Opportunistic Mold Research Articles

Triazole resistance surveillance in Aspergillus fumigatus.

Triazole resistance is an increasing concern in the opportunistic mold Aspergillus fumigatus. Resistance can develop through exposure to azole compounds during azole therapy or in the environment. Resistance mutations are commonly found in the Cyp51A-gene, although other known and unknown resistance mechanisms may be present. Surveillance studies show triazole resistance in six continents, although the presence of resistance remains unknown in many countries. In most countries, resistance mutations associated with the environment dominate, but it remains unclear if these resistance traits predominately migrate or arise locally. Patients with triazole-resistant aspergillus disease may fail to antifungal therapy, but only a limited number of cohort studies have been performed that show conflicting results. Treatment failure might be due to diagnostic delay or due to the limited number of alternative treatment options. The ISHAM/ECMM Aspergillus Resistance Surveillance working group was set up to facilitate surveillance studies and stimulate international collaborations. Important aims are to determine the resistance epidemiology in countries where this information is currently lacking, to gain more insight in the clinical implications of triazole resistance through a registry and to unify nomenclature through consensus definitions.

Important Infections Due To Molds

Mold-based fungal infections have become increasingly important over several decades, paradoxically because advances in medical practice have allowed patients with chronic medical conditions to live longer and have lives that are more productive. Allergic bronchopulmonary aspergillosis can affect those individuals with an atopic predisposition. Use of direct antimold antifungal agents can decrease the number of steroid treatment courses and monoclonal antibody therapy used in these patients. Pulmonary invasive aspergillosis remains the most important opportunistic mold infection among immunocompromised patients. Surrogate markers of diagnosis can include β-d-glucan or Aspergillus galactomannan antigen testing, although the specificity of both tests is not robust. There are three general classes of antifungal agents in use, with less nephrotoxic options. With safer therapeutic options, empirical treatment occurs with tremendous frequency among otherwise immunosuppressed individuals. Thus, clinicians will need to maintain a high suspicion for mold infections that can be resistant to a previously used antifungal therapy. Attention to liver function testing during long-term use of these advanced-generation azole antifungal agents, and at times therapeutic drug monitoring with blood levels, will be needed. The echinocandin class of antifungal agents does not have hepatic or renal toxicity in general, but these agents need to be administered via an intravenous route. With routine use of agents that have activity against aspergillosis, fusariosis, mucormycosis, or other mold infections become evident for a minority of at-risk patients. This review contains 5 figures, 3 tables and 90 references Key words: allergic bronchopulmonary aspergillosis, dematiaceous fungi, Exserohilum, fusariosis, invasive aspergillosis, mucormycosis, Scedosporium

Correction: IL-33 Signaling Regulates Innate IL-17A and IL-22 Production via Suppression of Prostaglandin E2 during Lung Fungal Infection.

Members of the IL-1 family play protective and regulatory roles in immune defense against the opportunistic mold Aspergillus fumigatus In this study, we investigated the IL-1 family member IL-33 in lung defense against A. fumigatus IL-33 was detected in the naive lung, which further increased after exposure to A. fumigatus in a dectin-1-independent manner. Mice deficient in the receptor for IL-33 (Il1rl1-/-) unexpectedly demonstrated enhanced lung clearance of A. fumigatus IL-33 functioned as a negative regulator of multiple inflammatory cytokines, as IL-1α, IL-1β, IL-6, IL-17A, and IL-22 were significantly elevated in fungal-exposed Il1rl1-/- mice. Subsequently, IL-33 administration to normal mice attenuated fungal-induced IL-17A and IL-22, but not IL-1α, IL-1β, or IL-6, production. IL-33-mediated regulation of IL-17A and IL-22 did not involve the modulation of IL-23 but rather PGE2; PGE2 was significantly increased in fungal-exposed Il1rl1-/- mice, and normal mice produced less PGE2 after fungal exposure when administered IL-33, suggesting that IL-33-mediated regulation of IL-17A and IL-22 occurred at the level of PGE2 This was confirmed by in vivo cyclooxygenase 2 inhibition, which attenuated fungal-induced IL-17A and IL-22, as well as IL-1α, IL-1β, and IL-6, production in Il1rl1-/- mice, resulting in impaired fungal clearance. We also show that a PGE2 receptor agonist increased, whereas a PGE2 synthase inhibitor decreased, the levels of IL-17A and IL-22 but not IL-1α, IL-1β, or IL-6. This study establishes novel mechanisms of innate IL-17A/IL-22 production via PGE2 and regulation of the PGE2/IL-17A/IL-22 axis via IL-33 signaling during lung fungal exposure.

The fungal meningitis outbreak five years later: what have we learned about Exserohilum rostratum?

ABSTRACTIntroduction: On 18 September 2012, United States health officials began to react to a large outbreak of fungal meningitis traceable to methylprednisolone from a compounding pharmacy in Framingham, Massachusetts. Although the index case was attributed to the opportunistic mold Aspergillus fumigatus, all subsequent cases were due to the dematiaceous mold Exserohilum rostratum, which had previously been an uncommon cause of disease in humans.Areas covered: In this paper, the authors examine recent advances in the diagnosis and treatment of Exserohilum infection and provide updates on how the innate and acquire immune responses enable clearance of human fungal pathogens.Expert commentary: The fungal meningitis outbreak of 2012 stretched across 20 states and resulted in 753 cases of central nervous system infection and 64 deaths. In this paper, the authors examine how the outbreak prompted investigators to develop novel diagnostic and therapeutic options that have advanced the study of human fungal pathogens and will benefit patients who are susceptible to invasive mycoses.

IL-33 Signaling Regulates Innate IL-17A and IL-22 Production via Suppression of Prostaglandin E2 during Lung Fungal Infection

Members of the IL-1 family play protective and regulatory roles in immune defense against the opportunistic mold Aspergillus fumigatus In this study, we investigated the IL-1 family member IL-33 in lung defense against A. fumigatus IL-33 was detected in the naive lung, which further increased after exposure to A. fumigatus in a dectin-1-independent manner. Mice deficient in the receptor for IL-33 (Il1rl1-/-) unexpectedly demonstrated enhanced lung clearance of A. fumigatus IL-33 functioned as a negative regulator of multiple inflammatory cytokines, as IL-1α, IL-1β, IL-6, IL-17A, and IL-22 were significantly elevated in fungal-exposed Il1rl1-/- mice. Subsequently, IL-33 administration to normal mice attenuated fungal-induced IL-17A and IL-22, but not IL-1α, IL-1β, or IL-6, production. IL-33-mediated regulation of IL-17A and IL-22 did not involve the modulation of IL-23 but rather PGE2; PGE2 was significantly increased in fungal-exposed Il1rl1-/- mice, and normal mice produced less PGE2 after fungal exposure when administered IL-33, suggesting that IL-33-mediated regulation of IL-17A and IL-22 occurred at the level of PGE2 This was confirmed by in vivo cyclooxygenase 2 inhibition, which attenuated fungal-induced IL-17A and IL-22, as well as IL-1α, IL-1β, and IL-6, production in Il1rl1-/- mice, resulting in impaired fungal clearance. We also show that a PGE2 receptor agonist increased, whereas a PGE2 synthase inhibitor decreased, the levels of IL-17A and IL-22 but not IL-1α, IL-1β, or IL-6. This study establishes novel mechanisms of innate IL-17A/IL-22 production via PGE2 and regulation of the PGE2/IL-17A/IL-22 axis via IL-33 signaling during lung fungal exposure.

CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells

Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.

Structural modification of cuminaldehyde thiosemicarbazone increases inhibition specificity toward aflatoxin biosynthesis and sclerotia development in Aspergillus flavus.

Aspergillus flavus is an opportunistic mold that represents a serious threat for human and animal health due to its ability to synthesize and release, on food and feed commodities, different toxic secondary metabolites. Among them, aflatoxin B1 is one of the most dangerous since it is provided with a strong cancerogenic and mutagenic activity. Controlling fungal contamination on the different crops that may host A. flavus is considered a priority by sanitary authorities of an increasing number of countries due also to the fact that, owing to global temperature increase, the geographic areas that are expected to be prone to experience sudden A. flavus outbreaks are widening. Among the different pre- and post-harvest strategies that may be put forward in order to prevent fungal and/or mycotoxin contamination, fungicides are still considered a prominent weapon. We have here analyzed different structural modifications of a natural-derived compound (cuminaldehyde thiosemicarbazone) for their fungistatic and anti-aflatoxigenic activity. In particular, we have focused our attention on one of the compound that presented a prominent anti-aflatoxin specificity, and performed a set of physiological and molecular analyses, taking also advantage of yeast (Saccharomyces cerevisiae) cell as an experimental model.

IL-33 signaling regulates innate IL-22 production via suppression of PGE2 during lung fungal infection

Abstract Members of the IL-1 family play both protective and regulatory roles in immune defense against the opportunistic mold Aspergillus fumigatus. Here, we investigated the role of the IL-1 family member IL-33 in lung defense after acute A. fumigatus exposure. IL-33 was detected in nanogram amounts in the naïve lung, which further increased after exposure to A. fumigatus in a Dectin-1 independent manner. Mice deficient in the receptor for IL-33 (IL-1RL1) unexpectedly demonstrated enhanced innate lung clearance of A. fumigatus. IL-33 functioned as a negative regulator of IL-22, as IL-22 was elevated in fungal-exposed Il1rl1−/− mice and IL-33 administration to normal mice attenuated fungal-induced IL-22 production. IL-33 mediated regulation of IL-22 did not involve the modulation of IL-23 but rather prostaglandin E2 (PGE2); PGE2 was significantly increased in fungal-exposed Il1rl1−/− mice and normal mice produced less PGE2 after fungal exposure when administered IL-33, suggesting that IL-33 mediated regulation of IL-22 occurred at the level of PGE2. This was confirmed by in vivo cyclooxygenase 2 (COX-2) inhibition and specific inhibition of PGE2 in vitro, both of which attenuated fungal-induced IL-22 in Il1rl1−/− mice. This study establishes novel mechanisms of IL-22 induction via PGE2 and regulation of the PGE2-IL-22 axis via IL-33 signaling during lung fungal exposure.

Intercountry Transfer of Triazole-Resistant Aspergillus fumigatus on Plant Bulbs.

We investigated whether plants imported to Ireland from the Netherlands might harbor triazole-resistant Aspergillus fumigatus. Samples of plant bulbs were positive for triazole-resistant A. fumigatus with CYP51A mutations. We hypothesize that this represents a route for intercountry transfer of an emerging resistance mechanism in a major opportunistic mold pathogen.

Aspergillus Species and Their Associated Mycotoxins.

The genus Aspergillus is among the most abundant and widely distributed organism on earth, and at the moment comprises 339 known species. It is one of the most important economically fungal genus and the biotechnological use of Aspergillus species is related to production of soy sauce, of different hydrolytic enzymes (amylases, lipases) and organic acid (citric acid, gluconic acid), as well as biologically active metabolites such as lovastatin. Although they are not considered to be major cause of plant diseases, Aspergillus species are responsible for several disorders in various plants and plant products, especially as opportunistic storage moulds. The notable consequence of their presence is contamination of foods and feeds by mycotoxins, among which the most important are aflatoxins, ochratoxin A, and, at a less extent, fumonisins. Aflatoxins B1, B2, G1, G2 are the most toxic and carcinogenic mycotoxins, due to their extreme hepatocarcinogenicity; ochratoxin A is a potent nephrotoxin, it is also carcinogenic, teratogenic, and immunotoxic in rats and possibly in humans; fumonisins are hepatotoxic and nephrotoxic with potential carcinogenic effects on rat and mice. In this chapter we summarize the main aspects of morphology, ecology, epidemiology, and toxigenicity of Aspergillus foodborne pathogens which belong to sections Flavi, Circumdati, and Nigri, occurring in several agricultural products and responsible of aflatoxin, ochratoxin A, and fumonisins contamination of food and feed.

Aspergillus in chronic lung disease: Modeling what goes on in the airways.

Aspergillus species cause a range of respiratory diseases in humans. While immunocompromised patients are at risk for the development of invasive infection with these opportunistic molds, patients with underlying pulmonary disease can develop chronic airway infection with Aspergillus species. These conditions span a range of inflammatory and allergic diseases including Aspergillus bronchitis, allergic bronchopulmonary aspergillosis, and severe asthma with fungal sensitization. Animal models are invaluable tools for the study of the molecular mechanism underlying the colonization of airways by Aspergillus and the host response to these non-invasive infections. In this review we summarize the state-of-the-art with respect to the available animal models of noninvasive and allergic Aspergillus airway disease; the key findings of host-pathogen interaction studies using these models; and the limitations and future directions that should guide the development and use of models for the study of these important pulmonary conditions.

Azole Resistance in Moulds—Approach to Detection in a Clinical Laboratory

The multitude of factors has contributed to the increasing number of fungal infections caused by species of difficult-to-treat opportunistic moulds, such as Fusarium, Scedosporium, and cryptic Aspergilli. Also, rare fungi sporadically encountered, such as Rasamsonia argillacea, Penicillium oxalicum, and melanized fungi, are now well recognized. The high mortality associated with these rare and uncommon fungi is primarily linked to the difficulty in diagnosis and limited therapeutic options, as many of them exhibit resistance to antifungals including azoles. Azole resistance in Aspergillus fumigatus has been increasingly reported because standardized methods for susceptibility testing and associated clinical breakpoints and epidemiological cutoff values became available. However, such advances in antifungal susceptibility testing (AFST) in non-Aspergillus moulds barring mucorales have been lacking. Notwithstanding the fact that the true incidence of these non-Aspergillus filamentous moulds in clinical settings is hitherto unknown, also data on AFST by standardized methods is largely lacking. Determination of minimum inhibitory concentration (MIC) by reference techniques is the gold standard to detect azole resistance in filamentous fungi. In recent years, some progress has been made toward the description of resistance mechanisms at molecular level especially in Aspergillus. This paper reviews the present state of azole resistance in Aspergillus and other filamentous mould species and discusses their relevance to clinical practice.

Treatment of mucormycosis in transplant patients: role of surgery and of old and new antifungal agents.

Mucormycosis is an opportunistic mold infection whose management is difficult, as there is a paucity of evidence-based data. We summarize the latest advances in diagnosis and management of mucormycosis in transplant recipients. There is promise for improvement in nonculture-based diagnostics with new biomarkers of Mucorales DNA that can be used for early diagnosis, and monitoring of response. Antifungal treatment consists of high-dose lipid formulations of amphotericin B or isavuconazole as the first-line therapy and posaconazole as salvage therapy. The new, pharmacokinetically more reliable formulations of posaconazole (intravenous, extended-release tablets) are welcomed improvements. Yet, the role of combination therapy is still uncertain. Surgery had a significant role in selected cases, such as in patients with rhinosinusitis form of mucormycosis, which nowadays can be performed with minimal invasive technique. Mucormycosis remain a life-threatening opportunistic mold infection among transplant patients. Early diagnosis, prompt treatment with effective antifungals in combination with surgery if feasible is essential. Immune adjunct therapy and improvement of early diagnostics are important areas for future research. There are good prospects of progress in diagnostics and management of mucormycosis in transplant patients.

Hypoxia attenuates anti‐Aspergillus fumigatus immune responses initiated by human dendritic cells

Aspergillus fumigatus is an opportunistic mould that causes invasive pulmonary aspergillosis (IPA), a life-threatening infection in immunocompromised patients. During the course of IPA, localised areas of tissue hypoxia occur. Bacterial infection models revealed that hypoxic microenvironments modulate the function of host immune cells. However, the influence of hypoxia on anti-fungal immunity has been largely unknown. We evaluated the impact of hypoxia on the human anti-A.fumigatus immune response. Human monocyte-derived dendritic cells (DCs) were stimulated invitro with germ tubes of A.fumigatus under normoxia or hypoxia (1% O2 ), followed by analysis of DC viability, maturation and cytokine release. While DC viability was unaffected, hypoxia attenuated cytokine release from DCs and maturation of DCs upon stimulation with A.fumigatus. These data suggest that hypoxia at the site of A.fumigatus infection inhibits full activation and function of human DCs. Thereby, this study identified hypoxia as a crucial immune-modulating factor in the human anti-fungal immune response that might influence the course and outcome of IPA in immunocompromised patients.

Mycobiota in the brood cells of the European beewolf, Philanthus triangulum (Hymenoptera: Crabronidae)

Mass provisioning insects have to cope with microbial spoilage of their food supplies. As their fitness is directly linked to the availability of high quality food for their offspring, they have evolved various mechanisms for preserving these resources. The European beewolf, Philanthus triangulum, uses several mechanisms to not only preserve the food for their larvae, paralyzed workers of the European honeybee, Apis mellifera, but also protect the larvae that develop on the stored food. To assess the spectrum of fungi that pose a threat to beewolf brood cells, we manipulated brood cells by removing the insect defenses. We monitored the subsequent fungal infestations that would have been prevented by the beewolf defense mechanisms and isolated and identified the mold fungi. The cosmopolitan and highly competitive species of Aspergillus, in particular A. flavus, dominated the mold in beewolf brood cells. All other infestations could also be attributed to generalist mold fungi that are commonly found in soil and also on insects. Our findings indicate that beewolf brood cells can be colonized by a broad range of opportunistic soil mold fungi. Thus, it seems highly adaptive that beewolves employ general, broad spectrum defense mechanisms.

Aspergillus species in indoor environments and their possible occupational and public health hazards.

The genus Aspergillus, which consists of a few hundred opportunistic mold species found in various climatic conditions, causes diseases including localized infections, fatal diseases, allergic responses, and inhaled conidia in humans. Herein, we present an overview of the most common diseases and allergic infections caused by Aspergillus species and their associated health hazards in various indoor environments worldwide.

Systemic Acremonium species infection in a dog.

A 2-year-old female Magyar Viszla was referred with fever, lethargy, polyuria/polydipsia, and suspected systemic cryptococcosis. At presentation increased rectal temperature and enlarged lymph nodes were detected. Main laboratory abnormalities included lymphocytosis, eosinophilia, and mildly reduced urine specific gravity. Abdominal ultrasound was unremarkable. Lymph node cytology revealed mycotic infection. Acremonium species was isolated from urine as well as from a popliteal lymph node by fungal culture. Therapy with itraconazol (10mg/kg p.o. q12h) was initiated based on susceptibility testing, but dosage had to be reduced by half due to adverse effects. Despite treatment, the dog developed progressive azotemia. Four months after initial presentation, the patient showed anorexia, lethargy, weight loss, diarrhea, vomitus, neurological signs, and severe azotemia and was euthanized. Acremonium species are emerging opportunistic mould fungi that can represent a potential threat for immunocompromised humans. In dogs, only two cases of systemic infection with this fungal species have been reported so far. This case highlights the fact that systemic fungal infections should be considered as a differential in cases of fever and lymphadenopathy.

Polymerase chain reaction blood tests for the diagnosis of invasive aspergillosis in immunocompromised people.

Invasive aspergillosis (IA) is the most common life-threatening opportunistic invasive mould infection in immunocompromised people. Early diagnosis of IA and prompt administration of appropriate antifungal treatment are critical to the survival of people with IA. Antifungal drugs can be given as prophylaxis or empirical therapy, instigated on the basis of a diagnostic strategy (the pre-emptive approach) or for treating established disease. Consequently there is an urgent need for research into both new diagnostic tools and drug treatment strategies. Newer methods such as polymerase chain reaction (PCR) to detect fungal nucleic acids are increasingly being investigated. To provide an overall summary of the diagnostic accuracy of PCR-based tests on blood specimens for the diagnosis of IA in immunocompromised people. We searched MEDLINE (1946 to June 2015) and EMBASE (1980 to June 2015). We also searched LILACS, DARE, Health Technology Assessment, Web of Science and Scopus to June 2015. We checked the reference lists of all the studies identified by the above methods and contacted relevant authors and researchers in the field. We included studies that: i) compared the results of blood PCR tests with the reference standard published by the European Organisation for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG); ii) reported data on false-positive, true-positive, false-negative and true-negative results of the diagnostic tests under investigation separately; and iii) evaluated the test(s) prospectively in cohorts of people from a relevant clinical population, defined as a group of individuals at high risk for invasive aspergillosis. Case-control studies were excluded from the analysis. Authors independently assessed quality and extracted data. For PCR assays, we evaluated the requirement for either one or two consecutive samples to be positive for diagnostic accuracy. We investigated heterogeneity by subgroup analyses. We plotted estimates of sensitivity and specificity from each study in receiver operating characteristics (ROC) space and constructed forest plots for visual examination of variation in test accuracy. We performed meta-analyses using the bivariate model to produce summary estimates of sensitivity and specificity. Eighteen primary studies, corresponding to 19 cohorts and 22 data sets, published between 2000 and 2013 were included in the meta-analyses, with a median prevalence of IA (proven or probable) of 12.0% (range 2.5 to 30.8 %). The majority of people had received chemotherapy for a haematological malignancy or had undergone a hematopoietic stem cell transplant. Several PCR techniques were used among the included studies. The sensitivity and specificity of PCR for the diagnosis of IA varied according to the interpretative criteria used to define a test as positive. The mean sensitivity and specificity were 80.5% (95% CI; 73.0 to 86.3) and 78.5% (67.8 to 86.4) for a single positive test result, and 58.0% (36.5 to 76.8) and 96.2% (89.6 to 98.6) for two consecutive positive test results. PCR shows moderate diagnostic accuracy when used as screening tests for IA in high-risk patient groups. Importantly the sensitivity of the test confers a high negative predictive value (NPV) such that a negative test allows the diagnosis to be excluded. Consecutive positives show good specificity in diagnosis of IA and could be used to trigger radiological and other investigations or for pre-emptive therapy in the absence of specific radiological signs when the clinical suspicion of infection is high. When a single PCR positive test is used as diagnostic criterion for IA in a population of 100 people with a disease prevalence of 13.0% (overall mean prevalence), three people with IA would be missed (sensitivity 80.5%, 19.5% false negatives), and 19 people would be unnecessarily treated or referred for further tests (specificity of 78.5%, 21.5% false positives). If we use the two positive test requirement in a population with the same disease prevalence, it would mean that six IA people would be missed (sensitivity 58.0%, 42.1% false negatives) and three people would be unnecessarily treated or referred for further tests (specificity of 96.2%, 3.8% false positives). Galactomannan and PCR have good NPV for excluding disease but the low prevalence of disease limits the ability to rule in a diagnosis. The biomarkers are detecting different aspects of disease and the combination of both together is likely to be more useful.

Polymerase chain reaction blood tests for the diagnosis of invasive aspergillosis in immunocompromised people.

Invasive aspergillosis (IA) is the most common life-threatening opportunistic invasive mould infection in immunocompromised people. Early diagnosis of IA and prompt administration of appropriate antifungal treatment are critical to the survival of people with IA. Antifungal drugs can be given as prophylaxis or empirical therapy, instigated on the basis of a diagnostic strategy (the pre-emptive approach) or for treating established disease. Consequently there is an urgent need for research into both new diagnostic tools and drug treatment strategies. Newer methods such as polymerase chain reaction (PCR) to detect fungal nucleic acids are increasingly being investigated. To provide an overall summary of the diagnostic accuracy of PCR-based tests on blood specimens for the diagnosis of IA in immunocompromised people. We searched MEDLINE (1946 to June 2015) and EMBASE (1980 to June 2015). We also searched LILACS, DARE, Health Technology Assessment, Web of Science and Scopus to June 2015. We checked the reference lists of all the studies identified by the above methods and contacted relevant authors and researchers in the field. We included studies that: i) compared the results of blood PCR tests with the reference standard published by the European Organisation for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG); ii) reported data on false-positive, true-positive, false-negative and true-negative results of the diagnostic tests under investigation separately; and iii) evaluated the test(s) prospectively in cohorts of people from a relevant clinical population, defined as a group of individuals at high risk for invasive aspergillosis. Case-control studies were excluded from the analysis. Authors independently assessed quality and extracted data. For PCR assays, we evaluated the requirement for either one or two consecutive samples to be positive for diagnostic accuracy. We investigated heterogeneity by subgroup analyses. We plotted estimates of sensitivity and specificity from each study in receiver operating characteristics (ROC) space and constructed forest plots for visual examination of variation in test accuracy. We performed meta-analyses using the bivariate model to produce summary estimates of sensitivity and specificity. Eighteen primary studies, corresponding to 19 cohorts and 22 data sets, published between 2000 and 2013 were included in the meta-analyses, with a median prevalence of IA (proven or probable) of 12.0% (range 2.5 to 30.8 %). The majority of people had received chemotherapy for a haematological malignancy or had undergone a hematopoietic stem cell transplant. Several PCR techniques were used among the included studies. The sensitivity and specificity of PCR for the diagnosis of IA varied according to the interpretative criteria used to define a test as positive. The mean sensitivity and specificity were 80.5% (95% CI; 73.0 to 86.3) and 78.5% (67.8 to 86.4) for a single positive test result, and 58.0% (36.5 to 76.8) and 96.2% (89.6 to 98.6) for two consecutive positive test results. PCR shows moderate diagnostic accuracy when used as screening tests for IA in high-risk patient groups. Importantly the sensitivity of the test confers a high negative predictive value (NPV) such that a negative test allows the diagnosis to be excluded. Consecutive positives show good specificity in diagnosis of IA and could be used to trigger radiological and other investigations or for pre-emptive therapy in the absence of specific radiological signs when the clinical suspicion of infection is high. When a single PCR positive test is used as diagnostic criterion for IA in a population of 100 people with a disease prevalence of 13.0% (overall mean prevalence), three people with IA would be missed (sensitivity 80.5%, 19.5% false negatives), and 19 people would be unnecessarily treated or referred for further tests (specificity of 78.5%, 21.5% false negatives). If we use the two positive test requirement in a population with the same disease prevalence, it would mean that six IA people would be missed (sensitivity 58.0%, 42.1% false negatives) and three people would be unnecessarily treated or referred for further tests (specificity of 96.2%, 3.8% false negatives). Galactamannan and PCR have good NPV for excluding disease but the low prevalence of disease limits the ability to rule in a diagnosis. The biomarkers are detecting different aspects of disease and the combination of both together is likely to be more useful.

Onychomycosis due to opportunistic molds.

BACKGROUND:Onychomycosis are caused by dermatophytes and Candida, but rarely by non- dermatophyte molds. These opportunistic agents are filamentous fungi found as soil and plant pathogens.OBJECTIVES:To determine the frequency of opportunistic molds in onychomycosis.METHODS:A retrospective analysis of 4,220 cases with onychomycosis, diagnosed in a 39-month period at the Institute of Dermatology and Skin surgery "Prof. Dr. Fernando A. Cordero C." in Guatemala City, and confirmed with a positive KOH test and culture.RESULTS:32 cases (0.76%) of onychomycosis caused by opportunistic molds were confirmed. The most affected age group ranged from 41 to 65 years (15 patients, 46.9%) and females were more commonly affected (21 cases, 65.6%) than males. Lateral and distal subungual onychomycosis (OSD-L) was detected in 20 cases (62.5%). The microscopic examination with KOH showed filaments in 19 cases (59.4%), dermatophytoma in 9 cases (28.1%), spores in 2 cases (6.25%), and filaments and spores in 2 cases (6.25%). Etiologic agents: Aspergillus sp., 11 cases (34.4%); Scopulariopsis brevicaulis, 8 cases (25.0%); Cladosporium sp., 3 cases (9.4%); Acremonium sp., 2 cases (6.25%); Paecilomyces sp., 2 cases (6.25%); Tritirachium oryzae, 2 cases (6.25%); Fusarium sp., Phialophora sp., Rhizopus sp. and Alternaria alternate, 1 case (3.1%) each.CONCLUSIONS:We found onychomycosis by opportunistic molds in 0.76% of the cases and DLSO was present in 62.5%. The most frequent isolated etiological agents were: Aspergillus sp. and Scopulariopsis brevicaulis.