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Indian Journal of Medical Microbiology Jun 2024Due to the potential for Aspergillus species to cause lethal infections and the rising rates of antifungal resistance, the significance of antifungal susceptibility...
PURPOSE
Due to the potential for Aspergillus species to cause lethal infections and the rising rates of antifungal resistance, the significance of antifungal susceptibility tests has increased. We aimed to assess the sensitivities of Aspergillus species to amphotericin B (AMB), voriconazole (VOR), itraconazole (ITZ), and caspofungin (CAS) using disk diffusion (DD) and gradient diffusion (GD) methods and compare them with broth microdilution (BMD) as the reference susceptibility method.
METHODS
The study involved 62 Aspergillus fumigatus, 28 Aspergillus flavus, and 16 Aspergillus terreus isolates, totaling 106 Aspergillus isolates. BMD and DD methods were performed in accordance with CLSI M38-A2 and CLSI M51-A documents, respectively. The GD method utilized nonsupplemented Mueller Hinton agar (MHA) as the medium.
RESULTS
In the BMD method, the lowest minimal inhibitory concentration (MIC) or minimal effective concentration (MEC) values were observed for VOR and CAS (0.5 μg/mL and 0.06 μg/mL, respectively). AMB and ITZ MIC values were both 2 μg/mL. In our comparison of the GD method with the BMD method at ±2 dilution, we observed essential agreement rates of 91.6%, 99.1%, 100%, and 38.6% for AMB, VOR, ITZ, and CAS, respectively. When comparing DD and BMD methods, we found categorical agreement rates of 65.1%, 99.1%, 77.3%, and 100% for AMB, VOR, ITZ, and CAS, respectively. For GD and BMD methods, these rates were 79.2%, 99.1%, 87.8%, and 100%.
CONCLUSIONS
Given the high essential and categorical agreement rates, we posit that the GD method is a viable alternative to the BMD method for AMB, ITZ and VOR but not for CAS. In addition, the use of nonsupplemented MHA in the GD method proves advantageous due to its cost-effectiveness and widespread availability compared to other growth media.
PubMed: 38830536
DOI: 10.1016/j.ijmmb.2024.100642 -
Infection and Drug Resistance 2024Azole resistance in poses a significant challenge in the management of invasive aspergillosis. This study aimed to investigate the antifungal susceptibility and...
PURPOSE
Azole resistance in poses a significant challenge in the management of invasive aspergillosis. This study aimed to investigate the antifungal susceptibility and mutation profiles of isolates in Malaysia.
PATIENTS AND METHODS
Sixty clinical isolates were collected and subjected to antifungal susceptibility testing (AFST) and molecular analysis. The antifungal susceptibility testing was performed according to CLSI M38 guideline. The geometric mean (GM) minimum inhibitory concentration (MIC), MIC/MIC for voriconazole, itraconazole, posaconazole, amphotericin B, and isavuconazole against in non-invasive cases and invasive cases were calculated. In addition, the presence of mutations was also identified.
RESULTS
The present study revealed an overall resistance rate of 6.7% among the isolates. In non-invasive cases, isavuconazole and posaconazole demonstrated the lowest GM MIC of 0.08 µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.15µg/mL, 0.16µg/mL and 0.90µg/mL, respectively. Similarly, in invasive cases, isavuconazole and posaconazole exhibited the lowest GM MIC of 0.09µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.14µg/mL, 0.17µg/mL and 0.80µg/mL, respectively. Genotypic analysis revealed various mutations, including F46Y, M172V, N248K, R34L, V244A, V244S, and E427K. However, not all mutations corresponded to antifungal resistance.
CONCLUSION
The majority of clinical isolates demonstrated susceptibility to the antifungal agents tested, with isavuconazole and posaconazole demonstrating the lowest MIC values. However, mutations were discovered without a consistent correlation to antifungal resistance, emphasising the need for additional research.
PubMed: 38828376
DOI: 10.2147/IDR.S452619 -
Cell Surface (Amsterdam, Netherlands) Jun 2024Cell wall biomass, Earth's most abundant natural resource, holds significant potential for sustainable biofuel production. Composed of cellulose, hemicellulose, lignin,... (Review)
Review
Cell wall biomass, Earth's most abundant natural resource, holds significant potential for sustainable biofuel production. Composed of cellulose, hemicellulose, lignin, pectin, and other polymers, the plant cell wall provides essential structural support to diverse organisms in nature. In contrast, non-plant species like insects, crustaceans, and fungi rely on chitin as their primary structural polysaccharide. The saprophytic fungus has been widely recognized for its adaptability to various environmental conditions. It achieves this by secreting different cell wall biomass degradation enzymes to obtain essential nutrients. This review compiles a comprehensive collection of cell wall degradation enzymes derived from , including cellulases, hemicellulases, various chitin degradation enzymes, and other polymer degradation enzymes. Notably, these enzymes exhibit biochemical characteristics such as temperature tolerance or acid adaptability, indicating their potential applications across a spectrum of industries.
PubMed: 38827922
DOI: 10.1016/j.tcsw.2024.100126 -
Journal of Family Medicine and Primary... Apr 2024SARS-COV virus operates as a significant risk factor for invasive fungal aspergillosis and mucormycosis. Successful management of this fulminant infection requires early...
BACKGROUND
SARS-COV virus operates as a significant risk factor for invasive fungal aspergillosis and mucormycosis. Successful management of this fulminant infection requires early recognition of the disease and aggressive medical or surgical interventions to prevent the high morbidity and mortality associated with the disease process.
AIMS AND OBJECTIVE OF THE STUDY
1. To isolate and identify different species of fungi among acute rhinosinusitis patients. 2. To assess the association of risk factors causing fungal rhinosinusitis. 3. To assess the changing trend in fungal rhinosinusitis during the COVID era.
MATERIAL AND METHODS
This is a retrospective observational study conducted from May 2020 to October 2022, attending the ENT department and relevant data were collected from the medical records department of ABVIMS and Dr RML Hospital, New Delhi, a Tertiary Care Referral Centre in India. The major risk factors studied were age, gender, COVID-19 infection and underlying diseases (such as diabetes mellitus, ischaemic heart disease, hypertension, malignancies, chronic kidney DISEASES, etc.); details of corticosteroid use of all patients were recorded in the datasheet. The pandemic data was divided into three distinct time periods/waves/eras, i.e., first, second, and third waves, each of which included ten months, to examine the changing trend in fungal rhinosinusitis in the pandemic era of COVID-19.
RESULTS
A total of 412 patients out of which 236 patients were clinically diagnosed with fungal sinusitis based on revised EORTC criteria. The most common site involved was the orbit with paranasal sinus and eye 86/236 (36.4%), followed by involvement of nasal and paranasal sinus alone 68/236 (28.8%). The most prevalent age range affected was 40 to 50 years. The most commonly associated comorbidity was diabetes mellitus (DM) in 176 (74.5%), followed by head and neck malignancies in 22 (9.32%) patients. Thirty-eight (50.6%) species and 18 (24%) were the most common isolated fungal species on culture, followed by spp. 14 (18.6%) and 5 (6.6%) in the period. In the second wave of COVID, there was a surge in cases 36 (45%) and after the second wave, the cases increased by 14 (19%) during Jan-Oct 2022.
CONCLUSION
With the continuing coronavirus pandemic, there is an unprecedented and discernible rise in the prevalence of acute invasive fungal sinusitis certainly a spike in cases of Aspergillus infection was observed, probably due to unprecedented usage of Amphotericin B for the treatment of mucormycosis during the third wave This underlines the importance of the need to tailor our treatment protocol as per the etiological agents hence the right antifungal drugs combined with urgent surgical procedures on a case-to-case basis may certainly increase the chances of survival.
PubMed: 38827671
DOI: 10.4103/jfmpc.jfmpc_871_23 -
BioRxiv : the Preprint Server For... May 2024Treatment of fungal infections associated with the filamentous fungus is becoming more problematic as this organism is developing resistance to the main...
Treatment of fungal infections associated with the filamentous fungus is becoming more problematic as this organism is developing resistance to the main chemotherapeutic drug at an increasing rate. Azole drugs represent the current standard-of-care in treatment of aspergillosis with this drug class acting by inhibiting a key step in biosynthesis of the fungal sterol ergosterol. Azole compounds block the activity of the lanosterol α-14 demethylase, encoded by the gene. A common route of azole resistance involves an increase in transcription of . This transcriptional increase requires the function of a Zn2Cys6 DNA-binding domain-containing transcription activator protein called AtrR. AtrR was identified through its action as a positive regulator of expression of an ATP-binding cassette transporter (/ here called ). Using both deletion and alanine scanning mutagenesis, we demonstrate that a conserved C-terminal domain in is required for expression of but dispensable for transcription. This domain is also found in several other fungal pathogen AtrR homologues consistent with a conserved gene-selective function of this protein segment being conserved. Using RNA-seq, we find that this gene-specific transcriptional defect extends to several other membrane transporter-encoding genes including a second ABC transporter locus. Our data reveal that AtrR uses at least two distinct mechanisms to induce gene expression and that normal susceptibility to azole drugs cannot be provided by maintenance of wild-type expression of the ergosterol biosynthetic pathway when ABC transporter expression is reduced.
PubMed: 38826412
DOI: 10.1101/2024.05.22.595332 -
Microbial Cell Factories May 2024Multi resistant fungi are on the rise, and our arsenal compounds are limited to few choices in the market such as polyenes, pyrimidine analogs, azoles, allylamines, and... (Review)
Review
Multi resistant fungi are on the rise, and our arsenal compounds are limited to few choices in the market such as polyenes, pyrimidine analogs, azoles, allylamines, and echinocandins. Although each of these drugs featured a unique mechanism, antifungal resistant strains did emerge and continued to arise against them worldwide. Moreover, the genetic variation between fungi and their host humans is small, which leads to significant challenges in new antifungal drug discovery. Endophytes are still an underexplored source of bioactive secondary metabolites. Many studies were conducted to isolate and screen endophytic pure compounds with efficacy against resistant yeasts and fungi; especially, Candida albicans, C. auris, Cryptococcus neoformans and Aspergillus fumigatus, which encouraged writing this review to critically analyze the chemical nature, potency, and fungal source of the isolated endophytic compounds as well as their novelty features and SAR when possible. Herein, we report a comprehensive list of around 320 assayed antifungal compounds against Candida albicans, C. auris, Cryptococcus neoformans and Aspergillus fumigatus in the period 1980-2024, the majority of which were isolated from fungi of orders Eurotiales and Hypocreales associated with terrestrial plants, probably due to the ease of laboratory cultivation of these strains. 46% of the reviewed compounds were active against C. albicans, 23% against C. neoformans, 29% against A. fumigatus and only 2% against C. auris. Coculturing was proved to be an effective technique to induce cryptic metabolites absent in other axenic cultures or host extract cultures, with Irperide as the most promising compounds MIC value 1 μg/mL. C. auris was susceptible to only persephacin and rubiginosin C. The latter showed potent inhibition against this recalcitrant strain in a non-fungicide way, which unveils the potential of fungal biofilm inhibition. Further development of culturing techniques and activation of silent metabolic pathways would be favorable to inspire the search for novel bioactive antifungals.
Topics: Antifungal Agents; Endophytes; Humans; Microbial Sensitivity Tests; Cryptococcus neoformans; Fungi; Aspergillus fumigatus; Candida albicans
PubMed: 38822407
DOI: 10.1186/s12934-024-02411-3 -
Journal of Clinical Microbiology May 2024Azole resistance screening in can be routinely carried out by using azole-containing agar plates (E.Def 10.2 procedure); however, conidial suspension filtering and...
Azole resistance screening in using the azole-containing agar method (EUCAST E.Def 10.2): conidial suspension filtration and inoculum adjustment before inoculum preparation may not be needed.
UNLABELLED
Azole resistance screening in can be routinely carried out by using azole-containing agar plates (E.Def 10.2 procedure); however, conidial suspension filtering and inoculum adjustment before inoculum preparation are time-consuming. We evaluated whether skipping the filtration and inoculum adjustment steps negatively influenced the performance of the E.Def 10.2 procedure. isolates ( = 98), previously classified as azole susceptible or azole resistant (E.Def 9.4 method), were studied. Azole-resistant isolates had either the wild-type gene sequence ( = 1) or the following gene substitutions: TR-L98H ( = 41), G54R ( = 5), TR-Y121F-T289A ( = 1), or G448S ( = 1). In-house azole-containing agar plates were prepared according to the EUCAST E.Def 10.2 procedure. Conidial suspensions obtained by adding distilled water (Tween 20 0.1%) were either filtered and the inocula adjusted to 0.5 McFarland or left unfiltered and unadjusted. Agreements between the agar screening methods using inocula prepared by each procedure were high for itraconazole (99%), voriconazole (100%), and posaconazole (94.9%). Sensitivity and specificity (considering the susceptibility category as per the microdilution E.Def 9.4 method as the gold standard) of E.Def 10.2 were 100% to rule in or rule out resistance when unfiltered and unadjusted suspensions were used; the resistance phenotype of isolates harboring the TR-L98H, G54R, or TR-Y121F-T289A substitutions was correctly detected. Unfiltered and unadjusted conidial suspensions do not negatively influence the performance of the E.Def 10.2 method when screening for azole resistance in .
IMPORTANCE
Azole resistance screening in can be routinely carried out by using azole-containing plates (E.Def 10.2 procedure); however, conidial suspension filtering and inoculum adjustment before inoculation of plates are time-consuming. We, here, showed that unfiltered and unadjusted conidial suspensions do not negatively influence the performance of the E.Def 10.2 method when screening for azole resistance in .
PubMed: 38819167
DOI: 10.1128/jcm.00369-24 -
MSphere Jun 2024is the leading cause of severe mold infections in immunocompromised patients. This common fungus possesses innate attributes that allow it to evade the immune system,...
is the leading cause of severe mold infections in immunocompromised patients. This common fungus possesses innate attributes that allow it to evade the immune system, including its ability to survive the high copper (Cu) levels in phagosomes. Our previous work has revealed that under high Cu levels, the transcription factor AceA is activated, inducing the expression of the copper exporter CrpA to expel excess Cu. To identify additional elements in Cu resistance, we evolved wild-type and mutant Δ or Δ strains under increasing Cu concentrations. Sequencing of the resultant resistant strains identified both shared and unique evolutionary pathways to resistance. Reintroduction of three of the most common mutations in genes encoding Pma1 (plasma membrane H-ATPase), Gcs1 (glutamate cysteine-ligase), and Cpa1 (carbamoyl-phosphate synthetase), alone and in combination, into wild-type confirmed their additive role in conferring Cu resistance. Detailed analysis indicated that the mutation L424I preserves Pma1 H-ATPase activity under high Cu concentrations and that the mutation A37V confers a survival advantage to conidia in the presence of Cu. Interestingly, simultaneous mutations of all three genes did not alter virulence in infected mice. Our work has identified novel Cu-resistance pathways and provides an evolutionary approach for dissecting the molecular basis of adaptation to diverse environmental challenges.IMPORTANCE is the most common mold infecting patients with weakened immunity. Infection is caused by the inhalation of mold spores into the lungs and is often fatal. In healthy individuals, spores are engulfed by lung immune cells and destroyed by a combination of enzymes, oxidants, and high levels of copper. However, the mold can protect itself by pumping out excess copper with specific transporters. Here, we evolved under high copper levels and identified new genetic mutations that help it resist the toxic effects of copper. We studied how these mutations affect the mold's ability to resist copper and how they impact its ability to cause disease. This is the first such study in a pathogenic mold, and it gives us a better understanding of how it manages to bypass our body's defenses during an infection.
Topics: Aspergillus fumigatus; Copper; Animals; Mice; Fungal Proteins; Aspergillosis; Mutation; Drug Resistance, Fungal; Virulence; Evolution, Molecular; Glutamate-Cysteine Ligase; Female; Proton-Translocating ATPases
PubMed: 38814077
DOI: 10.1128/msphere.00253-24 -
Mycology 2024Asexual spores, called conidia, are key reproductive fungal particles that enable survival in harsh environmental conditions or host systems. The conidia can infect...
Asexual spores, called conidia, are key reproductive fungal particles that enable survival in harsh environmental conditions or host systems. The conidia can infect humans, animals, and plants to cause various fungal diseases. Transcription factors, including VosA, WetA, and SscA, have key roles in conidia formation and long-term survival in . Herein, we report the pleiotropic functions of SscA in the conidia of the human pathogen . The deletion of increased conidia formation despite decreased fungal growth. Absence of impaired long-term survival and reduced spore resistance to various stresses, including heat, UV, and oxidation. Transcriptomic analyses showed that SscA involved the mRNA expression of cell wall organisation-related genes. Importantly, the deletion mutant conidia contained an increased amount of β-glucan and chitin compared to wild type conidia. In addition, conidial gliotoxin production was decreased in the deletion strain. Overall, SscA has pleiotropic roles in conidia formation, maturation and dormancy and mycotoxin production in .
PubMed: 38813476
DOI: 10.1080/21501203.2023.2294061 -
Cureus Apr 2024Fosmanogepix, a prodrug of Manogepix (MGX), is a groundbreaking antifungal agent with broad-spectrum activity against yeasts, including and , as well as molds. It... (Review)
Review
Fosmanogepix, a prodrug of Manogepix (MGX), is a groundbreaking antifungal agent with broad-spectrum activity against yeasts, including and , as well as molds. It exhibits effectiveness against drug-resistant strains, such as strains resistant to and strains resistant to azoles. Furthermore, fosmanogepix shows activity against pathogens that typically resist other classes of drugs, such as , , and , although its efficacy against Mucorales varies. In animal models, fosmanogepix has demonstrated notable effectiveness against disseminated infections caused by various species, , and . It has also shown efficacy in pulmonary infection models involving , , , , and . Clinical trials have revealed excellent oral bioavailability (>90%), enabling a seamless transition between intravenous and oral formulations without compromising blood concentrations. Fosmanogepix exhibits favorable profiles in terms of drug interactions, tolerability, and extensive distribution in various tissues, making it an appealing choice for treating invasive fungal infections. This comprehensive review aims to examine the outcomes of published data on fosmanogepix, encompassing in vitro, in vivo, and clinical investigations.
PubMed: 38807795
DOI: 10.7759/cureus.59210