Incidence of invasive aspergillosis following hematopoietic stem cell and solid organ transplantation: interim results of a prospective multicenter surveillance program

Granulomatous response to invasive pulmonary aspergillosis in an immunotherapy-naive host, a maladaptive response?

Pulmonary aspergillosis causes a wide spectrum of disease, ranging from asymptomatic airway colonization to severe invasive disease, contingent on the host's immune status and underlying pulmonary anatomy. The invasive form of aspergillosis is a rare occurrence in the immunocompetent population. Nevertheless, patients with a compromised innate immune response are at greatest risk. We present a case of a patient with known Crohn's disease who developed invasive pulmonary aspergillosis. His clinical picture was further complicated by an uncommon immune response characterized by the development of granulomas encasing the Aspergillus forms found on his lung biopsy, likely representing a maladaptive response, possibly related to the effects of his granulomatous disease in the lungs. He was successfully treated with antifungal therapy and video assisted thoracoscopic surgery with placement of thoracostomy tube drainage for a parapneumonic effusion. We will discuss the factors leading to his atypical presentation and clinical outcome.

Fungal infections in hematopoietic stem cell transplantation in children at a pediatric children's hospital in Argentina

Our primary objective was to describe the incidence of proven or probable invasive fungal infections (IFIs), a devastating complication of hematopoietic stem cell transplant (HSCT), in HCST in a middle-income country. Secondary objectives were to describe factors associated with IFIs and outcomes. In this single center retrospective study, pediatric patients who underwent a first allogeneic or autologous HSCT from 1998 to 2016 were included. Of the 251 HSCT recipients: 143 transplants were allogeneic and 108 were autologous. Overall, 23 (9%) experienced an IFI, mostly due to yeasts (83%). IFIs were more common in allogeneic HSCT (18/143, 13%) than in autologous HSCT (5/108, 5%; P = .045). Of the 23 patients with IFIs, 14 (61%) died, but only 1 directly from IFI (pulmonary aspergillosis). Overall survival at 3 years was 0.42 ± 0.11 in patients with IFIs and 0.60 ± 0.37 in those without IFIs (P = .049). In Argentina, IFIs during HSCT are common. Recipients of allogeneic HSCT are at higher risk, and IFI is associated with reduced overall survival. Future work should focus on interventions to reduce and improve IFI outcomes in children undergoing transplants in low- and middle-income countries.

Investigation of Multiple Resistance Mechanisms in Voriconazole-Resistant Aspergillus flavus Clinical Isolates from a Chest Hospital Surveillance in Delhi, India

Invasive and allergic infections by Aspergillus flavus are more common in tropical and subtropical countries. The emergence of voriconazole (VRC) resistance in A. flavus impacts the management of aspergillosis, as azoles are used as the first-line and empirical therapy. We screened 120 molecularly confirmed A. flavus isolates obtained from respiratory and sinonasal specimens in a chest hospital in Delhi, India, for azole resistance using the CLSI broth microdilution (CLSI-BMD) method. Overall, 2.5% (n = 3/120) of A. flavus isolates had VRC MICs above epidemiological cutoff values (>1 μg/ml). The whole-genome sequence analysis of three non-wild-type (WT) A. flavus isolates with high VRC MICs showed polymorphisms in azole target genes (cyp51A, cyp51B, and cyp51C). Further, four novel substitutions (S196F, A324P, N423D, and V465M) encoded in the cyp51C gene were found in a single non-WT isolate which also exhibited overexpression of cyp51 (cyp51A, -B, and -C) genes and transporter genes, namely, MDR1, MDR2, atrF, and mfs1 The homology model of the non-WT isolate suggests that substitutions S196F and N423D exhibited major structural and functional effects on cyp51C drug binding. The substrate (drug) may not be able to bind to binding pocket due to changes in the pocket size or closing down or narrowing of cavities in drug entry channels. Notably, the remaining two VRC-resistant A. flavus isolates, including the one which had a pan-azole resistance phenotype (itraconazole and posaconazole), did not show upregulation of any of the analyzed target genes. These results suggest that multiple target genes and mechanisms could simultaneously contribute to azole resistance in A. flavus.

Murine model to follow hyphal development in invasive pulmonary aspergillosis

Aspergillus fumigatus is an opportunistic pathogen, the leading cause of invasive and disseminated aspergillosis in systemic immunocompromised patients, and an important cause of mortality. The aim of the present study was to adapt a pulmonary aspergillosis murine model, to determine pathodynamical parameters quantitatively, and to follow the progression of fungal infection in vivo. The nasal inoculation of Aspergillus conidia in mice previously subjected to immunosuppression with cyclophosphamide (CP) turned out to be a more suitable model than that of immunosuppressed with hydrocortisone (HC). The following parameters were found to correlate quantitatively with the progress of the infection: (i) survival rate, (ii) weight loss of mice, (iii) infected focal plaque size, (iv) hyphal density, (v) hyphal length distribution of A. fumigatus, and the (vi) the histopathological status and scores. These parameters will be essential elements for the development of antifungal drugs and therapies, and important for the investigation of the pathogenicity in different strains of A. fumigatus.

The importance of risk factors for the prediction of patients with invasive pulmonary aspergillosis

OBJECTIVE

Invasive pulmonary aspergillosis (IPA) is a major challenge in the management of immunocompromised patients. Despite all the advances in diagnosis, it remains a problem. The purpose of our study was to investigate the risk factors associated with IPA seen in patients with hematological malignancies.

METHOD

A total of 152 febrile neutropenia (FEN) patients with hematological malignancies aged over 18 years and receiving high-dose chemotherapy or stem cell transplant between January 1, 2010, and December 31, 2012 were included in the study. Sixty-five (65) cases with IPA according to the European Organization for the Research and Treatment of Cancer and Infectious Diseases Mycoses Study Group criteria were enrolled as the case group, while 87 patients without IPA development during concomitant monitoring were enrolled as the control group. Incidence of IPA was 21.4% (3/14) in patients receiving bone marrow transplant (allogeneic 2, autologous 1) and those cases were also added into the case group. The two groups were compared in terms of demographic, clinical and laboratory findings and risk factors associated with IPA investigated retrospectively.

RESULTS

Presence of relapse of primary disease, neutropenia for more than 3 weeks, presence of bacterial infection, and non-administration of antifungal prophylaxis were identified as risk factors associated with IPA.

CONCLUSION

It may be possible to reduce the incidence of the disease by eliminating preventable risk factors. Predicting those risks would, per se, enable early diagnosis and treatment and, thus, the mortality rate of these patients would unquestionably decline.

Posaconazole Therapeutic Drug Monitoring in a Regional Hospital Setting

BACKGROUND

Posaconazole therapeutic drug monitoring (TDM) is recommended to promote effective antifungal prophylaxis, but its utility has yet to be optimized. Breakthrough invasive fungal infections have been reported with serum concentrations <700 mcg/L, but there is little evidence to determine the optimal serum concentration for efficacy or concentrations associated with toxicity. Challenges for effective monitoring are greater in settings without posaconazole TDM facilities because of the long turnaround time before receipt of results.

METHODS

Thirty-eight TDM episodes were performed on 18 patients in a regional center in Australia during a 30-month period. Australian guidelines recommend a trough serum concentration of ≥700 mcg/L. The response to concentrations below the recommendation threshold (700 mcg/L), the final serum plasma concentration for each patient, and the appropriateness of TDM were evaluated.

RESULTS

A total of 19 (50%) concentrations were recorded to be < 700 mcg/L. Of these 19 concentrations, the drug dose was increased on only 4 occasions. Eleven of 18 patients (61%) had initial concentrations <700 mcg/L, with only 3 (27%) among those achieving final concentration ≥ 700 mcg/L; 5 patients with initial concentrations <700 mcg/L did not have any further TDM testing. Nine of the 18 (50%) patients had a final concentration <700 mcg/L. Five of 7 (71%) patients with initial concentrations ≥700 mcg/L had further TDM with no reasoning documented.

CONCLUSIONS

The results demonstrate a lack of confidence and consistency in ordering, interpreting, and following up posaconazole concentrations. Therefore, the use of TDM should be carefully considered, especially in regional centers. Such settings should consider the practicalities of posaconazole TDM and try to improve the process to ensure consistency and optimization of patient care.

Evaluation of Posaconazole Pharmacokinetics in Adult Patients with Invasive Fungal Infection

Mortality and morbidity due to invasive fungal infections have increased over the years. Posaconazole is a second-generation triazole agent with an extended spectrum of activity, which shows a high interindividual variability in its plasma levels, rendering dosing in many patients inconsistent or inadequate. Hence, posaconazole therapeutic drug monitoring, which is easily available in clinical practice, may improve treatment success and safety. The aim of the study was to describe posaconazole pharmacokinetics, and to evaluate the utility of therapeutic drug monitoring for therapy and prophylaxis in a cohort of adult patients. A fully validated chromatographic method was used to quantify posaconazole concentration in plasma collected from adult patients at the end of the dosing interval. Associations between variables were tested using the Pearson test. The Mann-Whitney test was used to probe the influence of categorical variables on continuous ones. A high inter-individual variability was shown. Of the 172 enrolled patients, among those receiving the drug by the oral route (N = 170), gender significantly influenced drug exposure: males showed greater posaconazole concentration than females (p = 0.028). This study highlights the importance of therapeutic drug monitoring in those with invasive fungal infections and its significant clinical implications; moreover we propose, for the first time, the possible influence of gender on posaconazole exposure.

Respiratory Fungal Infections in Solid Organ and Hematopoietic Stem Cell Transplantation

Respiratory fungal infections are associated with high morbidity and mortality in hematopoietic stem cell (HSCT) and solid organ (SOT) transplant recipients, and are caused primarily by molds. Aspergillus is the most common pathogen. The net state of immunosuppression plays a major role in the risk of respiratory fungal infections after transplantation. Clinical presentation can be atypical and diagnosis can be delayed due to low sensitivity of diagnostic methods or inability to obtain adequate specimens. Fungal infections in HSCT and SOT carry a higher risk of dissemination. New prophylaxis strategies have changed the epidemiology of fungal infections in this patient population.

Pharmacokinetic evaluation of oral itraconazole for antifungal prophylaxis in children

Itraconazole is a first-generation triazole agent with an extended spectrum of activity; it is licensed in adults for superficial and systemic fungal infections; no recommendation has been yet established for use in children patients. Its variable and unpredictable oral bioavailability make it difficult to determine the optimal dosing regimen. Hence, therapeutic drug monitoring, highly available in clinical practice, may improve itraconazole treatment success and safety. The aim of the study was to describe in paediatrics the oral itraconazole pharmacokinetics, used for prophylaxis. Moreover, we evaluated the utility of its therapeutic drug monitoring in this cohort. A fully validated chromatographic method was used to quantify itraconazole concentration in plasma collected from paediatric patients, at the end of dosing interval. Associations between variables were tested using the Pearson test. Mann-Whitney U test has been used to probe the influence of categorical variables on continuous ones. Any predictive power of the considered variables was finally evaluated through univariate and multivariate linear and logistic regression analyses. A high inter-individual variability was shown; ethnicity (beta coefficient, β -0.161 and interval of confidence at 95%, IC -395.035; -62.383) and gender (β 0.123 and IC 9.590; 349.395) remained in the final linear regression model with P value of .007 and .038, respectively. This study highlights that therapeutic drug monitoring is required to achieve an adequate target itraconazole serum exposure.

An overview of the synergy and crosstalk between pentraxins and collectins/ficolins: their functional relevance in complement activation

The complement system is an innate immune defense machinery comprising components that deploy rapid immune responses and provide efficient protection against foreign invaders and unwanted host elements. The complement system is activated upon recognition of pathogenic microorganisms or altered self-cells by exclusive pattern recognition molecules (PRMs), such as collectins, ficolins and pentraxins. Recent accumulating evidence shows that the different classes of effector PRMs build up a co-operative network and exert synergistic effects on complement activation. In this review, we describe our updated view of the crosstalk between previously unlinked PRMs in complement activation and the potential pathogenic effects during infection and inflammation.

Clinical Presentation and Determinants of Mortality of Invasive Pulmonary Aspergillosis in Kidney Transplant Recipients: A Multinational Cohort Study

The prognostic factors and optimal therapy for invasive pulmonary aspergillosis (IPA) after kidney transplantation (KT) remain poorly studied. We included in this multinational retrospective study 112 recipients diagnosed with probable (75.0% of cases) or proven (25.0%) IPA between 2000 and 2013. The median interval from transplantation to diagnosis was 230 days. Cough, fever, and expectoration were the most common symptoms at presentation. Bilateral pulmonary involvement was observed in 63.6% of cases. Positivity rates for the galactomannan assay in serum and bronchoalveolar lavage samples were 61.3% and 57.1%, respectively. Aspergillus fumigatus was the most commonly identified species. Six- and 12-week survival rates were 68.8% and 60.7%, respectively, and 22.1% of survivors experienced graft loss. Occurrence of IPA within the first 6 months (hazard ratio [HR]: 2.29; p-value = 0.027) and bilateral involvement at diagnosis (HR: 3.00; p-value = 0.017) were independent predictors for 6-week all-cause mortality, whereas the initial use of a voriconazole-based regimen showed a protective effect (HR: 0.34; p-value = 0.007). The administration of antifungal combination therapy had no apparent impact on outcome. In conclusion, IPA entails a dismal prognosis among KT recipients. Maintaining a low clinical suspicion threshold is key to achieve a prompt diagnosis and to initiate voriconazole therapy.

Complications of invasive mycoses in organ transplant recipients

INTRODUCTION

Opportunistic mycoses remain a significant complication in organ recipients. Areas covered: This review is an evidence-based presentation of current state-of-knowledge and our perspective on recent developments in the field Expert commentary: Invasive fungal infections are associated with reduced allograft and patient survival, increase in healthcare resource utilization, and newly appreciated but largely unrecognized immunologic sequelae, such as immune reconstitution syndrome. Given adverse outcomes associated with established infections, prophylaxis is a widely used strategy for the prevention of these infections. Currently available biomarkers that detect circulating fungal cell wall constituents i.e., galactomannan and 1, 3-β-D-glucan have not proven to be beneficial as screening tools for employing targeted prophylaxis or as diagnostic assays in this patient population. However, subsets of patients at risk for opportunistic fungal infections can be identified based on clinically identifiable characteristics or events. Preventive strategies targeted towards these patients are a rational approach for optimizing outcomes.

Risk Factors Associated With Early Invasive Pulmonary Aspergillosis in Kidney Transplant Recipients: Results From a Multinational Matched Case-Control Study

Risk factors for invasive pulmonary aspergillosis (IPA) after kidney transplantation have been poorly explored. We performed a multinational case-control study that included 51 kidney transplant (KT) recipients diagnosed with early (first 180 posttransplant days) IPA at 19 institutions between 2000 and 2013. Control recipients were matched (1:1 ratio) by center and date of transplantation. Overall mortality among cases was 60.8%, and 25.0% of living recipients experienced graft loss. Pretransplant diagnosis of chronic pulmonary obstructive disease (COPD; odds ratio [OR]: 9.96; 95% confidence interval [CI]: 1.09-90.58; p = 0.041) and delayed graft function (OR: 3.40; 95% CI: 1.08-10.73; p = 0.037) were identified as independent risk factors for IPA among those variables already available in the immediate peritransplant period. The development of bloodstream infection (OR: 18.76; 95% CI: 1.04-339.37; p = 0.047) and acute graft rejection (OR: 40.73, 95% CI: 3.63-456.98; p = 0.003) within the 3 mo prior to the diagnosis of IPA acted as risk factors during the subsequent period. In conclusion, pretransplant COPD, impaired graft function and the occurrence of serious posttransplant infections may be useful to identify KT recipients at the highest risk of early IPA. Future studies should explore the potential benefit of antimold prophylaxis in this group.

Evaluation of the Vitek MS Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry System for Identification of Clinically Relevant Filamentous Fungi

Invasive fungal infections have a high rate of morbidity and mortality, and accurate identification is necessary to guide appropriate antifungal therapy. With the increasing incidence of invasive disease attributed to filamentous fungi, rapid and accurate species-level identification of these pathogens is necessary. Traditional methods for identification of filamentous fungi can be slow and may lack resolution. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a rapid and accurate method for identification of bacteria and yeasts, but a paucity of data exists on the performance characteristics of this method for identification of filamentous fungi. The objective of our study was to evaluate the accuracy of the Vitek MS for mold identification. A total of 319 mold isolates representing 43 genera recovered from clinical specimens were evaluated. Of these isolates, 213 (66.8%) were correctly identified using the Vitek MS Knowledge Base, version 3.0 database. When a modified SARAMIS (Spectral Archive and Microbial Identification System) database was used to augment the version 3.0 Knowledge Base, 245 (76.8%) isolates were correctly identified. Unidentified isolates were subcultured for repeat testing; 71/319 (22.3%) remained unidentified. Of the unidentified isolates, 69 were not in the database. Only 3 (0.9%) isolates were misidentified by MALDI-TOF MS (including Aspergillus amoenus [n = 2] and Aspergillus calidoustus [n = 1]) although 10 (3.1%) of the original phenotypic identifications were not correct. In addition, this methodology was able to accurately identify 133/144 (93.6%) Aspergillus sp. isolates to the species level. MALDI-TOF MS has the potential to expedite mold identification, and misidentifications are rare.

Triazole resistance mediated by mutations of a conserved active site tyrosine in fungal lanosterol 14α-demethylase

Emergence of fungal strains showing resistance to triazole drugs can make treatment of fungal disease problematic. Triazole resistance can arise due to single mutations in the drug target lanosterol 14α-demethylase (Erg11p/CYP51). We have determined how commonly occurring single site mutations in pathogenic fungi affect triazole binding using Saccharomyces cerevisiae Erg11p (ScErg11p) as a target surrogate. The mutations Y140F/H were introduced into full-length hexahistidine-tagged ScErg11p. Phenotypes and high-resolution X-ray crystal structures were determined for the mutant enzymes complexed with short-tailed (fluconazole and voriconazole) or long-tailed (itraconazole and posaconazole) triazoles and wild type enzyme complexed with voriconazole. The mutations disrupted a water-mediated hydrogen bond network involved in binding of short-tailed triazoles, which contain a tertiary hydroxyl not present in long-tailed triazoles. This appears to be the mechanism by which resistance to these short chain azoles occurs. Understanding how these mutations affect drug affinity will aid the design of azoles that overcome resistance.

Hide, Keep Quiet, and Keep Low: Properties That Make Aspergillus fumigatus a Successful Lung Pathogen

Representatives of the genus Aspergillus are opportunistic fungal pathogens. Their conidia can reach the alveoli by inhalation and can give rise to infections in immunocompromised individuals. Aspergillus fumigatus is the causal agent of invasive aspergillosis in nearly 90% of the cases. It is not yet well-established what makes this fungus more pathogenic than other aspergilli such as A. niger. Here, we show that A. fumigatus and A. niger conidia adhere with similar efficiency to lung epithelial A549 cells but A. fumigatus conidia internalized 17% more efficiently. Conidia of both aspergilli were taken up in phagolysosomes 8 h after the challenge. These organelles only acidified in the case of A. niger, which is probably due to the type of melanin coating of the conidia. Viability of both types of conidia was not affected after uptake in the phagolysosomes. Germination of A. fumigatus and A. niger conidia in the presence of epithelial cells was delayed when compared to conidia in the medium. However, germination of A. niger conidia was still higher than that of A. fumigatus 10 h after exposure to A549 cells. Remarkably, A. fumigatus hyphae grew mainly parallel to the epithelium, while growth direction of A. niger hyphae was predominantly perpendicular to the plane of the cells. Neutrophils reduced germination and hyphal growth of A. niger, but not of A fumigatus, in presence of epithelial cells. Taken together, efficient internalization, delayed germination, and hyphal growth parallel to the epithelium gives a new insight into what could be the causes for the success of A. fumigatus compared to A. niger as an opportunistic pathogen in the lung.

Detection of a Serum Siderophore by LC-MS/MS as a Potential Biomarker of Invasive Aspergillosis

Invasive aspergillosis (IA) is a life-threatening systemic mycosis caused primarily by Aspergillus fumigatus. Early diagnosis of IA is based, in part, on an immunoassay for circulating fungal cell wall carbohydrate, galactomannan (GM). However, a wide range of sensitivity and specificity rates have been reported for the GM test across various patient populations. To obtain iron in vivo, A. fumigatus secretes the siderophore, N,N',N"-triacetylfusarinine C (TAFC) and we hypothesize that TAFC may represent a possible biomarker for early detection of IA. We developed an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for TAFC analysis from serum, and measured TAFC in serum samples collected from patients at risk for IA. The method showed lower and upper limits of quantitation (LOQ) of 5 ng/ml and 750 ng/ml, respectively, and complete TAFC recovery from spiked serum. As proof of concept, we evaluated 76 serum samples from 58 patients with suspected IA that were investigated for the presence of GM. Fourteen serum samples obtained from 11 patients diagnosed with probable or proven IA were also analyzed for the presence of TAFC. Control sera (n = 16) were analyzed to establish a TAFC cut-off value (≥6 ng/ml). Of the 36 GM-positive samples (≥0.5 GM index) from suspected IA patients, TAFC was considered positive in 25 (69%). TAFC was also found in 28 additional GM-negative samples. TAFC was detected in 4 of the 14 samples (28%) from patients with proven/probable aspergillosis. Log-transformed TAFC and GM values from patients with proven/probable IA, healthy individuals and SLE patients showed a significant correlation with a Pearson r value of 0.77. In summary, we have developed a method for the detection of TAFC in serum that revealed this fungal product in the sera of patients at risk for invasive aspergillosis. A prospective study is warranted to determine whether this method provides improved early detection of IA.

Invasive pulmonary Aspergillosis in organ transplants--Focus on lung transplants

Infections with filamentous fungi are common in transplant recipients. The risk for aspergillosis and other invasive pulmonary mycosis (IPM) is high in patients undergoing stem cell and lung transplantations. The mortality rates range from 20% to 60% and depend on a number of risk factors. The typical manifestations of IPM are lung infiltrates, consolidations, and fungal tracheobronchitis. The most common infectious agent is Aspergillus fumigatus. Infections caused by non-Aspergillus molds are more frequent for various reasons. The species distribution of non-Aspergillus molds varies in different locations. Furthermore, infections caused by Mucor and Penicillium are increasing, as are infections caused by species resistant to azoles and amphotericin B. Most centers use antifungal prophylaxis with inhaled amphotericin B or oral azoles. Early diagnosis and therapy is crucial. Reliable information on the local microbiological spectrum is a prerequisite for the effective treatment of molds with primary or secondary resistance to antimycotic drugs.

Microsatellite Typing of Aspergillus flavus Strains in a Tunisian Onco-hematology Unit

Aspergillus flavus is the most common species associated with invasive aspergillosis in Tunisia. The molecular epidemiology of the species is poorly documented. We used five highly discriminative microsatellite markers for the genotyping of clinical and hospital environmental A. flavus strains to assess whether IA could be hospital-acquired in the onco-hematology unit of the Farhat Hached teaching hospital of Sousse, Tunisia. The genotyping of 18 clinical isolates, collected from sputa of 17 acute leukemia patients, and 81 isolates, collected in these patients' hospital environment and food, identified 57 isolates that were grouped in 10 clones, each of them including 2-17 isolates. The remaining 42 isolates showed a unique genotype. Two main transmission scenarios were observed: (1) the same clone was isolated from different patients; (2) the same clone was isolated from a patient, its hospital environment and/or food. These findings strongly suggest the occurrence of hospital-acquired A. flavus infection/colonization in the investigated onco-hematology unit.

The serum opsonin L-ficolin is detected in lungs of human transplant recipients following fungal infections and modulates inflammation and killing of Aspergillus fumigatus

BACKGROUND

Invasive aspergillosis (IA) is a life-threatening systemic fungal infection in immunocompromised individuals that is caused by Aspergillus fumigatus. The human serum opsonin, L-ficolin, has been observed to recognize A. fumigatus and could participate in fungal defense.

METHODS

Using lung epithelial cells, primary human monocyte-derived macrophages (MDMs), and neutrophils from healthy donors, we assessed phagocytosis and killing of L-ficolin-opsonized live A. fumigatus conidia by flow cytometry and microscopy. Additionally, cytokines were measured by cytometric bead array, and L-ficolin was measured in bronchoalveolar lavage (BAL) fluid from lung transplant recipients by enzyme-linked immunosorbent assay.

RESULTS

L-ficolin opsonization increased conidial uptake and enhanced killing of A. fumigatus by MDMs and neutrophils. Opsonization was also shown to manifest an increase in interleukin 8 release from A549 lung epithelial cells but decreased interleukin 1β, interleukin 6, interleukin 8, interleukin 10, and tumor necrosis factor α release from MDMs and neutrophils 24 hours after infection. The concentration of L-ficolin in BAL fluid from patients with fungal infection was significantly higher than that for control subjects (P = .00087), and receiving operating characteristic curve analysis highlighted the diagnostic potential of L-ficolin for lung infection (area under the curve, 0.842; P < .0001).

CONCLUSIONS

L-ficolin modulates the immune response to A. fumigatus. Additionally, for the first time, L-ficolin has been demonstrated to be present in human lungs.

Chemical Composition and Antifungal Activity of Ocimum basilicum L. Essential Oil

BACKGROUND

The leaves of Ocimum basilicum L. (basil) are used in traditional cuisine as spices; its essential oil has found a wide application in perfumery, dental products as well as antifungal agents.

AIM

To assess the chemical composition as well as the in vitro antifungal activity of O. basilicum L. essential oil against Aspergillus flavus fungal growth and aflatoxin B1 production.

MATERIAL AND METHODS

The essential oil of O. basilicum was obtained by hydrodistillation and analysed using gas chromatography (GC) and GC coupled with mass spectrometry (GC/MS). The essential oil was tested for its effects on Aspergillus flavus (A. flavus) mycelial growth and aflatoxin B1 production in Yeast Extract Sucrose (YES) growth media. Aflatoxin B1 production was determined by high performance liquid chromatography (HPLC).

RESULTS

Nineteen compounds, representing 96.7% of the total oil were identified. The main components were as follows: linalool (48.4%), 1,8-cineol (12.2%), eugenol (6.6%), methyl cinnamate (6.2%), α-cubebene (5.7%), caryophyllene (2.5%), β-ocimene (2.1%) and α-farnesene (2.0%). The tested oil showed significant antifungal activity that was dependent on the used oil concentration. The complete inhibition of A. flavus growth was observed at 1000 ppm oil concentration, while marked inhibition of aflatoxin B1 production was observed at all oil concentrations tested (500, 750 and 1000 ppm).

CONCLUSION

These results confirm the antifungal activities of O. basilicum L. oil and its potential use to cure mycotic infections and act as pharmaceutical preservative against A. flavus growth and aflatoxin B1 production.

Cytokines induce effector T-helper cells during invasive aspergillosis; what we have learned about T-helper cells?

Invasive aspergillosis caused by Aspergillus species (Aspergillus fumigatus, A. flavus, and A. terreus) is life-threatening infections in immunocompromised patients. Understanding the innate and adaptive immune response particularly T-helper cells (T_H-cells) against these Aspergillus species and how the different sub-set of T_H-cells are regulated by differentiating cytokines at primary target organ site like lung, kidney and brain is of great significance to human health. This review focuses on presentation of Aspergillus through Antigen presenting cells (APCs) to the naive CD4⁺ T-cells in the host. The production of differentiating/effector cytokines that activate following T_H-cells, e.g., T_H1, T_H2, T_H9, and T_H17 has been reported in association or alone in allergic or invasive aspergillosis. Chemokines (CXCL1, CXCL2, CCL1, and CCL20) and their receptors associated to these T_H-cells have also been observed in invasive aspergillosis. Thus, further study of these T_H-cells in invasive aspergillosis and other elements of adaptive immune response with Aspergillus species are required in order to have a better understanding of host response for safer and effective therapeutic outcome.

How to treat fungal infections in ICU patients

Fungal infections represent a major burden in the critical care setting with increasing morbidity and mortality. Candidiasis is the leading cause of such infections, with C. albicans being the most common causative agent, followed by Aspergillosis and Mucormycosis. The diagnosis of such infections is cumbersome requiring increased clinical vigilance and extensive laboratory testing, including radiology, cultures, biopsies and other indirect methods. However, it is not uncommon for definitive evidence to be unavailable. Risk and host factors indicating the probability of infections may greatly help in the diagnostic approach. Timely and adequate intervention is important for their successful treatment. The available therapeutic armamentarium, although not very extensive, is effective with low resistance rates for the newer antifungal agents. However, timely and prudent use is necessary to maximize favorable outcomes.

Fungal colonization of the respiratory tract in allogeneic and autologous hematopoietic stem cell transplant recipients: a study of 573 transplanted patients

Background

Fungal colonization and infections remain a major cause of infection morbidity and mortality following hematopoietic stem cell transplantation (HSCT) in patients with hematological malignancies. The aim of this study was to analyze the spectrum of fungal microflora of the respiratory tract (oral cavity, pharynx, epiglottis, and sputum) in patients undergoing HSCT and to evaluate the relationship between HSCT type and incidence of mycotic colonization and infections.

Material/Methods

Retrospective analysis of fungal isolates collected from the respiratory tract (oral cavity, pharynx, epiglottis, and sputum) of 573 patients undergoing HSCT was performed.

Results

The overall rate of fungal colonization in patients undergoing HSCT was 8.7%. Patients undergoing allogeneic HSCT were statistically significantly more often colonized (12.95%) compared to autologous HSCT recipients (4.7%). Colonizing cultures were mainly C. albicans and C. krusei, and sporadically C. glabrata, C. famata, Aspergillus spp. and Saccharomyces cerevisiae. C. albicans was the most frequent species found in isolates from the pharynx, sputum, and oral cavity collected from patients undergoing HSCT. Aspergillosis was more common after allogeneic than after autologous HSCT. The pharynx was the most frequently colonized site.

Conclusions

Allogeneic HSCT recipients are more susceptible to fungal infections compared to the autologous group. Selection of species during prophylaxis and antifungal therapy requires developing more effective prevention and treatment strategies based on new antifungal drugs and microbe-specific diagnoses.

Unusual fungal infections in renal transplant recipients

Fungal infections are an important cause of morbidity and mortality in renal transplant recipients. The causative agent and the risk factors differ depending on the period after the kidney transplant. Also the incidence varies according to the geographical area. We are reporting three cases of fungal infections in renal transplant recipients. Two of them have etiological agents which are common among immunosuppressed patients, but with an atypical clinical presentation, while one of them is a subcutaneous infection caused by a less frequent dematiaceous fungus, Aureobasidium pullulans. These cases highlight how a high index of clinical suspicion and prompt diagnosis is very much essential for better outcome. The emerging fungal infections and paucity of data regarding their management pose a challenge to the transplant physicians.

Aspergillus flavus induces granulomatous cerebral aspergillosis in mice with display of distinct cytokine profile

Aspergillus flavus is one of the leading Aspergillus spp. resulting in invasive aspergillosis of central nervous system (CNS) in human beings. Immunological status in aspergillosis of central nervous system remains elusive in case of both immunocompetent and immunocompromised patients. Since cytokines are the major mediators of host response, evaluation of disease pathology along with cytokine profile in brain may provide snapshots of neuro-immunological response. An intravenous model of A. flavus infection was utilized to determine the pathogenicity of infection and cytokine profile in the brain of male BALB/c mice. Enumeration of colony forming units and histopathological analyses were performed on the brain tissue at distinct time periods. The kinetics of cytokines (TNF-α, IFN-γ, IL-12/IL-23p40, IL-6, IL-23, IL-17A and IL-4) was evaluated at 6, 12, 24, 48, 72 and 96h post infection (hPI) in brain homogenates using murine cytokine specific enzyme linked immunosorbent assay. Histological analysis exhibited the hyphae with leukocyte infiltrations leading to formation of granulomata along with ischemia and pyknosis of neurons in the brain of infected mice. Diseased mice displayed increased secretion of IFN-γ, IL-12p40 and IL-6 with a concomitant reduction in the secretion of Th2 cytokine IL-4, and Th17 promoting cytokine, IL-23 during the late phase of infection. A.flavus induced inflammatory granulomatous cerebral aspergillosis in mice, characterized by a marked increase in the Th1 cytokines and neurons undergoing necrosis. A marked increase in necrosis of neurons with concurrent inflammatory responses might have led to the host mortality during late phase of infection.

Comparison of the Use of Administrative Data and an Active System for Surveillance of Invasive Aspergillosis

Background.

Administrative data, such as International Classification of Diseases, Ninth Revision (ICD-9) codes, are readily available and are an attractive option for surveillance and quality assessment within a single institution or for interinstitutional comparisons. To understand the usefulness of administrative data for the surveillance of invasive aspergillosis, we compared information obtained from a system based on ICD-9 codes with information obtained from an active, prospective surveillance system, which used more extensive case-finding methods (Transplant Associated Infection Surveillance Network).

Methods.

Patients with suspected inyasive aspergillosis were identified by aspergillosis-related ICD-9 codes assigned to hematopoietic stem cell transplant recipients and solid organ transplant recipients at a single hospital from April 1, 2001, through January 31, 2005. Suspected cases were classified as proven or probable invasive aspergillosis by medical record review using standard definitions. We calculated the sensitivity and positive predictive value (PPV) of identifying invasive aspergillosis by individual ICD-9 codes and by combinations of codes.

Results.

The sensitivity of code 117.3 was modest (63% [95% confidence interval {CI}, 38%-84%]), as was the PPV (71% [95% CI, 44%-90%]); the sensitivity of code 117.9 was poor (32% [95% CI, 13%-57%]), as was the PPV (15% [95% CI, 6%-31%]). The sensitivity of codes 117.3 and 117.9 combined was 84% (95% CI, 60%-97%); the PPV of the combined codes was 30% (95% CI, 18%-44%). Overall, ICD-9 codes triggered a review of medical records for 64 medical patients, only 16 (25%) of whom had proven or probable invasive aspergillosis.

Conclusions.

A surveillance system that involved multiple ICD-9 codes was sufficiently sensitive to identify most cases of invasive aspergillosis; however, the poor PPV of ICD-9 codes means that this approach is not adequate as the sole tool used to classify cases. Screening ICD-9 codes to trigger a medical record review might be a useful method of surveillance for invasive aspergillosis and quality assessment, although more investigation is needed.

Invasive mold infections in solid organ transplant recipients

Invasive mold infections represent an increasing source of morbidity and mortality in solid organ transplant recipients. Whereas there is a large literature regarding invasive molds infections in hematopoietic stem cell transplants, data in solid organ transplants are scarcer. In this comprehensive review, we focused on invasive mold infection in the specific population of solid organ transplant. We highlighted epidemiology and specific risk factors for these infections and we assessed the main clinical and imaging findings by fungi and by type of solid organ transplant. Finally, we attempted to summarize the diagnostic strategy for detection of these fungi and tried to give an overview of the current prophylaxis treatments and outcomes of these infections in solid organ transplant recipients.

The pH-responsive PacC transcription factor of Aspergillus fumigatus governs epithelial entry and tissue invasion during pulmonary aspergillosis

Destruction of the pulmonary epithelium is a major feature of lung diseases caused by the mould pathogen Aspergillus fumigatus. Although it is widely postulated that tissue invasion is governed by fungal proteases, A. fumigatus mutants lacking individual or multiple enzymes remain fully invasive, suggesting a concomitant requirement for other pathogenic activities during host invasion. In this study we discovered, and exploited, a novel, tissue non-invasive, phenotype in A. fumigatus mutants lacking the pH-responsive transcription factor PacC. Our study revealed a novel mode of epithelial entry, occurring in a cell wall-dependent manner prior to protease production, and via the Dectin-1 β-glucan receptor. ΔpacC mutants are defective in both contact-mediated epithelial entry and protease expression, and significantly attenuated for pathogenicity in leukopenic mice. We combined murine infection modelling, in vivo transcriptomics, and in vitro infections of human alveolar epithelia, to delineate two major, and sequentially acting, PacC-dependent processes impacting epithelial integrity in vitro and tissue invasion in the whole animal. We demonstrate that A. fumigatus spores and germlings are internalised by epithelial cells in a contact-, actin-, cell wall- and Dectin-1 dependent manner and ΔpacC mutants, which aberrantly remodel the cell wall during germinative growth, are unable to gain entry into epithelial cells, both in vitro and in vivo. We further show that PacC acts as a global transcriptional regulator of secreted molecules during growth in the leukopenic mammalian lung, and profile the full cohort of secreted gene products expressed during invasive infection. Our study reveals a combinatorial mode of tissue entry dependent upon sequential, and mechanistically distinct, perturbations of the pulmonary epithelium and demonstrates, for the first time a protective role for Dectin-1 blockade in epithelial defences. Infecting ΔpacC mutants are hypersensitive to cell wall-active antifungal agents highlighting the value of PacC signalling as a target for antifungal therapy.

Inhaled spores of the pathogenic mould Aspergillus fumigatus cause fungal lung infections in humans having immune defects. A. fumigatus spores germinate within the immunocompromised lung, producing invasively growing, elongated cells called hyphae. Hyphae degrade the surrounding pulmonary tissue, a process thought to be caused by secreted fungal enzymes; however, A. fumigatus mutants lacking one or more protease activities retain fully invasive phenotypes in mouse models of disease. Here we report the first discovery of a non-invasive A. fumigatus mutant, which lacks a pH-responsive transcription factor PacC. Using global transcriptional profiling of wild type and mutant isolates, and in vitro pulmonary invasion assays, we established that loss of PacC leads to a compound non-invasive phenotype characterised by deficits in both contact-mediated epithelial entry and protease expression. Consistent with an important role for epithelial entry in promoting invasive disease in mammalian tissues, PacC mutants remain surface-localised on mammalian epithelia, both in vitro and in vivo. Our study sets a new precedent for involvement of both host and pathogen activities in promoting epithelial invasion by A. fumigatus and supports a model wherein fungal protease activity acting subsequently to, or in parallel with, host-mediated epithelial entry provides the mechanistic basis for tissue invasion.

The potential hazards of Aspergillus sp. in foods and feeds, and the role of biological treatment: a review

The contamination of food and feed by Aspergillus has become a global issue with a significant worldwide economic impact. The growth of Aspergillus is unfavourable to the development of food and feed industries, where the problems happen mostly due to the presence of mycotoxins, which is a toxic metabolite secreted by most Aspergillus groups. Moreover, fungi can produce spores that cause diseases, such as allergies and asthma, especially to human beings. High temperature, high moisture, retarded crops, and poor food storage conditions encourage the growth of mold, as well as the development of mycotoxins. A variety of chemical, biological, and physical strategies have been developed to control the production of mycotoxins. A biological approach, using a mixed culture comprised of Saccharomyces cerevisiae and Lactobacillus rhamnosus resulted in the inhibition of the growth of fungi when inoculated into fermented food. The results reveal that the mixed culture has a higher potential (37.08%) to inhibit the growth of Aspergillus flavus (producer of Aflatoxin) compared to either single culture, L. rhamnosus NRRL B-442 and S. cerevisiae, which inhibit the growth by 63.07% and 64.24%, respectively.

Novel and sensitive qPCR assays for the detection and identification of aspergillosis causing species

Despite concerted efforts, diagnosis of aspergillosis is still a great challenge to clinical microbiology laboratories. Along with the requirement for high sensitivity and specificity, species-specific identification is important. We developed rapid, sensitive and species-specific qPCR assays using the TaqMan technology for the detection and identification of Aspergillus fumigatus and Aspergillus terreus. The assays were designed to target orthologs of the Streptomyces factor C gene that are only found in a few species of filamentous fungi. Fungi acquired this gene through horizontal gene transfer and divergence of the gene allows identification of species. The assays have potential as a molecular diagnosis tool for the early detection of fungal infection caused by Aspergillus fumigatus and Aspergillus terreus, which merits future diagnostic studies. The assays were sensitive enough to detect a few genomic equivalents in blood samples.

Pulmonary complications in hematopoietic SCT: a prospective study

Pulmonary complications are common and often lethal in hematopoietic SCT recipients. The objective of this prospective interventional study was to evaluate the etiology, diagnostic procedures, risk factors and outcome of pulmonary complications in a cohort of hematopoietic SCT recipients followed up for 1 year. For patients suffering from a pulmonary complication, a diagnostic algorithm that included non-invasive and bronchoscopic procedures was performed. We identified 73 pulmonary complications in 169 patients: 50 (68%) were pneumonias; 21 (29%) were non-infectious complications and 2 (3%) were undiagnosed. Viruses (particularly Rhinovirus) and bacteria (particularly P. aeruginosa) (28 and 26%, respectively) were the most common causes of pneumonia. A specific diagnosis was obtained in 83% of the cases. A non-invasive test gave a specific diagnosis in 59% of the episodes. The diagnostic yield of bronchoscopy was 67 and 78% in pulmonary infections. Early bronchoscopy (⩽5 days) had higher diagnostic yield than late bronchoscopy (78 vs 23%; P=0.02) for pulmonary infections. Overall mortality was 22 and 32% of all fatalities were due to pulmonary complications. Pulmonary complications are common and constitute an independent risk factor for mortality, stressing the importance of an appropriate clinical management.