Development and validation of a multiplex PCR for detection of Scedosporium spp. in respiratory tract specimens from patients with cystic fibrosis

Diagnosis and management of invasive fungal infections due to non-Aspergillus moulds

Invasive fungal infection (IFI) due to moulds other than Aspergillus are a significant cause of morbidity and mortality. Non-Aspergillus mould (NAM) infections appear to be on the increase due to an ever-expanding population of immunocompromised hosts. In this review, Mucorales, Scedosporium species, Lomentospora prolificans and Fusarium species are examined in detail, and the microbiology, risk factors, diagnosis and treatment of emerging NAMs such as Paecilomyces variotti, Purpureocillium lilacinum and Rasamsonia are summarized. The challenges in diagnosis are emphasized and the emerging importance of molecular methods is discussed. Treatment of IFI due to NAMs is a multi-pronged and multi-disciplinary approach. Surgery, correction of underlying risk factors, and augmentation of the host immune response are as important as antifungal therapy. Many of these NAMs are intrinsically resistant to the currently licensed antifungal agents, so selection of therapy needs to be guided by susceptibility testing. There are new antifungal agents in development, and these have the potential to improve the efficacy and safety of antifungal treatment in the future. Ongoing research is required to fully delineate the epidemiology of NAM infections, and to develop better diagnostic tools and treatments so that outcomes from these infections can continue to improve.

Scedosporiosis and lomentosporiosis: modern perspectives on these difficult-to-treat rare mold infections

SUMMARYAlthough Scedosporium species and Lomentospora prolificans are uncommon causes of invasive fungal diseases (IFDs), these infections are associated with high mortality and are costly to treat with a limited armamentarium of antifungal drugs. In light of recent advances, including in the area of new antifungals, the present review provides a timely and updated overview of these IFDs, with a focus on the taxonomy, clinical epidemiology, pathogenesis and host immune response, disease manifestations, diagnosis, antifungal susceptibility, and treatment. An expansion of hosts at risk for these difficult-to-treat infections has emerged over the last two decades given the increased use of, and broader population treated with, immunomodulatory and targeted molecular agents as well as wider adoption of antifungal prophylaxis. Clinical presentations differ not only between genera but also across the different Scedosporium species. L. prolificans is intrinsically resistant to most currently available antifungal agents, and the prognosis of immunocompromised patients with lomentosporiosis is poor. Development of, and improved access to, diagnostic modalities for early detection of these rare mold infections is paramount for timely targeted antifungal therapy and surgery if indicated. New antifungal agents (e.g., olorofim, fosmanogepix) with novel mechanisms of action and less cross-resistance to existing classes, availability of formulations for oral administration, and fewer drug-drug interactions are now in late-stage clinical trials, and soon, could extend options to treat scedosporiosis/lomentosporiosis. Much work remains to increase our understanding of these infections, especially in the pediatric setting. Knowledge gaps for future research are highlighted in the review.

Myocarditis and brain abscess caused by disseminated Scedosporium boydii infection

Scedosporium spp. is a fungal species documented as the cause of infections involving the lungs, brain, and other organ systems in both immunocompetent and immunocompromised individuals. Many cases of this type of fungal infection occurring in immunocompetent patients are subsequent to traumatic injury or drowning events in or near waters containing the fungi. Infection commonly involves the lungs. Rarely, it has been shown to cause disease in the endocardium, but there is even less documentation of the fungi invading the myocardium and causing myocarditis. In this report, we present a case of disseminated Scedosporium boydii infection in a 52-year-old male patient without any known risk factors. He presented with acute onset chest pain and dyspnea accompanied by bilateral lower extremity edema. He was found to have new onset heart failure with reduced ejection fraction, and his hospital course was complicated by pneumonia, disseminated intravascular coagulation (DIC), and brain abscess formation. Multiple blood cultures failed to reveal the source of the infection. At autopsy, septated branching hyphae were identified invading both the myocardium and the cortical brain tissue. DNA sequencing revealed the fungal organisms to be Scedosporium boydii. This case reinforces the importance of autopsies in the clinical setting. It not only established the definitive diagnosis of an unexpected fungal infection, but it also helped to recognize new clinical and pathologic features of this particular fungal organism.

PCR diagnostic platforms for non-Aspergillus mold infections: ready for routine implementation in the clinic?

INTRODUCTION

While Aspergillus spp. remain the predominant cause of invasive mold infections, non-Aspergillus molds, such as the Mucorales or Fusarium spp., account for an increasing proportion of cases. The diagnosis of non-Aspergillus invasive mold infections (NAIMI) is challenging because of the low sensitivity and delay of conventional microbiological tests. Therefore, there is a particular interest to develop molecular tools for their early detection in blood or other clinical samples.

AREAS COVERED

This extensive review of the literature discusses the performance of Mucorales-specific PCR and other genus-specific or broad-range fungal PCR that can be used for the diagnosis of NAIMI in diverse clinical samples, with a focus on novel technologies.

EXPERT OPINION

PCR currently represents the most promising approach, combining good sensitivity/specificity and ability to detect NAIMI in clinical samples before diagnosis by conventional cultures and histopathology. Several PCR assays have been designed for the detection of Mucorales in particular, but also Fusarium spp. or Scedosporium/Lomentospora spp. Some commercial Mucorales PCRs are now available. While efforts are still needed for standardized protocols and the development of more rapid and simpler techniques, PCR is on the way to becoming an essential test for the early diagnosis of mucormycosis and possibly other NAIMIs.

Pulmonary scedosporiosis caused by Lomentospora prolificans in a patient who is immunocompetent: A rare case report

Infections with Scedosporium and Lomentospora species are usually found in patients who are immunodeficient, particularly in the transplant population. However, they are relatively rare in patients who are immunocompetent, which is especially useful in ruling out near-drowning and aspiration situations. Here, we report a case of a patient who is immunocompetent, with clinically suspected community-acquired pneumonia caused by Lomentospora prolificans detected by metagenomics next-generation sequencing (mNGS) and polymerase chain reaction from bronchoalveolar lavage fluid. This case highlights mNGS in the clinical diagnosis of pulmonary invasive fungal disease. mNGS is proposed as an important adjunctive diagnostic approach for rare pathogens.

Non-Aspergillus Hyaline Molds: A Host-Based Perspective of Emerging Pathogenic Fungi Causing Sinopulmonary Diseases

The incidence of invasive sino-pulmonary diseases due to non-Aspergillus hyaline molds is increasing due to an enlarging and evolving population of immunosuppressed hosts as well as improvements in the capabilities of molecular-based diagnostics. Herein, we review the following opportunistic pathogens known to cause sinopulmonary disease, the most common manifestation of hyalohyphomycosis: Fusarium spp., Scedosporium spp., Lomentospora prolificans, Scopulariopsis spp., Trichoderma spp., Acremonium spp., Paecilomyces variotii, Purpureocillium lilacinum, Rasamsonia argillacea species complex, Arthrographis kalrae, and Penicillium species. To facilitate an understanding of the epidemiology and clinical features of sino-pulmonary hyalohyphomycoses in the context of host immune impairment, we utilized a host-based approach encompassing the following underlying conditions: neutropenia, hematologic malignancy, hematopoietic and solid organ transplantation, chronic granulomatous disease, acquired immunodeficiency syndrome, cystic fibrosis, and healthy individuals who sustain burns, trauma, or iatrogenic exposures. We further summarize the pre-clinical and clinical data informing antifungal management for each pathogen and consider the role of adjunctive surgery and/or immunomodulatory treatments to optimize patient outcome.

Lomentospora prolificans: An Emerging Opportunistic Fungal Pathogen

Lomentospora prolificans is an emerging opportunistic pathogen that primarily affects immunocompromised individuals leading to disseminated disease with high mortality rates while also causing infections in healthy populations. Successful recovery from infection is difficult due to high rates of intrinsic resistance to antifungals. Rapid and readily available diagnostic methods, aggressive surgical debridement wherever appropriate, and effective and timely antifungal treatment are the pillars for successful management. Future research will need to clarify the environmental niche of the fungus, further investigate the pathophysiology of infection and define species-specific therapeutic targets.

Consensus guidelines for the diagnosis and management of invasive fungal disease due to moulds other than Aspergillus in the haematology/oncology setting, 2021

Invasive fungal disease (IFD) due to moulds other than Aspergillus is a significant cause of mortality in patients with malignancies or post haemopoietic stem cell transplantation. The current guidelines focus on the diagnosis and management of the common non-Aspergillus moulds (NAM), such as Mucorales, Scedosporium species (spp.), Lomentospora prolificans and Fusarium spp. Rare but emerging NAM including Paecilomyces variotii, Purpureocillium lilacinum and Scopulariopsis spp. are also reviewed. Culture and histological examination of tissue biopsy specimens remain the mainstay of diagnosis, but molecular methods are increasingly being used. As NAM frequently disseminate, blood cultures and skin examination with biopsy of any suspicious lesions are critically important. Treatment requires a multidisciplinary approach with surgical debridement as a central component. Other management strategies include control of the underlying disease/predisposing factors, augmentation of the host response and the reduction of immunosuppression. Carefully selected antifungal therapy, guided by susceptibility testing, is critical to cure. We also outline novel antifungal agents still in clinical trial which offer substantial potential for improved outcomes in the future. Paediatric recommendations follow those of adults. Ongoing epidemiological research, improvement in diagnostics and the development of new antifungal agents will continue to improve the poor outcomes that have been traditionally associated with IFD due to NAM.

Relationship between Soil Fungi and Seedling Density in the Vicinity of Adult Conspecifics in an Arid Desert Forest

Research Highlights: 1. Soil fungi have a higher influence on seedling density compared to soil environmental factors; 2. Host-specific pathogens and beneficial fungi affect seeding density via different influencing mechanisms. Background and Objectives: The growth and development of seedlings are the key processes that affect forest regeneration and maintain community dynamics. However, the influencing factors of seedling growth around their adult conspecifics are not clear in arid desert forests. Probing the intrinsic relations among soil fungi, soil environmental factors (pH, water content, salinity, and nutrition), and seedling density will improve our understanding of forest development and provide a theoretical basis for forest management and protection. Materials and Methods: Four experimental plot types, depending on the distance to adult conspecifics, were set in an arid desert forest. Soil environmental factors, the diversity and composition of the soil fungal community, and the seedlings’ density and height were measured in the four experimental plot types, and their mutual relations were analyzed. Results: Seedling density as well as the diversity and composition of the soil fungal community varied significantly among the four plot types (p < 0.05). Soil environmental factors, especially soil salinity, pH, and soil water content, had significant influences on the seedling density and diversity and composition of the soil fungal community. The contribution of soil fungi (72.61%) to the variation in seedling density was much higher than the soil environmental factors (27.39%). The contribution of detrimental fungi to the variation in seedling density was higher than the beneficial fungi. Conclusions: Soil fungi mostly affected the distribution of seedling density in the vicinity of adult conspecifics in an arid desert forest. The distribution of seedling density in the vicinity of adults was mainly influenced by the detrimental fungi, while the adults in the periphery area was mainly influenced by the beneficial fungi.

Scedosporium and Lomentospora Infections: Contemporary Microbiological Tools for the Diagnosis of Invasive Disease

Scedosporium/Lomentospora fungi are increasingly recognized pathogens. As these fungi are resistant to many antifungal agents, early diagnosis is essential for initiating targeted drug therapy. Here, we review the microbiological tools for the detection and diagnosis of invasive scedosporiosis and lomentosporiosis. Of over 10 species, Lomentospora prolificans, Scedosporium apiospermum, S. boydii and S. aurantiacum cause the majority of infections. Definitive diagnosis relies on one or more of visualization, isolation or detection of the fungus from clinical specimens by microscopy techniques, culture and molecular methods such as panfungal PCR or genus-/species-specific multiplex PCR. For isolation from respiratory tract specimens, selective media have shown improved isolation rates. Species identification is achieved by macroscopic and microscopic examination of colonies, but species should be confirmed by ITS with or without β-tubulin gene sequencing or other molecular methods. Matrix-assisted laser desorption ionization-time of flight mass spectrometry databases are improving but may need supplementation by in-house spectra for species identification. Reference broth microdilution methods is preferred for antifungal susceptibility testing. Next-generation sequencing technologies have good potential for characterization of these pathogens. Diagnosis of Scedosporium/Lomentospora infections relies on multiple approaches encompassing both phenotypic- and molecular-based methods.

Comparative transcriptome analysis unveils the adaptative mechanisms of Scedosporium apiospermum to the microenvironment encountered in the lungs of patients with cystic fibrosis

Scedosporium species rank second among the filamentous fungi colonizing the lungs of patients with cystic fibrosis (CF). Apart from the context of immunodeficiency (lung transplantation), the colonization of the CF airways by these fungi usually remains asymptomatic. Why the colonization of the lower airways by Scedosporium species is fairly tolerated by CF patients while these fungi are able to induce a marked inflammatory reaction in other clinical contexts remains questionable. In this regards, we were interested here in exploring the transcriptional reprogramming that accompanies the adaptation of these fungi to the particular microenvironment encountered in the airways of CF patients. Cultivation of Scedosporium apiospermum in conditions mimicking the microenvironment in the CF lungs was shown to induce marked transcriptional changes. This includes notably the down-regulation of enzymes involved in the synthesis of some major components of the plasma membrane which may reflect the ability of the fungus to evade the host immune response by lowering the biosynthesis of some major antigenic determinants or inhibiting their targeting to the cell surface through alterations of the membrane fluidity. In addition, this analysis revealed that some genes encoding enzymes involved in the biosynthesis of some mycotoxins were down-regulated suggesting that, during the colonization process, S. apiospermum reduces the production of some toxic secondary metabolites to prevent exacerbation of the immune system response. Finally, a strong up-regulation of many genes encoding enzymes involved in the degradation of aromatic compounds was observed, suggesting that these catabolic properties would predispose the fungus to particular patterns of human pathogenicity. Together these data provide new insights into the adaptative mechanisms developed by S. apiospermum in the CF lungs, which should be considered for identification of potential targets for drug development, but also for the experimental conditions to be used in in vitro susceptibility testing of clinical isolates to current antifungals.

Multi-Omics Approaches: The Key to Improving Respiratory Health in People With Cystic Fibrosis?

The advent of high-throughput multi-omics technologies has underpinned the expansion in lung microbiome research, increasing our understanding of the nature, complexity and significance of the polymicrobial communities harbored by people with CF (PWCF). Having established that structurally complex microbial communities exist within the airways, the focus of recent research has now widened to investigating the function and dynamics of the resident microbiota during disease as well as in health. With further refinement, multi-omics approaches present the opportunity to untangle the complex interplay between microbe-microbe and microbe-host interactions in the lung and the relationship with respiratory disease progression, offering invaluable opportunities to discover new therapeutic approaches for our management of airway infection in CF.

Detection of the 'Big Five' mold killers of humans: Aspergillus, Fusarium, Lomentospora, Scedosporium and Mucormycetes

Fungi are an important but frequently overlooked cause of morbidity and mortality in humans. Life-threatening fungal infections mainly occur in immunocompromised patients, and are typically caused by environmental opportunists that take advantage of a weakened immune system. The filamentous fungus Aspergillus fumigatus is the most important and well-documented mold pathogen of humans, causing a number of complex respiratory diseases, including invasive pulmonary aspergillosis, an often fatal disease in patients with acute leukemia or in immunosuppressed bone marrow or solid organ transplant recipients. However, non-Aspergillus molds are increasingly reported as agents of disseminated diseases, with Fusarium, Scedosporium, Lomentospora and mucormycete species now firmly established as pathogens of immunosuppressed and immunocompetent individuals. Despite well-documented risk factors for invasive fungal diseases, and increased awareness of the risk factors for life-threatening infections, the number of deaths attributable to molds is likely to be severely underestimated driven, to a large extent, by the lack of readily accessible, cheap, and accurate tests that allow detection and differentiation of infecting species. Early diagnosis is critical to patient survival but, unlike Aspergillus diseases, where a number of CE-marked or FDA-approved biomarker tests are now available for clinical diagnosis, similar tests for fusariosis, scedosporiosis and mucormycosis remain experimental, with detection reliant on insensitive and slow culture of pathogens from invasive bronchoalveolar lavage fluid, tissue biopsy, or from blood. This review examines the ecology, epidemiology, and contemporary methods of detection of these mold pathogens, and the obstacles to diagnostic test development and translation of novel biomarkers to the clinical setting.

Scedosporium and Lomentospora: an updated overview of underrated opportunists

Species of Scedosporium and Lomentospora are considered as emerging opportunists, affecting immunosuppressed and otherwise debilitated patients, although classically they are known from causing trauma-associated infections in healthy individuals. Clinical manifestations range from local infection to pulmonary colonization and severe invasive disease, in which mortality rates may be over 80%. These unacceptably high rates are due to the clinical status of patients, diagnostic difficulties, and to intrinsic antifungal resistance of these fungi. In consequence, several consortia have been founded to increase research efforts on these orphan fungi. The current review presents recent findings and summarizes the most relevant points, including the Scedosporium/Lomentospora taxonomy, environmental distribution, epidemiology, pathology, virulence factors, immunology, diagnostic methods, and therapeutic strategies.

Direct detection of Exophiala and Scedosporium species in sputa of patients with cystic fibrosis

Detection of species of Exophiala and Scedosporium in the respiratory tracts of cystic fibrosis (CF) patients remains controversial because of highly variable results. The results of our study suggested a significantly higher prevalence and more complex colonization than previously estimated. Approximately 17% (27/162) of clinical sputum samples were found to be positive for Exophiala dermatitidis and 30% (49/162) were positive for Scedosporium apiospermum / S. boydii species complex determined by reverse line blot (RLB) hybridization. In contrast, only 14.2% (23/162) and 1.2% (2/162) of clinical sputa were positive for E. dermatitidis and S. apiospermum / S. boydii species complex when tested by culture, respectively. Molecular detection methods, such as loop-mediated isothermal amplification (LAMP) or reverse line blot (RLB) hybridization, have the potential to become powerful alternatives to selective culture, providing a more realistic understanding on the prevalence of E. dermatitidis and S. apiospermum / S. boydii species complex in the respiratory tract of CF patients.

Challenges in Laboratory Detection of Fungal Pathogens in the Airways of Cystic Fibrosis Patients

Study of the clinical significance of fungal colonization/infection in the airways of cystic fibrosis (CF) patients, especially by filamentous fungi, is challenged by the absence of standardized methodology for the detection and identification of an ever-broadening range of fungal pathogens. Culture-based methods remain the cornerstone diagnostic approaches, but current methods used in many clinical laboratories are insensitive and unstandardized, rendering comparative studies unfeasible. Guidelines for standardized processing of respiratory specimens and for their culture are urgently needed and should include recommendations for specific processing procedures, inoculum density, culture media, incubation temperature and duration of culture. Molecular techniques to detect fungi directly from clinical specimens include panfungal PCR assays, multiplex or pathogen-directed assays, real-time PCR, isothermal methods and probe-based assays. In general, these are used to complement culture. Fungal identification by DNA sequencing methods is often required to identify cultured isolates, but matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is increasingly used as an alternative to DNA sequencing. Genotyping of isolates is undertaken to investigate relatedness between isolates, to pinpoint the infection source and to study the population structure. Methods range from PCR fingerprinting and amplified fragment length polymorphism analysis, to short tandem repeat typing, multilocus sequencing typing (MLST) and whole genome sequencing (WGS). MLST is the current preferred method, whilst WGS offers best case resolution but currently is understudied.

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.

Systemic Scedosporium prolificans infection in an 11-month-old Border collie with cobalamin deficiency secondary to selective cobalamin malabsorption (canine Imerslund-Gräsbeck syndrome)

An 11-month-old Border collie presented collapsed and continued to deteriorate rapidly despite supportive treatment. The dog had a history of failure to thrive and recurring respiratory infection. Laboratory abnormalities included neutrophilic leucocytosis, Heinz body anaemia, hyperammonaemia, hyperbilirubinaemia, proteinuria and hypocobalaminaemia. Post-mortem examination revealed multi-focal necrosis within the heart, kidneys, pancreas, liver, meninges and cerebral cortex. Fungal hyphae in lesions were identified as Scedosporium prolificans following culture. Subsequent genotyping confirmed that the dog carried the CUBN:c.8392delC mutation in a homozygous state, verifying hereditary cobalamin deficiency (a.k.a. Imerslund-Gräsbeck syndrome). Cobalamin deficiency may have been a predisposing factor for the development of systemic fungal infection in this dog.

Rapid development of a mycotic aneurysm of the intracranial artery secondary to Scedosporium apiospermum sinusitis

An 85-year-old man complained of a 2-month history of pain on the left side of his face. Brain computed tomography (CT) and magnetic resonance imaging/magnetic resonance angiography did not clearly show any intracranial abnormality and only showed fluid effusion in his left sphenoid sinus. Filamentous fungi were detected from the left sphenoid sinus specimen. The isolate was Scedosporium apiospermum. He was empirically treated with voriconazole, to which the isolate was susceptible. His consciousness decreased rapidly. Urgent 3D-CT angiography revealed an intracranial aneurysm near the left sphenoid sinus. Despite urgent coil embolization, the aneurysm ruptured, and he died.

Emerging infections caused by non-Aspergillus filamentous fungi

There are three broad groups of non-Aspergillus moulds: the mucormycetes, the hyalohyphomycetes and the phaeohyphomycetes. Infections with these pathogens are increasingly reported, particularly in the context of increasing use of immunosuppressant agents and improved diagnostics. The epidemiology of non-Aspergillus mould infections varies with geography, climate and level of immunosuppression. Skin and soft-tissue infections are the predominant presentation in the immunocompetent host and pulmonary and other invasive infections in the immunocompromised host. The more common non-Aspergillus moulds include Rhizopus, Mucor, Fusarium and Scedosporium species; however, other emerging pathogens are Rasamsonia and Verruconis species, which are discussed in this article. Outbreaks of non-Aspergillus mould infections have been increasingly reported, with contaminated medical supplies and natural disasters as common sources. Currently culture and other conventional diagnostic methods are the cornerstone of diagnosis. Molecular methods to directly detect and identify mould pathogens in tissue and body fluids are increasingly used.

Towards proteomic species barcoding of fungi - An example using Scedosporium/Pseudallescheria complex isolates

MALDI-ToF mass spectrometry offers fast and reliable species identification for bacteria and yeasts under clinical routine conditions. Here, we produced mass spectra for identification of clinically important species of the Pseudallescheria/Scedosporium complex using the recently suggested new nomenclature and use this example to discuss to what extent the principle of DNA barcoding might be transferred to mass spectrometry.

ESCMID and ECMM joint guidelines on diagnosis and management of hyalohyphomycosis: Fusarium spp., Scedosporium spp. and others

Mycoses summarized in the hyalohyphomycosis group are heterogeneous, defined by the presence of hyaline (non-dematiaceous) hyphae. The number of organisms implicated in hyalohyphomycosis is increasing and the most clinically important species belong to the genera Fusarium, Scedosporium, Acremonium, Scopulariopsis, Purpureocillium and Paecilomyces. Severely immunocompromised patients are particularly vulnerable to infection, and clinical manifestations range from colonization to chronic localized lesions to acute invasive and/or disseminated diseases. Diagnosis usually requires isolation and identification of the infecting pathogen. A poor prognosis is associated with fusariosis and early therapy of localized disease is important to prevent progression to a more aggressive or disseminated infection. Therapy should include voriconazole and surgical debridement where possible or posaconazole as salvage treatment. Voriconazole represents the first-line treatment of infections due to members of the genus Scedosporium. For Acremonium spp., Scopulariopsis spp., Purpureocillium spp. and Paecilomyces spp. the optimal antifungal treatment has not been established. Management usually consists of surgery and antifungal treatment, depending on the clinical presentation.

Purification and characterization of a mycelial catalase from Scedosporium boydii, a useful tool for specific antibody detection in patients with cystic fibrosis

Scedosporium boydii is an opportunistic filamentous fungus which may be responsible for a wide variety of infections in immunocompetent and immunocompromised individuals. This fungus belongs to the Scedosporium apiospermum species complex, which usually ranks second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF) and may lead to allergic bronchopulmonary mycoses, sensitization, or respiratory infections. Upon microbial infection, host phagocytic cells release reactive oxygen species (ROS), such as hydrogen peroxide, as part of the antimicrobial response. Catalases are known to protect pathogens against ROS by detoxification of the hydrogen peroxide. Here, we investigated the catalase equipment of Scedosporium boydii, one of the major pathogenic species in the S. apiospermum species complex. Three catalases were identified, and the mycelial catalase A1 was purified to homogeneity by a three-step chromatographic process. This enzyme is a monofunctional tetrameric protein of 460 kDa, consisting of four 82-kDa glycosylated subunits. The potential usefulness of this enzyme in serodiagnosis of S. apiospermum infections was then investigated by an enzyme-linked immunosorbent assay (ELISA), using 64 serum samples from CF patients. Whatever the species involved in the S. apiospermum complex, sera from infected patients were clearly differentiated from sera from patients with an Aspergillus fumigatus infection or those from CF patients without clinical and biological signs of a fungal infection and without any fungus recovered from sputum samples. These results suggest that catalase A1 is a good candidate for the development of an immunoassay for serodiagnosis of infections caused by the S. apiospermum complex in patients with CF.

Classical pathology of sympathetic ophthalmia presented in a unique case

The ocular pathology of sympathetic ophthalmia is demonstrated in a 10 year-old boy who sustained a penetrating left globe injury and subsequently developed sympathetic ophthalmia in the right eye two months later. Two and a half weeks following extensive surgical repair of the left ruptured globe, he developed endophthalmitis and was treated with oral and topical fortified antibiotics. One month after the initial injury, a progressive corneal ulcer of the left eye led to perforation and the need for emergent corneal transplantation. The surgical specimen revealed fungus, Scedosporium dehoogii. The boy received systemic and topical anti-fungal therapy. Two months following the penetrating globe injury of the left eye, a granulomatous uveitis developed in the right eye. Sympathetic ophthalmia was suspected and the patient began treatment with topical and oral corticosteroids. Given the concern of vision loss secondary to sympathetic ophthalmia in the right eye, as well as poor vision and hypotony in the injured eye, the left eye was enucleated. Microscopically, granulomatous inflammation with giant cells was noted within a cyclitic membrane which filled the anterior and posterior chamber of the left globe. Other classic features including Dalen-Fuchs nodules were identified. Small, choroidal, ill-defined granulomas and relative sparing of the choriocapillaris were present. Molecular analysis did not identify evidence of remaining fungal infection. The pathology findings were consistent with previously described features of sympathetic ophthalmia. The present case is unique in that co-existing fungal infection may have potentiated the risk for developing sympathetic ophthalmia in the fellow eye.

Fungal infections and treatment in cystic fibrosis

PURPOSE OF REVIEW

This review summarizes some of the important recent findings concerning fungal airway infections in patients with cystic fibrosis (CF). For many years, both researchers and clinicians have focused on the problems in CF caused by chronic bacterial airway infection with organisms such as Haemophilus, Staphylococcus and Pseudomonas. However, until recently, the lack of sensitive culture techniques to isolate fungi in sputum, bronchoalveolar lavage fluid and other respiratory tract samples has limited the recognition of fungal species and their possible role in CF airway infections.

RECENT FINDINGS

Recent studies using fungal-selective culture media and molecular techniques have shown a plethora of different fungal species in the sputum expectorated from CF patients. Cross-sectional studies have shown associations between Aspergillus and Candida in the sputum and worse lung function. The presence of allergic bronchopulmonary aspergillosis is likely to be a negative prognostic factor, but whether simple fungal colonization itself indicates future problems is not clear. Current research is now examining these epidemiological associations to try to determine the clinical implications. This will help determine whether fungal colonization/infection is associated with worse outcome in CF patients.

SUMMARY

At present, there is no conclusive evidence that fungal organisms cause respiratory decline. Recent studies of antifungal therapy in CF patients have reported differing results, so further investigations in this area are needed.

Impact of multidrug-resistant organisms on patients considered for lung transplantation

Infections with multidrug-resistant organisms are a growing problem in lung transplant recipients. Carriage of drug-resistant bacteria and fungi before transplantation is an important risk factor for such infections. In that regard Pseudomonas aeruginosa and species of Burkholderia, Acinetobacter, non-tuberculous mycobacteria and Scedosporium are particularly important. An understanding of the impact of these organisms is essential to the evaluation of lung transplant candidates. The microbiology, epidemiology, clinical manifestations, and approach to these pathogens before transplant are reviewed in this article.

Detection, identification, and distribution of fungi in bronchoalveolar lavage specimens by use of multilocus PCR coupled with electrospray ionization/mass spectrometry

As pulmonary fungal infections continue to increase due to an increasing number of immunocompromised patients, rapid detection and accurate identification of these fungal pathogens are critical. A broad fungal assay was developed by incorporating broad-range multilocus PCR amplification and electrospray ionization/mass spectrometry (PCR/ESI-MS) to detect and identify fungal organisms directly from clinical specimens. The aims of this study were to evaluate the performance of PCR/ESI-MS for detection, identification, and determination of the distribution of fungal organisms in bronchoalveolar lavage (BAL) fluid specimens. The BAL fluid specimens submitted for fungal culture at Vanderbilt University Medical Center between May 2005 and October 2011 were included. Cultures and identification were done using standard procedures. In addition, DNA was extracted from BAL fluid specimens, and fungal DNA amplification/identification were performed by PCR/ESI-MS. The results were compared with those of the standard cultures. A total of 691 nonduplicated BAL fluid specimens with sufficient leftover volume for molecular testing were evaluated using PCR/ESI-MS. Among them, 134 specimens (19.4%) were positive for fungi by both culture and PCR/ESI-MS testing. Of the dual-positive specimens, 125 (93.3%) were positive for Candida and Aspergillus species, with concordances between culture and PCR/ESI-MS results being 84 (67.2%) at the species level and 109 (87.2%) at the genus level. In addition, 243 (35.2%) and 30 (4.3%) specimens were positive only by PCR/ESI-MS or by culture, respectively (odds ratio [OR] = 11.95, 95% confidence interval [CI] = 7.90 to 18.17, P = 0.0000). Codetection of fungal organisms was noted in 23 (3.3%) specimens by PCR/ESI-MS, which was significantly higher than the 4 (0.6%) in which they were noted by culture (OR = 5.91, 95% CI = 1.93 to 20.27, P = 0.0002). Among 53 specimens in which cultures failed because of bacterial overgrowth, at least one fungus was identified in 26 specimens (47.3%) by PCR/ESI-MS. PCR/ESI-MS provides an advanced tool for rapid and sensitive detection, identification, and determination of the distribution of fungal organisms directly from BAL fluid specimens. Moreover, it detected fungal organisms in specimens in which cultures failed because of bacterial overgrowth. The clinical relevance of the significantly higher detection rate of fungal organisms by PCR/ESI-MS merits further investigation.