Detection of fungal DNA in lysis-centrifugation blood culture for the diagnosis of invasive candidiasis in neonatal patients

Mucorales/Fusarium Mixed Infection in Hematologic Patient with COVID-19 Complications: An Unfortunate Combination

Hematological diseases, especially those causing severe neutropenia, represent the main factor in the development of invasive fungal infections (IFIs). Furthermore, COVID-19 has been considerably associated with IFIs due to immunological dysregulation, prolonged hospitalization in intensive care units, and immunomodulatory therapies. Opportunistic molds are correlated with elevated morbidity and mortality rates in these patients, due to immune impairment, diagnostic complexity, and therapeutic challenges. Among opportunistic fungal infections, the Mucorales and Fusarium species are considered particularly aggressive, especially during severe neutropenia. A mixed Mucorales/Fusarium infection has been rarely described in scientific literature. Herein, we report a case of Mucorales and Fusarium co-infection in a patient with acute leukemia whose clinical history was also complicated by COVID-19. Herein, we report a challenging case in order to encourage the clinical suspicion of combined fungal infections in immunosuppressed patients, performing a punctual microbiological diagnosis, and promptly administering the correct empiric and targeted antifungal therapy.

Systemic Candidosis Diagnostic Test with Candida Score and Monocyte Count in Premature Infants with Late-Onset Sepsis: Research in Low Resources Country

Abstract Introduction: Candida is the cause of most systemic fungal infections that plays a role in the pathophysiology of sepsis in newborns, especially in premature infants with late-onset sepsis. The candida score can be used to assess the occurrence of systemic candidosis where a candida score 2.5 can accurately identify patients who are at high risk for candidiasis infection. Monocytes also play an important role in preventing candida invasion. Materials and methods: This study used a cross sectional research design. Data was collected from premature infants with late-onset sepsis being suspected of systemic candidosis in neonatology inpatient ward. It was submitted from the period of November-December 2021. It takes a minimum of 31 samples to meet the criteria to process and analyze the data. The data obtained were processed and analyzed using the Receiver Operating Characteristic (ROC) method to obtain the Area Under Curve (AUC) value. Based on the AUC curve, the search for the most optimal intersection is carried out to obtain the sensitivity and specificity values. Results: Of the 31 research subjects, the number of subjects with positive PCR results was 27 (76.93%) while negative were 4 respondents (12.9%). The mean value of PCR density in the positive group of subjects was 76.93 and the range was 40.23 122.78. Meanwhile, in the group of subjects who were negative, the PCR density value was 0. The results of the candida score diagnostic test showed that the sensitivity obtained was 81%. Higher sensitivity and specificity 70% were found in the combined examination of candida scores and monocyte counts according to cut-off compared with separate examinations. Conclusions: The combined examination of candida score and monocyte count can be used as a diagnostic test for systemic candidosis in premature infants with late-onset sepsis, and could be used to consider the initiation of empirical antifungal therapy, either prophylactically or therapeutically, especially in limited laboratory facilities in Indonesia.

Application of High-Resolution Melting PCR to Detect the Genomic Fungal ITS 2 Region

BACKGROUND

Invasive fungal infections (IFIs) are a main cause of morbidity and mortality. High-resolution melting polymerase chain reaction (HRM PCR) is promising for the identification of fungal species via the detection of internal transcribed spacer 2 (ITS2).

OBJECTIVES

To assess the sensitivity and specificity of HRM PCR in diagnosing IFIs, compared with blood culture.

METHODS

Our study included 100 patients who were suspected of having IFIs; we analyzed their specimens via blood culture and HRM PCR.

RESULTS

Blood culture results were positive in 57 cases and negative in 43 cases. HRM PCR results were positive in 14 cases and negative in 86 cases. The 14 cases with positive results included 4 with Candida tropicalis, 4 with Candida glabrata, and 6 with Candida krusei. HRM PCR sensitivity was 24.6%, specificity was 100%, positive predictive value (PPV) was 100%, and negative predictive value (NPV) was 50%.

CONCLUSIONS

HRM PCR is specific but not sensitive. Blood culture is more sensitive and cannot be replaced by HRM PCR.

Diagnostic accuracy of serum (1,3)-beta-d-glucan for neonatal invasive candidiasis: systematic review and meta-analysis

OBJECTIVES

Neonatal invasive candidiasis (NIC) is a leading cause of infection-related morbidity and mortality in preterm neonates. Several studies have shown that (1,3)-Beta-d-glucan (BDG) was accurate in detecting invasive fungal infection in adults, but studies in neonates are scarce. The aim was to obtain summary estimates of the accuracy of BDG detection in serum for the diagnosis of NIC.

METHODS

We searched Medline, Embase, Clinicaltrials.gov, and Google Scholar (inception to July 2019). We checked the reference lists of included studies, clinical guidelines, and review articles. We included studies that assessed the accuracy of BDG against a reference standard that defined groups of patients with ordinal levels of NIC probability (e.g. proven, probable, possible) and included fungal blood culture. Participants were neonates suspected of having NIC. The intervention was BDG measurement in serum (Fungitell® assay). We assessed risk of bias and applicability using QUADAS-2. We used bivariate meta-analysis to produce summary estimates of diagnostic accuracy at prespecified positivity thresholds of 80 and 120 pg/mL. This study was registered with PROSPERO (CRD42018089545).

RESULTS

We included eight studies (465 participants). Of these, two were judged at low overall risk of bias. There was substantial variability across studies in the reference standards used. At a positivity threshold of 80 pg/mL, summary estimates of sensitivity and specificity of BDG were 89% (95% CI: 80-94%) and 60% (53-66%), respectively; summary sensitivity for detecting proven cases of NIC was 99% (93-100%). At a positivity threshold of 120 pg/mL, summary estimates of sensitivity and specificity were 81% (71-88%) and 80% (67-88%), respectively.

CONCLUSIONS

Because of high sensitivity, BDG seems promising to rule-out NIC. It might be too early to recommend its use because of the scarcity of reliable clinical data, heterogeneity in case definitions, and unstable accuracy estimates.

Nationwide survey of neonatal invasive fungal infection in Japan

Invasive fungal infection (IFI) is a life-threating infectious disease in high-risk neonates. Strategies for the treatment and prevention of IFI in neonates in Japan remain unclear. We conducted a nationwide retrospective survey to determine IFI incidence between January 2014 and October 2015. Primary survey questionnaires were submitted to 309 medical facilities that regularly treat high-risk neonates. The questionnaire assessed IFI incidence during the study period, methods for preventing fungal infection in early delivery neonates, and methods for preventing mother-to-child fungal transmission. The secondary questionnaire was for facilities that had IFI cases and replied to the primary questionnaire. In total, 128 medical facilities (41.4%) completed the primary questionnaire, 17/128 facilities recorded 23 proven or probable IFI cases. Estimated annual IFI incidence was 0.33/1000 live births of hospitalized neonates. Patient data at IFI onset were available for all 23 patients. Birth weight was < 1000 g in 18 patients. Causative microorganisms were identified in 22 patients. Candida species (n = 21) were the most common pathogens, and one patient had mucormycosis. The mortality rate was 17.4%. Regarding neonatal fungal prophylaxis, 55/128 facilities (43.0%) reported administering therapy. The most frequently used prophylactic drugs were fluconazole, then micafungin. Fungal prophylaxis for mothers who showed fungal colonization was performed in 30/128 facilities (23.4%). Oxiconazole vaginal tablets were most commonly used as prophylaxis for high-risk mothers. In Japan, the diagnosis, treatment, and prevention of neonatal IFI varied. Continuous surveillance and treatment regimen for neonatal IFI are required to improve outcomes in high-risk neonates.

Evaluation of the (1,3)-β-D-glucan assay for the diagnosis of neonatal invasive yeast infections

Most newborns in the neonatal intensive care unit (NICU) are premature and at risk of invasive fungal infections (IFIs). Invasive yeast infections (IYIs) are the most common fungal infections in this population. These infections are difficult to diagnose because symptoms are nonspecific, and the sensitivity of blood cultures is low. The serum (1,3)-β-D-glucan (BDG) assay provides a reliable marker for the diagnosis of IFIs in adults with haematological malignancies. We assessed the diagnostic performance of this test in neonatal IYIs and its contribution to the monitoring of antifungal treatment. A retrospective study was performed in the NICU of the French University Hospital of Amiens from February 2012 to February 2014. Forty-seven neonates (33 males, 14 females) with a median gestational age of 30 weeks (IQR: 27-31) and median birth weight of 1200 g (IQR: 968-1700) were included and divided into three groups: 21 control neonates (CTRL), 20 neonates with probable IYI (PB), and six with proven IYI (PV). Median BDG levels were significantly higher in the global IYI group (PB + PV): 149 pg/ml (IQR: 85-364) vs. CTRL group: 39 pg/ml (IQR: 20-94) (P < .001). The optimal cut-off was 106 pg/ml (sensitivity 61.5%; specificity 81%). BDG levels decreased with antifungal treatment. BDG was detectable in cerebrospinal fluid, but the interest of this for diagnostic purposes remains unclear. Our results suggest that the BDG assay may be useful for the early identification of IYIs in neonates and for monitoring antifungal therapy efficacy.

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.

Performance of a Quantitative PCR-Based Assay and Beta-d-Glucan Detection for Diagnosis of Invasive Candidiasis in Very-Low-Birth-Weight Preterm Neonatal Patients (CANDINEO Study)

An epidemiological, multicenter, noninterventional, observational case-control study was conducted to describe the performance of serum beta-d-glucan (BDG) and Candida PCR in blood, serum, and sterile samples for the diagnosis of invasive candidiasis (IC) in very-low-birth-weight (VLBW) preterm neonates and to compare these techniques with culture of samples from blood and other sterile sites. Seventeen centers participated in the study, and the number of episodes analyzed was 159. A total of 9 episodes of IC from 9 patients (7 confirmed and 2 probable) and 150 episodes of suspected sepsis from 117 controls were identified. The prevalence of IC was 5.7% (95% confidence interval [95% CI], 2.1 to 9.3). The mortality was significantly higher in episodes of IC (44.4%) than in the non-IC episodes (11.1%, P < 0.01). The sensitivity and specificity of the PCR performed on blood/serum samples were 87.5% and 81.6%, respectively. The sensitivity and specificity of the BDG results were lower (75.0% and 64.6%). For cases with negative culture results, the PCR and the BDG results were positive in 27 (17.4%) and 52 (33.5%) episodes, respectively. The presence of multiorgan failure, improvement with empirical antifungal therapy, thrombocytopenia, and Candida colonization were significantly associated (P < 0.01) with PCR or BDG positivity regardless of the results of the cultures. Serum BDG analysis and Candida PCR could be used as complementary diagnostic techniques to detect IC in VLBW neonates.

Molecular assays for the diagnosis of sepsis in neonates

BACKGROUND

Microbial cultures for diagnosis of neonatal sepsis have low sensitivity and reporting delay. Advances in molecular microbiology have fostered new molecular assays that are rapid and may improve neonatal outcomes.

OBJECTIVES

To assess the diagnostic accuracy of various molecular methods for the diagnosis of culture-positive bacterial and fungal sepsis in neonates and to explore heterogeneity among studies by analyzing subgroups classified by gestational age and type of sepsis onset and compare molecular tests with one another.

SEARCH METHODS

We performed the systematic review as recommended by the Cochrane Diagnostic Test Accuracy Working Group. On 19 January 2016, we searched electronic bibliographic databases (the Cochrane Library, PubMed (from 1966), Embase (from 1982), and CINAHL (from 1982)), conference proceedings of the Pediatric Academic Societies annual conference (from 1990), clinical trial registries (ClinicalTrials.gov, International Standard Randomised Controlled Trial Number (ISRCTN) registry, and World Health Organization (WHO) International Clinical Trials Platform (ICTRP) Search portal), and Science Citation Index. We contacted experts in the field for studies.

SELECTION CRITERIA

We included studies that were prospective or retrospective, cohort or cross-sectional design, which evaluated molecular assays (index test) in neonates with suspected sepsis (participants) in comparison with microbial cultures (reference standard).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodologic quality of the studies and extracted data. We performed meta-analyses using the bivariate and hierarchical summary receiver operating characteristic (HSROC) models and entered data into Review Manager 5.

MAIN RESULTS

Thirty-five studies were eligible for inclusion and the summary estimate of sensitivity was 0.90 (95% confidence interval (CI) 0.82 to 0.95) and of specificity was 0.93 (95% CI 0.89 to 0.96) (moderate quality evidence). We explored heterogeneity by subgroup analyses of type of test, gestational age, type of sepsis onset, and prevalence of sepsis and we did not find sufficient explanations for the heterogeneity (moderate to very low quality evidence). Sensitivity analyses by including studies that analyzed blood samples and by good methodology revealed similar results (moderate quality evidence).

AUTHORS' CONCLUSIONS

Molecular assays have the advantage of producing rapid results and may perform well as 'add-on' tests.

Molecular and nonmolecular diagnostic methods for invasive fungal infections

Invasive fungal infections constitute a serious threat to an ever-growing population of immunocompromised individuals and other individuals at risk. Traditional diagnostic methods, such as histopathology and culture, which are still considered the gold standards, have low sensitivity, which underscores the need for the development of new means of detecting fungal infectious agents. Indeed, novel serologic and molecular techniques have been developed and are currently under clinical evaluation. Tests like the galactomannan antigen test for aspergillosis and the β-glucan test for invasive Candida spp. and molds, as well as other antigen and antibody tests, for Cryptococcus spp., Pneumocystis spp., and dimorphic fungi, have already been established as important diagnostic approaches and are implemented in routine clinical practice. On the other hand, PCR and other molecular approaches, such as matrix-assisted laser desorption ionization (MALDI) and fluorescence in situ hybridization (FISH), have proved promising in clinical trials but still need to undergo standardization before their clinical use can become widespread. The purpose of this review is to highlight the different diagnostic approaches that are currently utilized or under development for invasive fungal infections and to identify their performance characteristics and the challenges associated with their use.

Nonculture techniques for the detection of bacteremia and fungemia

ABSTRACT: 

Bacteremia and fungemia account for a substantial proportion of all cases of severe sepsis. Antibiotic resistance is a contributing factor in many hospital-acquired infection deaths. Traditional phenotypic methods for the identification of bacteria and yeasts from positive blood cultures and determining antimicrobial susceptibility require 48–72 h, delaying optimal therapy and negatively impacting patient outcomes. Molecular methods, including nonamplified DNA probe panels and peptide nucleic acid probes, and nucleic acid amplification methods such as PCR, proteomic methods (matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry) and direct biochemical tests provide more rapid identification of bacteria and fungi, and in some cases antimicrobial resistance markers, from positive blood cultures, as well as directly from whole blood. These methods vary in the breadth of organisms that they detect, and equally important, their ease of use. This article examines the principles, performance and practicality of the various rapid, nonculture techniques for the detection of bacteremia and fungemia.

Invasive candidiasis in intensive care unit; consensus statement from an Iranian panel of experts, July 2013

Invasive candidiasis (IC) is associated with high mortality in intensive care unit (ICU) patients. Timely diagnosis of this potentially fatal condition remains a challenge; on the other hand, the criteria for initiating empirical antifungal therapy in critically ill patients are not well defined in different patient population and ICU settings. Alongside the international guidelines, reaching regional and local consensus on diagnosis and management of IC in ICU setting is essential. This report summarizes our present status of IC management in ICU, considered by a group of Iranian experts in the fields of intensive care and infectious diseases. A round table of 17 experts was held to review the available data and discuss the optimal treatment strategies for IC in critical care setting. Comparative published data on the management of IC were analytically reviewed and the commonly asked questions about the management of IC in ICU were isolated. These questions were interactively discussed by the panel and audience responses were taken to consolidate point-to-point agreement with the panel arriving at consensus in many instances. The responses indicated that patients’ risk stratification, clinical discretion, fungal diagnostic techniques and the empirical therapy for IC are likely to save more patients. Treatment options were recommended to be based on the disease severity, prior azole exposure, and the presence of suspected azole-resistant Candida species. This report was reviewed, edited and discussed by all participants to include further evidence-based insights. The panel expects such endorsed recommendations to be soon formulated for implementation across the country.