Aspergilosis. Formas clínicas y tratamiento

Cervico-Dorsal Intramedullary Spinal Cord Abscess with Aspergillus fumigates following Pulmonary Infection in an Immunocompetent Patient

Invasive forms of aspergillosis of the nervous system are relatively rare and are usually diagnosed in immunocompromised patients. We present the case of a young female patient, treated in the last two months with corticosteroids and antifungal drug for pulmonary aspergillosis, who developed progressive paraparesis. An intramedullary abscess at the C7-D1 level was identified and the lesion was treated with a combination of surgery and antifungal therapy. Histopathologic findings of surgical specimens showed myelomalacia with Aspergillus hyphae and a peripheral rim of neutrophils. We consider that the use of multiple drugs and corticosteroids for our patient's initial community pneumonia could be the factor that transformed her into a mildly immunocompromised individual and permitted the Aspergillus spp. to disseminate through the blood and into the spinal cord. Moreover, we highlight the fact that more attention should be paid to living and working conditions of the patients, as a simple colonization of the lung with Aspergillus spp. could develop, in a short time, into an invasive disease with a high risk of mortality.

A 9-Year Experience of Aspergillus Infections from Isfahan, Iran

Purpose

Aspergillosis is an important fungal disease affecting millions of individuals worldwide. The genus of Aspergillus consist of various complexes, causing a wide spectrum of diseases from superficial infections in immunocompetent hosts to life-threatening disseminated infections among immunocompromised patients. This study aimed to identify Aspergillus species by phenotypic (total isolates) and molecular tests (35 isolates), obtained from patients in Isfahan (the third-largest city of Iran) between 2010 and 2018, and determine the susceptibility of 35 clinical isolates to itraconazole (ITR), amphotericin-B (AMB), and voriconazole (VOR).

Patients and Methods

Based on clinical signs, a total of 2385 suspected cases were included in this retrospective study from January 2010 to December 2018. Direct microscopic examination with potassium hydroxide, sabouraud dextrose agar with chloramphenicol, and czapekdox agar media was applied to identify etiologic agents. Thirty-five Aspergillus species collected from January 2016 to December 2018 were identified by PCR-sequencing of ITS1-5.8SrDNA-ITS2 region, and their susceptibility to ITR, AMB, and VOR was determined using E-test.

Results

Based on direct microscopy and positive culture, 132 out of 2385 suspected cases had Aspergillus infection (5.5%). Fifty-four patients were male, and 78 patients were female. Patients in the age groups of 41–50 and 21–30 years had the highest and lowest frequencies, respectively. Aspergillus flavus/oryzae (n=54), A. fumigatus (n=24), A. niger (n=15), and A. terreus (n=12) were the most prevalent Aspergillus species, respectively. Among 35 Aspergillus species, the MIC ranges of AMB, ITR, and VOR for A. flavus/oryzae, A. niger, and A. terreus were (0.5–4 μg/mL; 0.5–16 μg/mL; 0.25–8 μg/mL), (1 μg/mL, 1 μg/mL, 1 μg/mL), and (4–4 μg/mL, 0.5–1 μg/mL, 0.5–1 μg/mL), respectively.

Conclusion

Aspergillus infections have a wide spectrum of clinical manifestations and often occur in immunocompromised patients. Accurate identification at the species level is essential since the emergence of cryptic species is connected to different patterns of AFST that affect patient treatment outcomes. Azole-resistant Aspergillus spp. is a global concern, and the detection of the route of resistance is pivotal to prevent and control infection.

Invasive aspergillosis manifesting as retinal necrosis in a patient treated with ruxolitinib

A 30 year-old man with acute myeloblastic leukaemia and secondary myelodysplastic syndrome developed graft-versus-host disease. The patient was treated with ruxolitinib. After being treated for 3 months with ruxolitinib, an inhibitor of Janus kinase, he developed Aspergillus retinal necrosis resistant to common treatment. Treatment with Janus kinase inhibitors may lead to an increased incidence of opportunistic infections. Janus kinase inhibitor administration may result in poor treatment efficacy.

Identification of clinical isolates of Aspergillus, including cryptic species, by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)

An expanded library of matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been constructed using the spectra generated from 42 clinical isolates and 11 reference strains, including 23 different species from 8 sections (16 cryptic plus 7 noncryptic species). Out of a total of 379 strains of Aspergillus isolated from clinical samples, 179 strains were selected to be identified by sequencing of beta-tubulin or calmodulin genes. Protein spectra of 53 strains, cultured in liquid medium, were used to construct an in-house reference database in the MALDI-TOF MS. One hundred ninety strains (179 clinical isolates previously identified by sequencing and the 11 reference strains), cultured on solid medium, were blindy analyzed by the MALDI-TOF MS technology to validate the generated in-house reference database. A 100% correlation was obtained with both identification methods, gene sequencing and MALDI-TOF MS, and no discordant identification was obtained. The HUVR database provided species level (score of ≥2.0) identification in 165 isolates (86.84%) and for the remaining 25 (13.16%) a genus level identification (score between 1.7 and 2.0) was obtained. The routine MALDI-TOF MS analysis with the new database, was then challenged with 200 Aspergillus clinical isolates grown on solid medium in a prospective evaluation. A species identification was obtained in 191 strains (95.5%), and only nine strains (4.5%) could not be identified at the species level. Among the 200 strains, A. tubingensis was the only cryptic species identified. We demonstrated the feasibility and usefulness of the new HUVR database in MALDI-TOF MS by the use of a standardized procedure for the identification of Aspergillus clinical isolates, including cryptic species, grown either on solid or liquid media.

Prevalence and in vitro antifungal susceptibility of cryptic species of the genus Aspergillus isolated in clinical samples

INTRODUCTION

The genus Aspergillus contains more than 300 species, which are divided into closely related groups called sections. Molecular studies have revealed numerous cryptic species within different sections of this genus, which have different profiles of antifungal susceptibility and lack diagnostic morphological features. However, there are few studies on the prevalence and in vitro antifungal susceptibility of the cryptic species of this genus. The aim of this study was to investigate the distribution of Aspergillus spp. among clinical samples, and to study their in vitro susceptibility to different antifungal drugs.

METHOD

Over a period of 2-years (2014-2015), a total of 379 strains of the genus Aspergillus were isolated. Most of the isolates were classified as respiratory colonizations; no cases of invasive aspergillosis were found. The strains were identified by MALDI-TOF mass spectrometry, and susceptibility testing was performed by the EUCAST reference procedure.

RESULTS

Twenty species belonging to 8 sections were identified, being A. fumigatus the most prevalent (44.1%). The prevalence of cryptic species was 15.3%, with a clear predominance of A. tubingensis. Among the tested antifungal drugs, amphotericin B was the less active in vitro, followed by triazole drugs and echinocandins. The cryptic species had minimun inhibitory concentrations (MICs) higher than the corresponding type species.

CONCLUSIONS

Accurate identification of the genus Aspergillus at the species level and in vitro antifungal susceptibility testing are necessary because, as it has been shown, some species of this genus may show resistance profiles against available antifungal drugs.

Efficacy, Biodistribution, and Nephrotoxicity of Experimental Amphotericin B-Deoxycholate Formulations for Pulmonary Aspergillosis

An experimental micellar formulation of 1:1.5 amphotericin B-sodium deoxycholate (AMB:DCH 1:1.5) was obtained and characterized to determine its aggregation state and particle size. The biodistribution, nephrotoxicity, and efficacy against pulmonary aspergillosis in a murine model were studied and compared to the liposomal commercial formulation of amphotericin B after intravenous administration. The administration of 5 mg/kg AMB:DCH 1:1.5 presented 2.8-fold-higher lung concentrations (18.125 ± 3.985 μg/g after 6 daily doses) and lower kidney exposure (0.391 ± 0.167 μg/g) than liposomal commercial amphotericin B (6.567 ± 1.536 and 5.374 ± 1.157 μg/g in lungs and kidneys, respectively). The different biodistribution of AMB:DCH micelle systems compared to liposomal commercial amphotericin B was attributed to their different morphologies and particle sizes. The efficacy study has shown that both drugs administered at 5 mg/kg produced similar survival percentages and reductions of fungal burden. A slightly lower nephrotoxicity, associated with amphotericin B, was observed with AMB:DCH 1:1.5 than the one induced by the liposomal commercial formulation. However, AMB:DCH 1:1.5 reached higher AMB concentrations in lungs, which could represent a therapeutic advantage over liposomal commercial amphotericin B-based treatment of pulmonary aspergillosis. These results are encouraging to explore the usefulness of AMB:DCH 1:1.5 against this disease.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

cipC is important for Aspergillus fumigatus virulence

Aspergillus fumigatus is the main causative agent of invasive aspergillosis, a disease that affects immunocompromised patients and has a high mortality rate. We previously observed that the transcription of a cipC-like gene was increased when A. fumigatus encountered an increased CO₂ concentration, as occurs during the infection process. CipC is a protein of unknown function that might be associated with fungal pathogenicity. In this study, the cipC gene was disrupted in A. fumigatus to evaluate its importance for fungal pathogenicity. The gene was replaced, and the germination, growth phenotype, stress responses, and virulence of the resultant mutant were assessed. Although cipC was not essential, its deletion attenuated A. fumigatus virulence in a low-dose murine infection model, suggesting the involvement of the cipC gene in the virulence of this fungus. This study is the first to disrupt the cipC gene in A. fumigatus.

Role of carbonic anhydrases in pathogenic micro-organisms: a focus on Aspergillus fumigatus

Aspergillus fumigatus is a ubiquitous saprophytic fungus responsible for organic material decomposition, and plays an important role in recycling environmental carbon and nitrogen. Besides its important role in the environment, this fungus has been reported as one of the most important fungal pathogens in immunocompromised patients. Due to changes in CO2 concentration that some pathogens face during the infection process, studies have been undertaken to understand the pathogenic roles of carbonic anhydrases (CAs), well-known CO2 hydration catalytic enzymes. As a basis for a discussion of the possible roles of CAs in A. fumigatus pathogenicity, this review describes the main characteristics of the A. fumigatus infection and the challenges for its treatment. In addition, it gathers findings from studies with CA inhibitor drugs as anti-infective agents in different pathogens.