T2MR and T2Candida: novel technology for the rapid diagnosis of candidemia and invasive candidiasis

Integrating omics techniques and culture-independent systems may improve the detection of persistent candidemia: data from an observational study

INTRODUCTION

Blood cultures have low sensitivity for candidemia. Sensitivity can be improved by the culture-independent system T2 Magnetic Resonance (T2). SeptiCyte RAPID is a host response assay quantifying the risk of infection-related inflammation through a scoring system (SeptiScore). We investigate the performance of SeptiScore in detecting persistent candidemia as defined by conventional cultures and T2.

METHODS

This is a prospective multicentre observational study on patients with candidemia. Blood cultures and blood samples for assessment by T2 and SeptiCyte were collected for 4 consecutive days after the index culture. The performance of SeptiScore was explored to predict persistent candidemia as defined by (1) positive follow-up blood culture (2) either positive follow-up blood culture or T2 sample.

RESULTS

10 patients were enrolled including 34 blood collections assessed with the 3 methods. Overall, 4/34 (12%) follow-up blood cultures and 6/34 (18%) T2 samples were positive. A mixed model showed significantly higher SeptiScores associated with persistent candidemia when this was defined as either a positive follow-up blood culture or T2 sample (0.82, 95%CI 0.06 to 1.58) but not when this was defined as a positive follow-up blood culture only (-0.57, 95%CI -1.28 to 0.14). ROC curve for detection of persistent candidemia by SeptiScore at day 1 follow-up showed an AUC of 0.85 (95%CI 0.52-1.00) when candidemia was defined by positive follow-up blood culture, and an AUC of 1.00 (95%CI 1.00-1.00) when candidemia was defined according to both methods.

CONCLUSION

Integrating transcriptome profiling with culture-independent systems and conventional cultures may increase our ability to diagnose persistent candidemia.

ISCCM Position Statement on the Management of Invasive Fungal Infections in the Intensive Care Unit

Rationale

Invasive fungal infections (IFI) in the intensive care unit (ICU) are an emerging problem owing to the use of broad-spectrum antibiotics, immunosuppressive agents, and frequency of indwelling catheters. Timely diagnosis which is imperative to improve outcomes can be challenging. This position statement is aimed at understanding risk factors, providing a rational diagnostic approach, and guiding clinicians to optimize antifungal therapy.

Objectives

To update evidence on epidemiology, risk factors, diagnostic approach, antifungal initiation strategy, therapeutic interventions including site-specific infections and role of therapeutic drug monitoring in IFI in ICU and focus on some practice points relevant to these domains.

Methodology

A committee comprising critical care specialists across the country was formed and specific aspects of fungal infections and antifungal treatment were assigned to each member. They extensively reviewed the literature including the electronic databases and the international guidelines and cross-references. The information was shared and discussed over several meetings and position statements were framed to ensure their reliability and relevance in critical practice. The draft document was prepared after obtaining inputs and consensus from all the members and was reviewed by an expert in this field.

Results

The existing evidence on the management of IFI was updated and practice points were prepared under each subheading to enable critical care practitioners to streamline diagnosis and treatment strategies for patients in the ICU with additional detail on site-specific infections therapeutic drug monitoring.

Conclusion

This position statement attempts to address the management of IFI in immunocompetent and non-neutropenic ICU patients. The practice points should guide in optimization of the management of critically ill patients with suspected or proven fungal infections.

How to cite this article

Bhattacharya PK, Chakrabarti A, Sinha S, Pande R, Gupta S, Kumar AAK, et al. ISCCM Position Statement on the Management of Invasive Fungal Infections in the Intensive Care Unit. Indian J Crit Care Med 2024;28(S2):S20-S41.

Diagnosis of mucormycosis from nasal swabs using commercial PCR platforms; a feasible alternative?

Rhino-orbital-cerebral mucormycosis (ROCM) is linked to uncontrolled diabetes, diabetic ketoacidosis, iron overload, corticosteroid therapy, and neutropenia. This study evaluated a commercial real-time PCR system's effectiveness in detecting Mucorales from nasal swabs in 50 high-risk patients. Nasal swab PCR showed 30% positivity, compared to 8% with KOH microscopy. Despite its improved sensitivity, nasal swab PCR has limitations, highlighting the importance of established sampling methods in mucormycosis diagnosis. Participants were predominantly male (64%), with diabetes (78%) and amphotericin B use (96%). Prior COVID-19 was 42%, with 30% positive for Mucorales by PCR, compared to 8% with KOH microscopy.

Should Empiric Anti-Fungals Be Administered Routinely for All Patients with Perforated Peptic Ulcers? A Critical Review of the Existing Literature

A perforated peptic ulcer (PPU) is a surgical emergency with a high mortality rate. PPUs cause secondary peritonitis due to bacterial and fungal peritoneal contamination. Surgery is the main treatment modality and patient's comorbidites impacts perioperative morbidity and surgical outcomes. Even after surgery, resuscitation efforts should continue. While empiric antibiotics are recommended, the role of empiric anti-fungal treatment is unclear due to a lack of scientific evidence. This literature review demonstrated a paucity of studies evaluating the role of empiric anti-fungals in PPUs, and with conflicting results. Studies were heterogeneous in terms of patient demographics and underlying surgical pathology (PPUs vs. any gastrointestinal perforation), type of anti-fungal agent, timing of administration and duration of use. Other considerations include the need to differentiate between fungal colonization vs. invasive fungal infection. Despite positive fungal isolates from fluid culture, it is important for clinical judgement to identify the right group of patients for anti-fungal administration. Biochemistry investigations including new fungal biomarkers may help to guide management. Multidisciplinary discussions may help in decision making for this conundrum. Moving forward, further research may be conducted to select the right group of patients who may benefit from empiric anti-fungal use.

Antimicrobial De-Escalation in Critically Ill Patients

Antimicrobial de-escalation (ADE) is defined as the discontinuation of one or more antimicrobials in empirical therapy, or the replacement of a broad-spectrum antimicrobial with a narrower-spectrum antimicrobial. The aim of this review is to provide an overview of the available literature on the effectiveness and safety of ADE in critically ill patients, with a focus on special conditions such as anti-fungal therapy and high-risk categories. Although it is widely considered a safe strategy for antimicrobial stewardship (AMS), to date, there has been no assessment of the effect of de-escalation on the development of resistance. Conversely, some authors suggest that prolonged antibiotic treatment may be a side effect of de-escalation, especially in high-risk categories such as neutropenic critically ill patients and intra-abdominal infections (IAIs). Moreover, microbiological documentation is crucial for increasing ADE rates in critically ill patients with infections, and efforts should be focused on exploring new diagnostic tools to accelerate pathogen identification. For these reasons, ADE can be safely used in patients with infections, as confirmed by high-quality and reliable microbiological samplings, although further studies are warranted to clarify its applicability in selected populations.

From bottle to bedside: Implementation considerations and antimicrobial stewardship considerations for bloodstream infection rapid diagnostic testing

Antimicrobial stewardship (AMS) programs have been quick to adopt novel molecular rapid diagnostic technologies (mRDTs) for bloodstream infections (BSIs) to improve antimicrobial management. As such, most of the literature demonstrating the clinical and economic benefits of mRDTs for BSI is in the presence of active AMS intervention. Leveraging mRDTs to improve antimicrobial therapy for BSI is increasingly integral to AMS program activities. This narrative review discusses available and future mRDTs, the relationship between the clinical microbiology laboratory and AMS programs, and practical considerations for optimizing the use of these tools within a health system. Antimicrobial stewardship programs must work closely with their clinical microbiology laboratories to ensure that mRDTs are used to their fullest benefit while remaining cognizant of their limitations. As more mRDT instruments and panels become available and AMS programs continue to expand, future efforts must consider the expansion beyond traditional settings of large academic medical centers and how combinations of tools can further improve patient care.

Invasive Candida infection: epidemiology, clinical and therapeutic aspects of an evolving disease and the role of rezafungin

INTRODUCTION

Invasive Candida Infections (ICIs) have undergone a series of significant epidemiological, pathophysiological, and clinical changes during the last decades, with a shift toward non-albicans species, an increase in the rate of exogenous infections and clinical manifestations ranging from candidemia to an array of highly invasive and life-threatening clinical syndromes. The long-acting echinocandin rezafungin exhibits potent in-vitro activity against most wild-type and azole-resistant Candida spp. including C.auris.

AREAS COVERED

The following topics regarding candidemia only and ICIs were reviewed and addressed: i) pathogenesis; ii) epidemiology and temporal evolution of Candida species; iii) clinical approach; iv) potential role of the novel long-acting rezafungin in the treatment of ICIs.

EXPERT OPINION

Authors' expert opinion focused on considering the potential role of rezafungin in the evolving context of ICIs. Rezafungin, which combines a potent in-vitro activity against Candida species, including azole-resistant strains and C.auris, with a low likelihood of drug-drug interactions and a good safety profile, may revolutionize the treatment of candidemia/ICI. Indeed, it may shorten the length of hospital stays when clinical conditions allow and extend outpatient access to treatment of invasive candidiasis, especially when prolonged treatment duration is expected.

Diagnosis of invasive fungal infections: challenges and recent developments

BACKGROUND

The global burden of invasive fungal infections (IFIs) has shown an upsurge in recent years due to the higher load of immunocompromised patients suffering from various diseases. The role of early and accurate diagnosis in the aggressive containment of the fungal infection at the initial stages becomes crucial thus, preventing the development of a life-threatening situation. With the changing demands of clinical mycology, the field of fungal diagnostics has evolved and come a long way from traditional methods of microscopy and culturing to more advanced non-culture-based tools. With the advent of more powerful approaches such as novel PCR assays, T2 Candida, microfluidic chip technology, next generation sequencing, new generation biosensors, nanotechnology-based tools, artificial intelligence-based models, the face of fungal diagnostics is constantly changing for the better. All these advances have been reviewed here giving the latest update to our readers in the most orderly flow.

MAIN TEXT

A detailed literature survey was conducted by the team followed by data collection, pertinent data extraction, in-depth analysis, and composing the various sub-sections and the final review. The review is unique in its kind as it discusses the advances in molecular methods; advances in serology-based methods; advances in biosensor technology; and advances in machine learning-based models, all under one roof. To the best of our knowledge, there has been no review covering all of these fields (especially biosensor technology and machine learning using artificial intelligence) with relevance to invasive fungal infections.

CONCLUSION

The review will undoubtedly assist in updating the scientific community's understanding of the most recent advancements that are on the horizon and that may be implemented as adjuncts to the traditional diagnostic algorithms.

Effective Rapid Diagnosis of Bacterial and Fungal Bloodstream Infections by T2 Magnetic Resonance Technology in the Pediatric Population

Children are prone to bloodstream infections (BSIs), the rapid and accurate diagnosis of which is an unmet clinical need. The T2MR technology is a direct molecular assay for identification of BSI pathogens, which can help to overcome the limits of blood culture (BC) such as diagnostic accuracy, blood volumes required, and turnaround time. We analyzed results obtained with the T2Bacteria (648) and T2Candida (106) panels in pediatric patients of the Bambino Gesù Children's Hospital between May 2018 and September 2020 in order to evaluate the performance of the T2Dx instrument with respect to BC. T2Bacteria and T2Candida panels showed 84.2% and 100% sensitivity with 85.9% and 94.1% specificity, respectively. The sensitivity and specificity of the T2Bacteria panel increased to 94.9% and 98.7%, respectively, when BC was negative but other laboratory data supported the molecular result. T2Bacteria sensitivity was 100% with blood volumes <2 mL in neonates and infants. T2Bacteria and T2Candida provided definitive microorganism identification in a mean time of 4.4 and 3.7 h, respectively, versus 65.7 and 125.5 h for BCs (P < 0.001). T2 panels rapidly and accurately enable a diagnosis of a pediatric BSI, even in children under 1 year of age and for very small blood volumes. These findings support their clinical use in life-threatening pediatric infections, where the time to diagnosis is of utmost importance, in order to improve survival and minimize the long-term sequalae of sepsis. The T2 technology could be further developed to include more bacteria and fungi species that are involved in the etiology of sepsis.

Key role of early source control in candidemic patients with sepsis or septic shock

Background

Despite advances in diagnostic and therapeutic approaches, candidemia remains associated with high mortality rates. This study aimed at identifying predictors of mortality among patients with candidemia, with a focus on early interventions that can improve prognosis.

Methods

This was a single-center retrospective study including all adult patients with at least 1 positive blood culture for Candida species from 2014 to 2021.

Results

A total of 222 episodes of candidemia were included. Most candidemias were of unknown origin (36%) or vascular catheter related (29%). Septic shock developed in 29% episodes. Overall, 14-day mortality rate was 23%. In univariate analyses, septic shock was associated with higher 14-day mortality, whereas catheter-related candidemia and early (<72 hours) interventions, such as appropriate antifungal therapy, source control, and infectious diseases consultation, were associated with improved survival. In a Cox multivariate regression model, septic shock (odds ratio [OR], 3.62 [95% confidence interval {CI}, 2.05–6.38]) was associated with higher mortality. While the impact of early antifungal therapy did not reach statistical significance, early (<72 hours) infectious diseases consultation (OR, 0.46 [95% CI, .23–.91]) and early source control (OR, 0.15 [95% CI, .08–.31]) were associated with better survival. Subanalyses showed that the benefits of early source control, specifically catheter removal, were significant among patients with sepsis or septic shock, but not among those without sepsis. These associations remained significant after exclusion of patients who died prematurely or were in palliative care.

Conclusions

Early source control, in particular catheter removal, was a key determinant of outcome among candidemic patients with sepsis or septic shock.

Burden of bacterial bloodstream infections and recent advances for diagnosis

Bloodstream infections (BSIs) and subsequent organ dysfunction (sepsis and septic shock) are conditions that rank among the top reasons for human mortality and have a great impact on healthcare systems. Their treatment mainly relies on the administration of broad-spectrum antimicrobials since the standard blood culture-based diagnostic methods remain time-consuming for the pathogen's identification. Consequently, the routine use of these antibiotics may lead to downstream antimicrobial resistance and failure in treatment outcomes. Recently, significant advances have been made in improving several methodologies for the identification of pathogens directly in whole blood especially regarding specificity and time to detection. Nevertheless, for the widespread implementation of these novel methods in healthcare facilities, further improvements are still needed concerning the sensitivity and cost-effectiveness to allow a faster and more appropriate antimicrobial therapy. This review is focused on the problem of BSIs and sepsis addressing several aspects like their origin, challenges, and causative agents. Also, it highlights current and emerging diagnostics technologies, discussing their strengths and weaknesses.

The epidemiology of bloodstream infection contributing to mortality: the difference between community-acquired, healthcare-associated, and hospital-acquired infections

BACKGROUND

The epidemiology of bloodstream infection (BSI) is well-established; however, little is known about the contribution of different pathogens to mortality. To understand true burden of BSI, pathogens contributing to mortality were investigated and compared according to where the BSI was acquired.

METHODS

Data from deceased patients in two teaching hospitals in the Republic of Korea were collected. BSI contributing mortality was defined as BSI within 2-weeks before death. Cases were grouped by acquisition sites: community-acquired (CA)-, healthcare-associated (HCA)-, and hospital-acquired (HA)-BSI. Drug resistance, BSI focus, and appropriateness of empirical antimicrobial therapy were also compared.

RESULTS

Among 1849 deceased patients in the hospitals, 280 (15.1%) patients experienced BSI within 2-weeks before death. In all, 71, 53, and 156 patients in the CA-, HCA-, and HA-BSI groups, respectively, with 316 total isolated pathogens were analyzed. The three most common pathogens were Klebsiella pneumoniae (17.1%), Escherichia coli (16.4%), and Staphylococcus aureus (11.4%). While K. pneumoniae and E. coli were the most common pathogens in CA- and HCA-BSI, Acinetobacter baumannii and Candida species were in HA-BSI. 26.3% (41/156) of patients experienced breakthrough HCA-BSI during administration of carbapenem and/or vancomycin. The proportion of central venous catheter-related infection (0%, 3.4% and 28.3%), carbapenem resistant-Gram negative bacilli (0%, 6.9% and 21.9%), and inappropriate empirical antimicrobial therapy (21.1%, 37.7% and 51.9%; all P < 0.001) were more frequently observed in HA-BSI.

CONCLUSION

The epidemiology of BSI related to mortality had unique characteristics according to the acquisition site. Given the epidemiology of HA-BSI, infection control and antibiotics stewardship programs should be emphasized.

Diagnostic Utility of CD64 and CD38 Biomarkers for the Differential Diagnosis of Infections

Purpose: Identification of infection type in patients with fever is particularly important in the emergency departments (EDs) of hospitals. This study aimed to evaluate the performance of two biomarkers, namely the modified neutrophil CD64 (nCD64) index and CD38 present on T cells, using flow cytometry. Methods: A total of 305 potentially infected patients with fever were admitted to the ED of Zhongda Hospital (Nanjing, China) between March 2021 and August 2021. This study grouped 180, 30, and 65 patients as having bacterial (local, Gram-positive, and Gram-negative infections), viral, or no infections, respectively, based on their diagnostic outcomes and clinical records. Results: The expression level of traditional/modified nCD64 was significantly increased in the bacterial infection group, especially in case of patients infected with Gram-negative bacteria, and the main infectious strains were Staphylococcus and Escherichia coli. Similarly, CD3⁺CD38⁺ cell percentages were elevated in patients with viral infections, which were mostly caused by Epstein-Barr virus and cytomegalovirus. CD38 expression is age dependent, and high percentages of CD3⁺CD38⁺ cells were observed in children with viral infections. For the prediction of bacterial infections, the area under the curve (AUC) of modified nCD64 (AUC: 0.800) was significantly higher than that of C-reactive protein and heparin-binding protein but slightly lower than that of traditional nCD64 (AUC: 0.831). The AUC, specificity, and sensitivity values for the prediction of viral infections using CD3⁺CD38⁺ cells percentages in children were 0.899 (0.785-1.000), 96.2%, and 85.9%, respectively. Conclusion: nCD64 levels and CD3⁺CD38⁺ cell percentage are potential biomarkers that facilitate identification of patients with bacterial and viral infections.

Isolation of Candida auris in Clinical Specimens

Candida auris is a multidrug-resistant yeast causing healthcare-associated outbreaks of blood stream infections worldwide. Currently, C. auris isolation and identification is complicated by issues such as misidentification and long turnaround time associated with application of commonly used diagnostic tools. Based on phenotypic characteristics, differentiation of C. auris from related Candida haemulonii complex spp. is problematic. Candida auris can be misidentified using biochemical-based systems such as VITEK 2 YST, API 20C, BD Phoenix yeast identification system, and MicroScan. C. auris growth at 42 °C and in the presence of 10% NaCl helps in presumptive identification of this yeast from related Candida haemulonii complex spp. A new CHROMagar™ Candida Plus agar is an excellent alternative to current conventional mycological media for the screening of patients colonized/infected with Candida auris. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) can differentiate C. auris from other Candida species, but not all the reference databases included in MALDI-TOF devices allow for detection. Currently, accurate identification of C. auris can be performed using the updated FDA-approved libraries or "research use-only" libraries. Molecular techniques have greatly enhanced the diagnosis of C. auris. Sequencing of rDNA genetic loci, namely, internal transcribed spacer and D1/D2 region of large subunit (LSU), and PCR/qPCR assays has successfully been applied for identification of C. auris. Real-time PCR assays bear incomparable potential of being the most efficient tool for high-throughput screening of surveillance samples. If properly validated, they can deliver the diagnostic result within several hours, since the DNA can be isolated directly from the patient specimen without the need of obtaining a colony. In this chapter we detailed the isolation of Candida auris from various clinical specimens and its currently available identification methods and hitches.

Biosensors for Fungal Detection

Due to the serious threat of invasive fungal infections, there is an emergent need for improved a sensitive and more accurate diagnostic tests for detection of systemic pathogenic fungi and plant health. Traditional fungal diagnosis can only be achieved at later growing phases. The complex and difficult immunodiagnostic is also widely employed. Enzyme-based immunoassays which lead to cross-interaction with different fungi still also obeyed. A polymerase chain reactions (PCRs)- based molecular diagnosis are does not enable precise identification of fungal pathogens, or the ability to test isolates for drug sensitivity. In the future, biosensing technologies and nanotechnological tools, will improve diagnosis of pathogenic fungi through a specific and sensitive pathogen detection. This report systematically reviews the most prominent biosensor trends for fungi detection.

Expression and Purification along with Evaluation of Serological Response and Diagnostic Potential of Recombinant Sap2 Protein from C. parapsilosis for Use in Systemic Candidiasis

Systemic candidiasis is the fourth most common bloodstream infection in ICU patients worldwide. Although C. albicans is a predominant species causing systemic candidiasis, infections caused by non-albicans Candida (NAC) species are increasingly becoming more prevalent globally along with the emergence of drug resistance. The diagnosis of systemic candidiasis is difficult due to the absence of significant clinical symptoms in patients. We investigated the diagnostic potential of recombinant secreted aspartyl proteinase 2 (rSap2) from C. parapsilosis for the detection of Candida infection. The rSap2 protein was successfully cloned, expressed and purified using Ni-NTA chromatography under denaturing conditions using an E. coli-based prokaryotic expression system, and refolded using a multi-step dialysis procedure. Structural analysis by CD and FTIR spectroscopy revealed the refolded protein to be in its near native conformation. Immunogenicity analysis demonstrated the rSap2 protein to be highly immunogenic as evident from significantly high titers of Sap2-specific antibodies in antigen immunized Balb/c mice, compared to sham-immunized controls. The diagnostic potential of rSap2 protein was evaluated using immunoblotting and ELISA assays using proven candidiasis patient serum and controls. Immunoblotting results indicate that reactivity to rSap2 was specific to candidiasis patient sera with no cross reactivity observed in healthy controls. Increased levels of anti-Sap2-specific Ig, IgG and IgM antibodies were observed in candidiasis patients compared to controls and was similar in sensitivity obtained when whole Candida was used as coating antigen. In summary, the rSap2 protein from C. parapsilosis has the potential to be used in the diagnosis of systemic candidiasis, providing a rapid, convenient, accurate and cost-effective strategy.

Nosocomial Fungal Infections: Epidemiology, Infection Control, and Prevention

Invasive fungal infections are an important cause of morbidity and mortality in hospitalized patients and in the immunocompromised population. This article reviews the current epidemiology of nosocomial fungal infections in adult patients, with an emphasis on invasive candidiasis (IC) and invasive aspergillosis (IA). Included are descriptions of nosocomial infections caused by Candida auris, an emerging pathogen, and IC- and IA-associated with coronavirus disease 2019. The characteristics and availability of newer nonculture-based tests for identification of nosocomial fungal pathogens are discussed. Recently published recommendations and guidelines for the control and prevention of these nosocomial fungal infections are summarized.

Culture independent detection systems for bloodstream infection

BACKGROUND

Sepsis and bloodstream infection are associated with significant morbidity and mortality, and early effective antimicrobial therapy has been demonstrated to improve patient outcomes. Traditional culture-based methods, however, have several limitations which hamper a prompt diagnosis in bloodstream infection, including long turnaround times and limited sensitivity. In the last years, advances have been made in the development of several technologies which allow the identification of pathogens and their resistance markers directly from whole blood, possibly representing promising alternatives to conventional culture methods.

OBJECTIVES

To review the currently commercially available emerging assays for the diagnosis of bloodstream infections directly from whole blood, including their performance and the available data about their impact on patients' outcome.

SOURCES

Peer-reviewed publications relevant to the topic have been searched through PubMed; manufacturers' websites have also been consulted as a data source.

CONTENT

We have reviewed available data about the following technologies: multiplex real-time PCR working directly from whole blood (Magicplex Sepsis Real-Time test, Seegene), PCR combined with T2 Magnetic Resonance (T2Candida and T2Bacteria panel, T2Biosystem), and metagenomics-based assays (including SepsiTest, Molzym; iDTECT Dx Blood, PathoQuest; Karius NGS plasma Test, Karius). Performance characteristics, advantages and pitfalls of each method are described, and available data about their impact on patients' clinical outcomes are discussed.

IMPLICATIONS

The potential of rapid diagnostic tests applied on whole blood in improving the management of patients with bloodstream infection and sepsis is high, both in terms of reducing turnaround times and improving the sensitivity of pathogen and antimicrobial resistance detection. However, overall, there is still a scarcity of data about the real-life performance of such tests, and well-designed studies are awaited for assessing the impact of these emerging technologies on patients' outcomes.

A discussion of syndromic molecular testing for clinical care

Current molecular detection methods for single or multiplex pathogens by real-time PCR generally offer great sensitivity and specificity. However, many infectious pathogens often result in very similar clinical presentations, complicating the test-order for physicians who have to narrow down the causative agent prior to in-house PCR testing. As a consequence, the intuitive response is to start empirical therapy to treat a broad spectrum of possible pathogens. Syndromic molecular testing has been increasingly integrated into routine clinical care, either to provide diagnostic, epidemiological or patient management information. These multiplex panels can be used to screen for predefined infectious disease pathogens simultaneously within a 1 h timeframe, creating opportunities for rapid diagnostics. Conversely, syndromic panels have their own challenges and must be adaptable to the evolving demands of the clinical setting. Firstly, questions have been raised regarding the clinical relevance of some of the targets included in the panels and secondly, there is the added expense of integration into the clinical laboratory. Here, we aim to discuss some of the factors that should be considered before performing syndromic testing rather than traditional low-plex in-house PCR.

Accuracy and Impact on Patient Management of New Tools for Diagnosis of Sepsis: Experience with the T2 Magnetic Resonance Bacteria Panel

The rapid and accurate identification of pathogens responsible for sepsis is essential for prompt and effective antimicrobial therapy. Molecular technologies have been developed to detect the most common causative agents, with high sensitivity and short time to result (TTR). T2 Bacteria Panel (T2), based on a combination of PCR and T2 magnetic resonance, can identify directly in blood samples Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium, and Acinetobacter baumannii pathogens. This study evaluates the role of T2 in the diagnosis of sepsis and its impact on patient management, specifically in terms of TTR and the switch from empirical to directed therapy, comparing results of blood culture (BC) and T2 assay in 82 patients with sepsis. T2 significantly improved the detection of the causative agents of sepsis. For pathogens included in the panel, T2 sensitivity was 100% (95% CI 86.3–100.0), significantly higher than that of BC (54.8%, 95% CI 36.0–72.7). The TTR (median, IQR) of positive T2 (3.66 h, 3.59–4.31) was significantly shorter than that of the positive BC (37.58 h, 20.10–47.32). A significant reduction in the duration of empiric therapy and an increase in the percentage of patients with switched therapy was observed in patients with a positive T2 result. In conclusion, T2 can shorten and improve the etiological diagnosis of sepsis with a positive impact on patient management.

Highly specific and rapid molecular detection of Candida glabrata in clinical samples

The most common nosocomial fungal infections are caused by several species of Candida, of which Candida glabrata is the second most frequently isolated species from bloodstream infections. C. glabrata displays relatively high minimal inhibitory concentration values (MIC) to the antifungal fluconazole and is associated with high mortality rates. To decrease mortality rates, the appropriate treatment must be administered promptly. C. glabrata contains in its genome several non-identical copies of species-specific sequences. We designed three pairs of C. glabrata-specific primers for endpoint PCR amplification that align to these species-specific sequences and amplify the different copies in the genome. Using these primers, we developed a fast, sensitive, inexpensive, and highly specific PCR-based method to positively detect C. glabrata DNA in a concentration-dependent manner from mixes of purified genomic DNA of several Candida species, as well as from hemocultures and urine clinical samples. This tool can be used for positive identification of C. glabrata in the clinic.

Candidemia Risk Prediction (CanDETEC) Model for Patients With Malignancy: Model Development and Validation in a Single-Center Retrospective Study

BACKGROUND

Appropriate empirical treatment for candidemia is associated with reduced mortality; however, the timely diagnosis of candidemia in patients with sepsis remains poor.

OBJECTIVE

We aimed to use machine learning algorithms to develop and validate a candidemia prediction model for patients with cancer.

METHODS

We conducted a single-center retrospective study using the cancer registry of a tertiary academic hospital. Adult patients diagnosed with malignancies between January 2010 and December 2018 were included. Our study outcome was the prediction of candidemia events. A stratified undersampling method was used to extract control data for algorithm learning. Multiple models were developed-a combination of 4 variable groups and 5 algorithms (auto-machine learning, deep neural network, gradient boosting, logistic regression, and random forest). The model with the largest area under the receiver operating characteristic curve (AUROC) was selected as the Candida detection (CanDETEC) model after comparing its performance indexes with those of the Candida Score Model.

RESULTS

From a total of 273,380 blood cultures from 186,404 registered patients with cancer, we extracted 501 records of candidemia events and 2000 records as control data. Performance among the different models varied (AUROC 0.771- 0.889), with all models demonstrating superior performance to that of the Candida Score (AUROC 0.677). The random forest model performed the best (AUROC 0.889, 95% CI 0.888-0.889); therefore, it was selected as the CanDETEC model.

CONCLUSIONS

The CanDETEC model predicted candidemia in patients with cancer with high discriminative power. This algorithm could be used for the timely diagnosis and appropriate empirical treatment of candidemia.

Update on Non-Culture-Based Diagnostics for Invasive Fungal Disease

Diagnostic tests for fungi provide the mycological evidence to strengthen diagnosis of invasive fungal disease. Conventional microbiology and histopathology have their limitations. Recognizing this, there have been attempts at developing new methods to improve yield of diagnosing invasive fungal disease (IFD). The recent focus has been on non-culture-based antigen detection and molecular methods. The use of antigen detection of IFD through 1,3-β-D-glucan and galactomannan assay have been expanded, followed by development of lateral flow assays, and in combination with other diagnostic modalities to further increase diagnostic yield. The molecular diagnostic front has seen initiatives to standardize polymerase chain reaction methodologies to detect fungi and anti-fungal resistance, new platforms such as the T2Candida Biosystems and foray into fungal metagenomics. As these newer assays undergo stringent validation before incorporation into the diagnostic algorithm, the clinician needs to be mindful of their bedside utility as well as their limitation.

New Microbiological Techniques for the Diagnosis of Bacterial Infections and Sepsis in ICU Including Point of Care

Purpose of Review

The aim of this article is to review current and emerging microbiological techniques that support the rapid diagnosis of bacterial infections in critically ill patients, including their performance, strengths and pitfalls, as well as available data evaluating their clinical impact.

Recent Findings

Bacterial infections and sepsis are responsible for significant morbidity and mortality in patients admitted to the intensive care unit and their management is further complicated by the increase in the global burden of antimicrobial resistance. In this setting, new diagnostic methods able to overcome the limits of traditional microbiology in terms of turn-around time and accuracy are highly warranted. We discuss the following broad themes: optimisation of existing culture-based methodologies, rapid antigen detection, nucleic acid detection (including multiplex PCR assays and microarrays), sepsis biomarkers, novel methods of pathogen detection (e.g. T2 magnetic resonance) and susceptibility testing (e.g. morphokinetic cellular analysis) and the application of direct metagenomics on clinical samples. The assessment of the host response through new “omics” technologies might also aid in early diagnosis of infections, as well as define non-infectious inflammatory states.

Summary

Despite being a promising field, there is still scarce evidence about the real-life impact of these assays on patient management. A common finding of available studies is that the performance of rapid diagnostic strategies highly depends on whether they are integrated within active antimicrobial stewardship programs. Assessing the impact of these emerging diagnostic methods through patient-centred clinical outcomes is a complex challenge for which large and well-designed studies are awaited.

Antimicrobial and resource utilization with T2 magnetic resonance for rapid diagnosis of bloodstream infections: systematic review with meta-analysis of controlled studies

Objectives: To compare antimicrobial and resource utilization with T2 Magnetic Resonance (T2MR) versus blood culture (BC) in patients with suspected bloodstream infection.Methods: We systematically searched MEDLINE, EMBASE, and CENTRAL for randomized trials or observational controlled studies of patients with suspected bloodstream infection receiving a diagnosis with T2MR or BC. Using an inverse variance meta-analysis model, we reported mortality using the risk ratio (RR) and the remaining outcomes as the mean difference (MD).Results: Fourteen studies were included in the meta-analysis. Time to detection (MD = -81 hours; p < 0.001) and time to species identification (MD = -77 hours; p < 0.001) were faster with T2MR. Patients testing positive on T2MR received targeted antimicrobial therapy faster (-42 hours; p < 0.001) and patients testing negative on T2MR were de-escalated from empirical therapy faster (-7 hours; p = 0.02) vs. BC. Length of intensive care unit stay (MD = -5.0 days; p = 0.03) and hospital stay (MD = -4.8 days; p = 0.03) were shorter with T2MR. Mortality rates were comparable between T2MR and BC (28.9% vs. 29.9%, RR = 1.02, p = 0.86).Conclusion: Utilization of T2MR for identification of bloodstream pathogens provides faster time to detection, faster transition to targeted microbial therapy, faster de-escalation of empirical therapy, shorter ICU and hospital stay, and with comparable mortality rate versus BC.

T2Candida for the Diagnosis and Management of Invasive Candida Infections

Invasive candidiasis is a common healthcare-associated infection with high mortality and is difficult to diagnose due to nonspecific symptoms and limitations of culture based diagnostic methods. T2Candida, based on T2 magnetic resonance technology, is FDA approved for the diagnosis of candidemia and can rapidly detect the five most commonly isolated Candida sp. in approximately 5 h directly from whole blood. We discuss the preclinical and clinical studies of T2Candida for the diagnosis of candidemia and review the current literature on its use in deep-seated candidiasis, its role in patient management and prognosis, clinical utility in unique populations and non-blood specimens, and as an antifungal stewardship tool. Lastly, we summarize the strengths and limitations of this promising nonculture-based diagnostic test.

Perspectives in process analytics using low field NMR

Low field NMR is a powerful analytical tool which creates an enormous added value in process analytics. Based on specific applications in process analytics and perspectives for low field NMR in form of spectroscopy, relaxation, diffusion, and imaging in quality control, diverse applications and technical realizations like spectrometers, time domain NMR, mobile NMR sensors and MRI will be discussed.

Molecular Diagnosis of Yeast Infections

PURPOSE OF REVIEW

The use of molecular tests to aid the diagnosis of invasive yeast infection, in particular invasive candidosis, has been described for over two decades, yet widespread application is limited, and diagnosis remains heavily dependent on classical microbiology. This article will review developments from the past decade in attempt to build on existing knowledge. It will highlight clinical performance and limitations while reviewing developments on recognized procedures; it will also provide insight into novel approaches incorporated in response to clinical demand (e.g. C. auris and antifungal resistance) or technological advances (e.g. next-generation sequencing).

RECENT FINDINGS

Limited methodological standardization and, until recently, unavailability of commercial options have hindered the integration of molecular diagnostics for yeasts. The development of certain, novel commercial methods has received considerable evaluation allowing a greater understanding of individual assay performance, but widespread multicentre evaluation of most commercial kits is lacking. The detection of emerging pathogens (e.g. C. auris) has been enhanced by the development of molecular tests. Molecular methods are providing a better understanding of the mycobiome, mechanisms of resistance and epidemiology/phylogeny.

SUMMARY

Despite over two decades of use, the incorporation of molecular methods to enhance the diagnosis of yeast infections remains limited to certain specialist centres. While the development of commercial tests will provide stimulus for broader application, further validation and reduced costs are required. Over the same period of time, Aspergillus PCR has become more widely accepted driven by international efforts to standardize methodology; it is critical that yeast PCR follows suit. Next-generation sequencing will provide significant information on the mycobiome, antifungal resistance mechanism and even broad-range detection directly from the specimen, which may be critical for the molecular detection of yeasts other than Candida species, which is currently limited.

PCR-detectable Candida DNA exists a short period in the blood of systemic candidiasis murine model

Invasive candidiasis is a major challenge to clinical medicine today. However, traditional fungal diagnostic techniques and empirical treatments have shown great limitations. Although efforts are necessarily needed in methodology standardization and multicenter validation, polymerase chain reaction (PCR) is a very promising assay in detecting fungal pathogens. Using a "heat-shock" DNA preparation method, a rapid and simple PCR protocol for quantification of the Candida albicans (C. albicans) ribosomal DNA was established. The PCR assay could detect Candida DNA as low as 10 CFU/mL in samples prepared by the heat-shock protocol, without any cross-reaction with DNA prepared from other Candida spp. and bacterial pathogens. For simulated blood samples, the PCR test sensitivity of whole blood samples was better than that of plasma and blood cells. In the systemic candidiasis murine model, detectable DNA was only observed within 24 h after C. albicans SC5314 injection, which is much shorter than that observed in the kidney.

Diagnosis and treatment of invasive fungal infections: looking ahead

Improved standards of care depend on the development of new laboratory diagnostic and imaging procedures and the development of new antifungal compounds. Immunochromatography technologies have led to the development of lateral flow devices for the diagnosis of cryptococcal meningitis and invasive aspergillosis (IA). Similar devices are being developed for the detection of histoplasmosis that meet the requirements for speed (∼15 min assay time) and ease of use for point-of-care diagnostics. The evolution of molecular tools for the detection of fungal pathogens has been slow but the introduction of new nucleic acid amplification techniques appears to be helpful, for example T2Candida. An Aspergillus proximity ligation assay has been developed for a rapid near-patient bedside diagnosis of IA. CT remains the cornerstone for radiological diagnosis of invasive pulmonary fungal infections. MRI of the lungs may be performed to avoid radiation exposure. MRI with T2-weighted turbo-spin-echo sequences exhibits sensitivity and specificity approaching that of CT for the diagnosis of invasive pulmonary aspergillosis. The final part of this review looks at new approaches to drug discovery that have yielded new classes with novel mechanisms of action. There are currently two new classes of antifungal drugs in Phase 2 study for systemic invasive fungal disease and one in Phase 1. These new antifungal drugs show promise in meeting unmet needs with oral and intravenous formulations available and some with decreased potential for drug-drug interactions. Novel mechanisms of action mean these agents are not susceptible to the common resistance mechanisms seen in Candida or Aspergillus. Modification of existing antifungal susceptibility testing techniques may be required to incorporate these new compounds.

Droplet digital polymerase chain reaction for rapid broad-spectrum detection of bloodstream infections

The droplet digital polymerase chain reaction (ddPCR) is a novel molecular technique that allows rapid quantification of rare target DNA sequences. Aim of this study was to explore the feasibility of the ddPCR technique to detect pathogen DNA in whole blood and to assess the diagnostic accuracy of ddPCR to detect bloodstream infections (BSIs), benchmarked against blood cultures. Broad-range primers and probes were designed to detect bacterial 16S rRNA (and Gram stain for differentiation) and fungal 28S rRNA. To determine the detection limit of ddPCR, 10-fold serial dilutions of E. coli and C. albicans were spiked in both PBS and whole blood. The diagnostic accuracy of ddPCR was tested in historically collected frozen blood samples from adult patients suspected of a BSI and compared with blood cultures. Analyses were independently performed by two research analysts. Outcomes included sensitivity and specificity of ddPCR. Within 4 h, blood samples were drawn, and DNA was isolated and analysed. The ddPCR detection limit was approximately 1-2 bacteria or fungi per ddPCR reaction. In total, 45 blood samples were collected from patients, of which 15 (33%) presented with positive blood cultures. The overall sensitivity of ddPCR was 80% (95% CI 52-96) and specificity 87% (95% CI 69-96). In conclusion, the ddPCR technique has considerable potential and is able to detect very low amounts of pathogen DNA in whole blood within 4 h. Currently, ddPCR has a reasonable sensitivity and specificity, but requires further optimization to make it more useful for clinical practice.

Performance of the T2Candida Panel for the Diagnosis of Intra-abdominal Candidiasis

Performance of T2Candida for detecting intra-abdominal candidiasis (IAC) was assessed in 48 high-risk patients. T2Candida sensitivity/specificity and positive/negative predictive values were 33%/93% and 71%/74%, respectively. IAC was present in 100% of cases with concordant positive T2Candida/1,3-beta-d-glucan and absent in 90% of concordant negative results. Combination T2Candida/1,3-beta-d-glucan may help guide treatment decisions.

Evaluation of a Rapid Fungal Detection Panel for Identification of Candidemia at an Academic Medical Center

This study was conducted to assess the utility of the T2Candida panel across an academic health center and identify potential areas for diagnostic optimization. A retrospective chart review was conducted on patients with a T2Candida panel and mycolytic/fungal (myco/f lytic) blood culture collected simultaneously during hospitalizations from February 2017 to March 2018. The primary outcome of this study was to determine the sensitivity, specificity, and positive and negative predictive values of the panel compared to myco/f lytic blood culture. Secondary outcomes included Candida species isolated from culture or detected on the panel, source of infection, days of therapy (DOT) of antifungals in patients with discordant results, and overall antifungal DOT/1,000 patient days. A total of 433 paired T2Candida panel and myco/f lytic blood cultures were identified. The pretest likelihood of candidemia was 4.4%. The sensitivity and specificity were 64.7% and 95.6%, respectively. The positive and negative predictive values were 40.7% and 98.5%, respectively. There were 16 patients with T2Candida panel positive and myco/f lytic blood culture negative results, while 6 patients had T2Candida panel negative and myco/f blood culture positive results. The overall antifungal DOT/1,000 patient days was improved after implementation of the T2Candida panel; however, the use of micafungin continued to decline after the panel was removed. We found that the T2Candida panel is a highly specific diagnostic tool; however, the sensitivity and positive predictive value may be lower than previously reported when employed in clinical practice. Clinicians should use this panel as an adjunct to blood cultures when making a definitive diagnosis of candidemia.

Direct Detection of Pathogens in Bloodstream During Sepsis: Are We There Yet?

Background

Advances in medicine have improved our understanding of sepsis, but it remains a major cause of morbidity and mortality. The detection of pathogens that cause sepsis remains a challenge for clinical microbiology laboratories.

Content

Routine blood cultures are time-consuming and are negative in a large proportion of cases, leading to excessive use of broad-spectrum antimicrobials. Molecular testing direct from patient blood without the need for incubation has the potential to fill the gaps in our diagnostic armament and complement blood cultures to provide results in a timely manner. Currently available platforms show promise but have yet to definitively address gaps in sensitivity and specificity.

Summary

Significant strides have been made in the detection of pathogens directly from blood. A number of hurdles, however, remain before this technology can be adapted for routine use.

Biomarkers of Infection and Sepsis

The role of biomarkers for detection of sepsis has come a long way. Molecular biomarkers are taking front stage at present, but machine learning and other computational measures using bigdata sets are promising. Clinical research in sepsis is hampered by lack of specificity of the diagnosis; sepsis is a syndrome with no uniformly agreed definition. This lack of diagnostic precision means there is no gold standard for this diagnosis. The final conclusion is expert opinion, which is not bad but not perfect. Perhaps machine learning will displace expert opinion as the final and most accurate definition for sepsis.

Pooled analysis of T2 Candida for rapid diagnosis of candidiasis

Background

The present meta-analysis examined the diagnostic accuracy of T2 Candida for candidiasis.

Methods

The literature databases, such as PubMed, Embase, DVIO, Cochrane library, Web of Science, and CNKI, were searched on T2 Candida detection.

Results

A total of 8 articles, comprising of 2717 research subjects, were included in the study. The pooled sensitivity and specificity were 0.91 (95% confidence interval (CI): 0.88–0.94) and 0.94 95% CI: 0.93–0.95), respectively. The pooled positive likelihood ratio and negative likelihood ratio was 10.16 (95% CI: 2.75–37.50) and 0.08 (95% CI: 0.02–0.35), respectively. The combined diagnostic odds ratio is 133.65 95% CI: 17.21–1037.73), and the AUC of SROC is 0.9702 [(SE = 0.0235), Q* = 0.9201(SE = 0.0381)].

Conclusions

The current evidence supported that T2 Candida has high accuracy and sensitivity and is of major clinical significance in the diagnosis of Candida infection.

Recent trends in molecular diagnostics of yeast infections: from PCR to NGS

The incidence of opportunistic yeast infections in humans has been increasing over recent years. These infections are difficult to treat and diagnose, in part due to the large number and broad diversity of species that can underlie the infection. In addition, resistance to one or several antifungal drugs in infecting strains is increasingly being reported, severely limiting therapeutic options and showcasing the need for rapid detection of the infecting agent and its drug susceptibility profile. Current methods for species and resistance identification lack satisfactory sensitivity and specificity, and often require prior culturing of the infecting agent, which delays diagnosis. Recently developed high-throughput technologies such as next generation sequencing or proteomics are opening completely new avenues for more sensitive, accurate and fast diagnosis of yeast pathogens. These approaches are the focus of intensive research, but translation into the clinics requires overcoming important challenges. In this review, we provide an overview of existing and recently emerged approaches that can be used in the identification of yeast pathogens and their drug resistance profiles. Throughout the text we highlight the advantages and disadvantages of each methodology and discuss the most promising developments in their path from bench to bedside.

Diagnosing and Managing Sepsis by Probing the Host Response to Infection: Advances, Opportunities, and Challenges

Sepsis is a major source of mortality and morbidity globally. Accurately diagnosing sepsis remains challenging due to the heterogeneous nature of the disease, and delays in diagnosis and intervention contribute to high mortality rates. Measuring the host response to infection enables more rapid diagnosis of sepsis than is possible through direct detection of the causative pathogen, and recent advances in host response diagnostics and prognostics hold promise for improving outcomes. The current review discusses recent advances in the technologies used to probe the host response to infection, particularly those based on transcriptomics. These are discussed in the context of contemporary approaches to diagnosing and prognosing sepsis, and recommendations are made for successful development and validation of host response technologies.

Microfluidic Chip for Detection of Fungal Infections

Fungal infections can lead to severe clinical outcomes such as multiple organ failure and septic shock. Rapid detection of fungal infections allows clinicians to treat patients in a timely manner and improves clinical outcomes. Conventional detection methods include blood culture followed by plate culture and polymerase chain reaction. These methods are time-consuming and require expensive equipment, hence, they are not suitable for point-of-care and clinical settings. There is an unmet need to develop a rapid and inexpensive detection method for fungal infections such as candidemia. We developed an innovative immuno-based microfluidic device that can rapidly detect and capture Candida albicans from phosphate-buffered saline (PBS) and human whole blood. Our microchip technology showed an efficient capture of C. albicans in PBS with an efficiency of 61-78% at various concentrations ranging from 10 to 10⁵ colony-forming units per milliliter (cfu/mL). The presented microfluidic technology will be useful to screen for various pathogens at the point-of-care and clinical settings.

T2Bacteria magnetic resonance assay for the rapid detection of ESKAPEc pathogens directly in whole blood

Objectives

To evaluate the magnetic resonance-based T2Bacteria Panel assay for direct detection of ESKAPEc (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) pathogens in blood samples of patients with suspected bloodstream infection (BSI).

Patients and methods

Adult patients admitted to the Emergency Medicine Department, Infectious Diseases Unit and ICU of a large tertiary-care hospital were included if they had a blood culture (BC) ordered concomitantly with a whole-blood sample for T2Bacteria testing. Results were compared with those of BC and other clinically relevant information.

Results

A total of 140 samples from 129 BSI patients were studied. Single bacteria were detected in 15.7% (22/140) and 12.1% (17/140), and multiple bacteria in 2.9% (4/140) and 1.4% (2/140), of samples tested by T2Bacteria and BC, respectively. With respect to the six target (ESKAPEc) species, overall sensitivity and specificity of T2Bacteria across all detection channels in comparison with BC were 83.3% and 97.6%, respectively; these values increased to 89.5% and 98.4%, respectively, when a true-infection criterion (i.e. the same microorganism detected only by T2Bacteria was cultured from another sample type reflecting the source of infection) was used as the comparator. There were 808 T2Bacteria detection results across 112 samples, with concordant negative results, yielding a negative predictive value of 99.8%. The mean time to negative result was 6.1 ± 1.5 h, whereas the mean time to detection/species identification was 5.5 ± 1.4 h.

Conclusions

The T2Bacteria Panel assay has the potential to provide accurate and timely diagnosis of ESKAPEc bacteraemia, which might support the direct therapeutic management of BSI patients.

T2 magnetic resonance for the diagnosis of bloodstream infections: charting a path forward

We discuss four studies in this issue of the Journal of Antimicrobial Chemotherapy that describe experience with T2 magnetic resonance (T2MR) nanodiagnostics for Candida and bacterial bloodstream infections, in the context of the T2MR literature. T2Candida and T2Bacteria panels use a dedicated instrument to detect amplified DNA from microbial cells directly in whole blood. T2Candida gives positive or negative results for C. albicans/C. tropicalis, C. glabrata/C. krusei, and C. parapsilosis. T2Bacteria detects Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli. In recent trials, T2Candida sensitivity and specificity for candidaemia were ∼90% and ∼98%, respectively. Two studies from Spanish hospitals now provide the first data on T2Candida as a prognostic tool. T2Candida was superior to cultures or serum β-d-glucan in identifying patients with complicated candidaemia, and in predicting the outcomes of empirical antifungal therapy for suspected candidiasis. In a retrospective study from US community hospitals, use of T2Candida was reported to reduce times to appropriate antifungal therapy, shorten courses of empirical therapy, and save an average of US$280 in antifungal costs per patient tested. Finally, a study from a hospital in Rome provides the first clinical data for T2Bacteria: sensitivity and specificity were 89% and 98%, respectively, among patients with positive blood cultures for bacteria detected by the panel, or fulfilling criteria for infection. We conclude that T2MR diagnostics are promising both for detecting bloodstream infections due to Candida and bacteria, and for providing prognostic information. More studies that present real-world performance data are needed.

Impact of rapid, culture-independent diagnosis of candidaemia and invasive candidiasis in a community health system

Background

Delay in treatment of candidaemia and invasive candidiasis remains a cause of significant morbidity and mortality in high-risk patients. Widespread empirical utilization of antifungal therapy often occurs in an effort to minimize this risk.

Objectives

This study assessed the impact of the T2Candida Panel in a multi-hospital community health system on time to initiation of antifungal therapy in candidaemic patients as well as the utilization of micafungin.

Methods

Outcomes were compared between those patients with candidaemia prior to T2Candida implementation and those after implementation. Micafungin utilization for patients with suspected candidaemia/invasive candidiasis was compared with that for patients with a negative T2Candida Panel post-implementation.

Results

There was a significant decrease in time to appropriate therapy in the post-T2Candida group (34 versus 6 h, P = 0.0147). Empirical antifungal therapy was avoided in 58.4% of T2Candida-negative patients.

Conclusions

These results support the implementation of T2Candida to improve time to appropriate therapy for candidaemic patients while simultaneously expanding antimicrobial stewardship efforts to appropriately utilize antifungals.

Combination antifungal therapy for treatment of Candida parapsilosis prosthetic valve endocarditis and utility of T2Candida Panel®: A case series

Although Candida species are common pathogens for nosocomial infections, Candida endocarditis is still considered a rare entity. Here, we report two cases of Candida parapsilosis endovascular infections in patients with prosthetic valves, both of which responded to combination antifungal therapy without surgical intervention. Additionally, T2 magnetic resonance (T2MR) was used to assess for resolution of invasive candidiasis. The first case is of an elderly man with Candida parapsilosis endovascular infection who responded to combination antifungal therapy with micafungin and fluconazole followed by suppressive therapy, without surgical intervention. The second case is of a middle-aged man with Candida parapsilosis prosthetic valve endocarditis who also responded to combination antifungal therapy with micafungin, flucytosine and fluconazole, without surgical intervention.

Cost-effectiveness of rapid diagnostic assays that perform directly on blood samples for the diagnosis of septic shock

Molecular diagnostic assays that test directly whole blood provide the ability to decrease inappropriate antimicrobial therapy and improve survival in patients with septic shock. We developed a decision analysis model to evaluate the cost-effectiveness of the addition of molecular assays to blood cultures in adults admitted to medical ICUs with septic shock. Under baseline assumptions, the use of molecular diagnostic methods was cost-saving in all cases that the length of hospital stay differed by 2 and 4 days between patients receiving appropriate and inappropriate antimicrobial therapy. In the case that the length of stay was the same, the use of molecular methods was cost-effective with an estimated incremental cost-effectiveness ratio (ICER) < $3000 per death averted. In the extreme that the length of stay between the 2 groups was the same, the highest cost reached was when the cost of the assay was $1000, with the estimated ICER being < $20,000 per death averted.