Progress on nonculture based diagnostic tests for invasive mould infection

PURPOSE OF REVIEW

This review describes the current status of diagnosing invasive mould disease and Pneumocystis pneumonia using nonconventional diagnostics methods.

RECENT FINDINGS

There has been significant development in the range of nonculture mycological tests. Lateral flow tests (LFTs) for diagnosing aspergillosis complement galactomannan ELISA testing, and LFTs for other fungal diseases are in development. Rapid and low through-put B-D-Glucan assays increase access to testing and there has been significant progress in the standardization/development of molecular tests. Despite this, no single perfect test exists and combining tests (e.g., antigen and molecular testing) is likely required for the optimal diagnosis of most fungal diseases.

SUMMARY

Based on established clinical performance few mycological tests can be used alone for optimal diagnosis of fungal disease (FD) and combining tests, including classical approaches is the preferred route for confirming and excluding disease. Next-generation sequencing will likely play an increasing role in how we diagnose disease, but optimization, standardization and validation of the entire molecular process is needed and we must consider how host biomarkers can stratify risk. Given the burden of FD in low- and medium-income countries, improved access to novel but more so existing diagnostic testing is critical along with simplification of testing processes.

Biosensors for detection of airborne pathogenic fungal spores: a review

The excessive presence of airborne fungal spores presents major concerns with potential adverse impacts on public health and food safety. These spores are recognized as pathogens and allergens prevalent in both outdoor and indoor environments, particularly in public spaces such as hospitals, schools, offices and hotels. Indoor environments pose a heightened risk of pulmonary diseases due to continuous exposure to airborne fungal spore particles through constant inhalation, especially in those individuals with weakened immunity and immunocompromised conditions. Detection methods for airborne fungal spores are often expensive, time-consuming, and lack sensitivity, making them unsuitable for indoor/outdoor monitoring. However, the emergence of micro-nano biosensor systems offers promising solutions with miniaturized designs, nanomaterial integration, and microfluidic systems. This review provides a comprehensive overview of recent advancements in bio-nano-sensor system technology for detecting airborne fungal spores, while also discussing future trends in biosensor device development aimed at achieving rapid and selective identification of pathogenic airborne fungi.

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Chronic disseminated candidiasis in a patient with acute leukemia - an illustrative case and brief review for clinicians

Chronic disseminated candidiasis (CDC) is a severe but rarely seen fungal infection presenting in patients with hematologic malignancies after a prolonged duration of neutropenia. A high index of suspicion is required to diagnose CDC as standard culture workup is often negative. While tissue biopsy is the gold standard of diagnosis, it is frequently avoided in patients with profound cytopenias and increased bleeding risks. A presumptive diagnosis can be made in patients with recent neutropenia, persistent fevers unresponsive to antibiotics, imaging findings of hypoechoic, non-rim enhancing target-like lesions in the spleen and liver, and mycologic evidence. Here, we describe the case of an 18-year-old woman with relapsed B-cell acute lymphoblastic leukemia treated with re-induction chemotherapy who subsequently developed CDC with multi-organ involvement. The diagnosis was made based on clinical and radiologic features with positive tissue culture from a skin nodule and hepatic lesion. The patient was treated for a total course of 11 months with anti-fungal therapy, most notably amphotericin B and micafungin, and splenectomy. After initial diagnosis, the patient was monitored with monthly CT abdomen imaging that showed disease control after 5 months of anti-fungal therapy and splenectomy. The diagnosis, treatment, and common challenges of CDC are outlined here to assist with better understanding, diagnosis, and treatment of this rare condition.

Evaluation of the Performance of the Dynamiker Fungus (1-3)-β-D-Glucan and Fungitell Assay for Diagnosis of Candidemia: Need for New Cut-off Development and Test Validation

(1-3)-Beta-D Glucan (BDG) detection has shown to be a highly effective tool to diagnose invasive fungal infections. Therefore, this study aimed to compare clinical characteristics of the Fungitell (FA) and Dynamiker Fungus (1-3)-β-D-Glucan assay (DFA) for the diagnosis of candidemia. Using DFA and FA, the BDG levels of 57 serum samples from case and control groups were determined. The kappa coefficient (κ) and Spearman's rank correlation (rs) were used to examine the consistency of assays on a quantitative and qualitative level, respectively. The sensitivity, specificity, and accuracy were 94.6 %, 65.0 %, and 87.7% for DFA, and 94.6 %, 75.0 %, and 89.4 % for FA, respectively. The performance of the DFA for the diagnosis of candidemia was highly consistent with that of the FA, both quantitatively (rs: 0.9) and qualitatively (kappa = 0.78). Collectively, the DFA assay performed excellently in comparison to the FA for the diagnosis of candidemia.

Comparison of Three β-Glucan Tests for the Diagnosis of Invasive Candidiasis in Intensive Care Units

The (1→3)-β-d-glucan (BDG) is a marker of invasive fungal infection that can be detected in serum by different commercial kits. In this study, we compared the performance of the Fungitell assay (FA), the Fungitell STAT assay (STAT), and the Wako β-glucan test (WA) for the diagnosis of invasive candidiasis (IC) in the intensive care unit (ICU). Patients for whom at least one BDG testing was required for a clinical suspicion of IC were retrospectively enrolled. A total of 85 serum samples from 56 patients were tested by the three BDG tests. The rate of IC was 23% (13/56) with a predominance of noncandidemic (intra-abdominal) IC. STAT and WA results exhibited overall good correlation with those obtained by FA (Spearman's coefficient R = 0.90 and R = 0.89, respectively). For the recommended cutoffs of positivity, sensitivity and specificity for IC diagnosis were 77%/51% (FA, 80 pg/mL), 69%/53% (STAT, ratio 1.2), and 54%/65% (WA, 7 pg/mL), respectively. Optimal performance was obtained at 50 pg/mL (FA), ratio 1.3 (STAT), and 3.3 pg/mL (WA) with sensitivity/specificity of 85%/51%, 69%/57%, and 77%/58%, respectively. Overall, the three BDG tests showed comparable but limited performance in this setting with positive and negative predictive values for an estimated IC prevalence of 20% that were in the range of 30 to 35% and 85 to 95%, respectively.

Noninvasive Testing and Surrogate Markers in Invasive Fungal Diseases

Invasive fungal infections continue to increase as at-risk populations expand. The high associated morbidity and mortality with fungal diseases mandate the continued investigation of novel antifungal agents and diagnostic strategies that include surrogate biomarkers. Biologic markers of disease are useful prognostic indicators during clinical care, and their use in place of traditional survival end points may allow for more rapid conduct of clinical trials requiring fewer participants, decreased trial expense, and limited need for long-term follow-up. A number of fungal biomarkers have been developed and extensively evaluated in prospective clinical trials and small series. We examine the evidence for these surrogate biomarkers in this review and provide recommendations for clinicians and regulatory authorities.

Risk factors of non-invasive ventilation failure in hematopoietic stem-cell transplantation patients with acute respiratory distress syndrome

Background:

Non-invasive ventilation (NIV) was one of the first-line ventilation supports for hematopoietic stem-cell transplantation (HSCT) patients with acute respiratory distress syndrome (ARDS). Successful NIV may avoid need for intubation. However, the influence NIV failure had on patients’ outcome and its risk factors were hardly known.

Methods:

In this retrospective observational study, we reported risk factors and incidence of NIV failure in HSCT patients who were admitted to the Intensive Care Unit (ICU) with a diagnosis of ARDS and supported with mechanical ventilation, in a 5-year period. Patient outcomes, such as ventilator-free days, ICU-free days, and ICU mortality were also reported.

Results:

Of all the 94 patients included, 70 patients were initially supported with NIV. NIV failure occurred in 44 (63%) patients. Male sex, elevated serum galactomannan (GM) test, (1-3)-β-D-glucan (BG) assay, or elevated serum creatinine level were risk factors for NIV failure. When compared with the NIV success group, failure of NIV was associated with much fewer ICU-free days (22 versus 0, p < 0.001, Cohen’s d = 0.62) and higher ICU mortality (9.5% versus 75.5%, p < 0.001, Pearson’s r = 0.75). There was no difference in ICU-free days, ventilator-free days and ICU mortality between NIV failure and initial invasive mechanical ventilation (IMV) groups. Patients who failed in NIV support had a higher ICU mortality (75.5%) than those who succeeded (9.5%).

Conclusion:

In a small cohort of HSCT patients with mainly moderate severity of ARDS, male patients with elevated serum GM/BG test or serum creatinine level had a higher risk of NIV failure. Both NIV failure and initial IMV groups were characterized by high mortality rate and extremely low ICU-free days and ventilator-free days; failure of NIV support may further aggravate patient prognosis.

The reviews of this paper are available via the supplemental material section.

Comparison of two β-D-glucan assays for detecting invasive fungal diseases in immunocompromised patients

(1-3)-β-D-glucan (BDG) is a major biomarker of invasive fungal diseases (IFDs), which are life-threatening for immunodeficient patients. We compared the clinical performance of two BDG-detection assays. The precision, linearity, reference interval, and limit of quantitation of the Wako BDG assay were analyzed and the performance was compared with that of the Goldstream BDG assay using 272 clinical serum samples. The repeatability, within-laboratory imprecision, and limit of quantitation of the Wako BDG assay were 3.8%, 5.9%, and 7.35 pg/mL, respectively (linearity, 23.8-557 pg/mL; R² = 0.998). The correlation coefficient, slope, and y-intercept for the Wako BDG assay versus Goldstream BDG assay were 0.29, 3.82, and 0.04, respectively. The sensitivity and specificity were 43.8% and 94.9% for the Wako BDG assay and 39.6% and 83.5% for the Goldstream BDG assay, respectively. In clinical settings, the Wako BDG assay is suitable for diagnosing patients with IFDs.

Assessment of the Role of 1,3-β-d-Glucan Testing for the Diagnosis of Invasive Fungal Infections in Adults

Detection of 1,3-β-d-glucan (BDG) in serum has been evaluated for its inclusion as a mycological criterion of invasive fungal infections (IFI) according to EORTC and Mycoses Study Group (MSG) definitions. BDG testing may be useful for the diagnosis of both invasive aspergillosis and invasive candidiasis, when interpreted in conjunction with other clinical/radiological signs and microbiological markers of IFI. However, its performance and utility vary according to patient population (hematologic cancer patients, solid-organ transplant recipients, intensive care unit patients) and pretest likelihood of IFI. The objectives of this article are to provide a systematic review of the performance of BDG testing and to assess recommendations for its use and interpretation in different clinical settings.

CLINICAL UTILITY OF BETA-D-GLUCAN TESTING FOR ENDOGENOUS FUNGAL CHORIORETINITIS OR ENDOPHTHALMITIS

PURPOSE

To evaluate serum beta-D-glucan (BDG) as a biomarker for endogenous fungal eye infection.

METHODS

Retrospective case-control study of 88 patients with a BDG test and eye examination at UPenn (2013-2018). Cases had endogenous fungal chorioretinitis or endophthalmitis diagnosed by eye examination and confirmed with positive culture; controls were without these fungal eye findings. Charts were reviewed for BDG values, blood/vitreous cultures, and eye examinations. Outcomes were BDG sensitivity, specificity, positive predictive value, and negative predictive value for fungal chorioretinitis or endophthalmitis, using prespecified BDG cut-off points of ≥80, ≥250, and ≥500 pg/mL as test positive.

RESULTS

Cases included six chorioretinitis and four endophthalmitis patients. Controls included 78 patients without chorioretinitis or endophthalmitis. Defining BDG ≥80 pg/mL as test positive, the BDG sensitivity (95% confidence interval) was 66.7% (22.3%-95.7%) for chorioretinitis and 100% (39.8%-100%) for endophthalmitis. The specificity was 74.4% (63.2%-83.6%) when BDG values ≥80 pg/mL were test positive, and 85.9% (76.2%-92.7%) when values ≥250 pg/mL were test positive. For a 1% endophthalmitis prevalence and BDG cut-off value of ≥80 pg/mL, the positive predictive value was 3.8% (2.4%-5.2%) and negative predictive value was 100% (99.1%-100%).

CONCLUSION

For endogenous fungal endophthalmitis, BDG's sensitivity and specificity seem good and the negative predictive value is high; a larger ophthalmic study is indicated.

Clinical Relevance and Prognostic Value of Persistently Negative (1,3)-β-D-Glucan in Adults With Candidemia: A 5-year Experience in a Tertiary Hospital

BACKGROUND

The clinical relevance and the potential prognostic role of persistently negative (1,3)-β-D-glucan (BDG) in adults with proven candidemia is unknown.

METHODS

This retrospective study included all adults diagnosed with candidemia our tertiary university hospital from 2012-2017 who had at least 2 serum BDG determinations throughout the episode of fungemia (Fungitell Assay; positive cut-off ≥80pg/mL). Epidemiology and clinical outcomes were compared between patients with all negative versus any positive BDG tests. Poor clinical outcomes included complications due to candidemia or 30-day all-cause mortality.

RESULTS

Overall, 26/148 (17.6%) candidemic adults had persistently negative BDG tests. These patients were less likely to present Candida growth in all 3 sets of blood cultures (15.4% vs 45.1%; P = .005) and had less severe clinical presentations (median Pitt score, 0 [interquartile range {IQR} 0-1] vs 1 [IQR 0-2] in patients with any positive BDG test; P = .039). Although adequate treatment was equally provided to both groups (96.2% in persistently negative group vs 93.4 in positive group; P = .599), the persistently negative group had a higher rate of microbiological clearance in the first follow-up blood cultures (92.3% vs 69.7% in positive group; P = .005), fewer complications due to candidemia (7.7% vs 33.6% in positive group; P = .008), a lower 30-day mortality rate (3.8% vs 23.8% in positive group; P = .004), and a shorter in-hospital stay (34 days [IQR 18-55] vs 51 days [IQR 35-91] in positive group; P = .003). In the multivariate analysis, persistently negative BDG tests were independently associated with better prognoses (odds ratio 0.12, 95% confidence interval 0.03-0.49; P = .003).

CONCLUSIONS

Candidemic patients with persistently negative BDG tests present a better prognosis than the comparative group, probably due to a lower systemic fungal burden. In this context, the appropriate use of persistently negative BDG results could be an aid to individualize therapeutic management in the near future.

Quantification of 1,3-β-d-glucan by Wako β-glucan assay for rapid exclusion of invasive fungal infections in critical patients: A diagnostic test accuracy study

OBJECTIVES

Rapid and reliable exclusion of invasive fungal infections (IFI) by markers able to avoid unnecessary empirical antifungal treatment is still a critical unmet clinical need. We investigated the diagnostic performance of a newly available β-d-Glucan (BDG) quantification assay, focusing on the optimisation of the BDG cut-off values for IFI exclusion.

METHODS

BDG results by Wako β-glucan assay (lower limit of detection [LLOD] = 2.16 pg/mL, positivity ≥ 11 pg/mL) on two consecutive serum samples were retrospectively analysed in 170 patients, admitted to haematological wards (N = 42), intensive care units (ICUs; N = 80), or other wards (N = 48), exhibiting clinical signs and/or symptoms suspected for IFI. Only patients with proven IFI (EORTC/MSG criteria) were considered as true positives in the assessment of BDG sensitivity, specificity and predictive values.

RESULTS

Patients were diagnosed with no IFI (69.4%), proven IFI (25.3%) or probable IFI (5.3%). Two consecutive BDG values < LLOD performed within a median of 1 (interquartile range: 1-3) day were able to exclude a proven IFI with 100% sensitivity and negative predictive value (primary study goal). Test's specificity improved by using two distinct positivity and negativity cut-offs (7.7 pg/mL and LLOD, respectively), but remained suboptimal in ICU patients (50%), as compared to haematological or other patients (93% and 90%, respectively).

CONCLUSIONS

The classification of Wako's results as negative when < LLOD, and positive when > 7.7 pg/mL, could be a promising diagnostic approach to confidently rule out an IFI in both ICU and non-ICU patients. The poor specificity in the ICU setting remains a concern, due to the difficulty to interpret positive results in this fragile population.

A Case of Invasive Aspergillus Rhinosinusitis Presenting with Unilateral Visual Loss and Subsequently Associated with Meningitis, Subarachnoid Hemorrhage, and Cerebral Infarction

Visual impairment can occur because of several mechanisms, including optic nerve disease and occasionally fungal sinusitis. An 87-year-old man presented with the loss of right visual acuity; he was diagnosed with optic neuritis. Steroid pulse therapy was not effective. One month later, he became unconscious because of meningitis, following which treatment with ceftriaxone and acyclovir was initiated. However, his consciousness deteriorated because of a subarachnoid hemorrhage caused by a ruptured aneurysm. Meningitis and vascular invasion caused by fungal rhinosinusitis were suspected, and the sinus mucosa was biopsied. He was pathologically diagnosed with invasive Aspergillus rhinosinusitis. Despite continuous liposomal amphotericin B administration, he died of cerebral infarction, following a right internal carotid artery occlusion. It is important to consider the possibility of Aspergillus as an etiological agent, especially when cerebrovascular events are associated with visual impairment.

(1→3)-β-D-glucan testing for the detection of invasive fungal infections in immunocompromised or critically ill people

BACKGROUND

Invasive fungal infections (IFIs) are life-threatening opportunistic infections that occur in immunocompromised or critically ill people. Early detection and treatment of IFIs is essential to reduce morbidity and mortality in these populations. (1→3)-β-D-glucan (BDG) is a component of the fungal cell wall that can be detected in the serum of infected individuals. The serum BDG test is a way to quickly detect these infections and initiate treatment before they become life-threatening. Five different versions of the BDG test are commercially available: Fungitell, Glucatell, Wako, Fungitec-G, and Dynamiker Fungus.

OBJECTIVES

To compare the diagnostic accuracy of commercially available tests for serum BDG to detect selected invasive fungal infections (IFIs) among immunocompromised or critically ill people.

SEARCH METHODS

We searched MEDLINE (via Ovid) and Embase (via Ovid) up to 26 June 2019. We used SCOPUS to perform a forward and backward citation search of relevant articles. We placed no restriction on language or study design.

SELECTION CRITERIA

We included all references published on or after 1995, which is when the first commercial BDG assays became available. We considered published, peer-reviewed studies on the diagnostic test accuracy of BDG for diagnosis of fungal infections in immunocompromised people or people in intensive care that used the European Organization for Research and Treatment of Cancer (EORTC) criteria or equivalent as a reference standard. We considered all study designs (case-control, prospective consecutive cohort, and retrospective cohort studies). We excluded case studies and studies with fewer than ten participants. We also excluded animal and laboratory studies. We excluded meeting abstracts because they provided insufficient information.

DATA COLLECTION AND ANALYSIS

We followed the standard procedures outlined in the Cochrane Handbook for Diagnostic Test Accuracy Reviews. Two review authors independently screened studies, extracted data, and performed a quality assessment for each study. For each study, we created a 2 × 2 matrix and calculated sensitivity and specificity, as well as a 95% confidence interval (CI). We evaluated the quality of included studies using the Quality Assessment of Studies of Diagnostic Accuracy-Revised (QUADAS-2). We were unable to perform a meta-analysis due to considerable variation between studies, with the exception of Candida, so we have provided descriptive statistics such as receiver operating characteristics (ROCs) and forest plots by test brand to show variation in study results.

MAIN RESULTS

We included in the review 49 studies with a total of 6244 participants. About half of these studies (24/49; 49%) were conducted with people who had cancer or hematologic malignancies. Most studies (36/49; 73%) focused on the Fungitell BDG test. This was followed by Glucatell (5 studies; 10%), Wako (3 studies; 6%), Fungitec-G (3 studies; 6%), and Dynamiker (2 studies; 4%). About three-quarters of studies (79%) utilized either a prospective or a retrospective consecutive study design; the remainder used a case-control design. Based on the manufacturer's recommended cut-off levels for the Fungitell test, sensitivity ranged from 27% to 100%, and specificity from 0% to 100%. For the Glucatell assay, sensitivity ranged from 50% to 92%, and specificity ranged from 41% to 94%. Limited studies have used the Dynamiker, Wako, and Fungitec-G assays, but individual sensitivities and specificities ranged from 50% to 88%, and from 60% to 100%, respectively. Results show considerable differences between studies, even by manufacturer, which prevented a formal meta-analysis. Most studies (32/49; 65%) had no reported high risk of bias in any of the QUADAS-2 domains. The QUADAS-2 domains that had higher risk of bias included participant selection and flow and timing.

AUTHORS' CONCLUSIONS

We noted considerable heterogeneity between studies, and these differences precluded a formal meta-analysis. Because of wide variation in the results, it is not possible to estimate the diagnostic accuracy of the BDG test in specific settings. Future studies estimating the accuracy of BDG tests should be linked to the way the test is used in clinical practice and should clearly describe the sampling protocol and the relationship of time of testing to time of diagnosis.

Diagnostic accuracy of serum (1-3)-β-D-glucan for Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) can be a life-threatening opportunistic infection in immunocompromised hosts. The diagnosis can be challenging, often requiring semi-invasive respiratory sampling. The serum 1,3-β-D-glucan (BDG) assay has been proposed as a minimally invasive test for the presumptive diagnosis of PJP.

METHOD

We carried out a systematic review and meta-analysis using articles in the English language published between January 1960 and September 2019. We estimated the pooled sensitivity and specificity of BDG testing using a bivariate random effects approach and compared test performance in human immunodeficiency virus (HIV) and non-HIV subgroups with meta-regression. Data from the pooled sensitivity and specificity were transformed to generate pre- and post-test probability curves.

RESULTS

Twenty-three studies were included. The pooled sensitivity and specificity of serum BDG testing for PJP were 91% (95%CI 87-94%) and 79% (95%CI 72-84%) respectively. The sensitivity in patients with HIV was better than in patients without (94%, 95%CI 91-96%) versus 86% (95%CI 78-91%) (p 0.02), with comparable specificity (83%, 95%CI 69-92% versus 83%, 95%CI 72-90%) (p 0.10). A negative BDG was only associated with a low post-test probability of PJP (≤5%) when the pre-test probability was low to intermediate (≤20% in non-HIV and ≤50% in HIV).

CONCLUSIONS

Among patients with a higher likelihood of PJP, the pooled sensitivity of BDG is insufficient to exclude infection. Similarly, for most cases, the pooled specificity is inadequate to diagnose PJP. Understanding the performance of BDG in the population being investigated is therefore essential to optimal clinical decision-making.

Cell wall polysaccharides from pathogenic fungi for diagnosis of fungal infectious disease

Invasive fungal diseases are associated with significant morbidity and mortality, particularly in immunocompromised individuals. Early and accurate diagnosis is crucial for effective treatment. Despite traditional methods such as microbiological culture, histopathology, radiology and direct microscopy are available, antigen/antibody-based diagnostics are emerging for diagnosis of invasive fungal infections (IFI). Fungal cell wall is a unique structure composed of polysaccharides that are well correlated with fungal burden during fungal infections. Based on this feature, cell wall polysaccharides have been explored as antigens in IFIs diagnostics such as the galactomannan assay, mannan test, β-glucan assay and cryptococcal CrAg test. Herein, we provide an overview on the cell wall polysaccharides from three opportunistic pathogens: Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans, and their applications for IFIs diagnosis. The clinical outcome of newly developed cell wall polysaccharides-based diagnostics is also discussed.

Utility of Intraocular Fluid β-D-glucan Testing in Fungal Endophthalmitis: A Series of 5 Cases

BACKGROUND In clinical practice, the presentation of fungal endophthalmitis is often occult and confusing, so it is difficult to make an early diagnosis. The aim of this study was to evaluate the utility of ß-d-glucan (BDG) testing in diagnosis, management, and prognosis of fungal endophthalmitis. CASE REPORT We present a retrospective, observational case series of 5 fungal endophthalmitis cases, 3 of which were endogenous and 2 exogenous. There were significantly elevated BDG levels in all cases, which was consistent with the pathological diagnosis. Four cases were diagnosed as fungal endophthalmitis through smear or culture and gene chip analysis of intraocular fluid. CONCLUSIONS Fungal endophthalmitis is rare, and its diagnosis is difficult because of its occult nature. Therefore, BDG testing may be required as an auxiliary examination for the early diagnosis of fungal endophthalmitis. Compared to cultures and smears, intraocular fluid BDG testing has a higher sensitivity for detecting fungal endophthalmitis.

Limited Positive Predictive Value of β-d-Glucan in Hematologic Patients Receiving Antimold Prophylaxis

Background

Diagnostic value of β-d-glucan (BDG) in populations with low prevalence of invasive fungal infection (IFI), such as hematologic patients receiving antimold prophylaxis, should be re-evaluated.

Methods

We retrospectively reviewed episodes with BDG results in hematologic patients receiving antimold prophylaxis from January 2017 to August 2019 in a tertiary hospital. The episodes were classified as true positive ([TP] positive BDG with IFI), true negative ([TN] negative BDG without IFI), false positive ([FP] positive BDG without IFI), false negative ([FN] negative BDG with IFI), and nonevaluable.

Results

A total of 203 episodes were analyzed: 101 episodes (49.8%) were from stem cell transplants, 89 (43.8%) were from induction chemotherapy, and 13 (6.4%) were from graft-versus-host disease treatment. There were 62 nonevaluable episodes. Among 141 evaluable ones, there were 8 (5.7%) episodes of probable/proven IFI. True positive, TN, FP, and FN cases were 4 (2.8%), 112 (79.4%), 21 (14.9%), and 4 (2.8%) episodes, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value were 50.0%, 84.2%, 16.1%, and 96.5%, respectively. Positive predictive value was 26.7% and 0.0% in diagnostic and surveillance episodes, respectively.

Conclusions

β-d-glucan test should be used to exclude IFI rather than for diagnosis in these patients.

Clinical features and outcome of hepatosplenic fungal infections in children with haematological malignancies

Hepatosplenic fungal infection (HSFI) is a severe invasive fungal infection observed during neutrophil recovery in patients with acute leukaemia treated with intensive chemotherapy. Retrospective analysis including all paediatric haematological malignancies patients with HSC treated in Children Cancer Hospital Egypt (2013-2018). Twenty-five patients with acute leukaemia developed HSFI (19 patients diagnosed as hepatosplenic candidiasis). Most of the cases (92%) occurred during the induction phase. Organs affected were as follows: liver in 18 patients, renal in 13 patients, spleen in 12 patients, skin in four patients and retina in one patient. Five (20%) patients had proven HSC, 14 (56%) probable and six (24%) possible HSFI. Ten patients had a PET-CT for response assessment. Candida tropicalis was the most common isolated spp. from blood/tissue culture. Six (24%) patients developed HSFI on top of antifungal prophylaxis. Steroids were given in 12 (52%) patients with HSFI as immune reconstitution syndrome (IRS). Caspofungin was the first line of treatment in 14 (56%) patients, liposomal amphotericin B in six (24%) patients and azoles in five (20%) patients. HSFI was associated with delayed of intensification phase of chemotherapy (median 42 days). The success rate was reported in 24 patients with complete response (68%) and partial response in (28%) patients, while failure (death) seen in 1(4%) patient. HSC is still a major challenge in paediatric leukaemias patients with impact on treatment delay and survival outcome. PET scan, non-culture diagnostics and steroid role evidence in IRS are growing. Antifungal stewardship for screening, early detection for high-risk patients and better response assessment is challenging.

Polymerase chain reaction blood tests for the diagnosis of invasive aspergillosis in immunocompromised people

BACKGROUND

This is an update of the original review published in the Cochrane Database of Systematic Reviews Issue 10, 2015.Invasive aspergillosis (IA) is the most common life-threatening opportunistic invasive mould infection in immunocompromised people. Early diagnosis of IA and prompt administration of appropriate antifungal treatment are critical to the survival of people with IA. Antifungal drugs can be given as prophylaxis or empirical therapy, instigated on the basis of a diagnostic strategy (the pre-emptive approach) or for treating established disease. Consequently, there is an urgent need for research into both new diagnostic tools and drug treatment strategies. Increasingly, newer methods such as polymerase chain reaction (PCR) to detect fungal nucleic acids are being investigated.

OBJECTIVES

To provide an overall summary of the diagnostic accuracy of PCR-based tests on blood specimens for the diagnosis of IA in immunocompromised people.

SEARCH METHODS

We searched MEDLINE (1946 to June 2015) and Embase (1980 to June 2015). We also searched LILACS, DARE, Health Technology Assessment, Web of Science and Scopus to June 2015. We checked the reference lists of all the studies identified by the above methods and contacted relevant authors and researchers in the field. For this review update we updated electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 3) in the Cochrane Library; MEDLINE via Ovid (June 2015 to March week 2 2018); and Embase via Ovid (June 2015 to 2018 week 12).

SELECTION CRITERIA

We included studies that: i) compared the results of blood PCR tests with the reference standard published by the European Organisation for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG); ii) reported data on false-positive, true-positive, false-negative and true-negative results of the diagnostic tests under investigation separately; and iii) evaluated the test(s) prospectively in cohorts of people from a relevant clinical population, defined as a group of individuals at high risk for invasive aspergillosis. Case-control and retrospective studies were excluded from the analysis.

DATA COLLECTION AND ANALYSIS

Authors independently assessed quality and extracted data. For PCR assays, we evaluated the requirement for either one or two consecutive samples to be positive for diagnostic accuracy. We investigated heterogeneity by subgroup analyses. We plotted estimates of sensitivity and specificity from each study in receiver operating characteristics (ROC) space and constructed forest plots for visual examination of variation in test accuracy. We performed meta-analyses using the bivariate model to produce summary estimates of sensitivity and specificity.

MAIN RESULTS

We included 29 primary studies (18 from the original review and 11 from this update), corresponding to 34 data sets, published between 2000 and 2018 in the meta-analyses, with a mean prevalence of proven or probable IA of 16.3 (median prevalence 11.1% , range 2.5% to 57.1%). Most patients had received chemotherapy for haematological malignancy or had undergone hematopoietic stem cell transplantation. Several PCR techniques were used among the included studies. The sensitivity and specificity of PCR for the diagnosis of IA varied according to the interpretative criteria used to define a test as positive. The summary estimates of sensitivity and specificity were 79.2% (95% confidence interval (CI) 71.0 to 85.5) and 79.6% (95% CI 69.9 to 86.6) for a single positive test result, and 59.6% (95% CI 40.7 to 76.0) and 95.1% (95% CI 87.0 to 98.2) for two consecutive positive test results.

AUTHORS' CONCLUSIONS

PCR shows moderate diagnostic accuracy when used as screening tests for IA in high-risk patient groups. Importantly the sensitivity of the test confers a high negative predictive value (NPV) such that a negative test allows the diagnosis to be excluded. Consecutive positives show good specificity in diagnosis of IA and could be used to trigger radiological and other investigations or for pre-emptive therapy in the absence of specific radiological signs when the clinical suspicion of infection is high. When a single PCR positive test is used as the diagnostic criterion for IA in a population of 100 people with a disease prevalence of 16.3% (overall mean prevalence), three people with IA would be missed (sensitivity 79.2%, 20.8% false negatives), and 17 people would be unnecessarily treated or referred for further tests (specificity of 79.6%, 21.4% false positives). If we use the two positive test requirement in a population with the same disease prevalence, it would mean that nine IA people would be missed (sensitivity 59.6%, 40.4% false negatives) and four people would be unnecessarily treated or referred for further tests (specificity of 95.1%, 4.9% false positives). Like galactomannan, PCR has good NPV for excluding disease, but the low prevalence of disease limits the ability to rule in a diagnosis. As these biomarkers detect different markers of disease, combining them is likely to prove more useful.

Changes in the epidemiological landscape of invasive candidiasis

The epidemiology of invasive candidiasis has evolved in recent years, warranting a review of the changes and the implications for current and future diagnosis and treatment. The overall burden of invasive candidiasis remains high, particularly in the expanding populations of patients at risk of opportunistic infection, such as the elderly or immunosuppressed. Progressive shifts from Candida albicans to non-albicans Candida spp. have been observed globally. The recent emergence of novel, multiresistant species, such as Candida auris, amplifies the call for vigilance in detection and advances in treatment. Among the current treatment options, fluconazole is still widely used throughout the world. Increased resistance to fluconazole, both acquired and naturally emerging, has been observed. Resistance to echinocandins is presently low but this may change with increased use. Improvement of diagnostic techniques and strategies, development of international surveillance networks and implementation of antifungal stewardship programmes represent major challenges for a better epidemiological control of invasive candidiasis.

Current State of the Diagnosis of Invasive Pulmonary Aspergillosis in Lung Transplantation

As the number of lung transplants performed worldwide each year continues to grow, the success of this procedure is threatened by the incidence of non-CMV infections such as invasive aspergillosis. Despite tremendous efforts and the availability of numerous diagnostic tests (especially in hematological malignancies) the diagnosis of invasive aspergillosis continues to be a challenge. Lung transplantation remains a unique clinical scenario, where additional host defenses are immunocompromized, making many of the available tests unsuitable. In this review we will navigate through the myriad of diagnostic tests currently available and how they apply to this unique patient population, as well as have a look into what the future holds.

Indian Antimicrobial Prescription Guidelines in Critically Ill Immunocompromised Patients

How to cite this article: Kulkarni AP, Sengar M, Chinnaswamy G, Hegde A, Rodrigues C, Soman R, Khilnani GC, Ramasubban S, Desai M, Pandit R, Khasne R, Shetty A, Gilada T, Bhosale S, Kothekar A, Dixit S, Zirpe K, Mehta Y, Pulinilkunnathil JG, Bhagat V, Khan MS, Narkhede AM, Baliga N, Ammapalli S, Bamne S, Turkar S, Bhat KV, Choudhary J, Kumar R, Divatia JV. Indian Journal of Critical Care Medicine 2019;23(Suppl 1): S64-S96.

Diagnostic Efficacy of Serum 1,3-β-D-glucan for Invasive Fungal Infection: An Update Meta-Analysis Based on 37 Case Or Cohort Studies

Objective

The aim of this study was to investigate the diagnostic performance of serum 1,3-β-D-gluan as biomarker for invasive fungal infection through meta-analysis.

Methods

The electronic databases of Medline, Cochrane, Embase, Web of Science, OVID and CNKI were systematic searched to identified the case-control or Cohort studies relevant to diagnostic efficacy of serum 1,3-β-D-glucan for invasive fungal infection. The data of true positive (tp), false positive (fp), false negative (fn) and true negative (tn) patients number were extracted from each of the original included studies. The diagnostic sensitivity, specificity and systematic receiver operating characteristic (SROC) curve were calculated and pooled through random or fixed effect method. The publication bias was evaluated by the Deek's funnel plot.

Results

Thirty-seven relevant studies were fulfilled the inclusion criteria and included in our present meta-analysis. The combined sensitivity, specificity, positive likely hood ratio (+lr), negative likely hood ratio (-lr) and diagnostic odds ratio(dor) for 1,3-β-D-glucan in diagnosis of invasive fungal infectionwere 0.83 (95%CI:0.38-0.61), 0.81 (95%CI:0.80-0.82), 5.13 (95%CI:3.98-6.62), 0.23 (95%CI:0.18-0.30), and 29.68 (95%CI:18.94-46.52) respectively. The pooled area under the ROC curve (AUC) was 0.91.The Deek's funnel plot asymmetry test showed there was no publication bias for 1,3-β-D-glucan in diagnosis of invasive fungal infection of the included 37 studies.

Conclusion

Serum 1,3-β-D-glucan assay was a promising biomarker for invasive fungal infection diagnosis.

Diagnosis of invasive fungal diseases in haematology and oncology: 2018 update of the recommendations of the infectious diseases working party of the German society for hematology and medical oncology (AGIHO)

Invasive fungal diseases (IFD) are a primary cause of morbidity and mortality in patients with haematological malignancies. These infections are mostly life-threatening and an early diagnosis and initiation of appropriate antifungal therapy are essential for the clinical outcome. Most commonly, Aspergillus and Candida species are involved. However, other Non-Aspergillus moulds are increasingly identified in case of documented IFD. For definite diagnosis of IFD, a combination of diagnostic tools have to be applied, including conventional mycological culture and non-conventional microbiological tests such as antibody/antigen and molecular tests, as well as histopathology and radiology. Although varying widely in cancer patients, the risk of invasive fungal infection is highest in those with allogeneic stem cell transplantation and those with acute leukaemia and markedly lower in patients with solid cancer. Since the last edition of Diagnosis of Invasive Fungal Diseases recommendations of the German Society for Hematology and Oncology in 2012, integrated care pathways have been proposed for the management and therapy of IFDs with either a diagnostic driven strategy as opposed to a clinical or empirical driven strategy. This update discusses the impact of this additional evidence and effective revisions.

BETA-D-GLUCAN TESTING IN PATIENTS WITH FUNGAL ENDOPHTHALMITIS

PURPOSE

To review the literature on beta-D-glucan (BDG) testing in fungal endophthalmitis.

METHODS

Review of primary literature using PubMed through April 2017 and presentation of an illustrative case report. A total of 231 articles were identified and 43 were ultimately chosen for review based on relevance and presence of ophthalmologic examination and objective data.

RESULTS

Beta-D-glucan is a major component of fungal cell walls. It is quantified using a calorimetry-based Fungitell assay based on modification of the limulus amebocyte lysate. Serum BDG levels are commonly used clinically in conjunction with other tests for early surveillance and diagnosis of invasive fungal infections. In the ophthalmic literature, elevated levels of BDG have been detected in vitreous fluid of patients undergoing vitrectomy for fungal endophthalmitis, tear fluid of patients with mycotic keratitis, and serum of a patient with bilateral endogenous subretinal abscesses. Elevated serum BDG levels appear to be highly associated with fungal endophthalmitis. Potential uses and considerations with regards to test limitations are discussed.

CONCLUSION

Beta-D-glucan testing may be used as an adjunct to support a diagnosis, initiate pharmacologic therapy or surgical intervention, and optimize overall clinical management in patients diagnosed with or under clinical suspicion for invasive fungal infections, including endophthalmitis. Additional clinical studies are necessary to fully characterize the utility of BDG testing in patients with fungal endophthalmitis.

Performance of serum (1,3)-ß-d-glucan screening for the diagnosis of invasive aspergillosis in neutropenic patients with haematological malignancies

We report our experience with the use of (1,3)-ß-d-glucan (BDG) screening for the diagnosis of invasive aspergillosis (IA) in neutropenic patients with haematological malignancies. The performance of BDG screening was assessed retrospectively in per patient and per sample analyses. Overall, 20 among 167 patients developed IA (12%). In the per patient analysis, BDG showed 60% sensitivity and 78% specificity when the criterion for positivity was the presence of at least one BDG value ≥80 pg/mL. For 2 consecutive positive results, sensitivity decreased to 40%, while specificity increased to 93% and was similar to that of a positive galactomannan (GM; 90%). The highest specificity (97%) was observed for combined positivity of at least one BDG and at least one GM. In the per sample analysis, the specificity of BDG was 100% in the best scenario, 96% in the median scenario and 89% in the worst scenario. BDG became positive before GM in 33% of IA patients with both markers positive (n = 12). Despite good specificity for 2 consecutive positive results, the BDG test offered unsatisfactory performance for the diagnosis of IA due to low sensitivity. The combination of BDG and GM showed the potential for increasing specificity.

Empirical antimicrobial treatment in haemato-/oncological patients with neutropenic sepsis

Neutropenic sepsis in haemato-/oncological patients is a medical emergency, as infections may show a fulminant clinical course. Early differentiation between sepsis and febrile neutropenic response often proves to be challenging. To assess the severity of the illness, different tools, which are discussed in this article, are available. Once the diagnosis has been established, the correct use of early empirical antibiotic and antifungal treatment is key in improving patient survival. Therefore, profound knowledge of local resistance patterns is mandatory and carefully designed antibiotic regimens have to be established in cooperation with local microbiologists or infectious diseases specialists. In the following, identification, therapy and management of high-risk, neutropenic patients will be reviewed based on experimental and clinical studies, guidelines and reviews.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

Evaluation of the Use of Novel Biomarkers to Augment Antimicrobial Stewardship Program Activities

As antimicrobial stewardship increasingly receives worldwide attention for improving patient care by optimizing antimicrobial therapy, programs are evaluating new tools that may augment antimicrobial stewardship activities. Biomarkers are objective, accurate, and reproducible measures that provide information about medical conditions. A systematic literature search using PubMed/MEDLINE databases was performed to evaluate the use of novel biomarkers as additions to the antimicrobial stewardship armamentarium. Procalcitonin may help clinicians discriminate between bacterial and viral infections, help with antimicrobial discontinuation decisions, and predict mortality. β-d-glucan, Candida albicans germ tube antibody, and galactomannan are useful in suspected fungal infections and may reduce inappropriate antifungal use. Adrenomedullin and soluble triggering receptor on myeloid cells-1 may be useful for mortality prediction and the determination of a need for empiric antibacterials. Although studies evaluating these biomarkers are promising, these biomarkers are not without limitations and should be used in combination with clinical signs, symptoms, or other biomarkers. For successful implementation of biomarker use, stewardship programs should consider the populations most likely to benefit, without using them indiscriminately in all patients. Antimicrobial stewardship programs should facilitate education of clinicians through institutional guidelines to ensure the appropriate use and interpretation of these biomarkers.

(1, 3)-β-D-glucan assay for diagnosing invasive fungal infections in critically ill patients with hematological malignancies

Invasive fungal infections (IFIs) are life-threatening complications of hematological malignancies that must be diagnosed early to allow effective treatment. Few data are available on the performance of serum (1–3)-β-D-glucan (BG) assays for diagnosing IFI in patients with hematological malignancies admitted to the intensive care unit (ICU). In this study, 737 consecutive patients with hematological malignancies admitted to 17 ICUs routinely underwent a BG assay at ICU admission. IFIs were diagnosed using standard criteria applied by three independent specialists. Among the 737 patients, 439 (60%) required mechanical ventilation and 273 (37%) died before hospital discharge. Factors known to alter BG concentrations were identified in most patients. IFIs were documented in 78 (10.6%) patients (invasive pulmonary aspergillosis, n = 54; Pneumocystis jirovecii pneumonia, n = 13; candidemia, n = 13; and fusarium infections, n = 3). BG concentrations (pg/mL) were higher in patients with than without IFI (144 (77–510) vs. 50 (30–125), < 0.0001). With 80 pg/mL as the cutoff, sensitivity was 72%, specificity 65%, and area-under-the-curve 0.74 (0.68–0.79). Assuming a prevalence of 10%, the negative and positive predictive values were 94% and 21%. By multivariable analysis, factors independently associated with BG > 80 pg/mL were IFI, admission SOFA score, autologous bone-marrow or hematopoietic stem-cell transplantation, and microbiologically documented bacterial infection. In conclusion, in unselected critically ill hematology patients with factors known to affect serum BG, this biomarker showed only moderate diagnostic performance and rarely detected IFI. However, the negative predictive value was high. Studies are needed to assess whether a negative BG test indicates that antifungal de-escalation is safe.

Use of 1,3-β-D-glucan in invasive fungal diseases in hematology patients

INTRODUCTION

Invasive fungal diseases (IFD) remain a leading cause of morbidity and mortality in hematology patients. Within a diagnostic-driven approach, the use of the serum (1,3)-ß-D-glucan (BDG) test represents a valid tool for the early diagnosis and treatment of IFD. Areas covered: The available literature on the use of BDG in hematology patients was systematically retrieved. Then, it was reviewed and discussed, to identify key issues pertaining to a clinically-oriented narrative presentation of the topic. Expert commentary: The use of BDG in hematology patients at risk for invasive aspergillosis (IA) is secondary to the use of galactomannan. However, since BDG is not specific for IA, it offers an advantage of diagnosing also other IFD, such as candidiasis and pneumocystosis. The limitations of BDG include high costs and lower sensitivity in hematology patients compared to other cohorts. The risk of false positive results is possibly lower in real life than in theory, since glucan-free equipment is available and modern dialysis membranes and blood products usually do not release BDG. Thus, in experienced hands and selected clinical situations, BDG is a useful diagnostic tool, particularly due to short turnover time to results and versatility in diagnosing different IFD.

Fungal Infections of the Central Nervous System in Children

Although uncommon in children, fungal infections of the central nervous system can be devastating and difficult to treat. A better understanding of basic mycologic, immunologic, and pharmacologic processes has led to important advances in the diagnosis and management of these diseases, but their mortality rates remain unacceptably high. In this focused review, we examine the epidemiology and clinical features of the most common fungal pathogens of the central nervous system in children and explore recent advances in diagnosis and antifungal therapy.

Diagnosis and empirical treatment of fever of unknown origin (FUO) in adult neutropenic patients: guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO)

Fever may be the only clinical symptom at the onset of infection in neutropenic cancer patients undergoing myelosuppressive chemotherapy. A prompt and evidence-based diagnostic and therapeutic approach is mandatory. A systematic search of current literature was conducted, including only full papers and excluding allogeneic hematopoietic stem cell transplant recipients. Recommendations for diagnosis and therapy were developed by an expert panel and approved after plenary discussion by the AGIHO. Randomized clinical trials were mainly available for therapeutic decisions, and new diagnostic procedures have been introduced into clinical practice in the past decade. Stratification into a high-risk versus low-risk patient population is recommended. In high-risk patients, initial empirical antimicrobial therapy should be active against pathogens most commonly involved in microbiologically documented and most threatening infections, including Pseudomonas aeruginosa, but excluding coagulase-negative staphylococci. In patients whose expected duration of neutropenia is more than 7 days and who do not respond to first-line antibacterial treatment, specifically in the absence of mold-active antifungal prophylaxis, further therapy should be directed also against fungi, in particular Aspergillus species. With regard to antimicrobial stewardship, treatment duration after defervescence in persistently neutropenic patients must be critically reconsidered and the choice of anti-infective agents adjusted to local epidemiology. This guideline updates recommendations for diagnosis and empirical therapy of fever of unknown origin in adult neutropenic cancer patients in light of the challenges of antimicrobial stewardship.

Combined use of serum (1,3)-β-D-glucan and procalcitonin for the early differential diagnosis between candidaemia and bacteraemia in intensive care units

Background

This study aimed to assess the combined performance of serum (1,3)-β-d-glucan (BDG) and procalcitonin (PCT) for the differential diagnosis between candidaemia and bacteraemia in three intensive care units (ICUs) in two large teaching hospitals in Italy.

Methods

From June 2014 to December 2015, all adult patients admitted to the ICU who had a culture-proven candidaemia or bacteraemia, as well as BDG and PCT measured closely to the time of the index culture, were included in the study. The diagnostic performance of BDG and PCT, used either separately or in combination, was assessed by calculating the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios (LR+ and LR–). Changes from pre-test probabilities to post-test probabilities of candidaemia and bacteraemia were inferred from Fagan’s nomograms.

Results

One hundred and sixty-six patients were included, 73 with candidaemia (44%) and 93 with bacteraemia (56%). When both markers indicated candidaemia (BDG ≥80 pg/ml and PCT <2 ng/ml) they showed higher PPV (96%) compared to 79% and 66% for BDG or PCT alone, respectively. When both markers indicated bacteraemia (BDG <80 pg/ml and PCT ≥2 ng/ml), their NPV for candidaemia was similar to that of BDG used alone (95% vs. 93%). Discordant BDG and PCT results (i.e. one indicating candidaemia and the other bacteraemia) only slightly altered the pre-test probabilities of the two diseases.

Conclusions

The combined use of PCT and BDG could be helpful in the diagnostic workflow for critically ill patients with suspected candidaemia.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1763-5) contains supplementary material, which is available to authorized users.

Yeasts

Yeasts are unicellular organisms that reproduce mostly by budding and less often by fission. Most medically important yeasts originate from Ascomycota or Basidiomycota. Here, we review taxonomy, epidemiology, disease spectrum, antifungal drug susceptibility patterns of medically important yeast, laboratory diagnosis, and diagnostic strategies.

Invasive Aspergillosis in Hematological Patients

Invasive aspergillosis (IA) is still one of the leading causes of morbidity and mortality in hematological patients, although its outcome has been improving. Prolonged and profound neutropenia in patients receiving intensive chemotherapy for acute leukemia and stem cell transplantation is a major risk factor for IA. Allogeneic stem cell transplant recipients with graft-versus-host disease and corticosteroid use are also at high risk. Management in a protective environment with high efficiency particular air (HEPA) filter is generally recommended to prevent aspergillosis in patients with prolonged and profound neutropenia. Antifungal prophylaxis against Aspergillus species should be considered in patients with past history of aspergillosis or colonization of Aspergillus species, at facilities with high incidence of IA and those without a protective environment. Early diagnosis and prompt antifungal treatment is important to improve outcome. Imaging studies such as computed tomography and biomarkers such as galactomannan antigen and β-D-glucan are useful for early diagnosis. Empirical antifungal treatment based on persistent or recurrent fever during neutropenia despite broad-spectrum antibiotic therapy is generally recommended in high-risk patients. Alternatively, a preemptive treatment strategy has recently been proposed in the context of progress in the early diagnosis of IA based on the results of imaging studies and biomarkers. Voriconazole is recommended for initial therapy for IA. Liposomal amphotericin B is considered as alternative initial therapy. Combination antifungal therapy of echinocandin with voriconazole or liposomal amphotericin B could be a choice for refractory cases.

Laboratory Diagnostics for Fungal Infections: A Review of Current and Future Diagnostic Assays

This article reviews the current diagnostic approaches, both serologic and molecular, for the detection of fungi associated with pulmonary disease. Classic serologic techniques, including immunodiffusion and complement fixation, both of which remain a cornerstone for fungal diagnostic testing, are reviewed and their performance characteristics presented. More recent advances in this field, including novel lateral-flow assays for fungal antigen detection, are also described. Molecular techniques for fungal identification both from culture and directly from patient specimens, including nucleic acid probes, mass spectrometry-based methods, nucleic acid amplification testing, and traditional and broad-range sequencing, are discussed and their performance evaluated.

Translational Development and Application of (1→3)-β-d-Glucan for Diagnosis and Therapeutic Monitoring of Invasive Mycoses

Early diagnosis and prompt initiation of appropriate antimicrobial therapy are crucial steps in the management of patients with invasive fungal infections. However, the diagnosis of invasive mycoses remains a major challenge in clinical practice, because presenting symptoms may be subtle and non-invasive diagnostic assays often lack sensitivity and specificity. Diagnosis is often expressed on a scale of probability (proven, probable and possible) based on a constellation of imaging findings, microbiological tools and histopathology, as there is no stand-alone assay for diagnosis. Recent data suggest that the carbohydrate biomarker (1→3)-β-d-glucan may be useful in both the diagnosis and therapeutic monitoring of invasive fungal infections due to some yeasts, molds, and dimorphic fungi. In this paper, we review recent advances in the use of (1→3)-β-d-glucan to monitor clinical response to antifungal therapy and explore how this assay may be used in the future.

The Predictive Value of Coefficient of PCT × BG for Anastomotic Leak in Esophageal Carcinoma Patients With ARDS After Esophagectomy

Anastomotic leak was a potentially severe life-threatening complication of esophagectomy, which drew attention in consequence of progressive dyspnea until acute respiratory distress syndrome (ARDS) due to the early asymptomatic presentation. Respiratory failure, caused by ARDS as the severe presentation of anastomotic leak, is the most common organ failure. CRP (C-reactive protein), procalcitonin (PCT), and Blood G (BG) test are the sensitivity markers for inflammatory, sepsis, and fungemia, respectively. Early recognition and intervention treatment of anastomotic leak may alleviate complication and improve outcome. We retrospectively analyzed 71 patients, accepting mechanical ventilation support because of ARDS as the complication after radical resection of esophagus cancer. Clinical data were collected from the patients' electronic medical records, including their clinically hematological examination, drainage fluid cultures, and sputum culture. Accord to appearance of anastomotic leak or not, all patients were divided into 2 groups, leak group and no-leak group. Inflammatory markers, such as CRP, PCT, and the coefficient of BG and PCT, were significantly different between the 2 groups. Respiratory index, white blood cell, hemoglobin (HBG), platelet (PLT), and other clinical factors were not significantly different between the 2 groups. Receiver operating characteristic curves were constructed to calculate the sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve for various cutoff levels of several factors. Blood G tests presented the better predicting value for anastomotic leak. Blood G tests and PCT should be tested after esophagectomy. The coefficient of PCT and BG (>260) is of great significance, and clinical value to predict anastomotic leak for patients with postesophagectomy ARDS, early PCT and BG test, and especially, dynamic variation may alleviate complication and improve outcome.