Positive result of the Aspergillus galactomannan antigen assay using bronchoalveolar lavage fluid from a patient with an invasive infection due to Lichtheimia ramosa

Case report: The clinical utility of metagenomic next-generation sequencing in mucormycosis diagnosis caused by fatal Lichtheimia ramosa infection in pediatric neuroblastoma

Lichtheimia ramosa (L. ramosa) is an opportunistic fungal pathogen of the order Mucorales that may result in a rare but serious mucormycosis infection. Mucormycosis could be angioinvasive, causing thrombosis and necrosis in the nose, brain, digestive tract, and respiratory tract. The infection is highly lethal, especially in immunocompromised hosts, and the incidence has been on the rise. However, due to its relatively low incidence in pediatric population and the challenges with diagnosis, the awareness and management experience for pediatric mucormycosis are extremely limited, which might lead to poor outcomes. In this study, we comprehensively reviewed the course of a fatal rhinocerebral mucormycosis case in a pediatric neuroblastoma patient receiving chemotherapy. Due to a lack of awareness of the infection, the standard care of amphotericin B treatment was delayed and not administered until the identification of L. ramosa by metagenomic next-generation sequencing (mNGS)-based pan-pathogen detection of the patient's peripheral blood sample. We also reviewed the literature on L. ramosa infection cases reported worldwide between 2010 and 2022, with an analysis of clinical manifestation, prognosis, and epidemiological data. Our study not only highlighted the clinical value of comprehensive mNGS in rapid pathogen detection but also raised awareness of recognizing lethal fungal infection early in immunocompromised hosts including pediatric cancer patients.

The application of metagenomic next-generation sequencing in patients with infection or colonization caused by Lichtheimia species

Background

Mucormycosis is considered the fourth most common invasive fungal disease after candidiasis, aspergillosis and cryptococcosis. Lichtheimia species accounted for 5%-29% of all mucormycosis. However, available data on species-specific analysis of Lichtheimia infections are limited.

Methods

This study included nine patients hospitalized in five hospitals in two cities in south China with mucormycosis or colonization caused by Lichtheimia species, diagnosed mainly by metagenomic next-generation sequencing (mNGS). The corresponding medical records were reviewed, and the clinical data analyzed included demographic characteristics, site of infection, host factors and type of underlying disease, diagnosis, clinical course, management, and prognosis.

Results

In this study, nine patients with Lichtheimia infections or colonization had a recent history of haematological malignancy (33.3%), solid organ transplants (33.3%), pulmonary disease (22.2%), and trauma (11.1%) and were categorized as 11.1% (one case) proven, 66.7% (six cases) probable mucormycosis and 22.2% (two cases) colonization. Pulmonary mucormycosis or colonization was the predominant presentation in 77.8% of cases and mucormycosis caused by Lichtheimia resulted in death in four out of seven patients (57.1%).

Conclusion

These cases highlight the importance of early diagnosis and combined therapy for these sporadic yet life-threatening infections. Further studies on the diagnosis and control of Lichtheimia infection in China are required.

Case report: A rare case of pulmonary mucormycosis caused by Lichtheimia ramosa in pediatric acute lymphoblastic leukemia and review of Lichtheimia infections in leukemia

Mucormycosis caused by Lichtheimia ramosa is an emerging and uncommon opportunistic infection in patients with hematological malignancies, with high mortality rates. Herein, we first report a case of pulmonary mucormycosis with Lichtheimia ramosa in a 3-year-old girl recently diagnosed with B-cell acute lymphoblastic leukemia. The diagnosis was made using computerized tomography of the lung, metagenomic next-generation sequencing (mNGS) of blood and sputum specimens, and microscopic examination to detect the development of Lichtheimia ramosa on the surgical specimen. She was effectively treated after receiving prompt treatment with amphotericin B and posaconazole, followed by aggressive surgical debridement. In our case, the fungal isolates were identified as Lichtheimia ramosa using mNGS, which assisted clinicians in quickly and accurately diagnosing and initiating early intensive treatment. This case also indicated the importance of strong clinical suspicion, as well as aggressive antifungal therapy combined with surgical debridement of affected tissues.

First Case of Rhinocerebral Mucormycosis Caused by Lichtheimia ornata, with a Review of Lichtheimia Infections

BACKGROUND

Lichtheimia species are emerging opportunistic fungal pathogens in the Mucorales, causing serious skin and respiratory infections in immunocompromised patients. Established agents are Lichtheimia corymbifera and L. ramosa, while L. ornata is a novel agent. Available data on a species-specific analysis of Lichtheimia infections are limited.

METHODS

The first case of a fatal rhino-orbital-cerebral infection in a hematopoietic stem cell transplantation recipient caused by L. ornata is reported; the agent was identified by sequencing the ITS ribosomal region. We reviewed the literature on mucormycosis due to Lichtheimia species between 2009 and 2018, with an analysis of risk factors and epidemiological and clinical data.

RESULTS

In addition to our Lichtheimia ornata case, 44 cases of human Lichtheimia were analyzed. Lichtheimia predominated in Europe (68.2%), followed by Asia (16%), and Africa (9%). The most common underlying condition was hematological malignancy (36.3%), followed by trauma/major surgery (27.3%), while diabetes mellitus was rare (11.4%). Site of infection was mostly skin and soft tissues (45.5%) and lung (25%), while relatively few cases were disseminated (13.6%) or rhinocerebral (11.4%). Mortality (36.4%) was mainly due to disseminated and rhinocerebral infections.

CONCLUSION

In contrast to Rhizopus, the most common agent of mucormycosis recorded in patients with diabetes mellitus, Lichtheimia infections were primarily associated with hematological malignancies and major skin barrier damage. Given the fact that classical rhinocerebral mucormycosis remains difficult to treat, independent of causative species, timely application of amphotericin B accessory to debridement may be required for patient survival.

Diagnostic performance of immunohistochemistry for the aspergillosis and mucormycosis

OBJECTIVE

To investigate the accuracy of immunohistochemistry (IHC) tests for distinguishing between mucormycosis and aspergillosis and compare the clinical characteristics of mucormycosis patients according to galactomannan (GM) results.

METHODS

We evaluated diagnostic performance of IHC test with tissue sections of patients with culture-proven invasive fungal infection. In addition, we conducted PCR assay with tissue sections of mucormycosis patients with positive GM results to evaluate the possibility of co-infection.

RESULTS

In culture-proven mucormycosis (n = 13) and aspergillosis (n = 20), the sensitivity and specificity of IHC test were both 100% for mucormycosis and 85% and 100%, respectively, for aspergillosis. Among the 53 patients who met the modified criteria for proven mucormycosis and had GM assay results, 24 (45%) were positive. Compared with those with negative GM results (n = 29), mucormycosis patients with positive GM results had significantly higher incidence of gastrointestinal tract infections (6/24 [25%] vs 0/29 [0%], P = .006) and were more likely to be histomorphologically diagnosed as aspergillosis (7/24 [29%] vs 2/29 [7%], P = .06). PCR assay amplified both Aspergillus- and Mucorales-specific DNA in 6 of these 24 cases.

CONCLUSIONS

Immunohistochemistry tests seem useful for compensating for the limitations of histomorphologic diagnosis in distinguishing between mucormycosis and aspergillosis. Some proven mucormycosis patients with positive GM results had histopathology consistent with aspergillosis and gastrointestinal mucormycosis. In addition, about one quarter of these patients revealed the evidence of co-infection with aspergillosis by PCR assay.

Emerging fungal infections in solid organ transplant recipients: Guidelines of the American Society of Transplantation Infectious Diseases Community of Practice

These updated AST-IDCOP guidelines review the epidemiology, diagnosis, and management of emerging fungi after organ transplantation. Infections due to numerous generally innocuous fungi are increasingly recognized in solid organ transplant (SOT) recipients, comprising about 7%-10% of fungal infections in this setting. Such infections are collectively referred to as emerging fungal infections and include Mucormycetes, Fusarium, Scedosporium, and dematiaceous fungi among others. The causative organisms are diverse in their pathophysiology, uncommon in the clinical setting, have evolving nomenclature, and are often resistant to multiple commonly used antifungal agents. In recent years significant advances have been made in understanding of the epidemiology of these emerging fungal infections, with improved diagnosis and expanded treatment options. Still, treatment guidelines are generally informed by and limited to experience from cohorts of patients with hematological malignancies and/or solid and stem cell transplants. While multicenter randomized controlled trials are not feasible for these uncommon infections in SOT recipients, collaborative prospective studies can be valuable in providing information on the epidemiology, clinical manifestations, treatment strategies, and outcomes associated with the more commonly encountered infections.

Correlation of fungal cultures from non-sterile sites and Galactomannan assay with the diagnosis of aspergillosis and mucormycosis based on sterile culture results and histopathologic findings

BACKGROUND

Data on whether positive non-sterile fungal culture has the same clinical value as a positive galactomannan (GM) result are limited.

METHODS

Patients with biopsy-proven invasive aspergillosis or mucormycosis (over an 8-year period) in whom the results of GM and fungal culture of sputum and/or sinus aspirates were available were enrolled. Biopsy-proven cases were defined if fungal culture from a sterile biopsy specimen gave a positive result and/or hyphae were demonstrated by immunohistochemical staining for aspergillosis and mucormycosis.

RESULTS

A total of 71 patients comprising 30 biopsy-proven cases of aspergillosis including 13 cases with positive sterile cultures and 41 biopsy-proven cases of mucormycosis including eight cases with positive sterile cultures were enrolled. Of 30 patients with aspergillosis, 15 (50%) revealed Aspergillus spp. growth from non-sterile site and none exhibited the agents of mucormycosis growth from non-sterile site. However, of 41 patients with mucormycosis, eight (20%) revealed the agents of mucormycosis growth from non-sterile site and three (7%) exhibited Aspergillus spp. growth from non-sterile site. In terms of GM assays, 23 (77%) of 30 patients with aspergillosis revealed positive GM results, and 17 (41%) of 41 patients with mucormycosis revealed positive GM assays. So, positive fungal culture from non-sterile site (88% [23/26]) were better correlated with the diagnosis than positive GM assay (57% [23/40]) (p value = .01).

CONCLUSIONS

Positive fungal cultures from non-sterile sites better correlate with the diagnosis of aspergillosis and mucormycosis based on sterile culture results and histopathological findings than positive GM results.

First case of proven invasive pulmonary infection due to Trichoderma longibrachiatum in a neutropenic patient with acute leukemia

Trichoderma species are saprophytic filamentous fungi that can be found all over the word. These fungi show increasing medical importance as opportunistic human pathogens, particularly in immunocompromised patients. Invasive infections due to Trichoderma are rare and definitive diagnosis is complex to achieve because of the lack of specific diagnosis tools. We report in this work the first proven case of invasive pulmonary infection due to T. longibrachiatum in a 69-year-old white male with hematologic malignancy. The patient was successfully treated initially with voriconazole alone followed by a combination of voriconazole and caspofungine.

Update on Actinomucor elegans, a mucormycete infrequently detected in human specimens: how combined microbiological tools contribute efficiently to a more accurate medical care

Actinomucor elegans is a fungus belonging to mucormycetes and is still probably underdiagnosed due to misidentification. Based on a recent first case of Actinomucor elegans sinusitis in Europe, in an immunocompromised patient under voriconazole treatment, this paper aims to summarize knowledge about A. elegans mucormycoses. Even if the diagnosis of mucormycosis was made using traditional mycology techniques, precise identification of the fungus could only be achieved using molecular tools. In this observation, the galactomannan dosage was positive until the introduction of treatment and surgical debridement. The patient experienced no relapse after one year. By reviewing the four previous A. elegans reported cases and describing the mycological characteristics of this species, we highlight the need to use a combination of tools to improve the diagnostic strategy in such rare and life-threatening clinical situations.

False-positive galactomannan assay in broncho-alveolar lavage after enteral nutrition solution inhalation: a case report

Introduction. Diagnosis of invasive aspergillosis is challenging and the gold standard for definite diagnosis remains histopathological tissue examination. However, invasive procedures such as lung biopsy are often not feasible in critically ill patients. The detection of fungal cell wall components like Aspergillus galactomannan in broncho-alveolar lavage remains a key component of the diagnostic procedure. False-positive of the Aspergillus galactomannan assay is not frequent. Case presentation. We report a case of positive galactomannan in broncho-alveolar lavage fluid after enteral nutrition aspiration without signs of invasive aspergillosis. Galactomannan was positive in the enteral nutrition solution. Conclusion. Physicians should be aware of this previously unrecognized cause of false-positive galactomannan in broncho-alveolar fluid which can result in unnecessary treatments.

Emergence of the Molds Other than Aspergillus in Immunocompromised Patients

Immunocompromised patients are at high risk for invasive fungal infections (IFIs); although Aspergillus remains the most common IFI caused by molds, other fungi, such as Mucorales, dematiaceous molds, and Fusarium spp, are being seen with increasing frequency. Presentations can vary, but sinopulmonary and disseminated infections are common. Our understanding of the pathogenesis of these infections is rudimentary. Fungal cultures and histopathology remain the backbone of diagnostics, as no good serologic markers are available. Polymerase chain reaction tests are being developed but currently remain investigational. Management of these infections is usually multidisciplinary, requiring surgical debridement along with antifungal therapy.

Lichtheimia ramosa: A Fatal Case of Mucormycosis

Mucormycosis due to Lichtheimia ramosa is an infrequent opportunistic infection that can potentially be angioinvasive when affecting inmunocompromised hosts. We present a fatal case of mucormycosis, affecting a 56-year-old male with diabetes mellitus and siderosis, initially admitted to our hospital due to an H1N1 infection. The subject's clinical condition worsened and he finally died because of a necrotizing bilateral pneumonia with disseminated mycotic thromboses due to Lichtheimia ramosa, which is an emerging Mucoralean fungus. This is an infrequent case because of the extent to which it affected a subject without overt immunocompromise. This case underlines the importance of an early premortem diagnosis and treatment in order to prevent rapid progression of this disease, as well as the need of considering mucormycosis when facing subjects with multiple emboli and fever unresponsive to usual antimicrobials.

Invasive mould sinusitis in patients with haematological malignancies: a 10 year single-centre study

OBJECTIVES

Invasive mould sinusitis (IMS) is a severe infection in patients with haematological malignancies. Because of a paucity of contemporaneous data about IMS, we sought to evaluate clinical aspects and outcome of IMS in these patients.

METHODS

The records of adult haematological malignancy patients with proven or probable IMS over a 10 year period were reviewed retrospectively.

RESULTS

We identified 44 patients with IMS. Mucorales were isolated in 13 (35.1%) patients and Fusarium and Aspergillus were isolated in 9 (24.3%) patients each. Patients with IMS owing to Mucorales were more likely to have a history of diabetes mellitus (P = 0.003) and high-dose corticosteroid use (P = 0.03). Thirty-five (80%) patients received antifungal combinations and 36 (82%) underwent surgical debridement. The 12 week IMS-attributable mortality was 36.4% (16 patients). A relapsed and/or refractory haematological malignancy was an independent risk factor for 6 week IMS-attributable (P = 0.038), 12 week all-cause (P = 0.005) and 12 week IMS-attributable (P = 0.0015) mortality. Neutrophil count <100/µL and lymphocyte count <200/µL were associated with increased 12 week IMS-attributable and 6 week all-cause mortality, respectively (P = 0.044 and 0.013). IMS due to Aspergillus was an independent risk factor for both 12 week all-cause (P = 0.011) and IMS-attributable (P = 0.026) mortality. Initial antifungal therapy with a triazole-containing regimen was associated with decreased 6 week all-cause (P = 0.032) and IMS-attributable (P = 0.038) mortality. Surgery was not an independent factor for improved outcome.

CONCLUSIONS

Despite combined medical and surgical therapy, IMS had high mortality. Mortality risk factors were relapsed and/or refractory malignancy, cytopenia and Aspergillus infection in this study.

Comparison of computed tomographic findings in pulmonary mucormycosis and invasive pulmonary aspergillosis

Because there are no available molecular markers for pulmonary mucormycosis (PM), which has low culture sensitivity, early diagnosis and treatment rely heavily on imaging modes such as computed tomography (CT). However, there are limited data comparing CT findings for PM with those for invasive pulmonary aspergillosis (IPA). Adult patients who met the modified criteria for proven and probable PM (over an 11-year period) and IPA (over a 6-year period, owing to the availability of the galactomannan assay) according to the modified European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions were retrospectively enrolled. IPA cases were selected at a 1 : 4 (PM/IPA) ratio. Thoracic CT scans were reviewed by two experienced radiologists blinded to the patients' demographics and clinical outcomes. A total of 24 patients with PM, including 20 (83%) with proven PM and four (17%) with probable PM, and 96 patients with IPA, including 12 (13%) with proven IPA and 84 (87%) with probable IPA, were eventually analysed. The reverse halo sign was more common in patients with PM (54%) than in those with IPA (6%, p < 0.001), whereas some airway-invasive features, such as clusters of centrilobular nodules, peribronchial consolidations, and bronchial wall thickening, were more common in patients with IPA (IPA 52% vs. PM 29%, p 0.04; IPA 49% vs. PM 21%, p 0.01; IPA 34% vs. PM 4%, p 0.003, respectively). The reverse halo sign was more common, and airway-invasive features were less common, in patients with PM than in those with IPA. These findings may help physicians to initiate Zygomycetes-active antifungal treatment earlier.

Mucormycoses caused by Lichtheimia species

Mucormycoses are life-threatening infections with fungi from the order Mucorales (Mucoromycotina). Although mucormycoses are uncommon compared to other fungal infections, e.g. aspergillosis and candidiasis, the number of cases is increasing especially in immunocompromised patients. Lichtheimia (formerly Absidia) species represent the second to third most common cause of mucormycoses in Europe. This mini review presents current knowledge about taxonomy and clinical relevance of Lichtheimia species. In addition, clinical presentation and risk factors will be discussed. Proper animal infection models are essential for the understanding of the pathogenesis and the identification of virulence factors of fungal pathogens. To date, several animal models have been used to study Lichtheimia infection. A brief overview of the different models and the main conclusions from the infection experiments is summarised in this review.

Translational research in pediatrics III: bronchoalveolar lavage

The role of flexible bronchoscopy and bronchoalveolar lavage (BAL) for the care of children with airway and pulmonary diseases is well established, with collected BAL fluid most often used clinically for microbiologic pathogen identification and cellular analyses. More recently, powerful analytic research methods have been used to investigate BAL samples to better understand the pathophysiological basis of pediatric respiratory disease. Investigations have focused on the cellular components contained in BAL fluid, such as macrophages, lymphocytes, neutrophils, eosinophils, and mast cells, as well as the noncellular components such as serum molecules, inflammatory proteins, and surfactant. Molecular techniques are frequently used to investigate BAL fluid for the presence of infectious pathologies and for cellular gene expression. Recent advances in proteomics allow identification of multiple protein expression patterns linked to specific respiratory diseases, whereas newer analytic techniques allow for investigations on surfactant quantification and function. These translational research studies on BAL fluid have aided our understanding of pulmonary inflammation and the injury/repair responses in children. We review the ethics and practices for the execution of BAL in children for translational research purposes, with an emphasis on the optimal handling and processing of BAL samples.

[Mixed invasive fungal infection due to Rhizomucor pusillus and Aspergillus niger in an immunocompetent patient]

BACKGROUND

Mucormycosis infections are rare in immunocompetent patients, and very few cases of mucormycosis associated with aspergillosis in non-haematological patients have been reported.

CASE REPORT

A 17-year-old male, immunocompetent and without any previously known risk factors, was admitted to hospital due to a seizure episode 11 days after a motorcycle accident. He had a complicated clinical course as he had a mixed invasive fungal infection with pulmonary involvement due to Aspergillus niger and disseminated mucormycosis due to Rhizomucor pusillus (histopathological and microbiological diagnosis in several non-contiguous sites). He was treated with liposomal amphotericin B for 7 weeks (total cumulative dose >10 g) and required several surgical operations. The patient survived and was discharged from ICU after 5 months and multiple complications.

CONCLUSIONS

Treatment with liposomal amphotericin B and aggressive surgical management achieved the eradication of a mixed invasive fungal infection. However, we emphasise the need to maintain a higher level of clinical suspicion and to perform microbiological techniques for early diagnosis of invasive fungal infections in non-immunocompromised patients, in order to prevent spread of the disease and the poor prognosis associated with it.

Wound infection caused by Lichtheimia ramosa due to a car accident

A 32-year-old immunocompetent man sustained severe traumas contaminated with organic material due to a car accident. An infection caused by Lichtheimia ramosa at the site of contamination was early diagnosed and cured by multiple surgical debridement and daily cleansing with antiseptic solution only.

The PATH (Prospective Antifungal Therapy) Alliance® registry and invasive fungal infections: update 2012

The Prospective Antifungal Therapy Alliance (PATH Alliance®) performed prospective surveillance of invasive fungal infections (IFIs) among patients hospitalized at 25 medical centers in North America between 2004 and 2008, collecting information on the epidemiology, diagnosis, treatment, and mortality rates of IFIs. In total, 7526 IFIs were identified in 6845 patients. Candida spp. (73.4%) were the most common pathogens, followed by Aspergillus spp. (13.3%), and other yeasts (6.2%). Culture was the most frequently used diagnostic test in the majority of IFI categories. Most patients with invasive candidiasis were treated with fluconazole (48.3%) and the echinocandins (34.0%), while voriconazole (45.5%) was the main antifungal agent for invasive aspergillosis. The 12-week survival rate ranged from 37.5% for hematopoietic stem cell transplant recipients to ~75.0% for those with HIV/AIDS. In summary, the findings of the PATH Alliance® registry provide a better understanding of the epidemiology of a vast variety and large numbers of IFIs.

Cross-reactivity of Aspergillus galactomannan in an HIV-infected patient with histoplasmosis

Non-invasive assays are increasingly being used in patients with suspected fungal infections. Limitations to these tests include limited sensitivity, specificity, and cross reactivity with other fungal pathogens. Herein we report a case of disseminated histoplasmosis producing a false positive serum and bronchoalveolar lavage (BAL) Aspergillus galactomannan assays. This test may have a role in the evaluation of patients with suspected histoplasmosis in settings where Histoplasma antigen testing is not widely available.

Antigen detection in bronchoalveolar lavage fluid for diagnosis of fungal pneumonia

PURPOSE OF REVIEW

The purpose of this review is to describe important findings published during the past 18 months using bronchoalveolar lavage (BAL) for diagnosis of pulmonary mycoses.

RECENT FINDINGS

Clinical studies and meta-analysis have established a high sensitivity and specificity for Aspergillus galactomannan testing of BAL specimens for diagnosis of invasive aspergillosis, superior to that observed with other diagnostic methods. Similar findings have been reported in histoplasmosis and blastomycosis.

SUMMARY

Fungal antigen testing of BAL specimens is recommended if bronchoscopy is performed for diagnosis of pulmonary infiltrates in patient groups at risk for aspergillosis or the endemic mycoses if the diagnosis cannot be established by evaluation of sputum specimens or detection of antigen in the urine or serum.

Invasive Myceliophthora thermophila infection mimicking invasive aspergillosis in a neutropenic patient: a new cause of cross-reactivity with the Aspergillus galactomannan serum antigen assay

Myceliophthora thermophila is a thermophilic mould widely found in the environment but rarely responsible for human infections. We describe a case of invasive Myceliophthora thermophila infection mimicking invasive aspergillosis in a neutropenic patient with haematological malignancy. Cross-reactivity with Aspergillus galactomannan assay (GM) was demonstrated by repeated positive results and confirmed by cross-reaction between the fungal isolate and the GM assay. The patient was successfully treated with voriconazole. Potential GM cross-reactivity must be considered in future studies including patients categorized as having probable invasive aspergillosis using the GM as the only mycological criterion.