Paecilomyces variotii central nervous system infection in a patient with cancer

Severe pneumonia with pleural effusion caused by co-infection of Paecilomyces variotii and Penicillium oxalicum in a diabetic patient

BACKGROUND PAECILOMYCES: and Penicillium are considered as rare opportunistic pathogens in immunocompromised hosts, and pneumonia caused by Paecilomyces and Penicillium is rare. In this study, we present first case of severe pneumonia with pleural effusion caused by co-infection of Paecilomyces variotii (P. variotii) and Penicillium oxalicum (P. oxalicum) in a 66-year-old female with poorly controlled type 2 diabetes. CASE PRESENTATION: A 56-year-old woman patient presented to hospital for nausea, poor appetite, and vomiting for one day. On the second day of admission, blood culture and renal puncture fluid culture grew multidrug-resistant Escherichia coli (imipenem/cilastatin sensitive), and she received combination therapy with imipenem/cilastatin (1 g, every 8 h) and vancomycin (0.5 g, every 12 h). On the fourth day, she developed symptoms of respiratory failure. Pulmonary computed tomography (CT) showed an increase in pneumonia compared to before, with minor pleural effusion on both sides. Two fungi were isolated repeatedly from BALF culture, which were confirmed as P. variotii and P. oxalicum by Internal transcribed spacer (ITS) sequencing. Her pleural effusion was completely absorbed, pneumonia symptoms have significantly improved and discharged with receiving liposomal amphotericin B treatment for four weeks. CONCLUSIONS: It is worth noting that clinicians and laboratory personnel should not simply consider Paecilomyces and Penicillium species as contaminants, especially in immunocompromised patients. Early fungal identification and antifungal drug sensitivity are crucial for clinical drug selection and patient prognosis.

Characterization of the complete mitochondrial genome of Paecilomyces variotii and comparative evolutionary mitochondriomics of 36 fungi

BACKGROUD

Paecilomyces variotii has important economic value in stimulating crop growth, biodegradation, and other aspects. Up to now, there are no research reports on its mitochondrial genome.

METHODS AND RESULTS

The mitochondrial genome of Paecilomyces variotii was determined with the next-generation sequencing method (Illumina, NovaSeq), and its characteristics were analyzed using various bioinformatics approaches. The length of complete mitochondrial genome sequence of P. variotii is 40,965 bp and consists of 14 protein-coding genes, 2 ribosomal RNA genes, 1 ribosomal protein S3 gene, 26 transport RNA genes. The results of phylogenetics analysis using Bayesian inference and Maximum likelihood methods showed that P. variotii belongs to the Eurotiales order in the Thermoascaceae family, and 9 genera within the Eurotiomycetes class were effectively distinguished with high support rates (bootstrap value > 92% and posterior probabilities > 99%). The analysis of synonymous substitution rates and nonsynonymous substitution rates indicated that the Ka/Ks values of the 14 PCGs in the mitochondrial genomes of the two orders in the Eurotiomycetes class ranged from 0 to 0.4333.

CONCLUSIONS

This study revealed the structural and sequence information characteristics of the mitochondrial genome of P. variotii, and the phylogenetic results strongly support its classification within the family Thermoascaceae, consistent with traditional morphological taxonomy studies. The 14 PCGs in the mitochondrial genomes of the two orders in the Eurotiomycetes class are subject to strong purifying (negative) selection. The results of this research provides an important molecular basis for the development of genomics, evolutionary genetics and molecular markers of P. variotii in the future.

Disseminated Intravascular Infection Caused by Paecilomyces variotii: Case Report and Review of the Literature

Paecilomyces variotii is a ubiquitous environmental saprophyte with worldwide distribution. Commonly found in soil and decomposing organic material [1, 2], P. variotii can also be isolated from drinking water [3] and indoor and outdoor air [4-6]. In immunocompetent hosts, P. variotii has been reported as a cause of locally invasive disease including prosthetic valve endocarditis [7, 8], endophthalmitis [9, 10], rhinosinusitis [11, 12], and dialysis-associated peritonitis [13, 14]. In contrast, disseminated infections are more commonly reported in immunocompromised patients, including those with chronic granulomatous disease [15], solid malignancy [16], acute leukemia [17], lymphoma [18], multiple myeloma [19], and after stem cell transplant for myelodysplasia [20]. In 1 case series examining invasive infections by non-Aspergillus molds, P. variotii was the most common cause after Fusarium spp. [21]. Here, we present the case of an immunocompetent patient with extensive intravascular infection involving prosthetic material. We describe successful induction therapy with combination antifungals and extended suppression with posaconazole with clinical quiescence and eventual normalization of serum fungal biomarkers.

β-(1→6)-D-glucan secreted during the optimised production of exopolysaccharides by Paecilomyces variotii has immunostimulatory activity

Paecilomyces variotii is a filamentous fungus that occurs worldwide in soil and decaying vegetation. Optimization of the fermentation process for exopolysaccharide (EPS) production from the fungus P. variotii, structure determination and immuno-stimulating activity of EPS were performed. Response surface methodology (RSM) coupled with central composite design (CCD) was used to optimize the physical and chemical factors required to produce EPS in submerged fermentation. Preliminary investigations to choose the three factors for the present work were made using a factorial experimental design. Glucose, ammonium nitrate (NH₄NO₃) and pH were used as variables for which, with constant temperature of 28 °C and agitation of 90 rpm, the optimal process parameters were determined as glucose values of 0.96%, NH₄NO₃ 0.26% and pH 8.0. The three parameters presented significant effects. In this condition of culture, the main composition of the isolated EPS was a linear β-(1 → 6)-linked-D-glucan, as determined by Nuclear Magnetic Resonance (NMR) and methylation analysis. This polysaccharide is a very unusual as an EPS from fungi, especially a filamentous fungus such as P. variotii. Murine peritoneal macrophages cultivated with β-glucan for 6 and 48 h showed an increase in TNF-α, IL-6 and nitric oxide release with increased polysaccharide concentrations. Therefore, we conclude that the β-(1 → 6)-linked-D-glucan produced in optimised conditions of P. variotii cultivation has an immune-stimulatory activity on murine macrophages.

Identification of Paecilomyces variotii in clinical samples and settings

Paecilomyces variotii is a commonly occurring species in air and food, but it is also associated with many types of human infections and is among the emerging causative agents of opportunistic mycoses in immunocompromised hosts. Paecilomyces can cause hyalohyphomycosis, and two species, Paecilomyces lilacinus and P. variotii, are the most frequently encountered organisms. In the present study, a set of 34 clinical isolates morphologically identified as P. variotii or P. lilacinus were formally identified by sequencing intergenic transcribed spacer regions 1 and 2 (including 5.8S rDNA) and a part of the beta-tubulin gene. Three isolates were identified as P. lilacinus, and five of the presumptive P. variotii isolates did not belong to the genus Paecilomyces but were identified as Talaromyces eburneus (anamorph, Geosmithia argillacea) or Hamigera avellanea (anamorph, Merimbla ingelheimense). Applying the most recent taxonomy, we found that the clinical P. variotii isolates could be identified as P. variotii sensu stricto (14 strains), P. formosus (11 strains), and P. dactylethromorphus (1 strain). These data indicate that P. formosus occurs in clinical samples as commonly as P. variotii. Susceptibility tests showed that the antifungal susceptibility profiles of P. variotii, P. formosus, and P. dactylethromorphus are similar and that all strains tested were susceptible to amphotericin B in vitro. P. lilanicus, T. eburneus, and H. avellanea had different susceptibility profiles; and flucytosine and voriconazole were the least active of the antifungal drugs tested against these species. Our results indicate that correct species identification is important to help guide appropriate antifungal therapy.

Real-time PCR for detection of the Aspergillus genus

Aspergillus is a genus of mold that has strong indoor sources, including several species capable of acting as opportunistic pathogens. Previous studies suggest that Aspergillus could serve as an indicator for abnormal mold growth or moisture, making it an important genus for environmental monitoring. Here, a quantitative polymerase chain reaction (qPCR, or real-time PCR) assay is presented for Aspergillus. The assay shows good specificity for the genus, detecting all Aspergillus species tested, although a few non-Aspergillus species are also amplified. Sensitivity testing demonstrates that DNA representing one conidium can be detected. A validation study compared qPCR results against direct microscopy counts using A. fumigatus conidia aerosolized into a laboratory chamber. The assay was then used to quantify Aspergillus in indoor air samples, demonstrating its utility for environmental monitoring. Analysis of a small number of clinical sputum samples showed complete agreement with culturing results.

Tratamiento de las infecciones fúngicas invasoras

Invasive fungal infections have increased progressively in the last decades, producing elevated morbidity and mortality. In recent years, there have been numerous advances in the treatment of these diseases, with the introduction of new drugs in clinical practice and the information derived from several types of studies. This has improved the prognosis of some invasive fungal infections and increased the therapeutic options in various clinical situations. This new knowledge must be assessed to determine its application in clinical practice, taking into account available scientific evidence and clinical experience. With this aim, the Andalusian Society of Infectious Diseases has developed this consensus document containing recommendations for the treatment of the invasive fungal infections.

Fungi growing on aromatic hydrocarbons: biotechnology's unexpected encounter with biohazard?

The biodegradation of aromatic hydrocarbons by fungi has traditionally been considered to be of a cometabolic nature. Recently, however, an increasing number of fungi isolated from air biofilters exposed to hydrocarbon-polluted gas streams have been shown to assimilate volatile aromatic hydrocarbons as the sole source of carbon and energy. The biosystematics, ecology, and metabolism of such fungi are reviewed here, based in part on re-evaluation of a collection of published hydrocarbon-degrading isolates obtained from authors around the world. Incorrect or outdated identifications in original publications are corrected by ribosomal DNA sequence analysis. The data show that many volatile-hydrocarbon-degrading strains are closely related to, or in some cases clearly conspecific with, the very restricted number of human-pathogenic fungal species causing severe mycoses, especially neurological infections, in immunocompetent individuals. Neurochemistry features a distinctive array of phenolic and aliphatic compounds that are related to molecules involved in the metabolism of aromatic hydrocarbons. Hence, there may be physiological connections between hydrocarbon assimilation and certain patterns of mammalian infection.

Infections of the central nervous system by melanized fungi: a review of cases presented between 1999 and 2004

Several types of infections of the central nervous system by melanized fungi can be distinguished: (a) single-organ infection of the cerebrum, (b) extension into the cerebrum from adjacent cavities, (c) fungal presence in the cerebrospinal fluid, or (d) meningitis. The fungal order Chaetothyriales (containing Exophiala-like black yeasts and relatives) is particularly rich in fungi causing cerebral infections. Cases by the main agents, Cladophialophora bantiana, Exophiala dermatitidis, and Ramichloridium mackenziei, published during the last 5 years are reviewed. Most of these infections prove to be fatal. Resection of the lesions in combination with antimycotic therapy may reduce mortality.

Development of mitochondrial SSU rDNA-based oligonucleotide probes for specific detection of common airborne fungi

In this study we sequenced partial mitochondrial small subunit rDNA from 32 fungal strains representing 31 species from 16 genera. Most of these species are common airborne fungi and pathogens that may cause various public health concerns. Sequence alignment showed several conserved and highly variable regions. The variable regions were deployed to design oligonucleotide probes for each fungal species. The specificity of the designed probes was first examined through homology search against GenBank database then further verified through hybridization experiments to 38 fungal strains. A total of 23 probes were verified as specific to 15 fungal species commonly detected in living and working environments. These new probes will have potential applications in clinical diagnosis and public health-related environmental monitoring.