From ASCA breakthrough in Crohn's disease and Candida albicans research to thirty years of investigations about their meaning in human health.

Anti-Saccharomyces cerevisiae antibodies (ASCA) are human antibodies that can be detected using an enzyme-linked immunosorbent assay involving a mannose polymer (mannan) extracted from the cell wall of the yeast S. cerevisiae. The ASCA test was developed in 1993 with the aim of differentiating the serological response in two forms of inflammatory bowel disease (IBD), Crohn's disease and ulcerative colitis. The test, which is based on the detection of anti-oligomannosidic antibodies, has been extensively performed worldwide and there have been hundreds of publications on ASCA. The earlier studies concerned the initial diagnostic indications of ASCA and investigations then extended to many human diseases, generally in association with studies on intestinal microorganisms and the interaction of the micro-mycobiome with the immune system. The more information accumulates, the more the mystery of the meaning of ASCA deepens. Many fundamental questions remain unanswered. These questions concern the heterogeneity of ASCA, the mechanisms of their generation and persistence, the existence of self-antigens, and the relationship between ASCA and inflammation and autoimmunity. This review aims to discuss the gray areas concerning the origin of ASCA from an analysis of the literature. Structured around glycobiology and the mannosylated antigens of S. cerevisiae and Candida albicans, this review will address these questions and will try to clarify some lines of thought. The importance of the questions relating to the pathophysiological significance of ASCA goes far beyond IBD, even though these diseases remain the preferred models for their understanding.

A rare case of presumptive pleural toxocariasis.

Toxocariasis is a cosmopolitan helminthiasis linked to contamination with Toxocara cati or Toxocara canis. Only six isolated cases of pleural toxocariasis have been reported in the literature. We describe a case of pleurisy with isolated eosinophilia varying between 600 and 1500/mm3 likely linked o presumptive toxocariasis in a 72-year-old patient. Our patient was admitted to hospital with severe dyspnoea, asthenia and diarrhoea. Imaging studies confirmed right unilateral pleurisy without any parenchymal involvement. Serology of serum and pleural fluid was positive for anti-Toxocara antibodies by ELISA and immunoblotting. Treatment by pleural drainage and anti-parasitic medication with albendazole for 8 days resulted in the resolution of symptoms. A decrease in the levels of polynuclear eosinophils and total IgE confirmed the clinical resolution. The presence of hypereosinophilia in pleural fluid should evoke a diagnosis of pleural toxocariasis. Clinical symptoms and imaging are non-specific, but positive serology for anti-Toxocara antibodies in serum and pleural fluid can confirm the diagnosis.

Parietal composition of Lichtheimia corymbifera: Differences between spore and germ tube stages and host-pathogen interactions.

The molecular composition and structural organization of the cell wall of filamentous fungi underlie the ability of the host to identify them as pathogens. Although the organization of the fungal cell wall, composed of 90% polysaccharides, is similar from one fungus to another, small variations condition their ability to trigger pattern recognition receptors. Because the incidence of mucormycosis, an emerging life-threatening infection caused by the species of the order Mucorales is increasing worldwide, the precise composition of the cell wall of two strains of Lichtheimia corymbifera was investigated in the early growth stages of germination (spores and germ-tubes) using trimethylsilylation and confocal microscopy. This study also characterizes the response of THP-1 cells to Mucorales. The study identified the presence of uncommon monosaccharides (fucose, galactose, and glucuronic acid) whose respective proportions vary according to the germination stage, revealing early parietal reorganization. Immunofluorescence studies confirmed the exposure of ß-glucan on the surface of swollen spores and germ-tubes. Both spores and germ-tubes of L. corymbifera promoted an early and strong pro-inflammatory response, through TLR-2. Our results show the singularity of the cell wall of the order Mucorales, opening perspectives for the development of specific diagnostic biomarkers.

Lichtheimia corymbifera is a causative agent of mucormycosis, an emerging invasive fungal infection. Deciphering cell wall composition can lead to the identification of a polysaccharide epitope, which could be used as a biomarker, useful for the diagnosis of mucormycosis.

The Changing Landscape of Invasive Fungal Infections in ICUs: A Need for Risk Stratification to Better Target Antifungal Drugs and the Threat of Resistance.

The landscape of invasive candidiasis and invasive aspergillosis has changed dramatically in intensive care units over the past two decades. Today, we are faced with new risk factors such as the emergence of resistance, but are also equipped with new therapeutic strategies and diagnostic tools which are changing epidemiological data and diagnostic algorithms. Some common points need to be addressed: (i) the best way to use microbiological tools and to integrate their results in decisional algorithms; (ii) the need to find the optimum balance between under-diagnosis and overtreatment; (iii) and the need to decipher pathophysiology. In this short review, we will try to illustrate these points.

Detection of circulating DNA for the diagnosis of invasive fusariosis: retrospective analysis of 15 proven cases.

Fusarium spp. are plant pathogens and opportunistic pathogens in severely immunocompromised (hematological malignancy, neutropenia, solid organ transplantation, etc.) and severely burned patients. Invasive fusariosis often disseminates and mortality remains high partly due to delayed diagnosis in the absence of a positive culture. The aim of our study is to design a quantitative PCR (qPCR) assay and evaluate the detection of Fusarium spp. DNA for early diagnosis of invasive infection. A qPCR assay was designed and optimized to identify all Fusarium species complex and secondarily evaluated on patient samples. A total of 81 blood samples from 15 patients diagnosed with proven invasive fusariosis from 9 centers in France were retrospectively tested. Circulating DNA was detected in 14 patients out of 15 (sensitivity of 93% [95% Confidence Interval (CI95), 70.1-99.7]). Detection was possible up to 18 days (median 6 days) before the diagnosis was confirmed by positive blood culture or biopsy. By comparison serum galactomannan and ß-D-glucan were positive in 7.1 and 58.3% of patients respectively. qPCR was negative for all patients with other invasive fungal diseases (IFD) tested (n = 12) and IFD-free control patients (n = 40). No cross-reactions were detected using DNA extracted from 81 other opportunistic fungi. We developed and validated a pan-Fusarium qPCR assay in serum/plasma with high sensitivity, specificity, and reproducibility that could facilitate early diagnosis and treatment monitoring of invasive fusariosis. LAY ABSTRACT: Fusariosis ranks third among invasive mould infections. It is frequently diagnosed late due to the lack of specific tools. We designed and evaluated a new qPCR assay with high sensitivity and specificity allowing detection of Fusarium DNA in serum samples up to 18 days before conventional diagnosis.

Invasive pulmonary aspergillosis among intubated patients with SARS-CoV-2 or influenza pneumonia: a European multicenter comparative cohort study.

BACKGROUND: Recent multicenter studies identified COVID-19 as a risk factor for invasive pulmonary aspergillosis (IPA). However, no large multicenter study has compared the incidence of IPA between COVID-19 and influenza patients. OBJECTIVES: To determine the incidence of putative IPA in critically ill SARS-CoV-2 patients, compared with influenza patients. METHODS: This study was a planned ancillary analysis of the coVAPid multicenter retrospective European cohort. Consecutive adult patients requiring invasive mechanical ventilation for > 48 h for SARS-CoV-2 pneumonia or influenza pneumonia were included. The 28-day cumulative incidence of putative IPA, based on Blot definition, was the primary outcome. IPA incidence was estimated using the Kalbfleisch and Prentice method, considering extubation (dead or alive) within 28 days as competing event. RESULTS: A total of 1047 patients were included (566 in the SARS-CoV-2 group and 481 in the influenza group). The incidence of putative IPA was lower in SARS-CoV-2 pneumonia group (14, 2.5%) than in influenza pneumonia group (29, 6%), adjusted cause-specific hazard ratio (cHR) 3.29 (95% CI 1.53-7.02, p = 0.0006). When putative IPA and Aspergillus respiratory tract colonization were combined, the incidence was also significantly lower in the SARS-CoV-2 group, as compared to influenza group (4.1% vs. 10.2%), adjusted cHR 3.21 (95% CI 1.88-5.46, p < 0.0001). In the whole study population, putative IPA was associated with significant increase in 28-day mortality rate, and length of ICU stay, compared with colonized patients, or those with no IPA or Aspergillus colonization. CONCLUSIONS: Overall, the incidence of putative IPA was low. Its incidence was significantly lower in patients with SARS-CoV-2 pneumonia than in those with influenza pneumonia. Clinical trial registration The study was registered at ClinicalTrials.gov, number NCT04359693 .

Coronavirus Disease 2019-Associated Mucormycosis in France: A Rare but Deadly Complication.

We studied COVID-19 associated mucormycosis based on 17 cases reported nationwide and assessed the differences with India. They differed by frequencies of diabetes mellitus (47% in France versus up to 95% in India), hematological malignancies (35% versus 1%), anatomical sites (12% versus >80% rhino-orbito-cerebral) and prognosis (88% mortality versus <50%).

Identification of fungal trehalose for the diagnosis of invasive candidiasis by mass spectrometry.

The rapidity of the diagnosis of invasive candidiasis (IC) is crucial to allow the early introduction of antifungal therapy that dramatically increases the survival rate of patients. Early diagnosis is unfortunately often delayed because Candida blood culture, the gold standard diagnostic test, is positive in only 50% of cases of IC and takes several days to obtain this result. Complementary non-culture-based methods relying on the detection of Candida cell wall polysaccharides in the serum, ß-glucans and mannans, by enzymatic and immunological reagents have been successfully developed to allow a more efficient patients care. We have previously demonstrated that detection of circulating glycans by mass spectrometry could provide a reliable and cost-effective early diagnosis method called MS-DS for Mass Spectrometry of Di-Saccharide. Here, by comparing patient's sera and Candida albicans strains deficient in carbohydrates synthesis, we demonstrate that trehalose derived from fungal metabolism can be specifically targeted by MS-DS to allow early diagnosis. In particular, the use of C. albicans strains deficient in the synthesis of trehalose synthesizing enzymes Tps1 and Tps2 show that MS-DS results were correlated to the metabolism of trehalose. Finally, we demonstrate that the performance of the IC diagnosis can be significantly improved by using high resolution mass spectrometry, which opens new perspectives in the management of the disease.

Adherent invasive Escherichia coli (AIEC) strain LF82, but not Candida albicans, plays a profibrogenic role in the intestine.

BACKGROUND: Intestinal fibrosis is a frequent complication of Crohn's disease. However, the factors that cause chronicity and promote fibrogenesis are not yet understood. AIMS: In the present study, we evaluated the profibrotic effects of adherent-invasive Escherichia coli (AIEC) LF82 strain and Candida albicans in the gut. METHODS: Colonic fibrosis was induced in C57BL/6 mice by administration of three cycles of 2.5% (w/v) dextran sulfate sodium (DSS) for 5 weeks. LF82 and C. albicans were administered orally once at the start of each week or each cycle, respectively. Expression of markers of myofibroblast activation was determined in TGF-ß1-stimulated human intestinal epithelial cells (IECs). RESULTS: LF82 administration exacerbated fibrosis in DSS-treated mice, revealed by increased colonic collagen deposition and expression of the profibrotic genes Col1a1, Col3a1, Fn1 and Vim. This was accompanied by enhanced gene expression of proinflammatory cytokines and chemokines, as well as more recruited inflammatory cells into the intestine. LF82 also potentiated TGF-ß1-stimulated epithelial-mesenchymal transition and myofibroblast activation in IECs, by further inducing gene expression of the main mesenchymal cell markers FN1 and VIM and downregulating the IEC marker OCLN. Proinflammatory cytokines were overexpressed with LF82 in TGF-ß1-stimulated IECs. Conversely, C. albicans did not affect intestinal fibrosis progression in DSS-treated mice or myofibroblast activation in TGF-ß1-stimulated IECs. CONCLUSIONS: These results demonstrate that AIEC strain LF82, but not C. albicans, may play a major profibrogenic role in the gut.

Polysaccharides Cell Wall Architecture of Mucorales.

Invasive fungal infections are some of the most life-threatening infectious diseases in the hospital setting. In industrialized countries, the most common fungal species isolated from immunocompromised patients are Candida and Aspergillus spp. However, the number of infections due to Mucorales spp. is constantly increasing and little is known about the virulence factors of these fungi. The fungal cell wall is an important structure protecting fungi from the environment. A better knowledge of its composition should improve our understanding of host-pathogen interactions. Cell wall molecules are involved in tissue adherence, immune escape strategies, and stimulation of host defenses including phagocytosis and mediators of humoral immunity. The fungal cell wall is also a target of choice for the development of diagnostic or therapeutic tools. The present review discusses our current knowledge on the cell wall structure of Mucorales in terms of the polysaccharides and glyco-enzymes involved in its biosynthesis and degradation, with an emphasis on the missing gaps in our knowledge.

Evaluation of Mass Spectrometry-Based Detection of Panfungal Serum Disaccharide for Diagnosis of Invasive Fungal Infections: Results from a Collaborative Study Involving Six European Clinical Centers.

A mass spectrometry (MS) method that detects a serum disaccharide (DS) (MS-DS) was recently described for the diagnosis of invasive fungal infections (IFI). We carried out a European collaborative study to evaluate this assay. Patients with the following IFI were selected according to the availability of sera obtained at about the time that IFI was documented: invasive candidiasis (IC; n = 26 patients), invasive aspergillosis (IA; n = 19), and mucormycosis (MM; n = 23). Control sera originated from 20 neutropenic patients and 20 patients with bacteremia. MS-DS was carried out in blind manner for the diagnosis of IFI. A diagnosis of IC or IA was confirmed by detection of mannan (Man) or galactomannan (GM), respectively, associated with detection of (1,3)-ß-d-glucan (BDG) in both infections. MM was detected by quantitative real-time PCR (qPCR). All tests discriminated sera from patients with IC from sera from control subjects with bacteremia (P ≤ 0.0009). For IC, the MS-DS sensitivity and specificity were 51% and 87%, respectively. MS-DS complemented the high specificity of Man monitoring. All tests discriminated sera from IA patients from sera from neutropenic controls (P ≤ 0.0009). For IA, MS-DS sensitivity and specificity were 64% and 95%, respectively. Only 13/36 serum samples from patients with MM were concordant by MS-DS and qPCR (6 were positive, and 7 were negative); 14 were positive by MS-DS alone. qPCR and MS-DS made a similar contribution to the diagnosis of MM. In patients undergoing long-term monitoring, the persistent circulation of serum disaccharide was observed, whereas DNA was detected only for a short period after initiation of treatment. MS-DS has an important role to play in the early diagnosis of IFI. Its panfungal nature and complementarity with other tests may justify its use in the management of IFI.

Chronic Mucocutaneous Candidiasis in Autoimmune Polyendocrine Syndrome Type 1.

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is an autosomal recessive disease caused by mutations in the autoimmune regulator (AIRE) gene, characterized by the clinical triad of chronic mucocutaneous candidiasis (CMC), hypoparathyroidism, and adrenal insufficiency. CMC can be complicated by systemic candidiasis or oral squamous cell carcinoma (SCC), and may lead to death. The role of chronic Candida infection in the etiopathogenesis of oral SCC is unclear. Long-term use of fluconazole has led to the emergence of Candida albicans strains with decreased susceptibility to azoles. CMC is associated with an impaired Th17 cell response; however, it remains unclear whether decreased serum IL-17 and IL-22 levels are related to a defect in cytokine production or to neutralizing autoantibodies resulting from mutations in the AIRE gene.

Successful outcome of disseminated mucormycosis in a 3-year-old child suffering from acute leukaemia: the role of isavuconazole? A case report.

BACKGROUND: The use of isavuconazole is approved for the management of invasive aspergillosis and mucormycosis, only in adults, as no paediatric pharmacology studies have been reported to date. Very few paediatric cases have been published concerning the use of isavuconazole. Amphotericin B is the only antifungal agent recommended in paediatric mucormycosis, but adverse effects and especially nephrotoxicity, even with the liposomal formulation, could be problematic. In this context, the use of other antifungal molecules active on Mucorales becomes needful. CASE PRESENTATION: We describe a case of mucormycosis with rapid onset dissemination in a 3-year-old girl recently diagnosed with acute lymphocytic leukaemia. She was successfully treated with isavuconazole alone and then in combination with liposomal amphotericin B. Isavuconazole therapy was guided by therapeutic drug monitoring. CONCLUSIONS: This case offers new perspectives on the potential use of isavuconazole in children with mucormycosis, as an alternative or adjunct to liposomal amphotericin B.

Case Report: Hemianopia: From Suspected Glioblastoma to the Diagnosis of Ectopic Schistosomiasis Haematobium Infection in a Traveler Returning from the Republic of the Congo.

Schistosomiasis due to Schistosoma haematobium is a widespread disease usually affecting the urinary tract associated with hematuria and kidney disorders. Neurological damage is rarely reported and symptoms are nonspecific and may suggest brain tumors such as glioma. We describe the first double ectopic haematobium schistosomiasis case involving the brain and intestine.

Case Report: Ocular Microsporidiosis: Case in a Patient Returning from India and Review of the Literature.

Microsporidia are protists close to the kingdom of fungi that may cause eye infections. Most cases are reported in Asia and affect both immunocompromised and immunocompetent patients. Here, we report a rare case of microsporidial keratoconjunctivitis in an immunocompetent French patient 3 weeks after returning from India. In our patient, Weber trichrome staining of conjunctival scrapings revealed rounded elements approximately 1-3 µm in size. Conventional polymerase chain reaction analysis by ribosomal RNA subunit sequencing showed 100% identity with Vittaforma corneae. Treatment by corneal debridement combined with fluoroquinolone eye drops allowed complete resolution of the lesions. Although rare, ocular microsporidiosis should be investigated in a patient who is native to Asia or has returned from an endemic area and presents with keratoconjunctivitis of undetermined etiology.

De-escalation of antifungal treatment in critically ill patients with suspected invasive Candida infection: incidence, associated factors, and safety.

BACKGROUND: Antifungal treatment is common in critically ill patients, but only a small proportion of patients receiving antifungals have a proven fungal infection. However, antifungal treatment has side effects such as toxicity, emergence of resistance, and high cost. Moreover, empirical antifungal treatment is still a matter for debate in these patients. Our study aimed to determine the incidence, associated factors, and safety of de-escalation of antifungals in critically ill patients. METHODS: This retrospective study was conducted in a 30-bed mixed ICU, from January 2012 through January 2013. Patients hospitalized for > 5 days and treated with antifungals for first suspected or proven invasive Candida infection were included. Exclusion criteria were prophylactic antifungals, suspected invasive aspergillosis, and neutropenia. De-escalation was defined as switch from initial systemic antifungals (except fluconazole) to triazoles, or stopping initial drugs within the 5 days following their initiation. RESULTS: One hundred and ninety patients were included. Antifungal treatment was empirical, preemptive, and targeted in 55, 27, and 24% of study patients, respectively. Caspofungin (53%), fluconazole (43%), voriconazole (4%), and liposomal amphotericin B (0.5%) were the more frequently used antifungals. De-escalation was performed in 38 (20%) patients. Invasive mechanical ventilation was independently associated with lower rates of de-escalation (OR 0.25 [95% CI 0.08-0.85], p = 0.013). Total duration of antifungal treatment was significantly shorter in patients with de-escalation, compared with those with no de-escalation (med [IQR] 6 (5, 18) vs. 13 days (7, 25), p = 0.023). No significant difference was found in duration of mechanical ventilation (22 [5-31] vs. 20 days [10-35], p = 0.43), length of ICU stay (25 [14-40) vs. 25 days [11-40], p = 0.99), ICU mortality (45 vs. 59%, p = 0.13), or 1-year mortality (55 vs. 64%, p = 0.33) between patients with de-escalation and those with no de-escalation, respectively. CONCLUSIONS: De-escalation was performed in 20% of patients receiving systemic antifungals for suspected or proven invasive Candida infection. Mechanical ventilation was independently associated with lower rates of de-escalation. De-escalation of antifungal treatment seems to be safe in critically ill patients.

Prospective Observational Study on the Association Between Serum Mannose-Binding Lectin Levels and Severe Outcome in Critically Ill Patients with Pandemic Influenza Type A (H1N1) Infection.

BACKGROUND: Mannose-binding lectin (MBL) plays an important role in the innate immune response. In addition to activating the complement, MBL can induce cytokine production and contribute to a deleterious inflammatory response with severe A(H1N1)pdm09 virus infection. Our aim was to determine if serum MBL levels correlate with the risk of mortality in intensive care units (ICU) patients with A(H1N1)pdm09 infection. METHODS: Prospective observational study was performed in ICU patients with acute respiratory distress syndrome due to influenza A(H1N1)pdm09 virus. Demographic characteristics and severity indices were recorded at ICU admission. MBL was assayed from blood drawn at influenza diagnosis within 24-48 h following the ICU admission. Outcomes were compared according to MBL levels. Results are expressed as median and interquartile range. RESULTS: Serum MBL levels were studied in 27 patients (age: 56 [IQR 29] years) with severe A(H1N1)pdm09 infection and in 70 healthy controls. Median admission SAPSII and SOFA scores were 49 [IQR 26] and 12 [IQR 5], respectively. Mortality rate after a 30-day was 37%. MBL was significantly higher in non-survivors (3741 [IQR 2336] ng/ml) vs survivors (215 [IQR 1307] ng/ml), p = 0.006, as well as control group (1814 [IQR 2250] ng/ml), p = 0.01. In contrast, MBL levels in survivors group were significantly lower than the controls group (215 [IQR 1307] ng/ml vs. 1814 [IQR 2250] ng/ml, p = 0.005). MBL cut-off > 1870 ng/ml had a sensitivity of 80% and a specificity of 88.2% for mortality [AUC = 0.82 (95% CI 0.63-0.94)]. Kaplan-Meier analysis demonstrated a strong association between MBL levels and mortality (log-rank 7.8, p = 0.005). MBL > 1870 ng/ml was independently associated with mortality (HR = 8.7, 95% CI 1.2-29.1, p = 0.007). CONCLUSIONS: This study shows that baseline MBL > 1870 ng/ml is associated with higher mortality in ICU patients with severe A(H1N1)pdm09 infection.

Evaluation of the (1,3)-ß-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)-ß-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.

Sushi, ceviche and gnathostomiasis - A case report and review of imported infections.

We describe a case of imported cutaneous gnathostomiasis in a Thai patient living in France. Gnathostomiasis is a zoonosis of food origin. The disease is endemic in Southeast Asia and Latin America. However, over the past 30 years, an increasing number of imported cases has been described in Europe and America. The disease is rare in Western Europe and the majority of cases described had a cutaneous clinical presentation. The disease may sometimes be confused with allergy, leading to a delay in diagnosis. Visceral symptoms are rare but may follow severe attacks. A definitive diagnosis can be obtained by the isolation of larvae from skin biopsies, but these are rarely performed. The diagnosis is usually presumptive, based on a combination of anamnestic, clinical, and biological factors. Several courses of the anti-helminths, albendazole or ivermectin, are often necessary. Although rare, the diagnosis should be evoked systematically in a migrant or traveller returning from an endemic area with cutaneous lesions.