The High Diversity and Variable Susceptibility of Clinically Relevant Acremonium-Like Species in China

Exploring Fungal Abundance and WHO Fungal Priority Pathogens in Agricultural Fields: A One Health Perspective in Northeast Thailand

Fungal pathogens prevalent in agricultural areas pose a significant risk to human health, with some exhibiting high fatality rates, as reported by the WHO Fungal Pathogen Priority List (WHO FPPL). This study investigates fungal communities in northeast Thailand's agricultural areas, focusing on potential reservoirs of the WHO FPPL. Samples were collected from rice, cassava, rubber trees, and sugarcane fields across 18 provinces with distinct geological features. Metabarcoding of the ITS1 region and taxonomic analysis were conducted, and potential pathogens were selected according to WHO FPPL criteria. The results showed that overall fungal community richness and diversity were influenced by plant fields but not significantly different by geological features. Soil organic matter and water content affected fungal dynamics only in rubber tree fields. Fungal pathogens from the WHO FPPL were found in all four plant fields, with higher abundance in Chaiyaphum province, especially in sugarcane fields, and the lowest in Nong Bua Lam Phu. Candida tropicalis, a high-priority pathogen, was predominantly associated with rock salt features. This study underscores the need for vigilance among farmers and emphasizes the importance of confirming fungal pathogenicity.

Enhanced Specificity in Colorimetric LAMP Assay for Sarocladium kiliense Detection Using a Combination of Two Additives

The genus Sarocladium comprises fungal species closely related to Acremonium, with S. kiliense and S. strictum being medically important. These species can cause infections in both immunocompetent and immunocompromised individuals. The current detection methods are limited, prompting the need for rapid and specific diagnostic tools. We developed a colorimetric loop-mediated isothermal amplification (LAMP) assay targeting S. kiliense (SK-LAMP). The initial prototype assay faced challenges with cross-reactivities with closely related species. To address this, we incorporated two additives, pullulan and tetramethylammonium chloride (TMAC), which are known to reduce non-specific signals in amplification assays. Our study found that a combination of 1% (v/v) pullulan and 0.03 M TMAC enhanced the specific detection of S. kiliense in a 45 min reaction, without non-specific false-positive results for other fungal species. This optimised LAMP assay demonstrated high sensitivity and specificity, offering a reliable and rapid method for detecting S. kiliense. The novel approach of combining additives to enhance assay specificity presents a promising strategy for improving LAMP assays targeting closely related fungal species. This advancement can aid in the timely diagnosis and management of infections caused by S. kiliense, contributing to better patient outcomes and infection control.

First Confirmed Description of Acremonium egyptiacum from Greece and Molecular Identification of Acremonium and Acremonium-like Clinical Isolates

Acremonium and the recently separated acremonium-like genera, such as Sarocladium, are emerging causes of opportunistic disease in humans, mainly post-traumatic infections in immunocompetent hosts, but also invasive infections in immunocompromised patients, such as those undergoing transplantation. Acremonium egyptiacum has emerged as the major pathogenic Acremonium species in humans, implicated mainly in nail but also in disseminated and organ specific infections. In this first study of acremonium-like clinical isolates in Greece, 34 isolates were identified and typed by sequencing the internal transcribed spacer, and their antifungal susceptibility was determined by a modified CLSI standard M38 3rd Edition method for filamentous fungi. A. egyptiacum was the primary species (18 isolates) followed by Sarocladium kiliense (8), Acremonium charticola, Gliomastix polychroma, Proxiovicillium blochii, Sarocladium terricola, Sarocladium zeae, and Stanjemonium dichromosporum (all with one isolate). Two isolates, each with a novel ITS sequence, possibly represent undescribed species with an affinity to Emericellopsis. All three A. egyptiacum ITS barcode types described to date were identified, with 3 being the major type. Flutrimazole, lanoconazole, and luliconazole presented the lower minimum inhibitory concentration (MIC) values against A. egyptiacum, with a geometric mean (GM) MIC of 2.50, 1.92, and 1.57 μg/mL, respectively. Amphotericin B, itraconazole, posaconazole, voriconazole, terbinafine, amorolfine, and griseofulvin MICs were overall high (GM 12.79-29.49 μg/mL). An analysis of variance performed on absolute values showed that flutrimazole, lanoconazole, and luliconazole were equivalent and notably lower than those of all the other drugs tested against A. egyptiacum. Antifungal susceptibility of the three different A. egyptiacum genotypes was homogeneous. Overall, the high MICs recorded for all systemically administered drugs, and for some topical antifungals against the tested A. egyptiacum and other acremonium-like clinical isolates, justify the routine susceptibility testing of clinical isolates.

An updated list of eumycetoma causative agents and their differences in grain formation and treatment response

SUMMARYIn 2023, the World Health Organization designated eumycetoma causative agents as high-priority pathogens on its list of fungal priority pathogens. Despite this recognition, a comprehensive understanding of these causative agents is lacking, and potential variations in clinical manifestations or therapeutic responses remain unclear. In this review, 12,379 eumycetoma cases were reviewed. In total, 69 different fungal species were identified as causative agents. However, some were only identified once, and there was no supporting evidence that they were indeed present in the grain. Madurella mycetomatis was by far the most commonly reported fungal causative agent. In most studies, identification of the fungus at the species level was based on culture or histology, which was prone to misidentifications. The newly used molecular identification tools identified new causative agents. Clinically, no differences were reported in the appearance of the lesion, but variations in mycetoma grain formation and antifungal susceptibility were observed. Although attempts were made to explore the differences in clinical outcomes based on antifungal susceptibility, the lack of large clinical trials and the inclusion of surgery as standard treatment posed challenges in drawing definitive conclusions. Limited case series suggested that eumycetoma cases caused by Fusarium species were less responsive to treatment than those caused by Madurella mycetomatis. However, further research is imperative for a comprehensive understanding.

Performance of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Scedosporium, Acremonium-Like, Scopulariopsis, and Microascus Species

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a powerful microorganism identification tool. Research on MALDI-TOF MS identification of rare filamentous fungi is still lacking. This study aimed to evaluate the performance of MALDI-TOF MS in the identification of Scedosporium, Acremonium-like, Scopulariopsis, and Microascus species. Sabouraud broth cultivation and formic acid/acetonitrile protein extraction were used for MALDI-TOF MS identification by a Bruker Biotyper system. An in-house database containing 29 isolates of Scedosporium, Acremonium-like, Scopulariopsis, and Microascus spp. was constructed. A total of 52 clinical isolates were identified using the Bruker Filamentous Fungi Library v1.0 (FFL v1.0) alone, and Filamentous Fungi Library v1.0 plus the in-house library, respectively. The mass spectrum profile (MSP) dendrograms of the 28 Scedosporium isolates, 26 Acremonium-like isolates, and 27 Scopulariopsis and Microascus isolates were constructed by MALDI Biotyper OC 4.0 software, respectively. The correct species identification rate significantly improved when using the combined databases compared with that when using FFL v1.0 alone (Scedosporium spp., 75% versus 0%; Acremonium-like spp., 100% versus 0%; Scopulariopsis and Microascus spp., 100% versus 62.5%). The MSP dendrograms differentiated Acremonium-like species, Scopulariopsis and Microascus species clearly, but cannot distinguish species in the Scedosporium apiospermum complex. In conclusion, with an expanded database, MALDI-TOF MS is an effective tool for the identification of Scedosporium, Acremonium-like, Scopulariopsis, and Microascus species.

Case Report: A Case of Sarocladium strictum Meningoencephalitis in an Immunocompetent Patient After Invasive Operation

As an opportunistic phytopathogen, Sarocladium strictum has only been shown to cause neurological disease in immunocompromised patients, where antifungal therapy was not effective. We report a case of Sarocladium strictum meningoencephalitis in an apparently immunocompetent young woman who presented with severe headache and slight fever after undergoing transnasal endoscopic repair of cerebrospinal fluid rhinorrhea. Chronic sinusitis and suspicious intracranial fungal lesions were observed on enhanced magnetic resonance imaging (MRI). Both culture and metagenomic next-generation sequencing of her cerebrospinal fluid were positive for Sarocladium strictum. After local debridement, treatment with amphotericin B plus voriconazole and Ommaya reservoir implantation, the patient improved significantly. Unfortunately, her symptoms worsened again despite plenty of antifungal therapy for a month.

Diversity and Drug Resistance of Filamentous Fungi Isolated from the Fresh Raspberries

Fungi are one of the most widely distributed microorganisms in the environment, including food such as fruits, vegetables and other crops, posing a potential threat to food safety and human health. The aim of this study was to determine the diversity, intensity and drug resistance of potentially pathogenic filamentous fungi isolated from the fresh raspberries (Rubus idaeus L.). A total of 50 strains belonging to genera Fusarium, Cladosporium, Alternaria, Penicillium, Mucor, Rhizopus, Aspergillus and Acremonium were tested for drug resistance against 11 antifungals by disc diffusion and gradient strips methods. The average mycological contamination in the examined samples of raspberries amounted to 4.34 log CFU/g. The Cladosporium was isolated from all tested samples, followed by Alternaria and Fusarium with a frequency of 61% and 34%, respectively. The highest level of drug resistance was observed for Acremonium genera and Fusarium strains recorded a wide variation in drug resistance as revealed by susceptibility with amphotericin B and voriconzole with MICs ranged from 0.5–4 µg/ml and posaconazole with MICs ranging from 3–8 µg/ml. All fungal strains showed 100% resistance to caspofungin, fluconazole and flucytosine with both the methods, and 100% resistance to micafungin and anidulafungin in the gradient strip method.

Sarocladium and Acremonium infections: New faces of an old opportunistic fungus

The genera Acremonium and Sarocladium comprise a high diversity of morphologically and genetically related fungi generally found in the environment, although a few species, mainly Sarocladium kiliense and Acremonium egyptiacum, can also be involved in many human infections. Clinical management of opportunistic infections caused by these fungi is very complex, since their correct identification is unreliable, and they generally show poor antifungal response. More than 300 clinical cases involving a broad range of Acremonium/Sarocladium infections have so far been published, and with this review we aim to compile and provide a detailed overview of the current knowledge on Acremonium/Sarocladium human infections in terms of presentation, diagnosis, treatments and prognoses. We also aim to summarise and discuss the data currently available on their antifungal susceptibility, emphasising the promising results obtained with voriconazole as well as their impact in terms of animal infections.