Population-based survey of filamentous fungi and antifungal resistance in Spain (FILPOP Study)

Post-surgical mediastinitis caused by Aspergillus calidoustus in a heart transplant recipient: A case report and review of the literature

Acute mediastinitis is a common infectious complication following heart transplant surgery. The etiology is typically bacterial, and the condition tends to have a favourable outcome with appropriate source control and antimicrobial treatment. Clinically, it often presents acutely, with early dehiscence of the surgical wound and systemic involvement, necessitating prompt surgical intervention. Fungal etiology is rare and usually associated with severely immunocompromised patients, conferring a dismal prognosis. Although most fungal infections are caused by Aspergillus fumigatus, the widespread use of azoles as prophylactic treatment has led to an increase in infections by unknown species and other azole-resistant fungi, posing a significant therapeutic challenge. We present the case of a 31-year-old heart transplant recipient who developed post-surgical mediastinitis due to Aspergillus calidoustus following a complicated postoperative course and humoral rejection. Despite appropriate antimicrobial therapy and source control, the infection progressed unfavourably.

Invasive aspergillosis caused by cryptic species in transplant recipients: A review

The clinical and microbiological characteristics of invasive aspergillosis (IA) caused by cryptic Aspergillus species have not been well-defined in transplant settings. However, IA is among the most common mould infections in solid organ and hematopoietic stem cell transplant recipients. Among 55 causative isolates in the 53 reported cases, Aspergillus calidoustus, A. lentulus, A. tubingensis, and A. udagawae were the four most common causative cryptic Aspergillus species. Newer diagnostic modalities, such as matrix-assisted laser desorption ionization-time of flight mass spectrometry, may help diagnose these cryptic species. Of the 24 cases with detailed clinical information, 13 had antifungal breakthrough infections. The 12-week mortality rates of all 24 cases, 7 cases of A. calidoustus, and 7 cases of A. lentulus were 46%, 43%, and 43%, respectively. Based on antifungal susceptibility profiles obtained from previous studies, an empiric antifungal regimen such as liposomal amphotericin B with or without echinocandin is recommended for A. calidoustus. A combination of an anti-mould azole and liposomal amphotericin B with or without an echinocandin is suggested for A. lentulus and A. udagawae. Additionally, any one of voriconazole, isavuconazole, or posaconazole with or without liposomal amphotericin B with or without an echinocandin is indicated for A. tubingensis. Newer antifungal agents may have more significant activity against Aspergillus cryptic species.

Species Diversity and Distribution of Non-fumigatus Aspergillus Species in Ogasawara Islands, Japan

Aspergillus sections Flavi, Nigri, and Terrei are known as common causative agents of aspergillosis, followed by section Fumigati. A previous study investigated the distribution of section Fumigati in Izu and Ogasawara Islands and found that the dominant species changes depending on the soil environment. This study investigated the species diversity and distribution of sections Flavi, Nigri, and Terrei in Mukojima, Hahajima, and Chichijima of Ogasawara Islands and clarified whether the dominant species vary depending on the soil environment, as in section Fumigati. The strains were isolated from soil samples collected in 2019 and 2020 at 18 sites in three islands, including different landscapes, and species identification was based on the nucleotide sequence of the calmodulin gene. Overall, 172 strains were isolated from all sites and identified to seven section Flavi, five section Nigri, and three section Terrei species. Three section Flavi, three section Nigri, and one section Terrei species have been reported as causative agents of aspergillosis. Three sections were distributed in Chichijima and Hahajima, but only section Nigri was found in Mukojima. The frequency of occurrence of Aspergillus tamarii and Aspergillus nomiae belonging to section Flavi and Aspergillus niger and Aspergillus tubingensis belonging to section Nigri were > 60% in forests, including shrub forests, whereas that of Aspergillus floccosus belonging to section Terrei was > 40% in bare land and grassland. Aspergillus pseudonomiae belonging to section Flavi was isolated at > 40% frequency of occurrence regardless of the landscape. Thus, differences of soil environments affected the distribution of the dominant species belonging to three sections.

Strain heterogeneity in a non-pathogenic Aspergillus fungus highlights factors associated with virulence

Fungal pathogens exhibit extensive strain heterogeneity, including variation in virulence. Whether closely related non-pathogenic species also exhibit strain heterogeneity remains unknown. Here, we comprehensively characterized the pathogenic potentials (i.e., the ability to cause morbidity and mortality) of 16 diverse strains of Aspergillus fischeri, a non-pathogenic close relative of the major pathogen Aspergillus fumigatus. In vitro immune response assays and in vivo virulence assays using a mouse model of pulmonary aspergillosis showed that A. fischeri strains varied widely in their pathogenic potential. Furthermore, pangenome analyses suggest that A. fischeri genomic and phenotypic diversity is even greater. Genomic, transcriptomic, and metabolic profiling identified several pathways and secondary metabolites associated with variation in virulence. Notably, strain virulence was associated with the simultaneous presence of the secondary metabolites hexadehydroastechrome and gliotoxin. We submit that examining the pathogenic potentials of non-pathogenic close relatives is key for understanding the origins of fungal pathogenicity.

Non-invasive detection of Aspergillosis in ventilated patients: Galactomannan analysis in exhaled breath

This study evaluates the non-invasive diagnosis of Invasive Aspergillosis Pneumonia (IPA) in mechanically ventilated patients by measuring galactomannan (GM) in exhaled breath condensate (EBC). Utilizing a rat model and a novel EBC collection device, we compared GM levels in bronchoalveolar lavage fluid (BALF) and EBC, supplemented by cytokine profiling. Analysis of 75 patients confirmed the device's efficacy, with EBC-GM and BALF-GM showing high diagnostic accuracy (AUC = 0.88). The threshold of 0.235 ng/ml for EBC-GM achieved 92.8 % sensitivity and 66.7 % specificity, with a strong correlation (r = 0.707, P < 0.001) with BALF-GM. This approach offers a safe, effective alternative to invasive diagnostics, enhancing precision with IL-6 and TNF-α measurements. The number registered on clinicaltrails.gov is NCT06333379.

Invasive aspergillosis: A comprehensive review

Invasive aspergillosis (IA) is a severe fungal infection caused by Aspergillus species, particularly Aspergillus fumigatus, although new species, sometimes resistant to antifungals are becoming more common. IA predominantly affects immunocompromised patients, such as those with haematological malignancies, solid organ transplant recipients, and critically ill patients. However, new at-risk populations have emerged in recent years, such as IA associated with severe viral infections. Advanced diagnostic methods are crucial, especially considering the rising concern of antifungal resistance. Early detection is critical for successful treatment, typically involving antifungal medications like voriconazole or amphotericin B, but new antifungals are arriving to complete the therapeutic strategies. Despite advancements, mortality rates remain high, underscoring the importance of timely interventions and ongoing research. Healthcare providers should maintain a high index of suspicion, especially in immunocompromised patients and other new risk factors that are arising, to promptly diagnose and manage invasive aspergillosis.

A Case of Aspergillus calidoustus Thoracic Spine Osteomyelitis

Aspergillus infections are of significant concern in patients who are immunocompromised, including transplant recipients. Aspergillus calidoustus is an emerging pathogen reported to cause a wide array of infections. We present a case of A. calidoustus thoracic spine osteomyelitis in a patient with an orthotopic heart transplant (OHT). To our knowledge, this is the first case of A. calidoustus osteomyelitis in a patient with OHT.

What do We Know about Cryptic Aspergillosis?

Cryptic Aspergillus species are increasingly recognized as pathogens involved in human disease. They are ubiquitarian fungi with high tenacity in their environment and can express various resistance mechanisms, often due to exposure to antifungal agents employed in agriculture and farming. The identification of such species is increasing thanks to molecular techniques, and a better description of this type of pathogen is granted. Nevertheless, the number of species and their importance in the clinical setting still need to be well studied. Furthermore, their cross-sectional involvement in animal disease, plants, and human activities requires a multidisciplinary approach involving experts from various fields. This comprehensive review aims to provide a sharp vision of the cryptic Aspergillus species, from the importance of correct identification to the better management of the infections caused by these pathogens. The review also accentuates the importance of the One Health approach for this kind of microorganism, given the interconnection between environmental exposure and aspergillosis, embracing transversely the multidisciplinary process for managing the cryptic Aspergillus species. The paper advocates the need for improving knowledge in this little-known species, given the burden of economic and health implications related to the diffusion of these bugs.

Pathogenic Aspergillus Strains Identification and Antifungal Susceptibility Analysis of 452 Cases with Otomycosis in Jingzhou, China

OBJECTIVE

To study the distribution of pathogenic Aspergillus strains of otomycosis in central China and the identification of their antifungal sensitivity.

METHODS

We collected external ear canal secretions clinically diagnosed as otomycosis from April 2020 to January 2023 from the Department of Otolaryngology-Head and Neck Surgery in central China. The pathogenic Aspergillus strains were identified through morphological examination and sequencing. The antifungal sensitivity was performed using the broth microdilution method described in the Clinical Laboratory Standard Institute document M38-A3.

RESULTS

In the 452 clinical strains isolated from the external ear canal, 284 were identified as Aspergillus terreus (62.83%), 92 as Aspergillus flavus (20.35%), 55 as Aspergillus niger (12.17%). In antifungal susceptibility tests the MIC of Aspergillus strains to bifonazole and clotrimazole was high,all the MIC90 is > 16 ug/mL. However, most Aspergillus isolates show moderate greatly against terbinafine, itraconazole and voriconazole.

CONCLUSION

A. terreus is the most common pathogenic Aspergillus strain in otomycosis in central China. The selected topical antifungal drugs were bifonazole and clotrimazole; the drug resistance rate was approximately 30%. If the infection is persistent and requires systemic treatment, terbinafine and itraconazole can be used. The resistance of Aspergillus in otomycosis to voriconazole should be screened to avoid the systemic spread of infection in immunocompromised people and poor compliance with treatment. However, the pan-azole-resistant strain of Aspergillus should be monitored, particularly in high-risk patients with otomycosis.

Distribution of Aspergillus species and prevalence of azole resistance in clinical and environmental samples from a Spanish hospital during a three-year study period

BACKGROUND

Surveillance studies are crucial for updating trends in Aspergillus species and antifungal susceptibility information.

OBJECTIVES

Determine the Aspergillus species distribution and azole resistance prevalence during this 3-year prospective surveillance study in a Spanish hospital.

MATERIALS AND METHODS

Three hundred thirty-five Aspergillus spp. clinical and environmental isolates were collected during a 3-year study. All isolates were screened for azole resistance using an agar-based screening method and resistance was confirmed by EUCAST antifungal susceptibility testing. The azole resistance mechanism was confirmed by sequencing the cyp51A gene and its promoter. All Aspergillus fumigatus strains were genotyped using TRESPERG analysis.

RESULTS

Aspergillus fumigatus was the predominant species recovered with a total of 174 strains (51.94%). The rest of Aspergillus spp. were less frequent: Aspergillus niger (14.93%), Aspergillus terreus (9.55%), Aspergillus flavus (8.36%), Aspergillus nidulans (5.37%) and Aspergillus lentulus (3.28%), among other Aspergillus species (6.57%). TRESPERG analysis showed 99 different genotypes, with 72.73% of the strains being represented as a single genotype. Some genotypes were common among clinical and environmental A. fumigatus azole-susceptible strains, even when isolated months apart. We describe the occurrence of two azole-resistant A. fumigatus strains, one clinical and another environmental, that were genotypically different and did not share genotypes with any of the azole-susceptible strains.

CONCLUSIONS

Aspergillus fumigatus strains showed a very diverse population although several genotypes were shared among clinical and environmental strains. The isolation of azole-resistant strains from both settings suggest that an efficient analysis of clinical and environmental sources must be done to detect azole resistance in A. fumigatus.

Nails and skin co-infection by Fusarium verticillioides and Proteus vulgaris secondary to arterial occlusion of lower extremity

BACKGROUND

Post-traumatic Fusarium infection is rare. Arterial occlusive disease, a common vascular disorder in the elderly, often leads to ischemic necrosis of the lower extremities, which in turn increases the likelihood of secondary infections. Those secondary infections can be caused by bacteria, virus, or fungi.

CASE REPORT

We present the case of a 64-year-old male patient with a co-infection by Fusarium verticillioides and Proteus vulgaris on nails and foot skin, secondary to senile arterial occlusion on the lower extremities. The skin and nails recovered well after following stent implantation and a combination treatment of itraconazole and a macrolide antibiotic. A retrospective analysis of the literature identified 17 patients with Fusarium infection, all of whom were immunocompetent.

CONCLUSIONS

Trauma may be a predisposing cause of Fusarium infection. Combination of oral itraconazole and terbinafine, or amphotericin B and surgical means, are all effective treatments.

Strain heterogeneity in a non-pathogenic fungus highlights factors contributing to virulence

Fungal pathogens exhibit extensive strain heterogeneity, including variation in virulence. Whether closely related non-pathogenic species also exhibit strain heterogeneity remains unknown. Here, we comprehensively characterized the pathogenic potentials (i.e., the ability to cause morbidity and mortality) of 16 diverse strains of Aspergillus fischeri, a non-pathogenic close relative of the major pathogen Aspergillus fumigatus. In vitro immune response assays and in vivo virulence assays using a mouse model of pulmonary aspergillosis showed that A. fischeri strains varied widely in their pathogenic potential. Furthermore, pangenome analyses suggest that A. fischeri genomic and phenotypic diversity is even greater. Genomic, transcriptomic, and metabolomic profiling identified several pathways and secondary metabolites associated with variation in virulence. Notably, strain virulence was associated with the simultaneous presence of the secondary metabolites hexadehydroastechrome and gliotoxin. We submit that examining the pathogenic potentials of non-pathogenic close relatives is key for understanding the origins of fungal pathogenicity.

Prevalence of Azole-Resistant Aspergillus Section Fumigati Strains Isolated from Romanian Vineyard Soil Samples

The relationship between fungal species and their resistance patterns in vineyard soils has important implications for agriculture and medicine. This study explored the prevalence of Aspergillus section Fumigati species and their resistance to azole compounds in Romanian vineyard soils.

METHODS

A total of 265 soil samples from various Romanian vineyards were screened for fungi resistant to azoles.

RESULTS

Aspergillus section Fumigati isolates exhibited significant resistance to itraconazole and voriconazole, but no azole-resistant Aspergillus fumigatus strains were detected. Six percent of the samples were positive for Aspergillus section Fumigati strains, all of which were azole-resistant. The strains were mainly Aspergillus udagawae (93.75%) and Aspergillus lentulus (6.25%). The predominant azole-resistant Aspergillus species were Aspergillus section Nigri strains, which were found in 75 soil samples.

CONCLUSIONS

This study highlights the importance of understanding fungal resistance in vineyard soils for both the agricultural and clinical sectors. The presence of resistant strains may affect vine health and wine production while also constituting a challenge in the selection of effective treatments against severe and potentially fatal fungal infections in humans, stressing the importance of species-specific antifungal resistance knowledge.

The changing epidemiology of fungal infections

Invasive fungal diseases are common complications in critically ill patients and in those with significant underlying imbalanced immune systems. Fungal co-, and/or super-infections are emerging and have become a rising concern within the last few years. In Europe, cases of candidiasis and aspergillosis dominate, followed by mucormycosis in India. Epidemiological studies show an increasing trend in the incidence of all three entities. Parallel to this, a shift within the underlying fungal pathogens is observed. More non-albicans Candida infections and aspergillosis with cryptic species are on the rise; cryptic species may cover intrinsic resistance to azoles and other antifungal drugs. The recent COVID-19 pandemic led to a significantly increasing incidence of invasive fungal diseases among hospitalized patients.

Presence of Aspergillus fumigatus with the TR34/L98H Cyp51A mutation and other azole-resistant aspergilli in the air of a zoological park

Antifungal-resistant fungi, including Aspergillus fumigatus and other Aspergillus species, pose an urgent threat to human and animal health. Furthermore, the environmental route of azole resistance selection due to the widespread use of azole fungicides in crop protection and other applications is a major public health issue. Although environmental surveillance of fungi is frequently performed in many zoological parks and wildlife rehabilitation centers, the antifungal susceptibility of recovered isolates is only rarely analyzed, which precludes a clear assessment of the threat posed by these fungi to captive animals. In this study, we assessed the presence of airborne azole-resistant Aspergillus spp., including the so-called 'cryptic species' (i.e., species which are phenotypically similar to more well-known aspergilli but clearly constitute different phylogenetic lineages) in a zoological park located in the city of Madrid, Spain. In general, our results revealed a low prevalence A. fumigatus and cryptic aspergilli with decreased susceptibility to azoles. However, we detected an A. fumigatus isolate with the TR34/L98H mutation in the gene encoding the lanosterol 14α-demethylase (Cyp51A), consisting of a tandem repeat of 34 base pairs in the promoter region and a lysine to histidine substitution at codon 98. Notably, this TR34/L98H mutation has been linked to the environmental route of azole resistance selection, thus highlighting the 'One Health' dimension of the emerging problem of antifungal resistance. In this context, continuous environmental surveillance of azole-resistant aspergilli in zoological parks and other similar animal facilities is recommended.

Invasive aspergillosis in adult patients in Australia and New Zealand: 2017-2020

Background

New and emerging risks for invasive aspergillosis (IA) bring the need for contemporary analyses of the epidemiology and outcomes of IA, in order to improve clinical practice.

Methods

The study was a retrospective, multicenter, cohort design of proven and probable IA in adults from 10 Australasian tertiary centres (January 2017-December 2020). Descriptive analyses were used to report patients' demographics, predisposing factors, mycological characteristics, diagnosis and management. Accelerated failure-time model was employed to determine factor(s) associated with 90-day all-cause mortality (ACM).

Findings

Of 382 IA episodes, 221 (in 221 patients) fulfilled inclusion criteria - 53 proven and 168 probable IA. Median patient age was 61 years (IQR 51-69). Patients with haematologic malignancies (HM) comprised 49.8% of cases. Fifteen patients (6.8%) had no pre-specified immunosuppression and eleven patients (5.0%) had no documented comorbidity. Only 30% of patients had neutropenia. Of 170 isolates identified, 40 (23.5%) were identified as non-Aspergillus fumigatus species complex. Azole-resistance was present in 3/46 (6.5%) of A. fumigatus sensu stricto isolates. Ninety-day ACM was 30.3%. HM (HR 1.90; 95% CI 1.04-3.46, p = 0.036) and ICU admission (HR 4.89; 95% CI 2.93-8.17, p < 0.001) but not neutropenia (HR 1.45; 95% CI 0.88-2.39, p = 0.135) were associated with mortality. Chronic kidney disease was also a significant predictor of death in the HM subgroup (HR 3.94; 95% CI 1.15-13.44, p = 0.028).

Interpretation

IA is identified in high number of patients with mild/no immunosuppression in our study. The relatively high proportion of non-A. fumigatus species complex isolates and 6.5% azole-resistance rate amongst A. fumigatus sensu stricto necessitates accurate species identification and susceptibility testing for optimal patient outcomes.

Funding

This work is unfunded. All authors' financial disclosures are listed in detail at the end of the manuscript.

Relationship Between Airborne Fungi Presence and the Position of the High Efficiency Particulate Air Filter in the Heating, Ventilation, and Air Conditioning System

AIM

Establish the influence of the terminal or nonterminal position of High Efficiency Particulate Air (HEPA) filters in the Heating, Ventilation, and Air Conditioning (HVAC) system on the presence of airborne fungi in controlled environment rooms.

BACKGROUND

Fungal infections are an important cause of morbidity and mortality in hospitalized patients.

METHODS

This study was realized from 2010 to 2017, in rooms with terminal and nonterminal HEPA filters, in eight Spanish hospitals. In rooms with terminal HEPA filters, 2,053 and 2,049 samples were recollected, and in rooms with nonterminal HEPA filters, 430 and 428 samples were recollected in the air discharge outlet (Point 1) and in the center of the room (Point 2), respectively. Temperature, relative humidity, air changes per hour, and differential pressure were recollected.

RESULTS

Multivariable analysis showed higher odds ratio (OR) of airborne fungi presence when HEPA filters were in nonterminal position (OR: 6.78; 95% CI [3.77, 12.20]) in Point 1 and (OR: 4.43; 95% CI [2.65, 7.40]) in Point 2. Other parameters influenced airborne fungi presence, such as temperature (OR: 1.23; 95% CI [1.06, 1.41]) in Point 2 differential pressure (OR: 0.86; 95% CI [0.84, 0.90]) and (OR: 0.88; 95% CI [0.86, 0.91]) in Points 1 and 2, respectively.

CONCLUSIONS

HEPA filter in terminal position of the HVAC system reduces the presence of airborne fungi. To decrease the presence of airborne fungi, adequate maintenance of the environmental and design parameters is necessary in addition to the terminal position of the HEPA filter.

Skin lesions by Scedosporium apiospermum and Nocardia pulmonary infection in an oncologic patient: a case report

BACKGROUND

Fungal infections, other than candidiasis and aspergillosis, are an uncommon entity. Despite this, emerging pathogens are a growing threat. In the following case report, we present the case of an immunocompromised patient suffering from two serious opportunistic infections in the same episode: the first of these, Nocardia multilobar pneumonia; and the second, skin infection by Scedosporium apiospermum. These required prolonged antibacterial and antifungal treatment.

CASE PRESENTATION

This case is a 71-year-old oncological patient admitted for recurrent pneumonias that was diagnosed for Nocardia pulmonary infection. Nervous system involvement was discarded and cotrimoxazole was started. Haemorrhagic skin ulcers in the lower limbs appeared after two weeks of hospital admission. We collected samples which were positive for Scedosporium apiospermum and we added voriconazole to the treatment. As a local complication, the patient presented a deep bruise that needed debridement. We completed 4 weeks of intravenous treatment with slow improvement and continued with oral treatment until the disappearance of the lesions occurs.

CONCLUSIONS

Opportunistic infections are a rising entity as the number of immunocompromised patients is growing due to more use of immunosuppressive therapies and transplants. Clinicians must have a high suspicion to diagnose and treat them. A fluid collaboration with Microbiology is necessary as antimicrobial resistance is frequent.

Soil Aspergillus Species, Pathogenicity and Control Perspectives

Five Aspergillus sections have members that are established agricultural pests and producers of different metabolites, threatening global food safety. Most of these pathogenic Aspergillus species have been isolated from almost all major biomes. The soil remains the primary habitat for most of these cryptic fungi. This review explored some of the ecological attributes that have contributed immensely to the success of the pathogenicity of some members of the genus Aspergillus over time. Hence, the virulence factors of the genus Aspergillus, their ecology and others were reviewed. Furthermore, some biological control techniques were recommended. Pathogenic effects of Aspergillus species are entirely accidental; therefore, the virulence evolution prediction model in such species becomes a challenge, unlike their obligate parasite counterparts. In all, differences in virulence among organisms involved both conserved and species-specific genetic factors. If the impacts of climate change continue, new cryptic Aspergillus species will emerge and mycotoxin contamination risks will increase in all ecosystems, as these species can metabolically adjust to nutritional and biophysical challenges. As most of their gene clusters are silent, fungi continue to be a source of underexplored bioactive compounds. The World Soil Charter recognizes the relevance of soil biodiversity in supporting healthy soil functions. The question of how a balance may be struck between supporting healthy soil biodiversity and the control of toxic fungi species in the field to ensure food security is therefore pertinent. Numerous advanced strategies and biocontrol methods so far remain the most environmentally sustainable solution to the control of toxigenic fungi in the field.

Novel Antifungals and Aspergillus Section Terrei with Potpourri Susceptibility Profiles to Conventional Antifungals

The epidemiology of invasive fungal infections (IFIs) is currently changing, driven by aggressive immunosuppressive therapy, leading to an expanded spectrum of patients at risk of IFIs. Aspergillosis is a leading cause of IFIs, which usually affects immunocompromised patients. There are a limited number of antifungal medications available for treating IFIs, and their effectiveness is often hindered by rising resistance rates and practical limitations. Consequently, new antifungals, especially those with novel mechanisms of action, are increasingly required. This study assessed the activity of four novel antifungal agents with different mechanisms of activity, namely, manogepix, rezafungin, ibrexafungerp, and olorofim, against 100 isolates of Aspergillus section Terrei, containing amphotericin-B (AmB)-wildtype/non-wildtype and azole-susceptible/-resistant strains, according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) method. In general, all tested agents showed potent and consistent activity against the tested isolates, exhibiting geometric mean (GM) and minimum effective concentration (MEC)/minimum inhibitory concentration (MIC) ranges, respectively, as follows: manogepix (0.048 mg/L, 0.032-0.5 mg/L), rezafungin (0.020 mg/L, 0.016-0.5 mg/L), ibrexafungerp (0.071 mg/L, 0.032-2 mg/L), and olorofim (0.008 mg/L, 0.008-0.032 mg/L). In terms of MIC90/MEC90, olorofim had the lowest values (0.008 mg/L), followed by rezafungin (0.032 mg/L), manogepix (0.125 mg/L), and ibrexafungerp (0.25 mg/L). All the antifungals tested demonstrated promising in vitro activity against Aspergillus section Terrei, including A. terreus as well as azole-resistant and AmB-non-wildtype cryptic species.

Probiotics and their postbiotics for the control of opportunistic fungal pathogens: A review

During past twenty years the opportunistic fungal infections have been emerging, causing morbidity and mortality. The fungi belonging to Aspergillus, Mucor, Rhizopus, Candida, Fusarium, Penicillium, Dermatophytes and others cause severe opportunistic fungal infections. Among these Aspergillus and Candida spp cause majority of the diseases. The continuum of fungal infections will prolong to progress in the surroundings of the growing inhabitants of immunocompromised individuals. Presently many chemical-based drugs were used as prophylactic and therapeutic agents. Prolonged usage of antibiotics may lead to some severe effect on the human health. Also, one of the major threats is that the fungal pathogens are becoming the drug resistant. There are many physical, chemical, and mechanical methods to prevent the contamination or to control the disease. Owing to the limitations that are observed in such methods, biological methods are gaining more interest because of the use of natural products which have comparatively less side effects and environment friendly. In recent years, research on the possible use of natural products such as probiotics for clinical use is gaining importance. Probiotics, one of the well studied biological products, are safe upon consumption and are explored to treat various fungal infections. The antifungal potency of major groups of probiotic cultures such as Lactobacillus spp, Leuconostoc spp, Saccharomyces etc. and their metabolic byproducts which act as postbiotics like organic acids, short chain fatty acids, bacteriocin like metabolites, Hydrogen peroxide, cyclic dipeptides etc. to inhibit these opportunistic fungal pathogens have been discussed here.

Clinical epidemiology of pulmonary aspergillosis in hospitalized patients and contribution of Cyp51A, Yap1, and Cdr1B mutations to voriconazole resistance in etiologic Aspergillus species

Pulmonary aspergillosis is a life-threatening fungal infection with worldwide distribution. In the present study, clinical epidemiology of pulmonary aspergillosis and antifungal susceptibility of etiologic Aspergillus species were evaluated in one-hundred fifty patients with special focus on the frequency of voriconazole resistance. All the cases were confirmed by the clinical pictures, laboratory findings, and isolation of etiologic Aspergillus species which belonged to two major species, i.e., A. flavus and A. fumigatus. Seventeen isolates displayed voriconazole MIC greater than or equal to the epidemiological cutoff value. Expression of cyp51A, Cdr1B, and Yap1 genes was analyzed in voriconazole-intermediate/resistant isolates. In A. flavus, Cyp51A protein sequencing showed the substitutions T335A and D282E. In the Yap1 gene, A78C replacement led to Q26H amino acid substitution that was not reported previously in A. flavus resistant to voriconazole. No mutations associated with voriconazole resistance were found in the three genes of A. fumigatus. The expression of Yap1 was higher than that of two other genes in both A. flavus and A. fumigatus. Overall, voriconazole-resistant strains of both A. fumigatus and A. flavus demonstrated overexpression of Cdr1B, Cyp51A, and Yap1 genes compared to voriconazole-susceptible strains. Although there are still ambiguous points about the mechanisms of azole resistance, our results showed that mutations were not present in majority of resistant and intermediate isolates, while all of these isolates showed overexpression in all three genes studied. As a conclusion, it seems that the main reason of the emergence of mutation in voriconazole-resistant isolates of A. flavus and A. fumigatus is previous or prolonged exposure to azoles.

Species distribution and antifungal susceptibility of clinical Aspergillus isolates: A multicentre study in Taiwan, 2016-2020

BACKGROUND

Epidemiological knowledge is important to guide antifungal therapy.

OBJECTIVE

This multicentre study aimed to investigate the species distribution and antifungal susceptibility of Aspergillus isolates in Taiwan.

METHOD

Four hundred and ninety-two clinical Aspergillus isolates, collected during 2016-2020, were identified by calmodulin sequencing and tested for antifungal susceptibility using CLSI M38-A3. The Cyp51A sequences of azole-resistant Aspergillus fumigatus and Aspergillus flavus isolates were analysed.

RESULTS

This collection comprised 30 species from eight Aspergillus sections-Flavi (33.5%), Nigri (26.0%), Fumigati (24.2%), Terrei (10.0%), Nidulantes (5.1%), Circumdati (0.8%), Restricti (0.2%) and Aspergillus (0.2%). Sections Fumigati, Flavi and Terrei were primarily represented by A. fumigatus (99.2%), A. flavus (95.8%) and A. terreus (100%), respectively. Section Nigri comprised nine species, mostly A. welwitschiae (60.2%), A. niger (12.5%), A. brunneoviolaceus (10.9%) and A. tubingensis (10.2%). A. fumigatus (39.6%) and A. flavus (26.4%) predominated among 53 isolates from lower respiratory samples, whereas section Nigri species (46.2%) and A. terreus (29.2%) predominated among 65 isolates from ear samples. Reduced susceptibility to amphotericin B (minimal inhibitory concentration (MIC) > 1 μg/mL) was noted in A. flavus (7.0%), A. terreus (6.1%), A. nidulans and section Circumdati (A. flocculosus, A. subramanianii and A. westerdijkiae) isolates. Acquired azole resistance was observed in seven A. fumigatus (5.9%), all of which carried TR₃₄ /L98H or TR₃₄ /L98H/S297T/F495I mutation, and three A. flavus (1.9%), one of which carried G441S mutation. Reduced susceptibility to itraconazole (MIC >1 μg/mL) was noted in 55.5% of section Nigri isolates, mainly in A. welwitschiae, A. niger and A. tubingensis, whereas A. brunneoviolaceus, A. aculeatinus and A. japonicus were hypersusceptible to azoles. Anidulafungin was active against all isolates except for one isolate.

CONCLUSIONS

This study depicted the molecular epidemiology and species-specific characteristics of Aspergillus in Taiwan, which aids in appropriate antifungal therapy and underlines the need of speciation and susceptibility testing of disease-causing Aspergillus.

Aspergillus Species Causing Invasive Fungal Disease in Queensland, Australia

BACKGROUND

Aspergillus species are important causes of invasive fungal disease, particularly among those with an impaired immune system. Increasing reports have revealed a rising incidence of antifungal drug resistance among Aspergillus spp., particularly among cryptic species. Understanding local antifungal susceptibility patterns is paramount to delivering optimal clinical care.

METHODS

Aspergillus spp. recovered from clinical specimens between 2000 and 2021 from Pathology Queensland were collected. Aspergillus spp. were identified routinely morphologically, and where there was ambiguity or a lack of sporulation, by sequencing of the internal transcribed spacer (ITS) region. All Aspergillus spp. that underwent antifungal susceptibility testing according to the CLSI M38-A3 method and were recorded and included in the study. Amphotericin B, voriconazole, posaconazole, isavuconazole, micafungin, caspofungin, and anidulafungin were tested. Pathology Queensland services all public healthcare facilities in Queensland, Australia.

RESULTS

236 Aspergillus spp. were identified from clinical specimens during the study period. The most frequent species identified were Aspergillus section Fumigati (n = 119), Aspergillus section Flavi (n = 35), Aspergillus terreus (n = 32) and Aspergillus niger (n = 29). Overall, MIC_50/90 values for voriconazole, posaconazole, itraconazole, and isavuconazole were 0.25/1, 0.25/0.5, 0.25/0.5, and 0.5/2 mg/L respectively. Echinocandins demonstrated low MIC values overall with micafungin and anidulafungin both having an MIC_50/90 of 0.015/0.03 mg/L. A total of 15 cryptic species were identified; high triazole MIC values were observed with a voriconazole MIC_50/90 of 2/8 mg/L. From 2017 to 2021 we observed an increase in incidence of isolates with high voriconazole MIC values. There was no difference in voriconazole MIC values between Aspergillus spp. acquired in North Queensland when compared to Southeast Queensland, Australia.

CONCLUSION

Increasing reports of antifungal resistance among Aspergillus spp. is concerning and warrants further investigation both locally and worldwide. Active surveillance of both the emergence of different Aspergillus spp. and changes in antifungal susceptibility patterns over time is crucial to informing clinicians and treatment guidelines.

Amesia hispanica sp. nov., Producer of the Antifungal Class of Antibiotics Dactylfungins

During a study of the diversity of soilborne fungi from Spain, a strain belonging to the family Chaetomiaceae (Sordariales) was isolated. The multigene phylogenetic inference using five DNA loci showed that this strain represents an undescribed species of the genus Amesia, herein introduced as A. hispanica sp. nov. Investigation of its secondary metabolome led to the isolation of two new derivatives (2 and 3) of the known antifungal antibiotic dactylfungin A (1), together with the known compound cochliodinol (4). The planar structures of 1-4 were determined by ultrahigh performance liquid chromatography coupled with diode array detection and ion mobility tandem mass spectrometry (UHPLC-DAD-IM-MS/MS) and extensive 1D and 2D nuclear magnetic resonance (NMR) spectroscopy after isolation by HPLC. All isolated secondary metabolites were tested for their antimicrobial and cytotoxic activities. Dactylfungin A (1) showed selective and strong antifungal activity against some of the tested human pathogens (Aspergillus fumigatus and Cryptococcus neoformans). The additional hydroxyl group in 2 resulted in the loss of activity against C. neoformans but still retained the inhibition of As. fumigatus in a lower concentration than that of the respective control, without showing any cytotoxic effects. In contrast, 25″-dehydroxy-dactylfungin A (3) exhibited improved activity against yeasts (Schizosaccharomyces pombe and Rhodotorula glutinis) than 1 and 2, but resulted in the appearance of slight cytotoxicity. The present study exemplifies how even in a well-studied taxonomic group such as the Chaetomiaceae, the investigation of novel taxa still brings chemistry novelty, as demonstrated in this first report of this antibiotic class for chaetomiaceous and sordarialean taxa.

Species Distribution and Antifungal Susceptibilities of Aspergillus Section Terrei Isolates in Clinical Samples from the United States and Description of Aspergillus pseudoalabamensis sp. nov

Aspergillus section Terrei consists of numerous cryptic species in addition to A. terreus sensu stricto. The treatment of invasive infections caused by these fungi may pose a unique challenge prior to diagnosis and species identification, in that they are often clinically resistant to amphotericin B, with poor outcomes and low survival rates in patients treated with this polyene. Data on the species distributions and susceptibility profiles of isolates within section Terrei from the United States (U.S.) are limited. Here, we report the species distributions and susceptibility profiles for amphotericin B, isavuconazole, itraconazole, posaconazole, voriconazole, and micafungin against 278 clinical isolates of this section from institutions across the U.S. collected over a 52-month period. Species identification was performed by DNA sequence analysis and phenotypic characterization. Susceptibility testing was performed using the CLSI broth microdilution method. The majority of isolates were identified as Aspergillus terreus sensu stricto (69.8%), although several other cryptic species were also identified. Most were cultured from specimens collected from the respiratory tract. Posaconazole demonstrated the most potent activity of the azoles (MIC range ≤ 0.03-1 mg/L), followed by itraconazole (≤0.03-2 mg/L), voriconazole, and isavuconazole (0.125-8 mg/L for each). Amphotericin B demonstrated reduced in vitro susceptibility against this section (MIC range 0.25-8 mg/L), although this appeared to be species-dependent. A new species within this section, A. pseudoalabamensis, is also described. Our results, which are specific to the U.S., are similar to previous surveillance studies of the Aspergillus section Terrei.

Invasive Aspergillosis and the Impact of Azole-resistance

Purpose of Review

IA (invasive aspergillosis) caused by azole-resistant strains has been associated with higher clinical burden and mortality rates. We review the current epidemiology, diagnostic, and therapeutic strategies of this clinical entity, with a special focus on patients with hematologic malignancies.

Recent Findings

There is an increase of azole resistance in Aspergillus spp. worldwide, probably due to environmental pressure and the increase of long-term azole prophylaxis and treatment in immunocompromised patients (e.g., in hematopoietic stem cell transplant recipients). The therapeutic approaches are challenging, due to multidrug-resistant strains, drug interactions, side effects, and patient-related conditions.

Summary

Rapid recognition of resistant Aspergillus spp. strains is fundamental to initiate an appropriate antifungal regimen, above all for allogeneic hematopoietic cell transplantation recipients. Clearly, more studies are needed in order to better understand the resistance mechanisms and optimize the diagnostic methods to identify Aspergillus spp. resistance to the existing antifungal agents/classes. More data on the susceptibility profile of Aspergillus spp. against the new classes of antifungal agents may allow for better treatment options and improved clinical outcomes in the coming years. In the meantime, continuous surveillance studies to monitor the prevalence of environmental and patient prevalence of azole resistance among Aspergillus spp. is absolutely crucial.

Systemic Antifungal Therapy for Invasive Pulmonary Infections

Antifungal therapy for pulmonary fungal diseases is in a state of flux. Amphotericin B, the time-honored standard of care for many years, has been replaced by agents demonstrating superior efficacy and safety, including extended-spectrum triazoles and liposomal amphotericin B. Voriconazole, which became the treatment of choice for most pulmonary mold diseases, has been compared with posaconazole and itraconazole, both of which have shown clinical efficacy similar to that of voriconazole, with fewer adverse events. With the worldwide expansion of azole-resistant Aspergillus fumigatus and infections with intrinsically resistant non-Aspergillus molds, the need for newer antifungals with novel mechanisms of action becomes ever more pressing.

Evaluation of the Results of a Periodic Environmental Biosecurity Assessment Program on Air Quality in Controlled Environment Rooms of Hospitals

AIM

Determine the utility of the Periodic Environmental Biosecurity Assessment Program (PEBAP) in achieving clean air as measured by the number of colony-forming units (CFU) of fungi and bacteria in the air.

BACKGROUND

There is no international consensus on the sampling frequency, the recommended limits for microorganisms in the air nor on the usefulness of routine microbiological air monitoring of hospitals.

METHODS

During the PEBAP, data were recollected between 2010 and 2017 in eight hospitals in southeast Spain. Air samples were collected in very high risk rooms (VHRRs) and high risk rooms (HRRs), unoccupied, using active sampling methods. Temperature, relative humidity, air changes per hour (ACH), and differential pressure were measured. When limits of CFU of opportunistic fungi and bacteria established in the PEBAP were exceeded, corrective measures were adopted.

RESULTS

We found a reduction (p < .01) of percentage of air samples with fungi growth throughout the years of PEBAP in all rooms. Aspergillus was the most frequent opportunistic fungus. We found a high compliance of the standards of CFU of bacteria in HRR, and the percentage of compliance in VHRR was lower than in HRR in all years. Differences in environmental and design parameters were statistically significant (p < .05) between rooms, except for ACH.

CONCLUSIONS

PEBAP resulted in a useful tool to maintain and improve air quality in hospitals. The control of environmental biosecurity requires a multidisciplinary approach from preventive medicine, engineering, and cleaning services. Aspergillus is the most frequent opportunistic fungus in southeast Spain.

A Practical Workflow for the Identification of Aspergillus, Fusarium, Mucorales by MALDI-TOF MS: Database, Medium, and Incubation Optimization

There is an increasing body of literature on the utility of MALDI-TOF MS in the identification of filamentous fungi. However, the process still lacks standardization. In this study, we attempted to establish a practical workflow for the identification of three clinically important molds: Aspergillus, Fusarium, and Mucorales using MALDI-TOF MS. We evaluated the performance of Bruker Filamentous Fungi database v3.0 for the identification of these fungi, highlighting when there would be a benefit of using an additional database, the MSI-2 for further identification. We also examined two other variables, namely, medium effect and incubation time on the accuracy of fungal identification. The Bruker database achieved correct species level identification in 85.7% of Aspergillus and 90% of Mucorales, and correct species-complex level in 94.4% of Fusarium. Analysis of spectra using the MSI-2 database would also offer additional value for species identification of Aspergillus species, especially when suspecting species with known identification limits within the Bruker database. This issue would only be of importance in selected cases where species-level identification would impact therapeutic options. Id-Fungi plates (IDFP) had almost equivalent performance to Sabouraud dextrose agar (SDA) for species-level identification of isolates and enabled an easier harvest of the isolates with occasional faster identification. Our study showed accurate identification at 24 h for Fusarium and Mucorales species, but not for Aspergillus species, which generally required 48 h.

Therapeutic Approaches for Combating Aspergillus Associated Infection

Now-a-days fungal infection emerges as a significant problem to healthcare management systems due to high frequency of associated morbidity, mortality toxicity, drug-drug interactions, and resistance of the antifungal agents. Aspergillus is the most common mold that cause infection in immunocompromised hosts. It's a hyaline mold that is cosmopolitan and ubiquitous in nature. Aspergillus infects around 10 million population each year with a mortality rate of 30-90%. Clinically available antifungal formulations are restricted to four classes (i.e., polyene, triazole, echinocandin, and allylamine), and each of them have their own limitations associated with the activity spectrum, the emergence of resistance, and toxicity. Consequently, novel antifungal agents with modified and altered chemical structures are required to combat these invasive fungal infections. To overcome these limitations, there is an urgent need for new antifungal agents that can act as potent drugs in near future. Currently, some compounds have shown effective antifungal activity. In this review article, we have discussed all potential antifungal therapies that contain old antifungal drugs, combination therapies, and recent novel antifungal formulations, with a focus on the Aspergillus associated infections.

Case report: a fatal case of Aspergillus felis infection in an immunocompetent host

We report a fatal case of Aspergillus felis invasive rhinosinusitis with secondary cerebral abscesses in an immunocompetent host despite aggressive surgical debridement and combination antifungals. Whilst this organism is known to cause fatalities in cats, only a few cases in humans have been documented, all of which had significant immunosuppression. This is the first human death due to A. felis described in an immunocompetent host.

The impact of mucormycosis (black fungus) on SARS-CoV-2-infected patients: at a glance

The emergence of various diseases during the COVID-19 pandemic made health workers more attentive, and one of the new pathogens is the black fungus (mucormycosis). As a result, millions of lives have already been lost. As a result of the mutation, the virus is constantly changing its traits, including the rate of disease transmission, virulence, pathogenesis, and clinical signs. A recent analysis revealed that some COVID-19 patients were also coinfected with a fungal disease called mucormycosis (black fungus). India has already categorized the COVID-19 patient black fungus outbreak as an epidemic. Only a few reports are observed in other countries. The immune system is weakened by COVID-19 medication, rendering it more prone to illnesses like black fungus (mucormycosis). COVID-19, which is caused by a B.1.617 strain of the SARS-CoV-2 virus, has been circulating in India since April 2021. Mucormycosis is a rare fungal infection induced by exposure to a fungus called mucormycete. The most typically implicated genera are Mucor rhyzuprhizopusdia and Cunninghamella. Mucormycosis is also known as zygomycosis. The main causes of infection are soil, dumping sites, ancient building walls, and other sources of infection (reservoir words "mucormycosis" and "zygomycosis" are occasionally interchanged). Zygomycota, on the other hand, has been identified as polyphyletic and is not currently included in fungal classification systems; also, zygomycosis includes Entomophthorales, but mucormycosis does not. This current review will be focused on the etiology and virulence factors of COVID-19/mucormycosis coinfections in COVID-19-associated mucormycosis patients, as well as their prevalence, diagnosis, and treatment.

New Perspectives on Antimicrobial Agents: Isavuconazole

Isavuconazole is the newest of the clinically available advanced generation triazole antifungals and is active against a variety of yeasts, molds, and dimorphic fungi. Its current FDA-approved indications include the management of invasive aspergillosis as well as mucormycosis, though the latter indication is supported by limited clinical data. Isavuconazole did not achieve noninferiority to caspofungin for the treatment of invasive candidiasis and therefore lacks an FDA-approved indication for this invasive disease. Significant advantages of isavuconazole, primarily over voriconazole but in some circumstances posaconazole as well, make it an appealing option for the management of complex patients with invasive fungal infections. These potential advantages include lack of QTc interval prolongation, more predictable pharmacokinetics, a less complicated drug interaction profile, and improved tolerability, particularly when compared to voriconazole. This review discusses these topics in addition to addressing the in vitro activity of the compound against a variety of fungi and provides insight into other distinguishing factors among isavuconazole, voriconazole, and posaconazole. The review concludes with an opinion section in which the authors provide the reader with a framework for the current role of isavuconazole in the antifungal armamentarium and where further data are required.

Trends in the Prevalence of Amphotericin B-Resistance (AmBR) among Clinical Isolates of Aspergillus Species

The challenges of the invasive infections caused by the resistant Aspergillus species include the limited access to antifungals for treatment and high mortality. This study aimed to provide a global perspective of the prevalence of amphotericin B resistance (AmBR), geographic distribution, and the trend of AmBR from 2010 to 2020. To analyze the prevalence of in vitro AmBR in clinical Aspergillus species, we reviewed the literature and identified a total of 72 articles. AmBR was observed in 1128 out of 3061 Aspergillus terreus (36.8%), 538 out of 3663 Aspergillus flavus (14.9%), 141 out of 2691 Aspergillus niger (5.2%), and 353 out of 17,494 Aspergillus fumigatus isolates (2.01%). An increasing trend in AmB-resistant isolates of A. fumigatus and a decreasing trend in AmB-resistant A. terreus and A. flavus isolates were observed between 2016 and 2020. AmB-resistant A. terreus and A. niger isolates, accounting for 40.4% and 20.9%, respectively, were the common AmB-resistant Aspergillus species in Asian studies. However, common AmB-resistant Aspergillus species reported by European and American studies were A. terreus and A. flavus isolates, accounting for 40.1% and 14.3% in 31 studies from Europe and 25.1% and 11.7% in 14 studies from America, respectively. The prevalence of AmB-resistant A. niger in Asian isolates was higher than in American and European. We found a low prevalence of A. terreus in American isolates (25.1%) compared to Asian (40.4%) and European (40.1%). Future studies should focus on analyzing the trend of AmBR on a regional basis and using the same methodologies.

Antifungal Resistance and the Role of New Therapeutic Agents

Purpose of Review

Advances in health care over time have led to an evolution in the epidemiology of invasive fungal infections. There is an increasing concern for antifungal resistance and emergence of less common fungal species for which optimal therapies are not well defined. The purpose of this review is to describe mechanisms of antifungal resistance and to evaluate the modern role of new and investigational antifungals.

Recent Findings

Isavuconazole and ibrexafungerp represent the two newest antifungal agents. Evidence from in vivo and in vitro studies has been published recently to help define their place in therapy and potential roles in treating resistant fungi. Isavuconazole is a broad-spectrum triazole antifungal with evidence to support its use in invasive aspergillosis and mucormycosis. Its utility in treating voriconazole-resistant Candida should be confirmed with susceptibility testing if available. Ibrexafungerp is an oral glucan synthase inhibitor with little cross-resistance among currently available antifungals, including echinocandins. It is a promising new agent for invasive candidiasis, including azole-resistant Candida species, and in combination therapy with voriconazole for aspergillosis. Multiple antifungals, some with novel mechanisms, are in development, including rezafungin, oteseconazole, olorofim, fosmanogepix, and opelconazole.

Summary

Both isavuconazole and ibrexafungerp are welcome additions to the arsenal of antifungals, and the prospect of more antifungal options in the future is encouraging. Such an array of antifungals will be important as antifungal resistance continues to expand alongside evolving medical practices. However, managing resistant fungal infections will grow in complexity as the unique role of each new agent is defined.

Aspergillosis by cryptic Aspergillus species: A case series and review of the literature

BACKGROUND

The cryptic Aspegillus species are rare, these microorganisms are usually more resistant to common antifungal therapies. Therefore, a correct identification is important when evaluating the impact of such species in aspergillosis.

AIMS

We aimed to describe the frequency, clinical and microbiological characteristics, and the outcomes of those cases of aspergillosis caused by cryptic species in a tertiary hospital.

METHODS

We retrospectively identified all microbiologically documented cases of aspergillosis between January 2013 and December 2018. Definitive species identification of clinically significant isolates was achieved via sequencing methods. The polymerase chain reaction (PCR) products were sequenced, and the results obtained were compared to sequences deposited in GenBank. Antifungal susceptibility testing was performed using the Sensititre® YeastOne® panel.

RESULTS

A total of 679 Aspergillus isolates were recovered from 489 patients, of which 109 were clinically relevant. Ten (9.2%) isolates were identified as cryptic species: Aspergillus arcoverdensis (2), Aspergillus lentulus (2), Aspergillus ellipticus (2), Aspergillus alliaceus (1), Aspergillus nomius (1), Aspergillus tubingensis (1) and Aspergillus montevidensis (1). Most patients already suffered some type of immunosuppression. Half of these patients had required intensive care before the infection showed up, and most of them had a pulmonary infection. Mortality at the 100-day follow-up was 40%. Antifungal susceptibility testing was performed on three of the isolates (A. arcoverdensis, A. tubingensis and A. nomius), which showed high minimum inhibitory concentrations (MIC) for azoles and amphotericin B.

CONCLUSIONS

The frequency of cryptic species in our centre was 9.2%. Most patients had some degree of immunosuppression, and the mortality rate was 40%.

Molecular identification and antifungal susceptibility of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri

Introduction. Aspergillus sections Flavi and Nigri comprise clinically relevant and cryptic species that differ significantly in drug susceptibility, meaning that effective treatment depends on correct species identification.Hypothesis/Gap Statement. There are no comprehensive data for molecular identification and antifungal susceptibility testing (AFST) of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri as the main agents of invasive and non-invasive aspergillosis in Iran. We aimed to perform molecular identification and AFST of 213 clinical Aspergillus isolates belonging to sections Flavi and Nigri. Molecular identification of isolates was performed using sequencing of the β-tubulin gene and in vitro AFST was conducted according to the Clinical and Laboratory Standards Institute (CLSI) M38-A3 guidelines.Results. The most common isolates in sections Flavi and Nigri were Aspergillus flavus (110/113, 97.3 %) and Aspergillus tubingensis (49/100, 49.0 %), respectively. A total of 62/213 (29.1 %) isolates belonging to cryptic species were identified; among them, A. tubingensis was the most prevalent (49/62, 79.0%). Aspergillus flavus and A. niger isolates that responded to the minimum inhibitory concentrations (MICs) of itraconazole above the epidemiological cutoff values were the most frequently detected: 8/110 (7.3 %) and 3/41 (7.3 %), respectively. In section Flavi, Aspergillus alliaceus responded to amphotericin B at a high MIC (>16 µg mL^-1) and in section Nigri, one of the three Aspergillus luchuensis/awamori isolates responded to itraconazole at an MIC >16 µg ml^-1. Interestingly, for all Aspergillus welwitschiae isolates, the MIC₅₀ and MIC₉₀ of itraconazole were both 16 µg ml^-1.Conclusion. A considerable presence of A. flavus and A. niger isolates showing non-wild-type responses to azoles in clinical cases of aspergillosis indicates the importance of classifying clinical Aspergillus isolates at the species level and performing antifungal susceptibility testing on the isolates, which would ensure appropriate treatment.

The Synergistic Effect of Tacrolimus (FK506) or Everolimus and Azoles Against Scedosporium and Lomentospora Species In Vivo and In Vitro

Scedosporium and Lomentospora infections in humans are generally chronic and stubborn. The use of azoles alone cannot usually inhibit the growth of these fungi. To further explore the combined effect of multiple drugs and potential mechanisms of action, we tested the antifungal effects of tacrolimus (FK506) and everolimus in combination with azoles in vitro and in vivo on 15 clinical strains of Scedosporium/Lomentospora species and detected the level of Rhodamine 6G, ROS activity, and apoptosis. The in vitro results showed that the combinations of tacrolimus with itraconazole, voriconazole, and posaconazole showed synergistic effects on 9 strains (60%), 10 strains (73%), and 7 strains (47%), respectively, and the combinations of everolimus with itraconazole, voriconazole, and posaconazole showed synergistic effects on 8 strains (53%), 8 strains (53%), and 7 strains (47%), respectively. The synergistic effects might correspond to the elevated ROS activity (the tacrolimus + itraconazole group compared to the itraconazole group, (P < 0.05)), early apoptosis (itraconazole (P < 0.05) and voriconazole (P < 0.05) combined with everolimus), and late apoptosis (the tacrolimus + itraconazole group compared to the itraconazole group, (P < 0.01); the tacrolimus + posaconazole group compared to the posaconazole group, (P < 0.05)), but not inhibition of efflux pump activity. Our in vitro results suggested that a combination of tacrolimus or everolimus and azoles have a synergistic effect against Scedosporium/Lomentospora. The synergistic mechanisms of action might be triggering excessive ROS activity and apoptosis. In vivo, the survival rate of G. mellonella (sixth instar larvae) was significantly improved by tacrolimus alone, everolimus alone, azoles alone, and tacrolimus and everolimus combined with azoles separately (P < 0.05 for the tacrolimus group; P < 0.01 for the everolimus group and the itraconazole group; P = 0.0001 for the tacrolimus and posaconazole group; P < 0.0001 for other groups except the everolimus and itraconazole group, everolimus and posaconazole group, and tacrolimus and itraconazole group). From the results, we infer that the combination of tacrolimus or everolimus with azoles has obvious synergistic effect on Scedosporium/Lomentospora, and might enhance the level of apoptosis and necrosis. However, the synergistic effects were not related to the efflux pump. In conclusion, from our in vitro and in vivo study, tacrolimus and everolimus combined with azoles may have a synergistic effect in the treatment against Scedosporium/Lomentospora, improving the drug activity of azoles and promoting a better prognosis for patients.

Species Distribution and Antifungal Susceptibilities of Aspergillus Section Fumigati Isolates in Clinical Samples from the United States

Aspergillus species are capable of causing both invasive disease and chronic infections in immunocompromised patients or those with preexisting lung conditions. Aspergillus fumigatus is the most commonly cultured species, and there is increasing concern regarding resistance to the azoles, which are the mainstays of antifungal therapy against aspergillosis. We evaluated the species distribution and susceptibility profiles of isolates within Aspergillus section Fumigati in the United States over a 52-month period.

Case Commentary: Long-term fosmanogepix use in a transplant recipient with disseminated aspergillosis caused by azole-resistant Aspergillus calidoustus

Aspergillus calidoustus is an emerging, azole-resistant, cryptic Aspergillus species in immunosuppressed patients that often features extrapulmonary involvement and carries high mortality. The case presented by J. F. Camargo, R. Jabr, A. D. Anderson, L. Lekakis, et al. (Antimicrob Agents Chemother 66:e02206-21, 2022, https://doi.org/10.1128/aac.02206-21 ) describes a transplant recipient with disseminated A. calidoustus infection who was successfully treated with surgical source control, tapering of immunosuppression, and long-term, combination antifungal treatment that included the first-in-class fosmanogepix, which targets fungal mannoprotein trafficking and anchoring.

Emerging Fungal Infections: New Species, New Names, and Antifungal Resistance

BACKGROUND

Infections caused by fungi can be important causes of morbidity and mortality in certain patient populations, including those who are highly immunocompromised or critically ill. Invasive mycoses can be caused by well-known species, as well as emerging pathogens, including those that are resistant to clinically available antifungals.

CONTENT

This review highlights emerging fungal infections, including newly described species, such as Candida auris, and those that having undergone taxonomic classification and were previously known by other names, including Blastomyces and Emergomyces species, members of the Rasamsonia argillacea species complex, Sporothrix brasiliensis, and Trichophyton indotinae. Antifungal resistance also is highlighted in several of these emerging species, as well as in the well-known opportunistic pathogen Aspergillus fumigatus. Finally, the increased recognition and importance of fungal co-infections with respiratory pathogens, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is discussed.

SUMMARY

Both clinicians and clinical microbiology laboratories should remain vigilant regarding emerging fungal infections. These may be difficult both to diagnose and treat due to the lack of experience of clinicians and laboratory personnel with these organisms and the infections they may cause. Many of these fungal infections have been associated with poor clinical outcomes, either due to inappropriate therapy or the development of antifungal resistance.

Ubiquitous Distribution of Azole-Resistant Aspergillus fumigatus- Related Species in Outdoor Environments in Japan

Aspergillus fumigatus-related species are responsible for causing aspergillosis, which is a fatal infectious disease. Recently, there has been a series of reports of A. fumigatus-related species that are resistant to azole drugs used in clinical practice for the treatment of fungal infections. Some of these species have been isolated from outdoor environments. Testing the drug susceptibility of the strains from outdoor environments, therefore, is important. In this study, we isolated and cultured 72 strains of A. fumigatus-related species from the outdoor environment in Japan. The isolates identified via morphological observation and molecular phylogenetic analysis were Aspergillus felis, Aspergillus lentulus, Aspergillus pseudoviridinutans, Aspergillus udagawae, and Aspergillus wyomingensis. The results of the drug susceptibility testing revealed that A. felis (6 of 14 strains) and A. pseudoviridinutans (13 of 17 strains) were resistant to itraconazole (ITCZ), with 4 mg/L or higher minimum inhibitory concentrations (MICs). The voriconazole (VRCZ)-resistant strains with 4 mg/L or higher MICs were A. felis (14 of 14), A. lentulus (4 of 4), A. pseudoviridinutans (15 of 17), A. udagawae (23 of 34), A. wyomingensis (1 of 3), and A. pseudoviridinutans (1 of 3). Among them, A. felis (1 of 14) and A. pseudoviridinutans (7 of 17) demonstrated 8 mg/L or higher MICs for ITCZ and VRCZ. These results indicate that A. fumigatus-related species resistant to ITCZ and VRCZ are widely distributed in outdoor environments in Japan.

An expanded agar-based screening method for azole-resistant Aspergillus fumigatus

Antifungal susceptibility testing is an essential tool for guiding antifungal therapy. Reference methods are complex and usually only available in specialised laboratories. We have designed an expanded agar-based screening method for the detection of azole-resistant Aspergillus fumigatus isolates. Normally, identification of resistance mechanisms is obtained only after sequencing the cyp51A gene and promoter. However, our screening method provides azole resistance detection and presumptive resistance mechanisms identification. A previous agar-based method consisting of four wells containing voriconazole, itraconazole, posaconazole and a growth control, detected azole resistance to clinical azoles. Here, we have modified the concentrations of voriconazole and posaconazole to adapt to the updated EUCAST breakpoints against A. fumigatus. We have also expanded the method to include environmental azoles to assess azole resistance and the azole resistance mechanism involved. We used a collection of A. fumigatus including 54 azole-resistant isolates with Cyp51A modifications (G54, M220, G448S, TR₅₃ , TR₃₄ /L98H, TR₄₆ /Y121F/T289A, TR₃₄ /L98H/S297T/F495I), and 50 azole susceptible isolates with wild-type Cyp51A. The screening method detects azole-resistant A. fumigatus isolates when there is growth in any of the azole-containing wells after 48h. The growth pattern in the seven azoles tested helps determine the underlying azole resistance mechanism. This approach is designed for surveillance screening of A. fumigatus azole-resistant isolates and can be useful for the clinical management of patients prior to antifungal susceptibility testing confirmation.

Clinical and microbiological characteristics of proven invasive aspergillosis due to rare/cryptic species in allogeneic hematopoietic stem cell transplant recipients

There are few reports on the clinical course of proven invasive aspergillosis (IA) due to rare/cryptic species in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. We retrospectively reviewed the electronic medical records of patients who underwent allo-HSCT between January 2012 and December 2018. Of 934 allo-HSCT recipients, 10 were diagnosed with proven IA and 61 were diagnosed with probable IA. DNA sequencing was performed in cases of proven IA, and Aspergillus could be identified to the species level in 8 of the 10 cases. Three were due to A. fumigatus, and 5 were due to rare/cryptic Aspergillus species, namely, A. turcosus, A. felis, A. viridinutans, A. nidulans, and A. calidoustus. In these 8 patients, no patients with IA due to A. fumigatus died, whereas 3 of the 5 with IA due to rare/cryptic species died within 12 weeks. The 2 surviving cases of IA due to rare/cryptic species were treated with surgical resection and antifungal treatment. Susceptibility testing for cryptic species in 4 cases showed an amphotericin B minimum inhibitory concentration (MIC) > 1 mg/L in 3 cases, itraconazole MIC > 1 mg/L in 2 cases, and voriconazole MIC > 1 mg/L in 2 cases. In conclusion, more than half of the causative pathogens of proven IA were rare/cryptic species, so it is important to accurately identify the Aspergillus species. In addition, surgical treatment might be an important option in cases of proven IA, given the possibility that the causative organisms are azole-resistant A. fumigatus or rare/cryptic species.

The Antifungal Pipeline: Fosmanogepix, Ibrexafungerp, Olorofim, Opelconazole, and Rezafungin

The epidemiology of invasive fungal infections is changing, with new populations at risk and the emergence of resistance caused by the selective pressure from increased usage of antifungal agents in prophylaxis, empiric therapy, and agriculture. Limited antifungal therapeutic options are further challenged by drug-drug interactions, toxicity, and constraints in administration routes. Despite the need for more antifungal drug options, no new classes of antifungal drugs have become available over the last 2 decades, and only one single new agent from a known antifungal class has been approved in the last decade. Nevertheless, there is hope on the horizon, with a number of new antifungal classes in late-stage clinical development. In this review, we describe the mechanisms of drug resistance employed by fungi and extensively discuss the most promising drugs in development, including fosmanogepix (a novel Gwt1 enzyme inhibitor), ibrexafungerp (a first-in-class triterpenoid), olorofim (a novel dihyroorotate dehydrogenase enzyme inhibitor), opelconazole (a novel triazole optimized for inhalation), and rezafungin (an echinocandin designed to be dosed once weekly). We focus on the mechanism of action and pharmacokinetics, as well as the spectrum of activity and stages of clinical development. We also highlight the potential future role of these drugs and unmet needs.