Comparative sensitivity of 1,3 beta‐D‐glucan for common causes of candidaemia in South Africa

Culture‐based diagnosis of candidaemia suffers poor sensitivity and prolonged turnaround time. The 1,3‐beta‐D‐glucan (BDG) assay is a non‐culture‐based broad fungal antigen with rapid turnaround time. To assess overall, species‐specific and population‐specific sensitivity of the BDG assay for candidaemia, to determine if the BDG assay is able to detect candidaemia prior to blood culture collection, and to evaluate the performance of the assay for the detection of Candida auris candidaemia. A retrospective review of all blood cultures (BC) with C albicans, C parapsilosis, C glabrata, C krusei and C auris was performed. A corresponding BDG result (Fungitell^®) within 10 days of the BC was sought on the laboratory information system. Overall sensitivity of the assay was 79% (95% CI 73‐85; 173/218). Per species sensitivity was 81% (95% CI 72‐90; 66/81) for C albicans, 72% (61‐83; 60/83) for C parapsilosis, 90% (95% CI 79‐100; 27/30) for C glabrata, 71% (95% CI 43‐99; 10/14) C auris and 100% (10/10) for C krusei. No statistically significant difference in sensitivity between species was noted (P = .093). The assay demonstrated 92% (59/64) sensitivity in neonatal ICU (P = .047) compared to 94% (15/16) in surgery, 81% (59/73) in adult ICUs and 71% (15/21) in Oncology. BDG results were positive up to 10 days prior to blood culture collection with no significant difference in detection rate (P = .563). BDG results were positive up to 10 days prior to blood culture collection. BDG when collected a mean of 2.5 days (range 1‐10 days) prior to blood culture collection were positive.     

Performance of 1,3‐β‐D‐glucan for diagnosing invasive fungal diseases in children

Plasma 1,3‐β‐D‐glucan (BDG) is indicated as a tool for early diagnosis of invasive fungal diseases (IFD). However, data on its diagnostic value are scarce in children. Therefore, definition of BDG test performance in paediatrics is needed. BDG was evaluated in children admitted to “Istituto Giannina Gaslini,” Genoa, Italy, who developed clinical conditions at risk for IFD. Results were analysed for sensitivity, specificity, predictive values, likelihood ratios, accuracy, informedness and probability of missing one case by a negative test. A total of 1577 BDG determinations were performed on 255 patients (49% males, median age 5.4 years). Overall 46 IFD were diagnosed, 72% proven/probable. The test performance was evaluated for 80 pg/mL, 120 pg/mL, 200 pg/mL, 350 pg/mL, 400 pg/mL cut offs. Sensitivity was always <0.80 and specificity > 0.90 only for cut offs ≥200 pg/mL. Negative predictive value was ≥0.90 for all the cut offs evaluated, while positive predictive value resulted barely 0.50 (8% IFD prevalence). Accuracy was never >0.90, and informedness was at best 0.50. The risk of missing one IFD by a negative result was < 10%. Analyses in haemato‐oncological or newborn patients did not show major differences. Detection of serum BDG does not appear a valuable adjunctive diagnostic tool for IFD in paediatrics.     

Use of (1→3)‐β‐d‐glucan for diagnosis and management of invasive mycoses in HIV‐infected patients

People living with HIV (PLHIV) are highly vulnerable to invasive fungal infections (IFIs) due to their immune dysfunction. Diagnosis and treatment of IFIs remain challenging due to the requirement of deep tissue sampling to visualise and culture fungi before initiating treatment. Such techniques are less practical in resource‐limited settings due to their cost and requirement of relatively invasive procedures. Hence, identification of surrogate markers for the early diagnosis and therapeutic monitoring of IFIs is required. Recent studies have shown that (1→3)‐β‐d ‐glucan (BDG), a major fungal cell wall antigen, represents a promising soluble marker for the presumptive diagnosis and therapeutic monitoring of IFIs in HIV‐infected patients. Herein, we review findings on the merits of BDG assays in the diagnosis of IFIs and monitoring of antifungal therapies for PLHIV. Conversely to other types of immunocompromised patients, HIV infection is associated with gut damage and subsequent bacterial and fungal translocation leading to elevated BDG plasma levels.     

1,3‐ß‐D‐glucan concentrations in blood products predict false positive post‐transfusion results

1,3‐ß‐D‐glucan (BDG) is increasingly used to diagnose invasive fungal infections (IFI), although false positive results are a concern. To evaluate the potential interaction of blood products with the BDG assay, human albumin (HA), fresh frozen plasma (FFP), undiluted platelet transfusion (UPT) and packed red blood cells (PRBC) were tested for their BDG content using two different b‐D‐glucan tests. UPTs tested negative, FFP, PBRC and HA tested positive for BDG. In serial dilution, BDG concentration correlated with blood product concentration. To investigate the clinical impact of blood product transfusions, we measured BDG levels before and after the transfusion in three patients (2 PRBC, 1 HA). In the patients receiving PRBC transfusions, BDG values increased from 13 and 17 pg ml^?1 to 183 and 361 pg ml^?1, the HA transfusion increased the serum level from 42 to 58 pg ml^?1. BDG concentrations measured in blood products can be used to predict false positive BDG results.     

Comparative evaluation of pan‐fungal real‐time PCR,galactomannan and (1‐3)‐β‐D‐glucan assay for invasive fungal infection in paediatric cancer patients

Limited specific data and investigations are available for the diagnosis of Invasive Fungal Infection (IFI) in paediatrics cancer patients. Three non‐invasive tests; Platelia Aspergillus EIA for galactomannan (GM), β‐D‐glucan (BDG) assay and pan‐fungal real‐time PCR for fungal DNA in blood were evaluated. One hundred twenty‐five paediatrics cancer patients at the high risk of IFI were enrolled. Single blood and serum samples were evaluated by all the three methods. Patients were classified into 10 proven, 52 probable and 63 no IFI cases in accordance with EORTC MSG 2008 revised guidelines. The sensitivity, specificity, PPV and NPV of all the three tests in proven, probable and no IFIs cases were analysed singly and in combination. The sensitivity, specificity, PPV and NPV of GM, BDG and pan‐fungal real‐time PCR were: 87%, 61%, 81%, 69.5% for GM, 88%, 59.5%, 81%, 71.4% for BDG and 89%, 69.2%, 85%, 67.5% for PCR (95% CI). Among different combinations, best combination was found to be GM and PCR with sensitivity, specificity, PPV and NPV of 98.2%, 89.3%, 97.1% and 90% respectively. Single samples must be evaluated by combination of tests.     

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.     

Reactivity of the 1,3‐β‐D‐glucan assay during bacteraemia: limited evidence from a prospective study

There are discrepancies in the retrospective studies published in literature of whether or not bacteraemia could lead to false positivity of 1,3‐β‐D (BG) glucan assay. We performed, for the first time, a prospective study evaluating the role of bacterial bloodstream infection to the reactivity of BG assay. Twenty‐six episodes of bacteraemia that occurred in high‐risk haematological patients were included in our study. Consecutive BG levels >80 pg ml^?1 were required for test positivity. Only 2 of 26 patients were BG positive – both with IFDs. Thus, we prospectively did not prove bacteraemia as the source of cross reactivity of BG assay in haematological patients.     

Reliability of serum 1,3‐beta‐d‐glucan assay in patients undergoing renal replacement therapy: a review of the literature

The serum 1,3‐beta‐d ‐glucan (BDG) test is a pan‐fungal serum marker considered to detect the majority of pathogenic fungi, including Aspergillus spp. and Candida spp. For this review we searched for publications dealing with serum BDG levels in patients undergoing renal replacement therapy (RRT). The influence of various different membrane materials used for RRTs in these publications on serum BDG has been reviewed. We found that unmodified cellulose containing membranes increased the serum BDG levels highly, whereas conflicting results have been observed for modified cellulose containing materials. Synthetic materials (e.g. polysuflone) had no influence on serum BDG levels in the majority of the reviewed publications.     

Detection of (1→3)‐β‐D‐glucan in same‐day urine and serum samples obtained from patients with haematological malignancies

Serum 1,3‐beta‐d ‐glucan (BDG) testing is an established diagnostic marker for invasive fungal infections (IFI) among patients with haematological malignancies. In contrast limited data exist regarding the application of urine BDG testing. Same‐day midstream urine and serum screening samples were collected in adult patients with underlying haematological malignancies. A total of 80 urine samples from 46 patients were investigated: Twenty‐six had positive corresponding serum BDG >120 pg ml^?1, 27 intermediate (60–80 pg ml^?1), and 27 negative serum BDG (<25 pg ml^?1). A significant positive correlation between BDG in serum and urine samples was observed (P = 0.025; r = 0.252). Sensitivity, specificity, positive predictive value and negative predictive value (compared with same‐day serum results) were: 42%, 76%, 46%, 73% when using an 80 pg ml^?1 urine cut‐off, and 35%, 96%, 82%, 75% for a 250 pg ml^?1 cut‐off. Urine BDG seemed to be higher in samples obtained from patients with probable IFI (n = 13, median 145, IQR 22–253) compared to those from patients without IFI (n = 56, median 24, IQR 15–88) but the difference was not significant (P = 0.069). Overall correlation of same‐day urine BDG and serum BDG was moderate. However, urine BDG testing may warrant further investigation in larger studies, as high‐positive urine results correlated with high‐positive corresponding serum levels and clinical performance was comparable to serum BDG.     

Serum 1,3‐beta‐d‐glucan for antifungal treatment stratification at the intensive care unit and the influence of surgery

The purpose of this study was to evaluate a preemptive approach with serum 1,3‐beta‐d ‐glucan (BDG) as a marker for treatment stratification of systemic antifungal (AF) therapy in patients with clinical suspected invasive fungal infections (IFI) at intensive care units (ICU), and the impact of surgical procedures. A total of 66 ICU patients with clinical suspected IFI were included in this retrospective analysis. Serum BDG testing was performed prior to initiation of AF treatment and in addition to routine diagnostic measures. Based on the BDG results the initial clinical decision whether or not to start systemic AF therapy was re‐evaluated. Impact of surgical procedures on clinical utility of serum BDG was evaluated in a sub‐group of 25 patients who had undergone surgical procedures prior to BDG evaluation. BDG test results led to discontinuation of AF therapy in 13 patients, and initiation of AF therapy in seven patients. In 46 patients the clinical decision was confirmed by BDG. The majority of suspected, probable and proven IFI cases (10/13, 77%) was predicted by the test. BDG testing turned out positive in 9/25 (36%) of patients that had undergone recent surgery and levels correlated with clinical findings. Serum BDG evaluation seems to be a promising tool to guide AF therapy in ICU patients even after recent surgical procedures.     

Disseminated fusariosis by Fusarium proliferatum in a patient with aplastic anaemia receiving primary posaconazole prophylaxis – case report and review of the literature

Disseminated fusariosis is a life‐threatening, invasive, opportunistic infection in immunocompromised patients, especially those with haematological malignancies. The prognosis is poor because these fungi are resistant to many of the available antifungal agents. We present a case of disseminated fusariosis caused by Fusarium proliferatum in a patient with severe aplastic anaemia complicated by a secondary infection of Aspergillus flavus, with a fatal outcome. We also review the documented Fusarium infections in immunocompromised hosts.     

Prospective evaluation of a combination of fungal biomarkers for the diagnosis of invasive fungal disease in high‐risk haematology patients

We prospectively evaluated a combination of fungal biomarkers in adult haematology patients with focus on their clinical utility at different time points during the course of infection. In total, 135 patients were monitored once to twice weekly for serum (1‐3)‐ß‐d ‐glucan (BG), galactomannan (GM), bis‐methyl‐gliotoxin and urinary d ‐arabinitol/l ‐arabinitol ratio. In all, 13 cases with proven or probable invasive fungal disease (IFD) were identified. The sensitivity of BG and GM at the time of diagnosis (TOD) was low, but within 2 weeks from the TOD the sensitivity of BG was 92%. BG >800 pg/mL was highly specific for IFD. At a pre‐test probability of 12%, both BG and GM had negative predictive values (NPV) >0.9 but low positive predictive values (PPV). In a subgroup analysis of patients with clinically suspected IFD (pre‐test probability of 35%), the NPV was lower, but the PPV for BG was 0.86 at cut‐off 160 pg/mL. Among IFD patients, 91% had patterns of consecutively positive and increasing BG levels. Bis‐methyl‐gliotoxin was undetectable in 15 patients with proven, probable and possible IA. To conclude, BG was the superior fungal marker for IFD diagnosis. Quantification above the limit of detection and graphical evaluation of the pattern of dynamics are warranted in the interpretation of BG results.     

Clinical evidence for caspofungin monotherapy in the first‐line and salvage therapy of invasive Aspergillus infections

In 2001, caspofungin received market authorisation by the FDA and EMA and is globally licensed for several indications, including candidiasis, empirical antifungal therapy in patients with neutropenic fever of unknown origin and treatment of invasive aspergillosis in patients refractory to or intolerant of amphotericin B, lipid formulations of amphotericin B or itraconazole. Despite the lack of phase III data in first‐line treatment of invasive aspergillosis, increasing evidence supports the use of first‐line therapy. Here, we analyse the evidence of therapeutic activity, represented by favourable response rates, of caspofungin for invasive aspergillosis. A systematic literature search was conducted to identify international presentations and papers reporting monotherapy with caspofungin. Efficacy data are summarised separately for first‐line and salvage therapy. Thirty‐one papers and published abstracts reported caspofungin therapy for aspergillosis. Fifteen full papers and two abstracts fulfilled the criteria of reporting significant outcome data for caspofungin monotherapy for invasive aspergillosis. Consistent with other analyses and the known safety profile, few adverse events and associated terminations of caspofungin medication have been reported. Although a randomised, comparative, prospective study using caspofungin in this indication is still lacking, growing evidence supports the efficacy of this echinocandin not only for salvage but also for first‐line therapy.     

Diagnostic value of serum galactomannan, (1,3)‐β‐d‐glucan,and Aspergillus fumigatus‐specific IgA and IgG assays for invasive pulmonary aspergillosis in non‐neutropenic patients

Detection of serum galactomannan (GM) and (1,3)‐β‐d ‐glucan (BG) is considered useful for non‐culture diagnosis of invasive pulmonary aspergillosis (IPA) in neutropenic patients. Only few studies evaluated these seromarkers in non‐neutropenic patients suspected of having IPA. The aim of this study was to evaluate both tests together with the Aspergillus fumigatus‐specific serum IgG and IgA (IgAG) test for serological IPA diagnosis in non‐neutropenic patients. Sera from 87 patients suspected of having IPA were retrospectively analysed. Patients were categorised into groups of proven IPA (n = 10), putative IPA (n = 31) and non‐IPA colonisation (n = 46). When the GM, BG and IgAG assays were used for patients included in the study, the sensitivity/specificity/positive predictive value (PPV)/negative predictive value (NPV) were 48.8%/91.3%/83.3%/66.7%, 82.9%/73.9%/73.9%/82.9% and 75.6%/95.7%/93.9%/81.5%, respectively. Thus, the highest specificity and PPV were confirmed for the IgAG assay. Improvements in the sensitivity and NPV were achieved by “at least one positive” analysis with the GM and BG assays, with the sensitivity/specificity/PPV/NPV values being 85.0%/69.6%/71.4%/84.2%. Nevertheless, the highest sensitivity and NPV were achieved by the “at least one positive” analysis combining the GM, BG and IgAG tests (97.6% and 96.8%, respectively). The involvement of the IgAG assay could improve IPA diagnosis in non‐neutropenic patients by increasing the sensitivity and NPV when combined with the GM or BG assays. Furthermore, improvement was achieved by combining the GM, BG and IgAG assays using the “at least one positive test” strategy, especially if doubt exists.     

Multidrug‐resistant Fusarium in keratitis: a clinico‐mycological study of keratitis infections in Chennai,India

In this study, we aimed to present the first molecular epidemiological data from Chennai, India, analyse keratitis cases that have been monitored in a university hospital during 2 years, identify the responsible Fusarium species and determine antifungal susceptibilities. A total of 10 cases of keratitis were included in the study. Fusarium isolates were identified using the second largest subunit of the RNA polymerase gene (RPB2) and the translation elongation factor 1 alpha (TEF1). Antifungal susceptibility was tested by the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) methodology. The aetiological agents belonged to Fusarium solani species complex (FSSC) (n = 9) and Fusarium sambucinum species complex (FSAMSC) (n = 1), and the identified species were Fusarium keratoplasticum (n = 7), Fusarium falciforme (n = 2) and Fusarium sporotrichioides (n = 1). All strains showed multidrug resistance to azoles and caspofungin but exhibited lower minimum inhibitory concentration (MIC) to natamycin and amphotericin B. Fusarium keratoplasticum and Fusarium falciforme belonging to the Fusarium solani species complex were the major aetiological agents of Fusarium keratitis in this study. Early presentation and 5% topical natamycin was associated with better patient outcome. Preventative measures and monitoring of local epidemiological data play an important role in clinical practice.     

Dual tumor‐suppressors miR‐139‐5p and miR‐139‐3p targeting matrix metalloprotease 11 in bladder cancer

Our recent study of the microRNA (miRNA) expression signature of bladder cancer (BC) by deep‐sequencing revealed that two miRNA, microRNA‐139‐5p/microRNA‐139‐3p were significantly downregulated in BC tissues. The aim of this study was to investigate the functional roles of these miRNA and their modulation of cancer networks in BC cells. Functional assays of BC cells were performed using transfection of mature miRNA or small interfering RNA (siRNA). Genome‐wide gene expression analysis, in silico analysis and dual‐luciferase reporter assays were applied to identify miRNA targets. The associations between the expression of miRNA and its targets and overall survival were estimated by the Kaplan–Meier method. Gain‐of‐function studies showed that miR‐139‐5p and miR‐139‐3p significantly inhibited cell migration and invasion by BC cells. The matrix metalloprotease 11 gene (MMP11) was identified as a direct target of miR‐139‐5p and miR‐139‐3p. Kaplan–Meier survival curves showed that higher expression of MMP11 predicted shorter survival of BC patients (P = 0.029). Downregulated miR‐139‐5p or miR‐139‐3p enhanced BC cell migration and invasion in BC cells. MMP11 was directly regulated by these miRNA and might be a good prognostic marker for survival of BC patients.     

Acute acalculous cholecystitis due to Fusarium species and review of the literature on fungal cholecystitis

Fungal cholecystitis is an uncommon entity, and no cases of cholecystitis associated with mould infection have been reported. We present a case of acute Fusarium cholecystitis in a cytopenic patient with leukaemia who had disseminated fusariosis. We also review the published cases of fungal cholecystitis, which is most often caused by Candida species. Although it is rare, fungal cholecystitis should be part of the differential diagnosis of acute cholecystitis in high‐risk patients with predisposing factors for opportunistic fungal infections.