Invasive aspergillosis. Disease spectrum, treatment practices, and outcomes. I3 Aspergillus Study Group

Minimally Invasive Diagnostic Strategy in Immunocompromised Patients with Pulmonary Infiltrates

Acute respiratory failure (ARF) is the main reason for ICU admission in patients with haematological malignancies. High mortality rates of up to 50% are reported in this situation, and mortality is highest when mechanical ventilation is needed. Rapid and accurate diagnostic methods are needed in these vulnerable patients to ensure the prompt initiation of effective treatment. However, the broad array of possible cause of ARF raises diagnostic challenges. In this review, we discuss the DIRECT strategy, which identifies the most plausible diagnosis in each patient based on the type of immune deficiency and clinical presentation. We will focus on non-invasive laboratory tests developed in recent years, discussing their sensitivity and specificity. We also discuss the usefulness in cancer patients with specific organ dysfunctions of biomarkers introduced over the past few years.

Coexistence of fatal disseminated invasive aspergillosis and pyoderma gangrenosum: a case report

OBJECTIVE

To report an unusual case of disseminated aspergillosis involving the lymph nodes, lungs, and skin in a patient with pyoderma gangrenosum (PG) and myelodysplastic syndrome (MDS).

CASE PRESENTATION AND INTERVENTION

A 46-year-old man presented with productive cough of 2 weeks' duration. Besides, several painless, fixed lymph nodes were palpated at his left neck. He had PG and MDS diagnosed in June 2004 with regular use of oral dapsone and prednisolone. His skin lesions healed with scar formation and no purulent discharge. A computed tomography scan of the head, neck and chest showed bilateral lung consolidation and abscesses at the left neck, right upper lung and right pleura. The neck abscess culture grew Aspergillus species. Dark reddish macules developed over the right arm, chest and abdominal wall, and the left lower limb 2 weeks after initiation of amphotericin B. The histology of the right arm skin biopsy showed invasive aspergillosis. Caspofungin was started then for suspicion of poor response to amphotericin B. He expired despite 35 days of antifungal therapy.

CONCLUSION

This report highlights the rarity of coexistence of disseminated aspergillosis and PG, and should alert physicians to the possibility of invasive fungal infection superimposed on a chronic skin lesion.

Galactomannan testing in bronchoalveolar lavage fluid facilitates the diagnosis of invasive pulmonary aspergillosis in patients with hematologic malignancies and stem cell transplant recipients

Invasive pulmonary aspergillosis (IPA) is a major cause of mortality in patients with stem cell transplants and hematologic malignancies. Timely diagnosis of IPA improves survival but is difficult to make. We evaluated the effectiveness of bronchoalveolar lavage (BAL) galactomannan (GM) in diagnosing IPA in these populations by retrospectively reviewing records of 67 consecutive patients, in whom 89 BAL GM tests were performed. For patients with IPA, only the first BAL sample linked to the IPA episode was analyzed. Eighty samples were associated with proven, 12 with probable, and 32 with possible invasive fungal infections (IFI), and 37 were associated with no IFI. Among patients with IFIs, 4 had proven, 11 probable, and 32 possible IPA. Using BAL GM ≥ 0.5 (cutoff for serum GM) and ≥ 0.85 (optimal cutoff identified by receiver-operating characteristic curve), the sensitivity in diagnosing proven or probable IPA was 73% (11/15) and 67% (10/15), respectively, and specificity was 89% (33/37) and 95% (35/37). At these cutoffs, positive and negative predictive values were 73% (11/15) and 83% (10/12), and 89% (33/37) and 87% (35/40), respectively. BAL GM was more sensitive than cytology (0%, 0/14), BAL culture (27%, 4/15), transbronchial biopsy (40%, 2/5), or serum GM (67%, 10/15) for diagnosing IPA. BAL GM was ≥ 0.85 and ≥ 0.5 in 86% (6/7) and 100% (7/7) of patients with proven or probable IPA who received a mold-active agent for ≤ 3 days. BAL GM added sensitivity to serum GM and other means of diagnosing IPA, and was not impacted by short courses of mold-active agents.

Aspergillus fumigatus AcuM regulates both iron acquisition and gluconeogenesis

Relatively few transcription factors that govern the virulence of Aspergillus fumigatus are known. We constructed 11 A. fumigatus transcription factor mutants and screened them for altered virulence in Galleria mellonella larvae. We discovered that the zinc cluster transcription factor, AcuM, is essential for maximal virulence in this model, as well as in murine models of haematogenously disseminated and invasive pulmonary aspergillosis. Transcriptional profiling experiments suggested that AcuM suppresses sreA and induces hapX to stimulate expression of genes involved in both reductive iron assimilation and siderophore-mediated iron uptake. Consistent with these results, a ΔacuM mutant had reduced iron incorporation, decreased extracellular siderophore production and impaired capacity to grow under iron-limited conditions. Interestingly, an Aspergillus nidulansΔacuM mutant had normal extracellular siderophore production and growth under iron-limited conditions, indicating that AcuM does not govern iron acquisition in this organism. A. fumigatus AcuM also regulated genes involved in gluconeogenesis, and the ΔacuM mutant had impaired growth on gluconeogenic carbon sources. Deletion of sreA in the ΔacuM mutant restored iron uptake, extracellular siderophore production and virulence, but not the defect in gluconeogenesis. Thus, AcuM represses SreA and thereby induces iron acquisition, a process that is essential for the maximal virulence of A. fumigatus.

Role of Aspergillus fumigatus DvrA in host cell interactions and virulence

The transcription factors that regulate Aspergillus fumigatus interactions with host cells and virulence are incompletely defined. We investigated the role of the putative C2H2 transcription factor DvrA in governing these processes. Although DvrA was identified by its limited homology to Candida albicans Bcr1, a ΔdvrA mutant strain of A. fumigatus had wild-type adherence to host constituents in vitro. However, it had increased capacity to damage both endothelial cells and a pulmonary epithelial cell line compared to the ability of the wild-type strain and a ΔdvrA::dvrA-complemented strain. This increase in damage required direct contact between the mutant and host cells. The ΔdvrA mutant also stimulated greater CCL20, interleukin-8, and tumor necrosis factor mRNA expression in a pulmonary epithelial cell line compared to levels induced by the control strains. Also, it was resistant to nikkomycin Z, suggesting an altered cell wall composition. As predicted by these in vitro results, the ΔdvrA mutant had increased virulence and stimulated a greater pulmonary inflammatory response than the wild-type strain and ΔdvrA::dvrA-complemented strains in the nonneutropenic mouse model of invasive pulmonary aspergillosis. These results indicate that DvrA influences A. fumigatus virulence as well as its capacity to damage host cells and stimulate a proinflammatory response.

Invasive aspergillosis in pediatric patients

This case-based review examines the growing literature on critical issues related to the epidemiology, diagnosis, and treatment of pediatric invasive aspergillosis. Immunocompromised children are at heightened risk for invasive aspergillosis. Children at highest risk include those with new-onset or relapsed hematologic malignancy and recipients of allogeneic stem cell transplants. Additional risk factors in stem cell transplant recipients include impaired lymphocyte engraftment and graft-versus-host disease. Pediatric invasive aspergillosis is associated with a high mortality rate (generally >50%) and requires prompt diagnosis and treatment to prevent dissemination and death. Tools available for diagnosis include radiologic examinations (primarily computed tomography), the galactomannan assay, bronchoalveolar lavage, and tissue biopsy. Age-related differences in computed tomography and galactomannan assay results have been suggested. Recommended primary therapy for pediatric invasive aspergillosis is voriconazole (7 mg/kg IV q12 hours). Currently approved alternative therapies include liposomal amphotericin B, amphotericin B lipid complex, and caspofungin. Posaconazole and itraconazole are also possibilities, but there is no established pediatric dose for posaconazole, and itraconazole dosing is difficult in children. In patients who do not benefit from initial antifungal therapy, options include switching to another agent with a different mechanism of action or combination therapy. Further research is required to better establish optimal approaches to the management of pediatric patients with invasive aspergillosis recalcitrant to initial primary therapy.

Anti-Aspergillus human host defence relies on type 1 T helper (Th1), rather than type 17 T helper (Th17), cellular immunity

Both interferon-gamma-producing type 1 T helper (Th1)- and interleukin-17 (IL-17)-producing Th17 cells have been proposed to be involved in anti-fungal host defence. Although invasive aspergillosis is one of the most severe human fungal infections, little is known regarding the relative importance of the Th1 versus Th17 cellular immune pathways for the human anti-Aspergillus host defence. Using human peripheral blood mononuclear cells and a system consisting of monocyte-derived macrophages with lymphocytes, we found that Aspergillus fumigatus is a weak inducer of human IL-17 but induces a strong Th1 response. These data were validated by the very low IL-17 levels in bronchoalveolar lavage fluid and serum of patients with invasive aspergillosis. Surprisingly, live A. fumigatus reduced IL-17 production induced by mitogenic stimuli. This effect was mediated through the propensity of A. fumigatus to metabolize tryptophan and release kynurenine, which modulates the inflammatory response through inhibition of IL-17 production. In conclusion, A. fumigatus does not stimulate production of IL-17 and human host defence against aspergillosis may not rely on potent Th17 responses.

Invasive pulmonary aspergillosis in acute exacerbation of chronic obstructive pulmonary disease and the diagnostic value of combined serological tests

BACKGROUND AND OBJECTIVES

Invasive pulmonary aspergillosis (IPA) among patients with chronic obstructive pulmonary disease (COPD) is increasing in frequency. We conducted this study to find out the approximate incidence of IPA in patients with acute exacerbation of COPD (AECOPD), and to determine whether using a combination of two tests (galactomannan [GM] antigen and 1,3-beta-glucan [BG] detection) would result in a more specific diagnosis of IPA.

METHODS

The study included 261 patients with AECOPD admitted over two years. The patients were categorized according to the modified definitions for IPA. GM antigen and BG were detected by the Platelia Aspergillus and Glucatell tests.

RESULTS

Two patients had proven IPA, three had probable IPA, and two had possible IPA. The rate of proven or probable IPA in patients with AECOPD was 1.91% (5/261). Four patients with proven and probable IPA had been treated with a systemic or inhaled corticosteroid before hospitalization and the typical symptoms and diagnostic signs of IPA were relatively less common in them. Mortality in patients with proven and probable IPA was 80%. The specificity of combined GM and BG detection was 98.8%.

CONCLUSION

Combining two serological tests increased the specificity of diagnosis but further trials are needed to prove the value of this approach.

Aspergillus niger: an unusual cause of invasive pulmonary aspergillosis

Infections due to Aspergillus species cause significant morbidity and mortality. Most are attributed to Aspergillus fumigatus, followed by Aspergillus flavus and Aspergillus terreus. Aspergillus niger is a mould that is rarely reported as a cause of pneumonia. A 72-year-old female with chronic obstructive pulmonary disease and temporal arteritis being treated with steroids long term presented with haemoptysis and pleuritic chest pain. Chest radiography revealed areas of heterogeneous consolidation with cavitation in the right upper lobe of the lung. Induced bacterial sputum cultures, and acid-fast smears and cultures were negative. Fungal sputum cultures grew A. niger. The patient clinically improved on a combination therapy of empiric antibacterials and voriconazole, followed by voriconazole monotherapy. After 4 weeks of voriconazole therapy, however, repeat chest computed tomography scanning showed a significant progression of the infection and near-complete necrosis of the right upper lobe of the lung. Serum voriconazole levels were low–normal (1.0 μg ml⁻¹, normal range for the assay 0.5–6.0 μg ml⁻¹). A. niger was again recovered from bronchoalveolar lavage specimens. A right upper lobectomy was performed, and lung tissue cultures grew A. niger. Furthermore, the lung histopathology showed acute and organizing pneumonia, fungal hyphae and oxalate crystallosis, confirming the diagnosis of invasive A. niger infection. A. niger, unlike A. fumigatus and A. flavus, is less commonly considered a cause of invasive aspergillosis (IA). The finding of calcium oxalate crystals in histopathology specimens is classic for A. niger infection and can be helpful in making a diagnosis even in the absence of conidia. Therapeutic drug monitoring may be useful in optimizing the treatment of IA given the wide variations in the oral bioavailability of voriconazole.

Cutaneous model of invasive aspergillosis

Cutaneous models have proven useful in studies of the pathogenesis and treatment of Gram-positive bacterial infections. Because cutaneous invasive aspergillosis (IA) occurs in the clinical setting, we sought to develop a nonlethal murine cutaneous model of IA. We induced cutaneous IA in cyclophosphamide-treated nude BALB/c mice by subcutaneous injection of Aspergillus fumigatus conidia. Skin lesion areas correlated well with tissue fungal burdens, allowing dynamic visual monitoring of cutaneous infections. The cutaneous model accurately reflected alterations in A. fumigatus pathogenicity resulting from deletions of recognized virulence genes (pabaA, sidA, and pksP). Moreover, analysis of the roles of conidial and mycelial catalases revealed that the former is required for the initiation of cutaneous aspergillosis, whereas the latter contributes to its propagation. Finally, posaconazole treatment reduced skin lesion areas relative to those of untreated and fluconazole-treated controls. This novel cutaneous model system should be applicable to comparative studies of the pathogenesis, treatment, and tissue specificity of IA.

Resolution of secondary pulmonary alveolar proteinosis following treatment of rhinocerebral aspergillosis

Pulmonary alveolar proteinosis can be secondary to inhaled dust exposure, malignancy, and chronic pulmonary infections. However, pulmonary alveolar proteinosis secondary to extrapulmonary aspergillosis has never been reported. We report herein a case of pulmonary alveolar proteinosis secondary to invasive rhinocerebral aspergillosis. Neither immune modulators nor whole lung lavage was applied during the treatment course. The severe respiratory distress subsided, hypoxia resolved, and radiological infiltrates improved following the successful treatment of invasive rhinocerebral aspergillosis alone.

Rare mycoses of the oral cavity: a literature epidemiologic review

Stomatologic fungal infections display different etiologies, pathogenesis, and clinical presentations. The incidence of rare mycoses of oral cavity is very low. These infections can involve both immunocompromised and immmunocompetent patients with common predisposing factors, such as diabetes or suffering from diseases causing immune system impairment. Oral mycoses can cause acute, chronic, and mucocutaneous lesions. Candidiasis is the most common mouth mycosis. Although occasionally primary mouth pathogens, Cryptococcus spp. or filamentous fungi (Aspergillus spp. and zygomycetes) can cause oral mycoses, with the oral localization more commonly secondary to a more serious systemic infection. The diagnosis of oral mycoses is based on clinical examination; for yeasts, culture is necessary to identify the etiologic agents; for filamentous fungi, in particular for zygomycetes and dimorphic, a definitive diagnosis can be made by histologic examination and pertinent stains with or without isolation of the fungus from the same site.

The transposon impala is activated by low temperatures: use of a controlled transposition system to identify genes critical for viability of Aspergillus fumigatus

Genes that are essential for viability represent potential targets for the development of anti-infective agents. However, relatively few have been determined in the filamentous fungal pathogen Aspergillus fumigatus. A novel solution employing parasexual genetics coupled with transposon mutagenesis using the Fusarium oxysporum transposon impala had previously enabled the identification of 20 essential genes from A. fumigatus; however, further use of this system required a better understanding of the mode of action of the transposon itself. Examination of a range of conditions indicated that impala is activated by prolonged exposure to low temperatures. This newly identified property was then harnessed to identify 96 loci that are critical for viability in A. fumigatus, including genes required for RNA metabolism, organelle organization, protein transport, ribosome biogenesis, and transcription, as well as a number of noncoding RNAs. A number of these genes represent potential targets for much-needed novel antifungal drugs.

Fatal Aspergillus flavus infection in a neonate

Aspergillosis is an uncommon perinatal infection diagnosed with increasing frequency in recent years. We report a premature infant who required both nutrition and ventilation artificially assisted and developed a disseminated invasive nosocomial infection from Aspergillus flavus. Autopsy revealed marked hypotrophy of the thymus and multisystem invasive aspergillosis chiefly involving the vascular and alimentary systems and also the respiratory tract, the central nervous system, and the skin. From what we know, this is the first case of the literature with a misleading initial clinical presentation involving the alimentary tract (hepatomegaly, ingravescent cholestatic icterus) and evolving in intestinal occlusion.

Clinical characteristics of 45 patients with invasive pulmonary aspergillosis: retrospective analysis of 1711 lung cancer cases

BACKGROUND

: Invasive aspergillosis (IA) is a common complication in patients with hematologic malignancies. Patients with solid tumors also are at risk for IA because they may develop neutropenia as a result of chemotherapy and radiotherapy. However, studies of IA in patients with solid tumors are rare. In this study, the risk factors and clinical characteristics of pulmonary infection and death mediated by invasive pulmonary aspergillosis (IPA) as complications in patients with lung cancer were determined.

METHODS

: The authors conducted a retrospective analysis of the clinical notes from 45 patients who had IPA.

RESULTS

: Among 1711 patients with lung cancer, 45 patients contracted pulmonary aspergillosis (2.63%). There were 10 cases of proven disease and 35 cases of probable disease. In univariate analysis, the main predisposing factors were clinical stage IV disease (P = .018), chemotherapy during the month preceding infection (P = .033), and corticosteroid use (> or =3 days; P = .038). In multivariate analysis, only clinical stage IV disease (P = .018) was associated with IPA. Furthermore, the mortality rate among lung cancer patients who had pulmonary aspergillosis was 51.1% (23 of 45 patients). Of the patients who died, corticosteroid therapy (P = .001) and grade 3/4 neutropenia (P = .013) were correlated statistically with pulmonary aspergillosis in patients with lung cancer.

CONCLUSIONS

: In univariate analysis, the risk factors for IPA in lung cancer included chemotherapy and corticosteroid use in the month preceding infection and clinical stage IV disease. However, in multivariate analysis, only clinical stage IV disease was identified as a risk factor for IPA. Cancer 2009. (c) 2009 American Cancer Society.

IFI = invasive fungal infections. What is that? A misnomer, because a non-invasive fungal infection does not exist!

In principle, one has to differentiate between a mere colonization and an invasive fungal infection (IFI) with quite different clinical manifestations and consequences. If the term invasive were used in its proper sense (expressis verbis), all fungal infections could be called invasive, even a fungal keratitis or an infection of the hairs by dermatophytes. In general, however, the term IFI is used only to characterize systemic, generalized, deep-seated, visceral and severe, life-threatening fungal infections, in contrast to superficial, local, benign, self-limiting fungal diseases. The term IFI as used generally is thus misleading, confusing, and not at all helpful to correctly differentiate mild, moderate, and severe fungal infections.

Defining fractional inhibitory concentration index cutoffs for additive interactions based on self-drug additive combinations, Monte Carlo simulation analysis, and in vitro-in vivo correlation data for antifungal drug combinations against Aspergillus fumigatus

The fractional inhibitory concentration (FIC) index range of 0.5 to 4 that is commonly used to define additivity results in no interactions in most combination studies of antifungal agents. These results may differ from those of in vivo studies, where positive and negative interactions may be observed. We reassessed this in vitro FIC index range based on (i) the experimental variation of the checkerboard technique using multiple replicates, (ii) the ability to correctly determine purely additive self-drug and two-drug antagonistic combinations of amphotericin B (AMB) and voriconazole (VRC), (iii) Monte Carlo simulation analysis, and (iv) in vitro-in vivo correlation using experimental models of invasive pulmonary aspergillosis against the same Aspergillus fumigatus isolate based on visual, spectrophotometric, and colorimetric determinations of FICs after 24 and 48 h of incubation. FICs obtained after 24 h of incubation ranged from 0.5 to 1.25 for the self-drug additive combinations of AMB plus AMB and VRC plus VRC and from 2.25 to 4.25 for the antagonistic combination of AMB plus VRC. Monte Carlo simulation analysis showed that self-drug combinations were correctly classified as additive and that the combination of AMB plus VRC was correctly classified as antagonistic for >85% of the simulated FICs when deviation of the 95% confidence interval (CI) of replicate FICs from the additivity range of 1 to 1.25 was used to assess interactions after 24 h. In vitro-in vivo correlation analysis showed that the 95% CIs of the FICs of the in vivo synergistic combination anidulafungin plus VRC determined after 24 h were lower than 1 and the 95% CIs of the FICs of the in vivo antagonistic combination AMB plus ravuconazole were higher than 1.25. Adequate insight into weak pharmacodynamic interactions with in vivo relevance may be obtained by demonstrating that triplicate FICs at 24 h are outside an inclusive additivity range of 1 to 1.25.

Aspergillus and the paediatric lung

Aspergillus spp produce a wide range of saprophytic and invasive syndromes in the lungs, including allergic bronchopulmonary aspergillosis (ABPA), aspergilloma and invasive pulmonary aspergillosis (IPA). ABPA results from hypersensitivity to the fungus, and mainly affects patients with asthma or cystic fibrosis (CF). The treatment of choice consists of systemic corticosteroids and itraconazole. Aspergilloma is managed by observation or surgery. IPA is predominantly seen in patients with haematological malignancies, chronic granulomatous disease or immunosuppressive treatment. With the use of aggressive therapies for end-stage CF, such as heart-lung transplantation, the potential for a patient to convert from colonization or ABPA to IPA has increased. Suggestive clinical and radiological findings, supplemented with mycological data using serology and molecular biology, have enhanced the capacity to diagnose IPA in paediatric patients. While voriconazole is considered the first-line therapy in IPA, several other antifungal agents may be appropriate alternatives.

Pulmonary aspergillosis in patients with chronic obstructive pulmonary disease: incidence, risk factors, and outcome

We describe a large series of patients with chronic obstructive pulmonary disease (COPD) and probable invasive pulmonary aspergillosis (IPA), and the risk factors and incidence of the disease in patients with isolation of Aspergillus from lower respiratory tract samples. From 2000 to 2007, we retrospectively studied all patients admitted with COPD and isolation of Aspergillus (239; 16.3/1000 admissions). Multivariate logistic regression and survival curves were used. Fifty-three patients had probable IPA (3.6 cases of IPA per 1000 COPD admissions). IPA affects at least 22.1% of patients with COPD and isolation of Aspergillus in culture. In 33 of the 53 patients with probable IPA, serum galactomannan was determined; in 14 (42.4%) of these, the result was positive. Five variables were independent predictors of IPA with statistical significance: admission to the intensive-care unit, chronic heart failure, antibiotic treatment received in the 3 months prior to admission, the accumulated dosage of corticosteroids equivalent to >700 mg prednisone received in the 3 months prior to admission, and the similar accumulated dosage of corticosteroids received from admission to the first clinical isolation of Aspergillus. Multivariate analysis gave an area under the curve of 0.925 (95% CI 0.888-0.962; p <0.001). The overall mean survival of the cohort was 64.1% (28.3% for IPA patients and 75.2% for non-IPA patients). The median number of days of survival was 48 (95% CI 33.07-62.92). However, we found statistically significant differences between patients with IPA (29 days; 95% CI 20.59-37.40) and patients without IPA (86 days; 95% CI 61.13-110.86) (log rank, p <0.001).

Invasive aspergillosis in patients with acute myeloid leukemia: a SEIFEM-2008 registry study

BACKGROUND

The aim of this study was to evaluate prognostic factors, treatments and outcome of invasive aspergillosis in patients with acute myeloid leukemia based on data collected in a registry.

DESIGN AND METHODS

The registry, which was activated in 2004 and closed in 2007, collected data on patients with acute myeloid leukemia, admitted to 21 hematologic divisions in tertiary care centers or university hospitals in Italy, who developed proven or probable invasive aspergillosis.

RESULTS

One hundred and forty cases of invasive aspergillosis were collected, with most cases occurring during the period of post-induction aplasia, the highest risk phase in acute myeloid leukemia. The mortality rate attributable to invasive aspergillosis was 27%, confirming previous reports of a downward trend in this rate. Univariate and multivariate analyses revealed that the stage of acute myeloid leukemia and the duration of, and recovery from, neutropenia were independent prognostic factors. We analyzed outcomes after treatment with the three most frequently used drugs (liposomal amphotericin B, caspofungin, voriconazole). No differences emerged in survival at day 120 or in the overall response rate which was 71%, ranging from 61% with caspofungin to 84% with voriconazole.

CONCLUSIONS

Our series confirms the downward trend in mortality rates reported in previous series, with all new drugs providing similar survival and response rates. Recovery from neutropenia and disease stage are crucial prognostic factors. Efficacious antifungal drugs bridge the period of maximum risk due to poor hematologic and immunological reconstitution.

Approach to the immunocompromised host with infection in the intensive care unit

Despite significant advances in the prevention, diagnosis, and treatment of infection in the immunocompromised host, it remains a major cause of morbidity, increased length of stay, total costs, and of course mortality. Intensive care mortality rates are significantly higher among immunocompromised hosts in part due to the higher incidence of infection severity. The superimposition of the compromised host defenses and critical illness makes the detection and management of infections in such patients more difficult, but crucial toward salvaging patient outcome. Moreover, although there is a rapidly increasing evidence base in intensive care medicine, many interventional trials for the management of severe sepsis (activated protein C, adjunctive corticosteroids, goal-based resuscitation), acute lung injury (low stretch ventilation), and other organ failures have excluded immunocompromised hosts.

Wild-type MIC distribution and epidemiological cutoff values for Aspergillus fumigatus and three triazoles as determined by the Clinical and Laboratory Standards Institute broth microdilution methods

Antifungal susceptibility testing of Aspergillus species has been standardized by both the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Recent studies suggest the emergence of strains of Aspergillus fumigatus with acquired resistance to azoles. The mechanisms of resistance involve mutations in the cyp51A (sterol demethylase) gene, and patterns of azole cross-resistance have been linked to specific mutations. Studies using the EUCAST broth microdilution (BMD) method have defined wild-type (WT) MIC distributions, epidemiological cutoff values (ECVs), and cross-resistance among the azoles. We tested a collection of 637 clinical isolates of A. fumigatus for which itraconazole MICs were < or = 2 microg/ml against posaconazole and voriconazole using the CLSI BMD method. An ECV of < or = 1 microg/ml encompassed the WT population of A. fumigatus for itraconazole and voriconazole, whereas an ECV of < or = 0.25 microg/ml was established for posaconazole. Our results demonstrate that the WT distribution and ECVs for A. fumigatus and the mold-active triazoles were the same when determined by the CLSI or the EUCAST BMD method. A collection of 43 isolates for which itraconazole MICs fell outside of the ECV were used to assess cross-resistance. Cross-resistance between itraconazole and posaconazole was seen for 53.5% of the isolates, whereas cross-resistance between itraconazole and voriconazole was apparent in only 7% of the isolates. The establishment of the WT MIC distribution and ECVs for the azoles and A. fumigatus will be useful in resistance surveillance and is an important step toward the development of clinical breakpoints.

Management of invasive aspergillosis in patients with COPD: rational use of voriconazole

Invasive pulmonary aspergillosis (IPA) is an important cause of mortality in patients with hematologic malignancies. The reported incidence of IPA in the context of chronic obstructive pulmonary disease (COPD) seems to increase. Approximately 1%-2% of overall fatal cases of IPA occur in COPD patients. The combination of factors such as lung immune imbalance, long-term corticosteroid use, increasing rate of bacterial exacerbations over time, and malnutrition are responsible for the emergence of IPA in these patients. The diagnosis of IPA is difficult to establish, which explains the delay in implementing accurate antifungal therapy and the high mortality rate. Persistent pneumonia nonresponsive to appropriate antibiotic treatment raises the concern of an invasive fungal infection. Definite diagnosis is obtained from tissue biopsy evidencing Aspergillus spp. on microscopic examination or in culture. Culture and microscopy of respiratory tract samples have a sensitivity and specificity of around 50%. Other diagnostic tools can be useful in documenting IPA: computed tomography (CT) scan, nonculture-based tests in serum and/or in bronchoalveolar lavage such as antibody/antigen tests for Aspergillus spp. More recent tools such as polymerase chain reaction or [1-->3]-beta-D-glucan have predictive values that need to be further investigated in COPD patients. Antifungal monotherapy using azole voriconazole is recommended as a first-line treatment of IPA. This review assesses the use of voriconazole in COPD patients.

Invasive mold infections in iatrogenically immunocompromised children: an eight-yr review

IMI are emerging as an important cause of mortality and morbidity among the growing number of immunocompromised children. A retrospective chart review was performed in all patients with a proven diagnosis of IMI over an eight-yr period (1997-2004) at The Hospital for Sick Children, Toronto, Canada to document the incidence, clinical spectrum, microbiology, treatment, and outcome of pediatric IMI. Twenty-eight patients developed IMI over the study period (10 cancer, 12 HCT, and six SOT patients). IMI occurred in 0.51%, 2.2% and 3.2% after a median time of 118, 60 and 71 days, among cancer, HCT and SOT recipients, respectively. Aspergillus spp. infection was diagnosed most commonly (23 patients) and the most common site of infection was the lung (21 patients). Patients at increased risk included those with acute myelogenous leukemia, allogeneic unrelated HCT recipients, graft-versus-host disease, and lung transplant recipients. The mortality after one yr was 60% among cancer patients, 58% among HCT patients, and 16% among SOT patients.

A safety and feasibility study comparing an intermittent high dose with a daily standard dose of liposomal amphotericin B for persistent neutropenic fever

A high intermittent dose regimen (group A: 10 mg kg(-1) on day 1, 5 mg kg(-1) on days 3 and 6) was compared with standard dosing (group B: 3 mg kg(-1) per day for 14 days) of liposomal amphotericin B (LAB) for empirical treatment of persistent febrile neutropenia. A total cumulative dose of 1275 mg (group A) and 2800 mg (group B) was administered. Infusion-related adverse drug events, mainly rigors/chills, occurred more frequently with group A (11/45, 24 % infusions) than with group B (12/201, 6 % infusions) (P=0.002), which extended the mean infusion time by 20 min (P=0.001). Creatinine levels were similar in the two regimens: the A : B ratio of the area under the curve for creatinine (AUC(CREATININE)) for days 2-7 was 1.09 (P=0.27) and for days 2-14 was 1.05 (P=0.51). Rises in creatinine were mild (clinical toxicity criteria 1) in all patients with elevations. Hypokalaemia tended to be less severe in group A with a lower proportion of hypokalaemic days [57/143 (39 %) vs 80/137 (58 %), P=0.21], a higher AUC(POTASSIUM) (A : B ratio of 1.06, P=0.12), a lower proportion of patients with hypokalaemia at the end of study (10 vs 61 %, P=0.01) and fewer potassium-supplemented days [12/210 (6 %) vs 41/210 (19.5 %), P<0.1]. There were mildly elevated median levels of serum bilirubin, alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, which were similar for the two regimens and were usually associated with other co-existing co-morbid conditions. The AUC for these enzymes was also similar in the two groups. No patient had discontinuation of the study drug due to toxicity. Composite success was identical for each regimen (11/15 patients, 73 %). Three of the fifteen patients in group B and none in group A developed invasive fungal infections (IFIs). Beta-D-Glucan levels were similar in both groups for patients without an IFI [AUC(GLUCAN) of 362 and 683 (P=0.36) for groups A and B, respectively]. The rate of defervescence was similar for each regimen (P=0.75). This feasibility study suggests that a short intermittent high-dose course of 10/5/5 mg LAB kg(-1) on days 1, 3 and 6 may be as safe and effective as a standard 14 day course of 3 mg kg(-1) per day, with drug-acquisition cost savings and reduced drug exposure. A larger study is indicated for confirmation of this.

The changing face of febrile neutropenia-from monotherapy to moulds to mucositis. Prevention of mould infections

Isolation of patients at risk of invasive mould infection might be suitable for the reduction of invasive aspergillosis or zygomycosis, if combined with high-efficiency particulate air filtration. Prophylactic wearing of filtering masks of N95 or FFP2 standards has not yet been demonstrated to be efficacious in reducing invasive mould infections outside of scenarios with excessive contamination of room air by fungal spore-loaded dust. The oral broad-spectrum antifungal azoles posaconazole and voriconazole offer protection against invasive Aspergillus infections in severely neutropenic leukaemia patients and allogeneic haematopoietic stem cell transplant recipients; however, their routine use might result not only in considerable side effects, but also in the spread of multi-azole-resistant Aspergillus species, so that careful selection of suitable high-risk patient populations is mandatory.

Surgical management of invasive pulmonary fungal infection in hematology patients

BACKGROUND

The purpose of this study was to analyze our institutional results with pulmonary resection in neutropenic patients with hematologic malignancies and suspected invasive pulmonary fungal infections.

METHODS

We performed a retrospective medical record review of 25 immunocompromised patients with hematologic malignancies who underwent pulmonary resection between 2000 and 2007. We analyzed preoperative diagnostic technique, degree of pulmonary resection, and postoperative morbidity and mortality to determine whether surgery is a viable treatment option in this subset of patients.

RESULTS

Twenty-three of 25 patients had a minithoracotomy compared with 2 who had video-assisted thorascopic surgery resection only. Thirteen had wedge resections, 9 had lobectomies, and 3 had segmentectomies. Early surgical morbidity was 2 of 25, involving 1 pneumothorax and 1 empyema. In-hospital mortality was 2, with 1 death primarily related to surgery. Median survival was 342 days, and survival was significantly better in patients with only one lesion. No patient experienced late recurrence of invasive pulmonary fungal infection. Resected pulmonary tissue also provided the best chance for a proven diagnosis in 19 of 25 (76%).

CONCLUSIONS

This study confirms that pulmonary resection in high-risk immunocompromised patients with suspected invasive fungal infection can be carried out with excellent operative morbidity and mortality.

Fluconazole-resistant Kodamaea ohmeri fungemia associated with cellulitis: case report and review of the literature

Kodamaea (Pichia) ohmeri was formerly considered a contaminant, but is now known to be a significant human pathogen that has been shown to cause fungemia, endocarditis, funguria, and peritonitis in immunocompromised patients. We report a case of fungemia caused by K. ohmeri in a 71-year-old man with cellulitis. The patient was sent to the emergency room due to leg edema, fever, and change of consciousness. During hospitalization, a series of examinations including blood cultures were performed. On hospital day 8, blood culture yielded a yeast colony. Fluconazole was given empirically, but had no effect. The pathogen was identified as K. ohmeri by Vitek YBC card, API 20C, sequencing of the 18S rRNA gene, and the D1/D2 domains of the 26S rRNA gene and the internally transcribed spacer (ITS) regions. Antifungal susceptibility testing was performed with the ATB-Fungus system, and a high minimum inhibitory concentration (level up to 64 mg/l) for fluconazole was found. Fluconazole was replaced with amphotericin B deoxylate, and the fever and cellulitis inflammation gradually subsided. The patient was discharged in a stable condition. This is the first case of K. ohmeri fungemia in Taiwan.

Modulation of Toll-like receptor 2 (TLR2) and TLR4 responses by Aspergillus fumigatus

Toll-like receptor (TLR)-based signaling pathways in the host may be modulated by pathogens during the course of infection. We describe a novel immunomodulatory mechanism in which Aspergillus fumigatus conidia induce attenuation of TLR2- and TLR4-mediated interleukin (IL)-6 and IL-1beta proinflammatory responses in human mononuclear cells with suppression of IL-1beta mRNA transcription. Background TLR2 and TLR4 mRNA transcription was not influenced. A. fumigatus conidia induced TLR2 internalization and uptake into the phagosome with a resultant decrease in surface receptor expression. A. fumigatus hyphae, on the other hand, selectively downregulated the TLR4-mediated response. These novel immunosuppressive effects may facilitate the invasiveness of A. fumigatus.

Monitoring trough concentration of voriconazole is important to ensure successful antifungal therapy and to avoid hepatic damage in patients with hematological disorders

We investigated the role of therapeutic dose monitoring (TDM) in the treatment of fungal infections with voriconazole through 49 analyses of 34 patients who received treatment for hematologic diseases. Voriconazole concentration was highly variable among patients regardless of renal, liver functions, or age, and the effect of dose enhancement was not constant. This indicates the difficulty of predicting voriconazole concentration without TDM. We evaluated the outcome with the composite assessment system where patients were assumed non-responders when they failed to show improvement in at least 2 of the following 3 criteria: clinical, radiologic, and mycologic. We showed that concentration-response relationship depended on the status of underlying hematologic diseases; this relationship was observed only in cases without refractory hematologic diseases, but not in those with refractory diseases. In the former group, cases with >2 mg/L of concentration were associated with good response to voriconazole. On the other hand, elevation of hepatic enzyme was frequently observed when voriconazole concentration was >6 mg/L. From these results, we concluded that TDM should be executed and targeted to 2-6 mg/L to improve efficacy and to avoid side effects.

The Aspergillus fumigatus transcription factor Ace2 governs pigment production, conidiation and virulence

Aspergillus fumigatus causes serious and frequently fatal infections in immunocompromised patients. To investigate the regulation of virulence of this fungus, we constructed and analysed an A. fumigatus mutant that lacked the transcription factor Ace2, which influences virulence in other fungi. The Deltaace2 mutant had dysmorphic conidiophores, reduced conidia production and abnormal conidial cell wall architecture. This mutant produced an orange pigment when grown on solid media, although its conidia had normal pigmentation. Conidia of the Deltaace2 mutant were larger and had accelerated germination. The resulting germlings were resistant to hydrogen peroxide, but not other stressors. Non-neutropenic mice that were immunosuppressed with cortisone acetate and infected with the Deltaace2 mutant had accelerated mortality, greater pulmonary fungal burden, and increased pulmonary inflammatory responses compared with mice infected with the wild-type or Deltaace2::ace2-complemented strains. The Deltaace2 mutant had reduced ppoC, ecm33 and ags3 mRNA expression. It is known that A. fumigatus mutants with absent or reduced expression of these genes have increased virulence in mice, as well as other phenotypic similarities to the Deltaace2 mutant. Therefore, reduced expression of these genes likely contributes to the increased virulence of the Deltaace2 mutant.

Combination therapy in treatment of experimental pulmonary aspergillosis: in vitro and in vivo correlations of the concentration- and dose- dependent interactions between anidulafungin and voriconazole by Bliss independence drug interaction analysis

We studied the antifungal activity of anidulafungin (AFG) in combination with voriconazole (VRC) against experimental invasive pulmonary aspergillosis (IPA) in persistently neutropenic rabbits and further explored the in vitro and in vivo correlations by using Bliss independence drug interaction analysis. Treatment groups consisted of those receiving AFG at 5 (AFG5 group) and 10 (AFG10 group) mg/kg of body weight/day, VRC at 10 mg/kg every 8 h (VRC group), AFG5 plus VRC (AFG5+VRC group), and AFG10 plus VRC (AFG10+VRC group) and untreated controls. Survival throughout the study was 60% for the AFG5+VRC group, 50% for the VRC group, 27% for the AFG10+VRC group, 22% for the AFG5 group, 18% for the AFG10 group, and 0% for control rabbits (P < 0.001). There was a significant reduction of organism-mediated pulmonary injury, measured by infarct scores, lung weights, residual fungal burdens, and galactomannan indexes, in AFG5+VRC-treated rabbits versus those treated with AFG5 and VRC alone (P < 0.05). In comparison, AFG10+VRC significantly lowered only infarct scores and lung weights in comparison to those of AFG10-treated animals (P < 0.05). AFG10+VRC showed no significant difference in other outcome variables. Significant Bliss synergy was found in vivo between AFG5 and VRC, with observed effects being 24 to 30% higher than expected levels if the drugs were acting independently. These synergistic interactions were also found between AFG and VRC in vitro. However, for AFG10+VRC, only independence and antagonism were observed among the outcome variables. We concluded that the combination of AFG with VRC in treatment of experimental IPA in persistently neutropenic rabbits was independent to synergistic at a dosage of 5 mg/kg/day but independent to antagonistic at 10 mg/kg/day, as assessed by Bliss independence analysis, suggesting that higher dosages of an echinocandin may be deleterious to the combination.