand, patients’ clinical status and local epidemiology data may justify the empiric antifungal approach using the proper antifungal option. The clinical approach to the management of IC in febrile, non-neutropenic critically ill patients has been defined in available international guidelines; nevertheless such recommendations need to be customized when applied to our local practice. Over the past three years, Iranian experts from intensive care and infectious diseases disciplines have tried to draw a consensus on the management of IFI with a particular focus on IC in the ICU. The established IFI-clinical forum (IFI-CF), comprising the scientific leaders in the field, has recently come up with and updated recommendation on the same (June 2014). The purpose of this review is to put together literature insights and Iranian experts’ opinion at the IFI-CF, to propose an updated practical overview on recommended approaches for the management of IC in the ICU.

The Rbf1, Hfl1 and Dbp4 of Candida albicans regulate common as well as transcription factor-specific mitochondrial and other cell activities

BACKGROUND

Our interest in Candida albicans mitochondria began with the identification of GOA1. We demonstrated its role in cell energy production, cross-talk among mitochondria and peroxisomes, non-glucose energy metabolism, maintenance of stationary phase growth, and prevention of premature apoptosis. Its absence results in avirulence. However, what regulated transcription of GOA1 was unknown.

RESULTS

To identify transcriptional regulators (TRs) of GOA1, we screened a C. albicans TF knockout library (TRKO) and identified Rbf1p, Hfl1p, and Dpb4p as positive TRs of GOA1. The phenotypes of each mutant (reduced respiration, inability to grow on glycerol, reduced ETC CI and CIV activities) are reasonable evidence for their required roles especially in mitochondrial functions. While the integration of mitochondria with cell metabolic activities is presumed to occur, there is minimal information on this subject at the genome level. Therefore, microarray analysis was used to provide this information for each TR mutant. Transcriptional profiles of Rbf1p and Hfl1p are more similar than that of Dpn4p. Our data demonstrate common and also gene-specific regulatory functions for each TR. We establish their roles in carbon metabolism, stress adaptation, cell wall synthesis, transporter efflux, peroxisomal metabolism, phospholipid synthesis, rRNA processing, and nuclear/mtDNA replication.

CONCLUSIONS

The TRs regulate a number of common genes but each also regulates specific gene transcription. These data for the first time create a genome roadmap that can be used to integrate mitochondria with other cell processes. Of interest, the TRs are fungal-specific, warranting consideration as antifungal drug targets.

Invasive fungal infections in the ICU: how to approach, how to treat

Invasive fungal infections are a growing problem in critically ill patients and are associated with increased morbidity and mortality. Most of them are due to Candida species, especially Candida albicans. Invasive candidiasis includes candidaemia, disseminated candidiasis with deep organ involvement and chronic disseminated candidiasis. During the last decades rare pathogenic fungi, such as Aspergillus species, Zygomycetes, Fusarium species and Scedosporium have also emerged. Timely diagnosis and proper treatment are of paramount importance for a favorable outcome. Besides blood cultures, several laboratory tests have been developed in the hope of facilitating an earlier detection of infection. The antifungal armamentarium has also been expanded allowing a treatment choice tailored to individual patients' needs. The physician can choose among the old class of polyenes, the older and newer azoles and the echinocandins. Factors related to patient's clinical situation and present co-morbidities, local epidemiology data and purpose of treatment (prophylactic, pre-emptive, empiric or definitive) should be taken into account for the appropriate choice of antifungal agent.

Liposomal amphotericin B displays rapid dose-dependent activity against Candida albicans biofilms

Biofilms formed by Candida albicans bloodstream isolates on catheters are an important clinical problem. Devising chemotherapeutic strategies to treat these in situ is an attractive option. We report here that liposomal amphotericin effectively kills C. albicans biofilms rapidly (12 h) and effectively (>90%) in a dose-dependent manner, whereas caspofungin displays an inverse concentration-dependent effect. This study has implications for considering the effective doses of antifungal agents used for catheter lock therapy.

Setting Time Comparison of Four Antimicrobial Laden Calcium Sulfate Plasters

Background

The surgeon may implant calcium sulfate pellets (aka gypsum) as a resorbable antimicrobial vehicle at the surgical site in severe cases of osteomyelitis. Gypsum setting times with or without antibiotic additives are found scattered throughout the literature, but often factors known to alter setting time are either not disclosed or not held constant between experiments. To our knowledge, no prior study compares the setting time of calcium sulfate plaster mixed with the four commonly used antibiotics under constant conditions as presented here.

Purpose

To compare the setting times of calcium sulfate hemihydrate mixtures containing vancomycin, cefazolin, tobramycin, or amphotericin B.

Materials and methods

Groups consisted of samples comprised of 6.3 gm calcium sulfate hemihydrate (CSH) mixed with approximately 1/4th a vial of lyophilized antimicrobial (vancomycin, cefazolin, tobramycin or amphotericin B) with CSH powder to normal saline ratio of 1.7 gm/ml and mixed for 30 seconds at controlled speed and humidity. Each sample initial setting time (Ti) and final setting time (Tf) were established by Gillmore needles method according to ASTM standard C266- 08 apparatus specifications.

Results

Kruskal-Wallis one-way analysis of variance by ranks revealed that antibiotic type affected the initial and final setting times of gypsum (p < 0.05). Post hoc analysis using Dunn's multiple comparisons indicated that there was no difference between control Ti (7.2 ± 1.1 min) and that of vancomycin or cefazolin group (9.8 ± 1.7 or 14.2 ± 1.3 min, respectively, p > 0.05), but the Ti of the tobramycin and amphotericin B groups (31.8 ± 5.7 and 140.4 ± 18.0 min) differed from the control Ti (p < 0.05). Likewise, there was no difference of control Tf (p > 0.05, 12.2 ± 1.1 min) when compared to vancomycin or cefazolin groups (22.2 ± 6.9 or 25.7 ± 4.1 min), but that the Tf of tobramycin and amphotericin B groups (76.3 ± 5.9 and 200.0 ± 21.1 min) each differed from the control group (p < 0.05).

Conclusion

This experiment is aimed to help surgeons plan when they should begin preparing their calcium sulfate antibiotic beads during surgery. As a general guideline, allow 15 minutes to set when adding a 1 gm vial of vancomycin or cefazolin, 30 minutes for adding a 1.2 gm vial tobramycin, and 2.5 hours for adding a 50 mg vial of amphotericin B.

Kroger J, Beaufond P, Inceoglu S, Maskiewicz V, Cheng W, Brier-Jones JE. Setting Time Comparison of Four Antimicrobial Laden Calcium Sulfate Plasters. The Duke Orthop J 2013;3(1):36-40.

Amino acid-derived 1,2-benzisothiazolinone derivatives as novel small-molecule antifungal inhibitors: identification of potential genetic targets

We have identified four synthetic compounds (DFD-VI-15, BD-I-186, DFD-V-49, and DFD-V-66) from an amino acid-derived 1,2-benzisothiazolinone (BZT) scaffold that have reasonable MIC(50) values against a panel of fungal pathogens. These compounds have no structural similarity to existing antifungal drugs. Three of the four compounds have fungicidal activity against Candida spp., Cryptococcus neoformans, and several dermatophytes, while one is fungicidal to Aspergillus fumigatus. The kill rates of our compounds are equal to those in clinical usage. The BZT compounds remain active against azole-, polyene-, and micafungin-resistant strains of Candida spp. A genetics-based approach, along with phenotype analysis, was used to begin mode of action (MOA) studies of one of these compounds, DFD-VI-15. The genetics-based screen utilized a homozygous deletion collection of approximately 4,700 Saccharomyces cerevisiae mutants. We identified mutants that are both hypersensitive and resistant. Using FunSpec, the hypersensitive mutants and a resistant ace2 mutant clustered within a category of genes related directly or indirectly to mitochondrial functions. In Candida albicans, the functions of the Ace2p transcription factor include the regulation of glycolysis. Our model is that DFD-VI-15 targets a respiratory pathway that limits energy production. Supporting this hypothesis are phenotypic data indicating that DFD-VI-15 causes increased cell-reactive oxidants (ROS) and a decrease in mitochondrial membrane potential. Also, the same compound has activity when cells are grown in a medium containing glycerol (mitochondrial substrate) but is much less active when cells are grown anaerobically.

Impact of first-line antifungal agents on the outcomes and costs of candidemia

Candida species are the leading causes of invasive fungal infection among hospitalized patients and are responsible for major economic burdens. The goals of this study were to estimate the costs directly associated with the treatment of candidemia and factors associated with increased costs, as well as the impact of first-line antifungal agents on the outcomes and costs. A retrospective study was conducted in a sample of 199 patients from four university-affiliated tertiary care hospitals in Korea over 1 year. Only costs attributable to the treatment of candidemia were estimated by reviewing resource utilization during treatment. Risk factors for increased costs, treatment outcome, and hospital length of stay (LOS) were analyzed. Approximately 65% of the patients were treated with fluconazole, and 28% were treated with conventional amphotericin B. The overall treatment success rate was 52.8%, and the 30-day mortality rate was 47.9%. Hematologic malignancy, need for mechanical ventilation, and treatment failure of first-line antifungal agents were independent risk factors for mortality. The mean total cost for the treatment of candidemia was $4,743 per patient. Intensive care unit stay at candidemia onset and antifungal switch to second-line agents were independent risk factors for increased costs. The LOS was also significantly longer in patients who switched antifungal agents to second-line drugs. Antifungal switch to second-line agents for any reasons was the only modifiable risk factor of increased costs and LOS. Choosing an appropriate first-line antifungal agent is crucial for better outcomes and reduced hospital costs of candidemia.

Resource utilization and cost of treatment with anidulafungin or fluconazole for candidaemia and other forms of invasive candidiasis: focus on critically ill patients

BACKGROUND

Candidaemia and other forms of invasive candidiasis (C/IC) are serious and costly events for hospitalized patients, particularly those in the ICU. Both fluconazole and the echinocandins are recommended as first-line therapy for C/IC. Resource use and cost considerations are important in selecting appropriate treatment but little information is available on the economic implications of using echinocandins in this setting.

OBJECTIVE

To compare resource utilization and treatment costs (in $US) associated with the echinocandin anidulafungin (200 mg intravenously on day 1, then 100 mg intravenously daily) versus those of fluconazole (800 mg intravenously on day 1, then 400 mg intravenously daily) as first-line treatment for C/IC.

METHODS

Available charts from patients enrolled in a recent clinical trial comparing anidulafungin and fluconazole for C/IC were reviewed. Patients who were in the ICU at study entry were identified, and the following data, collected during the 13-week study period, were compared between treatment groups: global response at end of study treatment, number of days patients survived after hospital discharge ('hospital-free' days), hospital resource use, and C/IC-related costs (year 2008 values) to a US hospital payer. These comparisons were also conducted for all non-ICU hospitalized patients, and for survivors in both study populations. Sensitivity analyses explored the cost impact of variability in the hospitalization costs between ICUs and non-ICU wards and of reduced duration intravenous therapy. Statistical comparisons between the two treatment groups were conducted for clinical outcomes, resource use and cost measures, using regression models. All statistical comparisons were adjusted for baseline co-variates (Acute Physiology and Chronic Health Evaluation [APACHE] II score, absolute neutrophil count and catheter removal status).

RESULTS

For ICU patients with C/IC (n = 63), global response was significantly higher for anidulafungin than fluconazole (68.6% vs 42.9%; p = 0.03). ICU patients treated with anidulafungin had an average of 13.9 more hospital-free days (18.2 vs 4.3 days; p = 0.04) than those treated with fluconazole. After adjustment for co-variates, although lower costs were observed for anidulafungin vs fluconazole in ICU patients and in ICU patients who survived, no statistical differences were found. For all hospitalized patients (n = 159), global response was also higher for anidulafungin (78.3% vs 60.5%; p < 0.01). There was no difference in average length of hospitalization (29.6 days) or hospital-free days. After adjustment for co-variates, anidulafungin treatment resulted in an incremental C/IC-related cost of $US2680 (p = 0.73). For hospitalized patients who survived (anidulafungin 81.9%, fluconazole 69.7%), anidulafungin treatment was associated with an incremental cost of $US231 (p = 0.98).

CONCLUSION

Anidulafungin as first-line treatment of C/IC appears to be of particular benefit to ICU patients, improving clinical outcomes and possibly decreasing costs, driven by reduced ICU and hospital stay, when compared with fluconazole. Anidulafungin also yielded significantly improved treatment outcomes in the general inpatient population, with total costs similar to fluconazole.

Treatment and prophylaxis of invasive candidiasis with anidulafungin, caspofungin and micafungin and its impact on use and costs: review of the literature

Invasive fungal infections are on the rise. Echinocandins are a relatively new class of antifungal drugs that act by inhibition of a key enzyme necessary for integrity of the fungal cell wall. Currently there are three available agents: caspofungin, micafungin and anidulafungin. While the individual echinocandin antifungals have a different spectrum of licensed indications, basically all of them are available for the treatment of candidemia and invasive candidiasis. Antifungal treatment modalities basically include in therapy for suspected or proven infection and prophylaxis. All three drugs are comparatively expensive. Therefore a systematic review of the literature was performed to investigate the following aspects: * General aspects of cost-effectiveness in the treatment of invasive fungal infections * Cost-effectiveness of the treatment with the above-mentioned antifungals * Cost-effectiveness in two settings: therapy and prophylaxis - Early initiation of antifungal therapy, adjustment after availability of microbiological results, duration of therapy, success and occurrence of severe complications (e.g. renal failure) are the most important cost drivers in antifungal therapy. - Considering the specific antifungals, for caspofungin the best evidence for cost-effectiveness is found in treatment of invasive candidiasis and in empiric therapy of suspected infections. Favourable economic data are available for micafungin as a cost-effective alternative to LAmB for prophylaxis in patients with hematopoietic stem cell transplantation (HSCT). For anidulafungin, cost-effectiveness was demostrated in a pharmacoeconomic model. Net savings - yet not significant - were observed in a retrospective chart review of 234 patients. Generally, however, most analyses are still based on pharmacoeconomic modelling rather than direct analysis of trial data or real-life clinical populations. - As an overall conclusion, using caspofungin, micafungin, or anidulafungin is not more expensive than using other established therapies. Micafungin has proven to be cost-effective in prophylaxis if the local fungal epidemiology indicates a high level of resistance to fluconazole. Switch strategies involving early initiation of broadly active therapy with switch to cheaper alternatives according to microbiology results and clinical status and early initiation of an appropriate therapy have been proven to be cost-efficient independent of the antifungal agent.

Cost and resource utilization associated with fluconazole as first-line therapy for invasive candidiasis: a retrospective database analysis

BACKGROUND

Fluconazole is a standard first-line therapy for candidemia/invasive candidiasis (C/IC), based on its efficacy, safety profile, and comparatively low acquisition cost. However, little is known about the total costs associated with fluconazole treatment for this indication, particularly in cases of clinical failure.

OBJECTIVE

The aim of this study was to examine overall costs, resource use, and treatment outcomes associated with fluconazole as first-line therapy for invasive Candida infections in the United States.

METHODS

A retrospective analysis of data from a US hospital-based (>500 hospitals), service-level database was performed. All patients aged >16 years with primary or secondary International Classification of Diseases, Ninth Revision, Clinical Modification codes for IC or septicemia, receiving intravenous fluconazole treatment, and discharged between October 1, 2004 and September 30, 2005 were selected. Costs and resource use were calculated from the start of antifungal therapy until discharge. Two groups were analyzed: patients who received fluconazole only and those who required a second-line antifungal. Separate analyses for the survivor subpopulations were also conducted.

RESULTS

A total of 7170 patients met the inclusion criteria; 21.2% required an additional antifungal agent. Overall mortality was 27.1%, and total mean treatment cost for all patients was $44,482 (in 2005 US dollars). Patients treated with fluconazole alone incurred mean costs of $36,319. Mean hospital and intensive care unit stays in the fluconazole monotherapy group were 17.9 days and 7.1 days, respectively. Patients requiring additional therapy had a mortality rate of 34.5% and a mean treatment cost of $76,329; in this group, the mean hospital and intensive care unit stays were 31.7 days and 14.8 days, respectively.

CONCLUSIONS

The overall resource use associated with fluconazole as first-line treatment for C/IC was high, especially in patients who required additional antifungal therapy. Future studies should examine the patterns of care and costs associated with alternative treatment options as first-line C/IC therapy.

Anidulafungin for the treatment of invasive candidiasis

Candidaemia/invasive candidiasis (C/IC) is the most frequently occurring invasive fungal infection worldwide, with a particularly strong impact and high incidence in the intensive-care unit, where there is a need for new treatment options and strategies. The echinocandin anidulafungin has broad in vitro activity against a wide range of Candida species, along with favourable pharmacokinetics that allow administration in hepatic and renal impairment and with any comedication without the need for dose adjustments. The efficacy and safety of anidulafungin for the treatment of C/IC were demonstrated in a number of clinical studies and by some limited data from clinical practice. In a randomized comparative trial for the treatment of C/IC in adults, 76% of patients receiving anidulafungin and 60% of those given fluconazole were treated successfully (95% CI for difference: 4-27; p 0.01). Post hoc analyses suggest that anidulafungin is significantly more effective than standard-dose fluconazole for the treatment of candidaemia in critically ill patients. Anidulafungin is generally well tolerated, with commonly reported side effects including headache, hypokalaemia, gastrointestinal symptoms, abnormal liver function test results, and rash. In pharmaco-economic analyses, anidulafungin compared favourably with fluconazole (in terms of overall costs and hospital resource use) as well as with other echinocandins. Echinocandins, including anidulafungin, are now generally recommended as first-line therapy in moderately to severely ill patients, those with prior azole exposure, and patients with C/IC caused by Candida glabrata or Candida krusei.