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Soil and plant-associated protistan communities play a key role in shaping bacterial and fungal communities, primarily through their function as top-down predators. However, our understanding of how pathogen invasion influences these protistan communities and their relationships with bacterial and fungal communities remains limited. Here, we studied the protistan communities along the soil-plant continuum of healthy chilli peppers and those affected by Fusarium wilt disease (FWD), and integrated bacterial and fungal community data from our previous research. Our research showed that FWD was associated with a significant enrichment of phagotrophic protists in roots, and also increased the proportion and connectivity of these protists (especially Cercozoa and Ciliophora) in both intra- and inter-kingdom networks. Furthermore, the microbiome of diseased plants not only showed a higher relative abundance of functional genes related to bacterial anti-predator responses than healthy plants, but also contained a greater abundance of metagenome-assembled genomes with functional traits involved in this response. The increased microbial inter-kingdom associations between bacteria and protists, coupled with the notable bacterial anti-predator feedback in the microbiome of diseased plants, suggest that FWD may catalyse the associations between protists and their microbial prey. These findings highlight the potential role of predatory protists in influencing microbial assembly and functionality through top-down forces under pathogenic stress.
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Cilióforos , Microbiota , Micobioma , Plantas , Bactérias/genética , Solo , Microbiologia do SoloRESUMO
Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, is one of the most devastating infectious agents in the world. Chemical-genetic characterization through in vitro evolution combined with whole genome sequencing analysis was used identify novel drug targets and drug resistance genes in Mtb associated with its intracellular growth in human macrophages. We performed a genome analysis of 53 Mtb mutants resistant to 15 different hit compounds. We found nonsynonymous mutations/indels in 30 genes that may be associated with drug resistance acquisitions. Beyond confirming previously identified drug resistance mechanisms such as rpoB and lead targets reported in novel anti-tuberculosis drug screenings such as mmpL3, ethA, and mbtA, we have discovered several unrecognized candidate drug targets including prrB. The exploration of the Mtb chemical mutant genomes could help novel drug discovery and the structural biology of compounds and associated mechanisms of action relevant to tuberculosis treatment.
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Antituberculosos , Mycobacterium tuberculosis , Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Humanos , Mutação INDEL , Macrófagos/microbiologia , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Tuberculose/microbiologiaRESUMO
One hundred forty-nine carbapenem-resistant Enterobacterales from clinical samples obtained between April 2014 and November 2017 were subjected to whole genome sequencing and multi-locus sequence typing. Klebsiella pneumoniae (81, 54.4%) and Escherichia coli (38, 25.5%) were the most common species. Genes encoding metallo-ß-lactamases were detected in 68 (45.8%) isolates, and OXA-48-like enzymes in 60 (40.3%). blaNDM-1 (45; 30.2%) and blaOXA-48 (29; 19.5%) were the most frequent. KPC-encoding genes were identified in 5 (3.6%) isolates. Most common sequence types were E. coli ST410 (8; 21.1%) and ST38 (7; 18.4%), and K. pneumoniae ST147 (13; 16%) and ST231 (7; 8.6%).
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Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/efeitos dos fármacos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/tratamento farmacológico , Infecções por Enterobacteriaceae/epidemiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Catar/epidemiologia , Adulto JovemRESUMO
Puccinia striiformis f. sp. tritici causes severe global epidemics of wheat stripe rust primarily by airborne urediniospores. Understanding long-distance migration patterns of P. striiformis f. sp. tritici is critical for disease forecasting and management. Although the western epidemic areas in China have been considered as the source of inoculum spread eastward across the country, migration pathways among different populations within the western epidemic areas are poorly understood. In this study, we investigated the population genetics of 200 P. striiformis f. sp. tritici isolates from western epidemic areas using amplified fragment length polymorphism and simple sequence repeat markers. A coalescent approach was also used to calculate the migration rates among populations. Data analyses with both marker systems indicated high genetic diversity in each regional population. The Mantel test revealed significant positive correlation between genetic and geographic distances. Both discriminant analysis of principal components and STRUCTURE analysis supported moderate population structure shaped by seasonality and geography. The calculated migration rates indicated the presence of asymmetric migration between major populations in western epidemic areas, with greater migration rates from high elevation, oversummering areas to low elevation, overwintering areas. Sichuan Basin, one of the low elevation, overwintering areas, sampled in both fall and spring, was inferred as a recipient in fall but a donor in spring. Migration among P. striiformis f. sp. tritici populations may be partly attributable to terrace farming and prevailing wind direction in different seasons. Our study provides a better understanding of fine-scale population structure and the interregional migration pattern of P. striiformis f. sp. tritici in northwestern China and will inform future rust management.
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Basidiomycota , Epidemias , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Basidiomycota/genética , Estruturas Genéticas , Genótipo , Doenças das Plantas , TriticumRESUMO
Mucormycosis is one of the most invasive mycosis and has caused global concern in public health. Cutaneous mucormycosis caused by Mucor irregularis (formerly Rhizomucor variabilis) is an emerging disease in China. To survive in the human body, M. irregularis must overcome the hypoxic (low oxygen) host microenvironment. However, the exact molecular mechanism of its pathogenicity and adaptation to low oxygen stress environment is relatively unexplored. In this study, we used Illumina HiSeq technology (RNA-Seq) to determine and compare the transcriptome profile of M. irregularis CBS103.93 under normal growth condition and hypoxic stress. Our analyses demonstrated a series of genes involved in TCA, glyoxylate cycle, pentose phosphate pathway, and GABA shunt were down-regulated under hypoxic condition, while certain genes in the lipid/fatty acid metabolism and endocytosis were up-regulated, indicating that lipid metabolism was more active under hypoxia. Comparing the data with other important human pathogenic fungi such as Aspergillus spp., we found that the gene expression pattern and metabolism in responses to hypoxia in M. irregularis were unique and different. We proposed that these metabolic changes can represent a species-specific hypoxic adaptation in M. irregularis, and we hypothesized that M. irregularis could use the intra-lipid pool and lipid secreted in the infection region, as an extracellular nutrient source to support its hypoxic growth. Characterizing the significant differential gene expression in this species could be beneficial to uncover their role in hypoxia adaptation and fungalpathogenesis and further facilitate the development of novel targets in disease diagnosis and treatment against mucormycosis.
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Dermatomicoses/microbiologia , Regulação Fúngica da Expressão Gênica , Mucor/genética , Mucor/metabolismo , Oxigênio/metabolismo , Transcriptoma , Adaptação Fisiológica , Carbono/metabolismo , Dermatomicoses/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genes Fúngicos/genética , Humanos , Metabolismo dos Lipídeos , Redes e Vias Metabólicas/genética , Mucor/crescimento & desenvolvimento , Mucormicose/metabolismo , Mucormicose/microbiologia , RNA Mensageiro/genética , Reprodutibilidade dos TestesRESUMO
Bark beetles form multipartite symbiotic associations with blue stain fungi (Ophiostomatales, Ascomycota). These fungal symbionts play an important role during the beetle's life cycle by providing nutritional supplementation, overcoming tree defences and modifying host tissues to favour brood development. The maintenance of stable multipartite symbioses with seemingly less competitive symbionts in similar habitats is of fundamental interest to ecology and evolution. We tested the hypothesis that the coexistence of three fungal species associated with the mountain pine beetle is the result of niche partitioning and adaptive radiation using SNP genotyping coupled with genotype-environment association analysis and phenotypic characterization of growth rate under different temperatures. We found that genetic variation and population structure within each species is best explained by distinct spatial and environmental variables. We observed both common (temperature seasonality and the host species) and distinct (drought, cold stress, precipitation) environmental and spatial factors that shaped the genomes of these fungi resulting in contrasting outcomes. Phenotypic intraspecific variations in Grosmannia clavigera and Leptographium longiclavatum, together with high heritability, suggest potential for adaptive selection in these species. By contrast, Ophiostoma montium displayed narrower intraspecific variation but greater tolerance to extreme high temperatures. Our study highlights unique phenotypic and genotypic characteristics in these symbionts that are consistent with our hypothesis. By maintaining this multipartite relationship, the bark beetles have a greater likelihood of obtaining the benefits afforded by the fungi and reduce the risk of being left aposymbiotic. Complementarity among species could facilitate colonization of new habitats and survival under adverse conditions.
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Adaptação Fisiológica/genética , Evolução Biológica , Besouros/microbiologia , Ophiostomatales/genética , Simbiose , Animais , DNA Fúngico/genética , Ecossistema , Meio Ambiente , Frequência do Gene , Genética Populacional , Genômica , Fenótipo , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Sporotrichosis is one of the most frequent subcutaneous fungal infections in humans and animals caused by members of the plant-associated, dimorphic genus Sporothrix. Three of the four medically important Sporothrix species found in Brazil have been considered asexual as no sexual stage has ever been reported in Sporothrix schenckii, Sporothrix brasiliensis, or Sporothrix globosa. We have identified the mating type (MAT) loci in the S. schenckii (strain 1099-18/ATCC MYA-4821) and S. brasiliensis (strain 5110/ATCC MYA-4823) genomes by using comparative genomic approaches to determine the mating type ratio in these pathogen populations. Our analysis revealed the presence of a MAT1-1 locus in S. schenckii while a MAT1-2 locus was found in S. brasiliensis representing genomic synteny to other Sordariomycetes. Furthermore, the components of the mitogen-activated protein kinase (MAPK)-pheromone pathway, pheromone processing enzymes, and meiotic regulators have also been identified in the two pathogens, suggesting the potential for sexual reproduction. The ratio of MAT1-1 to MAT1-2 was not significantly different from 1:1 for all three Sporothrix species, but the population of S. brasiliensis in the outbreaks originated from a single mating type. We also explored the population genetic structure of these pathogens using sequence data of two loci to improve our knowledge of the pattern of geographic distribution, genetic variation, and virulence phenotypes. Population genetics data showed significant population differentiation and clonality with a low level of haplotype diversity in S. brasiliensis isolates from different regions of sporotrichosis outbreaks in Brazil. In contrast, S. schenckii isolates demonstrated a high degree of genetic variability without significant geographic differentiation, indicating the presence of recombination. This study demonstrated that two species causing the same disease have contrasting reproductive strategies and genetic variability patterns.
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Genes Fúngicos Tipo Acasalamento/genética , Reprodução Assexuada , Sporothrix/genética , Esporotricose/transmissão , Animais , Brasil , Gatos , Surtos de Doenças , Humanos , Sistema de Sinalização das MAP Quinases , Polimorfismo Genético , Sporothrix/patogenicidade , Sporothrix/fisiologia , Esporotricose/veterinária , Virulência/genéticaRESUMO
Giardia is the most common parasitic cause of gastrointestinal infections worldwide, with transmission through surface water playing an important role in various parts of the world. Giardia duodenalis (synonyms: G. intestinalis and G. lamblia), a multispecies complex, has two zoonotic subtypes, assemblages A and B. When British Columbia (BC), a western Canadian province, experienced several waterborne giardiasis outbreaks due to unfiltered surface drinking water in the late 1980s, collection of isolates from surface water, as well as from humans and beavers (Castor canadensis), throughout the province was carried out. To better understand Giardia in surface water, 71 isolates, including 29 from raw surface water samples, 29 from human giardiasis cases, and 13 from beavers in watersheds from this historical library were characterized by PCR. Study isolates also included isolates from waterborne giardiasis outbreaks. Both assemblages A and B were identified in surface water, human, and beavers samples, including a mixture of both assemblages A and B in waterborne outbreaks. PCR results were confirmed by whole-genome sequencing (WGS) for one waterborne outbreak and supported the clustering of human, water, and beaver isolates within both assemblages. We concluded that contamination of surface water by Giardia is complex, that the majority of our surface water isolates were assemblage B, and that both assemblages A and B may cause waterborne outbreaks. The higher-resolution data provided by WGS warrants further study to better understand the spread of Giardia.
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Água Doce/parasitologia , Giardia lamblia/classificação , Giardia lamblia/isolamento & purificação , Colúmbia Britânica , Genoma de Protozoário , Genótipo , Giardia lamblia/genética , Giardíase/parasitologia , Humanos , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da PolimeraseRESUMO
In order to understand the reproductive biology of pathogenic species in the Sporothrix schenckii complex, we characterized the partial mating type (MAT1-1) loci of Sporothrix schenckii, as well as the S. globosa MAT1-1-1 gene, which encoded 262 amino acid sequences. The data confirmed that the MAT1-1 locus of S. globosa was divergent from the MAT1-2 locus of the opposite mating type, suggesting that the fungus is heterothallic. To determine the mating type ratio of 20 isolates from Japanese patients, we analyzed the MAT loci by specific PCR amplification of MAT1-1-1 and MAT1-2-1 genes. The MAT1-1-1 was detected in 5 isolates but not in the other 15 isolates with the presence of MAT1-2-1. The MAT1-1:1-2 ratio of S. globosa isolates in Japan was estimated to be 1:3. Phylogenetic analysis indicated that the sequences of the MAT1-1-1 were identical among S. globosa isolates but different from S. schenckii and Ophiostoma montium.
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Genes Fúngicos Tipo Acasalamento/genética , Reprodução/genética , Sporothrix/genética , Sequência de Bases , DNA Fúngico/genética , Humanos , Japão , Filogenia , Reprodução/fisiologia , Análise de Sequência de DNA , Sporothrix/isolamento & purificação , Esporotricose/microbiologiaRESUMO
In western North America, the current outbreak of the mountain pine beetle (MPB) and its microbial associates has destroyed wide areas of lodgepole pine forest, including more than 16 million hectares in British Columbia. Grosmannia clavigera (Gc), a critical component of the outbreak, is a symbiont of the MPB and a pathogen of pine trees. To better understand the interactions between Gc, MPB, and lodgepole pine hosts, we sequenced the â¼30-Mb Gc genome and assembled it into 18 supercontigs. We predict 8,314 protein-coding genes, and support the gene models with proteome, expressed sequence tag, and RNA-seq data. We establish that Gc is heterothallic, and report evidence for repeat-induced point mutation. We report insights, from genome and transcriptome analyses, into how Gc tolerates conifer-defense chemicals, including oleoresin terpenoids, as they colonize a host tree. RNA-seq data indicate that terpenoids induce a substantial antimicrobial stress in Gc, and suggest that the fungus may detoxify these chemicals by using them as a carbon source. Terpenoid treatment strongly activated a â¼100-kb region of the Gc genome that contains a set of genes that may be important for detoxification of these host-defense chemicals. This work is a major step toward understanding the biological interactions between the tripartite MPB/fungus/forest system.
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Proteínas Fúngicas/genética , Genoma Fúngico/genética , Ophiostomatales/genética , Transcrição Gênica/genética , Animais , Besouros/microbiologia , Estudo de Associação Genômica Ampla , Pinus/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Simbiose/fisiologiaRESUMO
Candida glabrata is a commensal yeast of the gastrointestinal tract and skin of humans. However, it causes opportunistic infections in immunocompromised patients, and is the second most common Candida pathogen causing bloodstream infections. Although there are many studies on the epidemiology of C. glabrata infections, the fine- and large-scale geographical nature of C. glabrata remain incompletely understood. Here we investigated both the fine- and large-scale population structure of C. glabrata through genome sequencing of 80 clinical isolates obtained from six tertiary hospitals in Qatar and by comparing with global collections. Our fine-scale analyses revealed high genetic diversity within the Qatari population of C. glabrata and identified signatures of recombination, inbreeding and clonal expansion within and between hospitals, including evidence for nosocomial transmission among coronavirus disease 2019 (COVID-19) patients. In addition to signatures of recombination at the population level, both MATa and MATα alleles were detected in most hospitals, indicating the potential for sexual reproduction in clinical environments. Comparisons with global samples showed that the Qatari C. glabrata population was very similar to those from other parts of the world, consistent with the significant role of recent anthropogenic activities in shaping its population structure. Genome-wide association studies identified both known and novel genomic variants associated with reduced susceptibilities to fluconazole, 5-flucytosine and echinocandins. Together, our genomic analyses revealed the diversity, transmission patterns and antifungal drug resistance mechanisms of C. glabrata in Qatar as well as the relationships between Qatari isolates and those from other parts of the world.
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Candida glabrata , Infecção Hospitalar , Humanos , Candida glabrata/genética , Infecção Hospitalar/epidemiologia , Estudo de Associação Genômica Ampla , Metagenômica , Genômica , Recombinação GenéticaRESUMO
Background: Resistant Salmonella infections are a major global public health challenge particularly for multidrug-resistant (MDR) isolates manifesting as bloodstream infections (BSIs). Objectives: To evaluate clinical, phenotypic, and genotypic characteristics of extended-spectrum beta-lactamase (ESBL) producing Salmonella enterica BSIs from Qatar. Methods: Phenotypic ESBL Salmonella enterica from adult patients presenting with positive BSIs were collected between January 2019 to May 2020. Microbiological identification and characterization were performed using standard methods while genetic characteristics were examined through whole genome sequencing studies. Results: Of 151 episodes of Salmonella enterica BSI, 15 (10%) phenotypic ESBL isolates were collected. Recent travel was recorded in most cases (80%) with recent exposure to antimicrobials (27%). High-level resistance to quinolines, aminoglycosides, and cephalosporins was recorded (80-100%) while meropenem, tigecycline and colistin demonstrated universal susceptibility. Genomic evaluation demonstrated dominance of serotype Salmonella Typhi sequence type 1 (93%) while antimicrobial resistance genes revealed dominance of aminoglycoside resistance (100%), qnrS1 quinolones resistance (80%), blaCTX-M-15 ESBLs (86.7%), and paucity of AmpC resistance genes (6.7%). Conclusions: Invasive MDR Salmonella enterica is mainly imported, connected to patients from high prevalent regions with recent travel and antimicrobial use caused by specific resistant clones. In suspected cases of multidrug resistance, carbapenem therapy is recommended.
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Antimicrobial resistance is a global healthcare threat with significant clinical and economic consequences peaking at secondary and tertiary care hospitals where multidrug-resistant Gram-negative bacteria (MDR GNB) lead to poor outcomes. A prospective study was conducted between January and December 2019 for all invasive bloodstream infections (BSIs) secondary to MDR GNB in Qatar identified during routine microbiological service to examine their clinical, microbiological, and genomic characteristics. Out of 3238 episodes of GNB BSIs, the prevalence of MDR GNB was 13% (429/3238). The predominant MDR pathogens were Escherichia coli (62.7%), Klebsiella pneumoniae (20.4%), Salmonella species (6.6%), and Pseudomonas aeruginosa (5.3%), while out of 245 clinically evaluated patients, the majority were adult males, with the elderly constituting almost one-third of the cohort and with highest observed risk for prolonged hospital stays. The risk factors identified included multiple comorbidities, recent healthcare contact, previous antimicrobial therapy, and admission to critical care. The in-hospital mortality rate was recorded at 25.7%, associated with multiple comorbidities, admission to critical care, and the acquisition of MDR Pseudomonas aeruginosa. Resistant pathogens demonstrated high levels of antimicrobial resistance but noticeable susceptibility to amikacin and carbapenems. Genomic analysis revealed that Escherichia coli ST131 and Salmonella enterica ST1 were the predominant clones not observed with other pathogens.
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The continuing emergence of invasive fungal pathogens poses an increasing threat to public health. Here, through the China Hospital Invasive Fungal Surveillance Net programme, we identified two independent cases of human infection with a previously undescribed invasive fungal pathogen, Rhodosporidiobolus fluvialis, from a genus in which many species are highly resistant to fluconazole and caspofungin. We demonstrate that R. fluvialis can undergo yeast-to-pseudohyphal transition and that pseudohyphal growth enhances its virulence, revealed by the development of a mouse model. Furthermore, we show that mouse infection or mammalian body temperature induces its mutagenesis, allowing the emergence of hypervirulent mutants favouring pseudohyphal growth. Temperature-induced mutagenesis can also elicit the development of pan-resistance to three of the most commonly used first-line antifungals (fluconazole, caspofungin and amphotericin B) in different Rhodosporidiobolus species. Furthermore, polymyxin B was found to exhibit potent activity against the pan-resistant Rhodosporidiobolus mutants. Collectively, by identifying and characterizing a fungal pathogen in the drug-resistant genus Rhodosporidiobolus, we provide evidence that temperature-dependent mutagenesis can enable the development of pan-drug resistance and hypervirulence in fungi, and support the idea that global warming can promote the evolution of new fungal pathogens.
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Antifúngicos , Mutagênese , Animais , Camundongos , Humanos , Virulência/genética , Antifúngicos/farmacologia , China , Temperatura Corporal , Modelos Animais de Doenças , Ascomicetos/genética , Ascomicetos/patogenicidade , Ascomicetos/efeitos dos fármacos , Caspofungina/farmacologia , Testes de Sensibilidade Microbiana , Fluconazol/farmacologia , Micoses/microbiologia , Farmacorresistência Fúngica Múltipla/genética , Farmacorresistência Fúngica/genéticaRESUMO
Introduction: The rapid rise of azole resistance in Candida tropicalis causing invasive infections has become a public health concern; however, the prevalence of resistant isolates in urine samples was not well studied, because the clinical significance of candiduria was not unambiguous due to possible host colonization. Methods: We performed a 12-year laboratory-based surveillance study of C. tropicalis causing either invasive infection or candiduria and studied their susceptibility profiles to common antifungal drugs. The complete coding domain sequence of the ERG11 gene was amplified in all fluconazole resistant isolates, and aligned with the wild-type sequence to detect nucleotide mutations. Results: A total of 519 unique C. tropicalis strains isolates, 69.9% of which were isolated from urine samples and remaining 30.1% were invasive strains. Overall, 16.5% isolates were confirmed to be resistant to fluconazole, of which 91.9% were cross-resistant voriconazole. Of note, at the beginning of surveillance (2010-2011), the fluconazole resistance rates were low in both candiduria and invasive groups (6.8% and 5.9%, respectively). However, the resistant rate in the candiduria group significantly increased to 29.5% since 2012-2013 (p = 0.001) and stayed high since then, whilst the resistance rate in the invasive group only showed a gradually increasing trends till 2021 (p > 0.05). Sequence analysis of ERG11 from fluconazole-resistant strains revealed the prevalence of A395T/W mutations were relatively low (16.7%) in the beginning but reached 87.5-100% after 2014. Moreover, the A395W heterozygous mutation isolates became predominant (>60% of resistant strains) after 2016, and indeed isolates carrying corresponding amino acid substitution (Y132F) was highly resistant to fluconazole with MIC50 exceeded 256 µg/ml. Conclusion: Our study revealed high azole resistant rate in candiduria with its increasing trends observed much earlier than stains causing invasive infections. Given antimicrobial resistance as a critical "One Health" issue, the emergence of antifungal resistance in Candida species that are common commensal colonizers in the human body should be concerned.
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Rust fungi are characterized by large genomes with high repeat content and have two haploid nuclei in most life stages, which makes achieving high-quality genome assemblies challenging. Here, we described a pipeline using HiFi reads and Hi-C data to assemble a gigabase-sized fungal pathogen, Puccinia polysora f.sp. zeae, to haplotype-phased and chromosome-scale. The final assembled genome is 1.71 Gbp, with ~850 Mbp and 18 chromosomes in each haplotype, being currently one of the two giga-scale fungi assembled to chromosome level. Transcript-based annotation identified 47,512 genes for the dikaryotic genome with a similar number for each haplotype. A high level of interhaplotype variation was found with 10% haplotype-specific BUSCO genes, 5.8 SNPs/kbp, and structural variation accounting for 3% of the genome size. The P. polysora genome displayed over 85% repeat contents, with genome-size expansion and copy number increasing of species-specific orthogroups. Interestingly, these features did not affect overall synteny with other Puccinia species having smaller genomes. Fine-time-point transcriptomics revealed seven clusters of coexpressed secreted proteins that are conserved between two haplotypes. The fact that candidate effectors interspersed with all genes indicated the absence of a "two-speed genome" evolution in P. polysora. Genome resequencing of 79 additional isolates revealed a clonal population structure of P. polysora in China with low geographic differentiation. Nevertheless, a minor population differentiated from the major population by having mutations on secreted proteins including AvrRppC, indicating the ongoing virulence to evade recognition by RppC, a major resistance gene in Chinese corn cultivars. The high-quality assembly provides valuable genomic resources for future studies on disease management and the evolution of P. polysora.
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Basidiomycota , Puccinia , Puccinia/genética , Haplótipos , Zea mays/genética , Basidiomycota/genética , Cromossomos , Genoma FúngicoRESUMO
We report the draft genome sequences of two Phytobacter diazotrophicus isolates recovered from a swab specimen from the water faucet located in the Neonatal Intensive Care Unit (ICU), National University Hospital, Singapore. The isolates were misidentified as Cronobacter sakazakii and Klebsiella oxytoca using biochemical methods. Whole-genome sequencing (WGS) was performed to determine their identity.
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OBJECTIVES: During the COVID-19 pandemic in Qatar, many patients who were severely ill were colonized and infected by Candida auris, an invasive multidrug-resistant yeast pathogen that spreads through nosocomial transmission within healthcare facilities. Here, we investigated the molecular epidemiology of these C. auris isolates and the mechanisms associated with antifungal drug resistance. METHODS: Whole genomes of 76 clinical C. auris isolates, including 65 from patients with COVID-19 collected from March 2020 to June 2021, from nine major hospitals were sequenced on Illumina NextSeq. Single nucleotide polymorphisms were used to determine their epidemiological patterns and mechanisms for antifungal resistance. The data were compared with those published prior to the COVID-19 pandemic from 2018 to 2020 in Qatar. RESULTS: Genomic analysis revealed low genetic variability among the isolates from patients with and without COVID-19, confirming a clonal outbreak and ongoing dissemination of C. auris among various healthcare facilities. Based on antifungal susceptibility profiles, more than 70% (22/28) of isolates were resistant to both fluconazole and amphotericin B. Variant analysis revealed the presence of multi-antifungal resistant isolates with prominent amino acid substitutions: Y132F in ERG11 and V704L in CDR1 linked to reduced azole susceptibility and the emergence of echinocandin resistance samples bearing mutations in FKS1 in comparison with pre-COVID-19 pandemic samples. One sample (CAS109) was resistant to three classes of antifungal drugs with a unique premature stop codon in ERG3 and novel mutations in CDR2, which may be associated with elevated amphotericin B and azole resistance. DISCUSSION: Candida auris isolates from patients with COVID-19 and from most patient samples without COVID-19 in Qatar were highly clonal. The data demonstrated the emergence of multidrug-resistant strains that carry novel mutations linked to enhanced resistance to azoles, echinocandins, and amphotericin B. Understanding the epidemiology and drug resistance will inform the infection control strategy and drug therapy.