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Antimicrobial Agents and Chemotherapy Oct 2019
Topics: Caspofungin; Catalytic Domain; Echinocandins; Glucosyltransferases; Humans; Mutagenesis, Site-Directed; Pneumocystis carinii; Pneumonia, Pneumocystis
PubMed: 31548210
DOI: 10.1128/AAC.01296-19 -
Medical Science Monitor : International... Aug 2022BACKGROUND Sepsis is a serious threat to human life, particularly in immunocompromised patients; hence, early diagnosis and targeted treatment are important. Metagenomic...
BACKGROUND Sepsis is a serious threat to human life, particularly in immunocompromised patients; hence, early diagnosis and targeted treatment are important. Metagenomic next-generation sequencing (NGS) has significant advantages over traditional diagnostic methods. This study investigated the clinical value of NGS for pathogen identification in immunocompromised patients with sepsis. MATERIAL AND METHODS From July 2020 to September 2021, 90 consecutive patients with sepsis were enrolled in this prospective study. The patients were divided into 2 groups: an immunocompromised group (n=30) and an immunocompetent group (n=60). The pathogens causing sepsis were concurrently identified using NGS and traditional diagnostic methods. The pathogen detection rates and the spectrum of pathogens identified were compared according to the method of detection and between the immunocompromised and immunocompetent groups. RESULTS Of the 90 patients, 77 (86%) were positive for 1 or more pathogens using NGS, and 50 (56%) were positive using traditional detection methods. The positivity rate of sputum and bronchoalveolar lavage fluid was higher than that of blood samples. Pneumocystis jirovecii and cytomegalovirus infections were more common in the immunocompromised group than in the immunocompetent group. CONCLUSIONS The performance of NGS in identifying pathogens for patients with sepsis is better than that of traditional detection methods, especially in immunocompromised patients. Pneumocystis jirovecii and cytomegalovirus infections are more common in immunocompromised patients.
Topics: Bronchoalveolar Lavage Fluid; Cytomegalovirus Infections; High-Throughput Nucleotide Sequencing; Humans; Immunocompromised Host; Pneumocystis carinii; Prospective Studies; Sepsis
PubMed: 35957507
DOI: 10.12659/MSM.937041 -
MBio Dec 2016Fungi in the genus Pneumocystis live in the lungs of mammals, where they can cause a fatal pneumonia (PCP [Pneumocystis pneumonia]) in hosts with compromised immune...
UNLABELLED
Fungi in the genus Pneumocystis live in the lungs of mammals, where they can cause a fatal pneumonia (PCP [Pneumocystis pneumonia]) in hosts with compromised immune systems. The absence of a continuous in vitro culture system for any species of Pneumocystis has led to limited understanding of these fungi, especially for the discovery of new therapies. We recently reported that Pneumocystis carinii, Pneumocystis murina, and most significantly, Pneumocystis jirovecii lack both enzymes necessary for myo-inositol biosynthesis but contain genes with homologies to fungal myo-inositol transporters. Since myo-inositol is essential for eukaryotic viability, the primary transporter, ITR1, was functionally and structurally characterized in P. carinii The predicted structure of P. carinii ITR1 (PcITR1) contained 12 transmembrane alpha-helices with intracellular C and N termini, consistent with other inositol transporters. The apparent K was 0.94 ± 0.08 (mean ± standard deviation), suggesting that myo-inositol transport in P. carinii is likely through a low-affinity, highly selective transport system, as no other sugars or inositol stereoisomers were significant competitive inhibitors. Glucose transport was shown to use a different transport system. The myo-inositol transport was distinct from mammalian transporters, as it was not sodium dependent and was cytochalasin B resistant. Inositol transport in these fungi offers an attractive new drug target because of the reliance of the fungi on its transport, clear differences between the mammalian and fungal transporters, and the ability of the host to both synthesize and transport this critical nutrient, predicting low toxicity of potential inhibitors to the fungal transporter.
IMPORTANCE
myo-Inositol is a sugarlike nutrient that is essential for life in most organisms. Humans and microbes alike can obtain it by making it, which involves only 2 enzymes, by taking it from the environment by a transport process, or by recycling it from other cellular constituents. Inspection of the genomes of the pathogenic fungi of the genus Pneumocystis showed that these pneumonia-causing parasites could not make myo-inositol, as they lacked the 2 enzymes. Instead, we found evidence of inositol transporters, which would import the sugar from the lungs where the fungi reside. In the present report, we characterized the transport of myo-inositol in the fungus and found that the transporter was highly selective for myo-inositol and did not transport any other molecules. The transport was distinct from that in mammalian cells, and since mammals can both make and transport myo-inositol, while Pneumocystis fungi must transport it, this process offers a potential new drug target.
Topics: Biological Transport; Carbohydrate Metabolism; Cytochalasin B; Fungal Proteins; Glucose; Inositol; Kinetics; Membrane Transport Proteins; Pneumocystis carinii
PubMed: 27965450
DOI: 10.1128/mBio.01851-16 -
Journal of Medical Microbiology Dec 2021Pathogen-associated molecular patterns' (PAMPs) are microbial signatures that are recognized by host myeloid C-type lectin receptors (CLRs). These CLRs interact with...
Pathogen-associated molecular patterns' (PAMPs) are microbial signatures that are recognized by host myeloid C-type lectin receptors (CLRs). These CLRs interact with micro-organisms via their carbohydrate recognition domains (CRDs) and engage signalling pathways within the cell resulting in pro-inflammatory and microbicidal responses. In this article, we extend our laboratory study of additional CLRs that recognize fungal ligands against and and their purified major surface glycoproteins (Msgs). To study the potential of newly synthesized hFc-CLR fusions on binding to and its Msg. A library of new synthesized hFc-CLR fusions was screened against and organisms and their purified major surface glycoproteins (Msgs) found on the respective fungi via modified ELISA. Immunofluorescence assay (IFA) was implemented and quantified to verify results. mRNA expression analysis by quantitative PCR (q-PCR) was employed to detect respective CLRs found to bind fungal organisms in the ELISA and determine their expression levels in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model. We detected a number of the CLR hFc-fusions displayed significant binding with and organisms, and similarly to their respective Msgs. Significant organism and Msg binding was observed for CLR members C-type lectin domain family 12 member A (CLEC12A), Langerin, macrophage galactose-type lectin-1 (MGL-1), and specific intracellular adhesion molecule-3 grabbing non-integrin homologue-related 3 (SIGNR3). Immunofluorescence assay (IFA) with the respective CLR hFc-fusions against whole life forms corroborated these findings. Lastly, we surveyed the mRNA expression profiles of the respective CLRs tested above in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model and determined that macrophage galactose type C-type lectin (), implicated in recognizing terminal N-acetylgalactosamine (GalNAc) found in the glycoproteins of microbial pathogens was significantly up-regulated during infection. The data herein add to the growing list of CLRs recognizing and provide insights for further study of organism/host immune cell interactions.
Topics: Animals; Mice; Fungal Proteins; Galactose; Host-Pathogen Interactions; Lectins, C-Type; Membrane Glycoproteins; Pneumocystis; Pneumocystis carinii; Pneumonia, Pneumocystis; RNA, Messenger
PubMed: 34889727
DOI: 10.1099/jmm.0.001470 -
Current Opinion in Microbiology Dec 2017Pneumocystis jirovecii causes clinical pneumonia in immunocompromised hosts. Despite this, the inability to cultivate this organism in vitro has likely hindered the... (Review)
Review
Pneumocystis jirovecii causes clinical pneumonia in immunocompromised hosts. Despite this, the inability to cultivate this organism in vitro has likely hindered the field in ascertaining the true impact of Pneumocystis in human infection. However the recent release of the genome as well as in advances in understanding host genetics, and other risk factors for infection and robust experimental models of disease have shed new light on the impact of this fungal pathogen as to better define populations at risk. This review will highlight these recent advances as well as highlight future needed areas of research.
Topics: Animals; Humans; Pneumocystis carinii; Pneumonia, Pneumocystis
PubMed: 29136537
DOI: 10.1016/j.mib.2017.10.019 -
Antimicrobial Agents and Chemotherapy Oct 2020, the opportunistic fungus that causes pneumonia (PCP) in humans, is a significant contributor to morbidity and mortality in immunocompromised patients. Given the...
, the opportunistic fungus that causes pneumonia (PCP) in humans, is a significant contributor to morbidity and mortality in immunocompromised patients. Given the profound deleterious inflammatory effects of the major β-glucan cell wall carbohydrate constituents of through Dectin-1 engagement and downstream caspase recruitment domain-containing protein 9 (CARD9) immune activation, we sought to determine whether the pharmacodynamic activity of the known CARD9 inhibitor BRD5529 might have a therapeutic effect on macrophage innate immune signaling and subsequent downstream anti-inflammatory activity. The small-molecule inhibitor BRD5529 was able to significantly reduce both phospho-p38 and phospho-pERK1 signaling and tumor necrosis factor alpha (TNF-α) release during stimulation of macrophages with cell wall β-glucans.
Topics: CARD Signaling Adaptor Proteins; Humans; Immunity, Innate; Pneumocystis; Pneumocystis carinii; Pneumonia, Pneumocystis; beta-Glucans
PubMed: 32839216
DOI: 10.1128/AAC.01210-20 -
RoFo : Fortschritte Auf Dem Gebiete Der... Nov 2021Clinical signs and symptoms related to invasive fungal disease are nonspecific and need to be followed up by appropriate diagnostic procedures. The goal of this study...
Radiological CT Patterns and Distribution of Invasive Pulmonary Aspergillus, Non-Aspergillus, Cryptococcus and Pneumocystis Jirovecii Mold Infections - A Multicenter Study.
PURPOSE
Clinical signs and symptoms related to invasive fungal disease are nonspecific and need to be followed up by appropriate diagnostic procedures. The goal of this study was to analyze CT imaging patterns in invasive fungal infections and their correlation with the immune status and clinical outcome.
MATERIALS AND METHODS
We performed a retrospective multicenter study including 85 consecutive patients with invasive pulmonary fungal infection (2011-2014). Lung patterns on computed tomography (CT) scans were classified according to the Fleischner Society glossary. The patients were grouped according to immune status (neutropenia, steroid therapy, organ transplant recipient, and other cause) and outcome (positive outcome, progressive disease, and death). The Chi square test or Fisher exact test was used. Bonferroni correction was applied.
RESULTS
The total number of patients with invasive Aspergillus and non-Aspergillus infection (IANA), Pneumocystis jirovecii pneumonia (PCP), and Cryptococcus (CRY) was 60, 22, and 3, respectively. Patients with IANA demonstrated significantly more nodules (93 % vs. 59 %, p = 0.001), significantly fewer ground glass opacities (58 % vs. 96 %, p = 0.005), and significantly fewer positive lymph nodes (5 % vs. 41 %, p < 0.001) than patients with PCP. All patients with PCP and CRY had a favorable outcome. Patients with IANA and an adverse outcome demonstrated significantly more nodules with halo sign than patients with IANA and a favorable outcome (42.5 % vs. 15.9 %, p < 0.0001). Interestingly, patients with IANA and a favorable outcome had a higher prevalence of pulmonary infarction than patients with an adverse outcome (8 % vs. 1 %, p = 0.047). Patients with neutropenia showed significantly more consolidations (66 %) than organ transplant recipients (27 %, p = 0.045).
CONCLUSION
Patients with IANA showed a higher prevalence of nodules and a lower prevalence of ground glass opacities than patients with PCP. In patients with IANA, nodules with halo sign were associated with an adverse outcome. Patients with neutropenia showed generally more consolidations, but the consolidations were not associated with an adverse outcome.
KEY POINTS
· Nodules, ground glass opacities, and consolidations are common CT findings in all invasive pulmonary fungal infections.. · There is no pattern that is unique for one specific pathogen, although nodules are more predominant in IANA and Cryptococcus, and ground glass opacities are more predominant in PCP patients.. · Immune status had an impact on CT findings in fungal pneumonia with less consolidation in patients after organ transplantation compared to patients with neutropenia.. · Nodules with a halo sign are associated with a worse outcome..
CITATION FORMAT
· Obmann VC, Bickel F, Hosek N et al. Radiological CT Patterns and Distribution of Invasive Pulmonary Aspergillus, Non-Aspergillus, Cryptococcus and Pneumocystis Jirovecii Mold Infections - A Multicenter Study. Fortschr Röntgenstr 2021; 193: 1304 - 1314.
Topics: Aspergillus; Cryptococcus; Humans; Lung; Pneumocystis carinii; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 34034346
DOI: 10.1055/a-1482-8336 -
Acta Crystallographica. Section F,... Jun 2015To further define the interactions that enhance the selectivity of binding and to directly compare the binding of the most potent analogue...
To further define the interactions that enhance the selectivity of binding and to directly compare the binding of the most potent analogue {N(6)-methyl-N(6)-(3,4,5-trifluorophenyl)pyrido[2,3-d]pyrimidine-2,4,6-triamine; compound 26} in the series of bicyclic pyrido[2,3-d]pyrimidine analogues of piritrexim (PTX) with native human (h), Pneumocystis carinii (pc) and Pneumocystis jirovecii (pj) dihydrofolate reductase (DHFR) enzymes, the crystal structures of hDHFR complexed with N(6)-methyl-N(6)-(4-isopropylphenyl)pyrido[2,3-d]pyrimidine-2,4,6-triamine (compound 22), of hDHFR complexed with compound 26 and of pcDHFR complexed with N(6)-methyl-N(6)-1-naphthylpyrido[2,3-d]pyrimidine-2,4,6-triamine (compound 24) are reported as ternary complexes with NADPH. This series of bicyclic pyrido[2,3-d]pyrimidines were designed in which there was a transposition of the 5-methyl group of PTX to the N9 position of the pyrido[2,3-d]pyrimidine. It was hypothesized that the N9-methyl group would preferentially interact with Ile123 of pcDHFR (and Ile123 of pjDHFR), but not with the shorter Val115 in hDHFR. Structure-activity data for this series of antifolates revealed that a trifluoro derivative (26) was the most selective against pjDHFR compared with mammalian DHFR (h/pj = 35.7). Structural data for the hDHFR-26 complex revealed that 26 binds in a different conformation from that observed in the pcDHFR-26 complex. In the hDHFR-26 complex the trifluorophenyl ring of 26 occupies a position near the cofactor-binding site, with close intermolecular contacts with Asp21, Ser59 and Ile60, whereas this ring in the pcDHFR-26 complex is positioned away from the cofactor site and near Ile65, with weaker contacts with Ile65, Phe69 and Ile123. Comparison of the intermolecular contacts between the N9-methyl group with Val115/Ile123 validates the hypothesis that the N9-methyl substituent preferentially interacts with Ile123 compared with Val115 of hDHFR, as the weaker contact with Val115 in the hDHFR structure is consistent with its weaker binding affinity compared with pcDHFR. The results for the structures of hDHFR-22 and pcDHFR-24 show that their inhibitor-binding orientation is similar to that observed in pcDHFR-26 and the pcDHFR variant (F69N) reported previously. The naphthyl moiety of 24 makes several intermolecular contacts with the active-site residues in pcDHFR that help to stabilize the binding, resulting in a more potent inhibitor.
Topics: Amino Acid Motifs; Anti-Bacterial Agents; Catalytic Domain; Crystallization; Crystallography, X-Ray; Folic Acid Antagonists; Halogenation; Humans; Models, Molecular; Molecular Sequence Data; NADP; Pneumocystis carinii; Protein Binding; Pyrimidines; Recombinant Proteins; Species Specificity; Structure-Activity Relationship; Tetrahydrofolate Dehydrogenase
PubMed: 26057816
DOI: 10.1107/S2053230X15008468 -
Muscle & Nerve Mar 2022Pneumocystis jirovecii (PJ) is ubiquitously present in the environment and capable of causing an interstitial pneumonia in immunocompromised subjects. It has been...
Pneumocystis jirovecii (PJ) is ubiquitously present in the environment and capable of causing an interstitial pneumonia in immunocompromised subjects. It has been advocated that routine prophylaxis against PJ be given to patients with autoimmune neuromuscular conditions that require prolonged use of corticosteroid therapy and/or other immunosuppressive agents. Available data, however, suggest that the risk of PJ infection in patients with autoimmune neuromuscular diseases is extremely low and the widespread use of prophylactic therapy is likely unnecessary. Comorbidities, including intestinal lung disease, prolonged lymphopenia, low CD4 count, parenchymal organ failure, and active cancer status, appear to increase the risk for PJ infection, and it is our opinion that these risk factors should be considered to determine the risk of PJ infection and the requirement for prophylaxis.
Topics: Autoimmune Diseases; Humans; Immunocompromised Host; Neuromuscular Diseases; Pneumocystis carinii; Pneumonia, Pneumocystis
PubMed: 34952994
DOI: 10.1002/mus.27481 -
The Journal of Infectious Diseases Sep 2020Pneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we...
BACKGROUND
Pneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we show that Msg significantly impairs tumor necrosis factor (TNF)-α secretion by macrophages induced by Saccharomyces cerevisiae and Pneumocystis carinii (Pc) β-glucans.
METHODS
Major surface glycoprotein was shown to greatly reduce β-glucan-induced Dectin-1 immunoreceptor tyrosine-based activating motif (ITAM) phosphorylation. Major surface glycoprotein also down regulated Dectin-1 receptor messenger ribonucleic acid (mRNA) expression in the macrophages. It is interesting that Msg incubation with macrophages resulted in significant mRNA upregulation of both C-type lectin receptors (CLR) Mincle and MCL in Msg protein presence alone but to even greater amounts in the presence of Pc β-glucan.
RESULTS
The silencing of MCL and Mincle resulted in TNF-α secretions similar to that of macrophages treated with Pneumocystis β-glucan alone, which is suggestive of an inhibitory role for these 2 CLRs in Msg-suppressive effects on host cell immune response.
CONCLUSIONS
Taken together, these data indicate that the Pneumocystis Msg surface protein complex can act to suppress host macrophage inflammatory responses to the proinflammatory β -glucan components of the organisms.
Topics: Animals; Fungal Proteins; Lectins, C-Type; Macrophages; Membrane Glycoproteins; Mice; Pneumocystis; Pneumocystis carinii; Pneumonia, Pneumocystis; RAW 264.7 Cells; RNA, Messenger; Saccharomyces cerevisiae; Tumor Necrosis Factor-alpha; beta-Glucans
PubMed: 32363390
DOI: 10.1093/infdis/jiaa218