Occurrence of Pathogenic and Allergenic Molds in the Outdoor and Indoor Environment of a Major Hospital and Molecular Epidemiology of Aspergillus fumigatus in Kuwait

Aspergilli and other molds are prevalent in the environment and are an important cause of opportunistic infections and seasonal allergies in susceptible patients. This study determined species distribution of various molds in outdoor/indoor air in and around a major hospital and performed antifungal susceptibility testing and molecular fingerprinting of environmental and clinical Aspergillus fumigatus isolates in Kuwait. Sampling for the isolation of molds was performed for a 17-month-period from the water/indoor air of medical/surgical wards/ICUs and outdoor air. Molds were identified by phenotypic characteristics and/or by the PCR-sequencing of rDNA/β-tubulin/calmodulin genes. Antifungal susceptibility testing was done by Etest. Fingerprinting was performed by nine-loci-based microsatellite analysis. A total of 6179 isolates were obtained from outdoor (n = 4406) and indoor (n = 1773) environments. These included Cladosporium spp. (n = 2311), Aspergillus spp. (n = 1327), Penicillium spp. (n = 1325), Paecilomyces spp. (n = 473), Alternaria spp. (n = 218), Bipolaris spp. (n = 133), and other molds (n = 392). Fingerprinting data revealed heterogeneity among clinical and environmental A. fumigatus and shared genotypes among outdoor air and hospital environmental isolates. Itraconazole-resistant A. fumigatus isolates with TR34/L98H mutations in Cyp51A were also recovered from outdoor air (n = 1), a hospital environment (n = 3), and clinical samples (n = 2). More than 15 fungal genera and all four Aspergillus (Nigri, Flavi, Fumigati, and Terrei) sections and nine rare aspergilli were detected. The isolation frequency was higher during the peak allergy season of October/November. The presence of shared genotypes among outdoor air and the hospital environment including triazole-resistant A. fumigatus suggests a reservoir for invasive infections among susceptible hospitalized patients.

Accelerating the understanding of Aspergillus terreus: Epidemiology, physiology, immunology and advances

Aspergillus species encompass a variety of infections, ranging from invasive aspergillosis to allergic conditions, contingent upon the immune status of the host. In this spectrum, Aspergillus terreus stands out due to its emergence as a notable pathogen and its intrinsic resistance to amphotericin-B. The significance of Aspergillus-associated infections has witnessed a marked increase in the past few decades, particularly with the increasing number of immunocompromised individuals. The exploration of epidemiology, morphological transitions, immunopathology, and novel treatment approaches such as new antifungal drugs (PC945, olorofim) and combinational therapy using antifungal drugs and phytochemicals (Phytochemicals: quercetin, shikonin, artemisinin), also using immunotherapies to modulate immune response has resulted in better outcomes. Furthermore, in the context COVID-19 era and its aftermath, fungal infections have emerged as a substantial challenge for both immunocompromised and immunocompetent individuals. This is attributed to the use of immune-suppressing therapies during COVID-19 infections and the increase in transplant cases. Consequently, this review aims to provide an updated overview encompassing the epidemiology, germination events, immunopathology, and novel drug treatment strategies against Aspergillus terreus-associated infections.

Collective outbreak of severe acute histoplasmosis in immunocompetent Chinese in South America: the clinical characteristics and continuous monitoring of serum cytokines/chemokines

Background

Acute histoplasmosis is a rare fungal disease in China. This study is aimed to summarize the clinical characteristics of the first large-scale outbreak of imported acute histoplasmosis in Chinese, so as to provide suggestions for clinical diagnosis and treatment.

Methods

We collected the symptoms, signs, laboratory examination and imaging data of 10 patients in so far the biggest outbreak of imported acute histoplasmosis in immunocompetent Chinese. Their clinical characteristics and time-varying cytokine/chemokine levels were analyzed, and rank correlation analysis between these markers was utilized to show their condition.

Results

The 10 patients of imported acute histoplasmosis were working without any respiratory protection in an abandoned mine tunnel in Guyana. The most common symptoms were fever and cough. Their chest CT imaging showed multiple nodular shadows in lungs. Laboratory examination showed that at admission the CRP, PCT, LDH, CysC, G-test, β2-MG were all increased in at least 9 patients, and the CD4/CD8 was decreased to < 1 in all patients. Most cytokines/chemokines (other than IL-4, IL-12, INF-α, TNF-α) varied widely with patients and time, but their overall trend is higher at admission and decreasing gradually during hospitalization, especially for the IL-6, IL-8, IL-10 and IFN-γ. The LDH, CysC, G-test, β2-MG, N/L, IL-6, IL-8, IL-10, IFN-γ, IL-27 are in positive associations to both CRP and PCT.

Conclusions

The diagnosis of acute histoplasmosis needs a comprehensive analysis of epidemiological history, clinical symptoms and signs, and results of imaging, laboratory, microbiological and pathological examinations. Although none of the CRP, PCT, G-test, N/L, LDH, CysC, β2-MG, IL-6, IL-8, IL-10, IFN-γ shows specificity in the diagnosis of acute histoplasmosis, there is possibility that the above factors might help in the inflammation and prognosis estimation. However, more studies and further investigation are still required for the verification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01771-2.

Simultaneous detection of fungal (1,3)-β-d-glucan and procalcitonin using a dual-label time-resolved fluorescence immunoassay

Neonatal infectious diseases are a serious threat to the health of newborns. The aim was to establish a new detection method for the simultaneous measurement of (1,3)-β-d-glucan and procalcitonin in serum for the early screening and efficacy testing of neonatal infectious diseases. We established a sandwich dual-label time-resolved fluorescence immunoassay (TRFIA): anti-(1,3)-β-d-glucan/procalcitonin antibodies immobilized on 96-well plates captured (1,3)-β-d-glucan/procalcitonin antigens and then banded together with the detection antibodies labeled with europium(III) (Eu³⁺ )/samarium(III) (Sm³⁺ ) chelates. Finally, time-resolved fluorometry was used to measure the fluorescence intensity. The linear correlation coefficient (R² ) of the (1,3)-β-d-glucan standard curve was 0.9913, and the R² of the procalcitonin standard curve was 0.9911. The detection sensitivity for (1,3)-β-d-glucan was 0.4 pg/mL (dynamic range: 0.6-90 pg/mL), and the average recovery was 101.55%. The detection sensitivity for procalcitonin was 0.02 ng/mL (dynamic range: 0.05-95 ng/mL), and the average recovery was 104.61%. There was a high R² between the present TRFIA method and a commercially available assay (R²  = 0.9829 for (1,3)-β-d-glucan and R²  = 0.9704 for procalcitonin). Additionally, the cutoff values for (1,3)-β-d-glucan and procalcitonin were 23.95 pg/mL and 0.055 ng/mL, respectively. The present TRFIA method has high sensitivity, accuracy, and specificity and is an effective method for early screening and efficient testing of neonatal invasive fungal infection.

Periprosthetic hip joint infection with Aspergillus terreus: A clinical case and a review of the literature

Fungal periprosthetic joint infections due to Aspergillus species are rare but are associated with significant cost and morbidity. We present a case of Asperigillus terreus prosthetic joint infection of the hip. The patient was successfully treated with a prolonged course of systemic antifungals along with surgical management.

Effect of involved Aspergillus species on galactomannan in bronchoalveolar lavage of patients with invasive aspergillosis

PURPOSE

The detection of galactomannan (GM) in bronchoalveolar lavage (BAL) fluid is an important surrogate marker for the early diagnosis and therapeutic monitoring of invasive aspergillosis (IA), regardless of the involved species of Aspergillus. Here, we utilized the Platelia Aspergillus GM enzyme immunoassay (Bio-Rad) to evaluate the GM index in BAL fluid samples from patients with proven, probable or putative IA due to Aspergillusflavus versus Aspergillusfumigatus.

METHODOLOGY

In a prospective study between 2009 and 2015, 116 BAL samples were collected from suspected IA patients referred to two university hospitals in Tehran, Iran.

KEY FINDINGS

According to European Organization for Research and Treatment of Cancer and Mycoses Study Group and Blot criteria, 35 patients were classified as IA patients, of which 33 cases tested positive for GM above 0.5 and, among these patients, 22 had a GM index ≥1. Twenty-eight were culture positive for A. flavus and seven for A. fumigatus. The GM index for A. flavus cases was between 0.5-6.5 and those of A. fumigatus ranged from 1 to 6.5. The sensitivity and specificity of a GM index ≥0.5 in cases with A. flavus were 86 and 88 % and for A. fumigatus patients were 100 and 73 %, respectively.

CONCLUSION

Overall, the mean GM index in patients with A. fumigatus (3.1) was significantly higher than those of A. flavus (1.6; P-value=0.031) and the sensitivity of GM lower for A. flavus when compared to A. fumigatus. This finding has implications for diagnosis in hospitals and countries with a high proportion of A. flavus infections.

Prognostic value of galactomannan: current evidence for monitoring response to antifungal therapy in patients with invasive aspergillosis

Galactomannan (GM) is a polysaccharide present in the cell wall of Aspergillus spp. that is released during growth of the organism. It has been successfully used to aide in the diagnosis of invasive aspergillosis allowing for earlier recognition of disease compared to conventional methods. Since its implementation in the clinic as a diagnostic tool, GM has been used in experimental models to measure therapeutic response. Several clinical studies describe the prognostic value of GM. Herein, we review the evidence supporting the utilization of GM antigen as a biomarker to measure response to systemic antifungal therapy.

Treatment of Aspergillus terreus infections: a clinical problem not yet resolved

Despite the use of recommended therapies, invasive infections by Aspergillus terreus show a poor response. For years, investigative studies on the failure of therapy of fungal infections have focused on in vitro susceptibility data. However, it is well known that low minimum inhibitory concentrations (MICs) are not always predictive of response to therapy despite a correct dosage schedule. Many experimental and clinical studies have tried to establish a relationship between MICs and outcome in serious fungal infections but have come to contradictory and even surprising conclusions. The success or failure of treatment is determined by many factors, including the in vitro susceptibility of the causative fungal isolate, the pharmacokinetics/pharmacodynamics of the drug used for treatment, pharmacokinetic variability in the population, and the underlying disease that patients suffer. To try to understand this poor response to treatment, available data on the in vitro susceptibility of A. terreus, the experimental and clinical response to amphotericin B, triazoles and echinocandins, and the pharmacokinetics/pharmacodynamics of these antifungals have been reviewed. Of special interest are the fungistatic activites of these drugs against A. terreus and the high interpatient variability of serum drug levels observed in therapy based on triazoles, which make monitoring of infected patients necessary.

Development of a novel inhalational model of invasive pulmonary aspergillosis in rats and comparative evaluation of three biomarkers for its diagnosis

Aspergillus fumigatus, a thermotolerant fungus, is the main causative agent of invasive pulmonary aspergillosis (IPA) in immunocompromised patients that is associated with high mortality rates. Early diagnosis of IPA is crucial for mortality reduction and improved prognosis. An experimental inhalational model of IPA was developed in rats and the efficacy of three biomarkers, namely β-D-glucan (BDG), a panfungal marker, galactomannan (GM), a genus-specific marker, and A. fumigatus DNA, a species-specific marker was evaluated in serum and bronchoalveolar lavage (BAL) specimens at different time points postinfection for early diagnosis of IPA. BDG and GM were detected by using commercial Fungitell and Platelia Aspergillus EIA kits, respectively. A. fumigatus DNA was detected by developing a sensitive, single-step PCR assay. IPA was successfully developed in immunosuppressed rats and all animals until 5 days post-infection were positive for A. fumigatus by culture and KOH-calcofluor microscopy also showed A. fumigatus in 19 of 24 (79%) lung tissue samples. Fourteen of 30 (47%) and 27 of 30 (90%) serum and BAL specimens, respectively, were positive for all three biomarkers with 100% specificity (none of sera or BAL specimens of 12 control rats was positive for biomarkers). Our data show that BAL is a superior specimen than serum and combined detection of BDG, GM and A. fumigatus DNA provide a sensitive diagnosis of IPA in an experimental animal model. Moreover, combined detection of GM and DNA in BAL and detection of either GM or DNA in serum was also positive in 27 of 30 (90%) animals. For economic reasons and considering that the positive predictive value of BDG is low, the detection of GM and/or DNA in serum and BAL samples has the potential to serve as an integral component of the diagnostic-driven strategy in high-risk patients suspected for IPA.

Laboratory diagnosis of invasive aspergillosis: from diagnosis to prediction of outcome

Invasive aspergillosis (IA), an infection caused by fungi in the genus Aspergillus, is seen in patients with immunological deficits, particularly acute leukaemia and stem cell transplantation, and has been associated with high rates of mortality in previous years. Diagnosing IA has long been problematic owing to the inability to culture the main causal agent A. fumigatus from blood. Microscopic examination and culture of respiratory tract specimens have lacked sensitivity, and biopsy tissue for histopathological examination is rarely obtainable. Thus, for many years there has been a great interest in nonculture-based techniques such as the detection of galactomannan, β -D-glucan, and DNA by PCR-based methods. Recent meta-analyses suggest that these approaches have broadly similar performance parameters in terms of sensitivity and specificity to diagnose IA. Improvements have been made in our understanding of the limitations of antigen assays and the standardisation of PCR-based DNA detection. Thus, in more recent years, the debate has focussed on how these assays can be incorporated into diagnostic strategies to maximise improvements in outcome whilst limiting unnecessary use of antifungal therapy. Furthermore, there is a current interest in applying these tests to monitor the effectiveness of therapy after diagnosis and predict clinical outcomes. The search for improved markers for the early and sensitive diagnosis of IA continues to be a challenge.

Detection of urinary excreted fungal galactomannan-like antigens for diagnosis of invasive aspergillosis

Mortality associated with invasive aspergillosis (IA) remains high, partly because of delayed diagnosis. Detection of microbial exoantigens, released in serum and other body fluids during infection, may help timely diagnosis. In course of IA, Aspergillus galactomannan (GM), a well established polysaccharide biomarker, is released in body fluids including urine. Urine is an abundant, safely collected specimen, well-suited for point-of-care (POC) testing, which could play an increasing role in screening for early disease. Our main objective was to demonstrate GM antigenuria as a clinically relevant biological phenomenon in IA and establish proof-of-concept that it could be translated to POC diagnosis. Utilizing a novel IgM monoclonal antibody (MAb476) that recognizes GM-like antigens from Aspergillus and other molds, we demonstrated antigenuria in an experimental animal IA model (guinea pig), as well as in human patients. In addition, we investigated the chemical nature of the urinary excreted antigen in human samples, characterized antigen detection in urine by immunoassays, described a putative assay inhibitor in urine, and indicated means of alleviation of the inhibition. We also designed and used a lateral flow immunochromatographic assay to detect urinary excreted antigen in a limited number of IA patient urine samples. In this study, we establish that POC diagnosis of IA based on urinary GM detection is feasible. Prospective studies will be necessary to establish the performance characteristics of an optimized device and define its optimal clinical use.

First case of breakthrough pneumonia due to Aspergillus nomius in a patient with acute myeloid leukemia

We report the first known case of a breakthrough pulmonary infection caused by Aspergillus nomius in an acute myeloid leukemia patient receiving caspofungin therapy. The isolate was identified using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and sequencing-based methods. The organism was found to be fully susceptible, in vitro, to echinocandin antifungal agents.

Emerging moulds: epidemiological trends and antifungal resistance

Invasive fungal infections (IFIs) are associated with high morbidity and mortality in immunocompromised patients. Although Aspergillus spp. remain an important cause of IFI, other moulds such as Fusarium spp., dematiaceous fungi and Mucorales have become increasingly prevalent among this patient population. Diagnosis and treatment of invasive mould infections remain a challenge. Because of the poor prognosis associated with IFIs, understanding the activity, efficacy and limitations of the available drugs is critical to select the appropriate antifungal agent on an individualised basis.