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Expert Review of Respiratory Medicine 2022is an opportunistic, human-specific fungus that causes pneumonia (PCP). PCP symptoms are nonspecific. A patient with and another lung infection faces a diagnostic... (Review)
Review
INTRODUCTION
is an opportunistic, human-specific fungus that causes pneumonia (PCP). PCP symptoms are nonspecific. A patient with and another lung infection faces a diagnostic challenge. It may be difficult to determine which of these agents is responsible for the clinical symptoms, preventing effective treatment. Diagnostic and treatment efforts have been made more difficult by the rising frequency with which coronavirus 2019 (COVID-19) and PCP co-occur.
AREAS COVERED
Herein, we provide a comprehensive review of clinical and pharmacological recommendations along with a literature review of PCP in immunocompromised patients focusing on HIV-uninfected patients.
EXPERT OPINION
PCP may be masked by identifying co-existing pathogens that are not necessarily responsible for the observed infection. Patients with severe form COVID-19 should be examined for underlying immunodeficiency, and co-infections must be considered as co-infection with may worsen COVID-19's severity and fatality. PCP should be investigated in patients with PCP risk factors who come with pneumonia and suggestive radiographic symptoms but have not previously received PCP prophylaxis. PCP prophylaxis should be explored in individuals with various conditions that impair the immune system, depending on their PCP risk.
Topics: Humans; Pneumonia, Pneumocystis; COVID-19; Pneumocystis carinii; Immunocompromised Host; HIV Infections
PubMed: 36440485
DOI: 10.1080/17476348.2022.2152332 -
Journal of Medical Microbiology Jun 2023C-type lectin receptors (CLRs) are prominently expressed on myeloid cells where they perform multiple functions including serving as pattern recognition receptors...
C-type lectin receptors (CLRs) are prominently expressed on myeloid cells where they perform multiple functions including serving as pattern recognition receptors (PRRs) to drive innate as well as adaptive immunity to pathogens. Depending on the presence of a tyrosine-based signalling motif, CLR-microbial pathogen engagement may result in either anti- or pro-inflammatory signalling. In this manuscript, we report our laboratory study of two novel CLRs that recognize cell wall homogenates (CWH) and a purified cell wall fraction (CWF). To study the potential of newly generated hFc-CLR fusions on binding to CWHs and CWFs and subsequent downstream inflammatory signalling analysis. Newly generated hFc-CLR fusion CLEC4A and CLEC12B were screened against CWHs and CWFs preparations via modified ELISA. Immunofluorescence assay (IFA) was utilized to visualize hFc-CLR fusion binding against intact fixed fungal life forms to verify results. Quantitative PCR (q-PCR) analysis of lung mRNA from the mouse immunosuppressed Pneumocystis pneumonia (PCP) model versus uninfected mice was employed to detect possible changes in the respective and transcripts. Lastly, siRNA technology of both CLRs was conducted to determine effects on downstream inflammatory events in mouse macrophages stimulated in the presence of CWFs. We determined that both CLEC4A and CLEC12B hFc-CLRs displayed significant binding with CWHs and CWFs. Binding events showed significant binding to both curdlan and laminarin, both polysaccharides containing β-(1,3) glucans as well as -acetylglucosamine (GlcNAc) residues and modest yet non-significant binding to the negative control carbohydrate dextran. IFA with both CLR hFc-fusions against whole life forms corroborated these findings. Lastly, we surveyed the mRNA expression profiles of both CLRs tested above in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model and determined that both CLRs were significantly up regulated during infection. Lastly, siRNA of both CLRs in the mouse RAW macrophage cell line was conducted and results demonstrated that silencing of resulted in no significant changes in TNF-alpha generation in CWF stimulated macrophages. On the contrary, silencing of CLR resulted in significant decreases in TNF-alpha in RAW cells stimulated with the same CWF. The data presented here provide new members of the CLRs family recognizing . Future studies using CLEC4A and/or CLEC12B deficient mice in the PCP mouse model should provide further insights into the host immunological response to .
Topics: Mice; Animals; Lectins, C-Type; Pneumonia, Pneumocystis; Tumor Necrosis Factor-alpha; Pneumocystis; Cell Wall; RNA, Small Interfering; RNA, Messenger
PubMed: 37294293
DOI: 10.1099/jmm.0.001714 -
Frontiers in Cellular and Infection... 2020pneumonia (PCP) is an AIDS-defining illness. In patients with HIV, the benefit of PCP prophylaxis is well-defined when the CD4 T-cell count decreases below 200...
pneumonia (PCP) is an AIDS-defining illness. In patients with HIV, the benefit of PCP prophylaxis is well-defined when the CD4 T-cell count decreases below 200 cells/μL. In other immunocompromised patients, the value of PCP prophylaxis is not always as well-established. This study aimed to describe the epidemiology of PCP in recent years and assess how many patients with PCP did or did not receive prophylaxis in the month preceding the infection. A multicenter retrospective study was performed in 3 tertiary care hospital. A list of patients that underwent broncho-alveolar lavage sampling and (PJ) PCR testing was retrieved from the microbiology laboratories. An in-house PJ quantitative PCR (qPCR) was used in each center. A cycle threshold (Ct) value of ≤ 28.5-30 was considered a probable PCP. For patients with a positive PJ qPCR but above this threshold, a predefined case definition of possible PCP was defined as a qPCR Ct value ≤ 34-35 and both of the following criteria: 1. Clinical and radiological features compatible with PCP and 2. The patient died or received PCP therapy and survived. Patient files from those with a qPCR Ct value ≤ 35 were reviewed to determine whether the patient fulfilled the case definition and if PCP prophylaxis had been used in the weeks preceding the PCP. Disease-specific guidelines, as well as hospital-wide guidelines, were used to evaluate if prophylaxis could be considered indicated. From 2012 to 2018, 482 BAL samples were tested. Two hundred and four had a qPCR Ct value ≤ 35 and were further evaluated: 90 fulfilled the definition of probable and 63 of possible PCP while the remaining 51 were considered colonized. Seventy-four percentages of the patients with PCP were HIV-negative. Only 11 (7%) of the 153 patients had received prophylaxis, despite that in 133 (87%) cases prophylaxis was indicated according to guidelines. In regions where HIV testing and treatment is available without restrictions, PCP is mainly diagnosed in non-HIV immunocompromised patients. More than four out of five patients with PCP had not received prophylaxis. Strategies to improve awareness of antimicrobial prophylaxis guidelines in immunocompromised patients are urgently needed.
Topics: Humans; Immunocompromised Host; Pneumocystis carinii; Pneumonia, Pneumocystis; Real-Time Polymerase Chain Reaction; Retrospective Studies
PubMed: 32500040
DOI: 10.3389/fcimb.2020.00224 -
Computer Methods and Programs in... Nov 2021Computed tomography (CT) examination plays an important role in screening suspected and confirmed patients in pneumocystis carinii pneumonia (PCP), and the efficient...
BACKGROUND AND OBJECTIVE
Computed tomography (CT) examination plays an important role in screening suspected and confirmed patients in pneumocystis carinii pneumonia (PCP), and the efficient acquisition of high-quality medical CT images is essential for the clinical application of computer-aided diagnosis technology. Therefore, improving the resolution of CT images of pneumonia is a very important task.
METHODS
Aiming at the problem of how to recover the texture details of the reconstructed PCP CT super-resolution image, we propose the image super-resolution reconstruction model based on self-attention generation adversarial network (SAGAN). In the SAGAN algorithm, a generator based on self-attention mechanism and residual module is used to transform a low-resolution image into a super-resolution image. A discriminator based on depth convolution network tries to distinguish the difference between the reconstructed super-resolution image and the real super-resolution image. In terms of loss function construction, on the one hand, the Charbonnier content loss function is used to improve the accuracy of image reconstruction, and on the other hand, the feature value before activation of the pre-trained VGGNet is used to calculate the perceptual loss to achieve accurate texture detail reconstruction of super-resolution images.
RESULTS
Experimental results show that our SAGAN algorithm is superior to other state-of-the-art algorithms in both peak signal-to-noise ratio (PSNR) and structural similarity score (SSIM). Specifically, our SAGAN method can obtain 31.94 dB which is 1.53 dB better than SRGAN on Set5 dataset for 4 enlargements.
CONCLUSION
Our SAGAN method can reconstruct more realistic PCP CT images with clear texture, which can help experts diagnose the condition of PCP.
Topics: Algorithms; Humans; Image Processing, Computer-Assisted; Pneumonia, Pneumocystis; Signal-To-Noise Ratio; Tomography, X-Ray Computed
PubMed: 34715519
DOI: 10.1016/j.cmpb.2021.106467 -
Antimicrobial Agents and Chemotherapy Mar 2024cyst life forms contain abundant β-glucan carbohydrates, synthesized using β-1,3 and β-1,6 glucan synthase enzymes and the donor uridine diphosphate (UDP)-glucose....
cyst life forms contain abundant β-glucan carbohydrates, synthesized using β-1,3 and β-1,6 glucan synthase enzymes and the donor uridine diphosphate (UDP)-glucose. In yeast, phosphoglucomutase (PGM) plays a crucial role in carbohydrate metabolism by interconverting glucose 1-phosphate and glucose 6-phosphate, a vital step in UDP pools for β-glucan cell wall formation. This pathway has not yet been defined in . Herein, we surveyed the and genomes, which predicted a homolog of the major PGM enzyme. Furthermore, we show that PjPgm2p and PmPgm2p function similarly to the yeast counterpart. When both homologs are heterologously expressed in cells, both genes can restore growth and sedimentation rates to wild-type levels. Additionally, we demonstrate that yeast cell lysates expressing the two transcripts individually can restore PGM activities significantly altered in the yeast strain. The addition of lithium, a competitive inhibitor of yeast PGM activity, significantly reduces PGM activity. Next, we tested the effects of lithium on viability and found the compound displays significant anti- activity. Finally, we demonstrate that a para-aryl derivative (ISFP10) with known inhibitory activity against the PGM protein and exhibiting 50-fold selectivity over the human PGM enzyme homolog can also significantly reduce Pmpgm2 activity . Collectively, our data genetically and functionally validate phosphoglucomutases in both and and suggest the potential of this protein as a selective therapeutic target for individuals with pneumonia.
Topics: Humans; Pneumocystis carinii; Pneumonia, Pneumocystis; Phosphoglucomutase; Saccharomyces cerevisiae; Lithium; Pneumocystis; beta-Glucans; Phosphates; Glucose; Uridine Diphosphate
PubMed: 38259086
DOI: 10.1128/aac.00756-23 -
The Journal of Infectious Diseases Jul 2019Glucan is the major cell wall component of Pneumocystis cysts. In the current study, we have characterized Pneumocystis Bgl2 (EC 3.2.1.58), an enzyme with...
Glucan is the major cell wall component of Pneumocystis cysts. In the current study, we have characterized Pneumocystis Bgl2 (EC 3.2.1.58), an enzyme with glucanosyltransferase and β-1,3 endoglucanase activity in other fungi. Pneumocystis murina, Pneumocystis carinii, and Pneumocystis jirovecii bgl2 complementary DNA sequences encode proteins of 437, 447, and 408 amino acids, respectively. Recombinant P. murina Bgl2 expressed in COS-1 cells demonstrated β-glucanase activity, as shown by degradation of the cell wall of Pneumocystis cysts. It also cleaved reduced laminaripentaose and transferred oligosaccharides, resulting in polymers of 6 and 7 glucan residues, demonstrating glucanosyltransferase activity. Surprisingly, confocal immunofluorescence analysis of P. murina-infected mouse lung sections using an antibody against recombinant Bgl2 showed that the native protein is localized primarily to the trophic form of Pneumocystis in both untreated mice and mice treated with caspofungin, an antifungal drug that inhibits β-1,3-glucan synthase. Thus, like other fungi, Bgl2 of Pneumocystis has both endoglucanase and glucanosyltransferase activities. Given that it is expressed primarily in trophic forms, further studies are needed to better understand its role in the biology of Pneumocystis.
Topics: Amino Acid Sequence; Animals; Antifungal Agents; CD40 Ligand; COS Cells; Caspofungin; Cell Wall; Chlorocebus aethiops; Glucan Endo-1,3-beta-D-Glucosidase; Glucans; Lung; Mice; Mice, Inbred C57BL; Mice, Knockout; Pneumocystis; Pneumonia, Pneumocystis; Recombinant Proteins; Sequence Alignment
PubMed: 31100118
DOI: 10.1093/infdis/jiz172 -
Journal of Comparative Pathology Feb 2020A 1-year and 7-months-old neutered male toy poodle was presented with persistent respiratory distress, gradual weight loss and melaena. Thoracic radiography showed an...
A 1-year and 7-months-old neutered male toy poodle was presented with persistent respiratory distress, gradual weight loss and melaena. Thoracic radiography showed an unstructured interstitial lung pattern. Histopathological examination of tissues collected at necropsy examination revealed disseminated infection by Pneumocystis carinii. The organisms were detected in the lungs, lymph nodes, liver, heart, kidneys, spleen, gastrointestinal tract and pancreas. In the lungs, the organisms were present in the alveolar space and interstitial tissue, and calcified foci containing P. carinii were observed. The presence of the organism in non-thoracic lymph nodes provided evidence of lymphogenous spread. A definitive diagnosis of disseminated pneumocystosis was achieved through the use of Grocott methenamine silver staining, immunohistochemistry (IHC) and polymerase chain reaction for P. carinii. Depletion of cells expressing immunoglobulin (Ig)A and IgG was confirmed by IHC of lymphoid tissue, suggesting possible underlying immunodeficiency.
Topics: Animals; Dog Diseases; Dogs; Male; Pneumocystis Infections; Pneumocystis carinii
PubMed: 32138848
DOI: 10.1016/j.jcpa.2019.12.009 -
BioRxiv : the Preprint Server For... Sep 2023spp. are host obligate fungal pathogens that can cause severe pneumonia in mammals and rely heavily on their host for essential nutrients. The lack of a sustainable...
spp. are host obligate fungal pathogens that can cause severe pneumonia in mammals and rely heavily on their host for essential nutrients. The lack of a sustainable culture system poses challenges in understanding their metabolism and the acquisition of essential nutrients from host lungs remains unexplored. Transmission electron micrographs show Extracellular Vesicles (EVs) are found near spp. within the lung. We hypothesized that EVs transport essential nutrients to the fungi during infection. To investigate this, EVs from and infected rodents were biochemically and functionally characterized. These EVs contained host proteins involved in cellular, metabolic, and immune processes as well as proteins with homologs found in other fungal EV proteomes, indicating may release EVs. Notably, EV uptake by indicated their potential involvement in nutrient acquisition and indicate a possibility for using engineered EVs for efficient therapeutic delivery. However, EVs added to , did not show increased growth or viability, implying that additional nutrients or factors are necessary to support their metabolic requirements. Exposure of macrophages to EVs increased proinflammatory cytokine levels, but did not affect macrophages' ability to kill or phagocytose . These findings provide vital insights into and host EV interactions, yet the mechanisms underlying 's survival in the lung remain uncertain. These studies are the first to isolate, characterize, and functionally assess EVs from -infected rodents, promising to enhance our understanding of host-pathogen dynamics and therapeutic potential.
PubMed: 37786700
DOI: 10.1101/2023.09.19.558454 -
Frontiers in Cellular and Infection... 2020pneumonia (PCP) remains the most frequent AIDS-defining illness in developed countries. This infection also occurs in non-AIDS immunosuppressed patients, e.g., those... (Review)
Review
pneumonia (PCP) remains the most frequent AIDS-defining illness in developed countries. This infection also occurs in non-AIDS immunosuppressed patients, e.g., those who have undergone an organ transplantation. Moreover, mild infections related to low pulmonary fungal burden, frequently designated as pulmonary colonization, occurs in patients with chronic pulmonary diseases, e.g., cystic fibrosis (CF). Indeed, this autosomal recessive disorder alters mucociliary clearance leading to bacterial and fungal colonization of the airways. This mini-review compiles and discusses available information on and CF. It highlights significant differences in the prevalence of pulmonary colonization in European and Brazilian CF patients. It also describes the microbiota associated with in CF patients colonized by . Furthermore, we have described genomic diversity in colonized CF patients. In addition of pulmonary colonization, it appears that PCP can occur in CF patients specifically after lung transplantation, thus requiring preventive strategies. In other respects, primary infection is a worldwide phenomenon occurring in non-immunosuppressed infants within their first months. The primary infection is mostly asymptomatic but it can also present as a benign self-limiting infection. It probably occurs in the same manner in CF infants. Nonetheless, two cases of severe primary infection mimicking PCP in CF infants have been reported, the genetic disease appearing in these circumstances as a risk factor of PCP while the host-pathogen interaction in older children and adults with pulmonary colonization remains to be clarified.
Topics: Adult; Brazil; Child; Cystic Fibrosis; Humans; Infant; Lung; Pneumocystis carinii; Pneumonia, Pneumocystis
PubMed: 33117730
DOI: 10.3389/fcimb.2020.571253 -
Infection Dec 2021Pneumocystis jirovecii (P. jirovecii) is increasingly identified on lower respiratory tract specimens of COVID-19 patients. Our narrative review aims to determine... (Review)
Review
BACKGROUND
Pneumocystis jirovecii (P. jirovecii) is increasingly identified on lower respiratory tract specimens of COVID-19 patients. Our narrative review aims to determine whether the diagnosis of pneumocystis jirovecii pneumonia (PJP) in COVID-19 patients represents coinfection or colonization based on the evidence available in the literature. We also discuss the decision to treat COVID-19 patients with coinfection by PJP.
METHODS
A literature search was performed through the Pubmed and Web of Science databases from inception to March 10, 2021.
RESULTS
We identified 12 COVID-19 patients suspected to have PJP coinfection. All patients were critically ill and required mechanical ventilation. Many were immunosuppressed from HIV or long-term corticosteroids and other immunosuppressive agents. In both the HIV and non-HIV groups, severe lymphocytopenia was encountered with absolute lymphocyte and CD4+T cell count less than 900 and 200 cells/mm, respectively. The time to PJP diagnosis from the initial presentation was 7.8 (range 2-21) days. Serum lactate dehydrogenase and beta-D-glucan were elevated in those coinfected with PJP. All patients were treated with anti-PJP therapy, predominantly sulfamethoxazole-trimethoprim with corticosteroids. The overall mortality rate was 41.6%, and comparable for both HIV and non-HIV groups.
CONCLUSION
As the current evidence is restricted to case reports, the true incidence, risk factors, and prognosis of COVID-19 patients with PJP coinfections cannot be accurately determined. Comorbidities of poorly controlled HIV with lymphocytopenia and multiple immunosuppressive therapies are likely predisposing factors for PJP coinfection.
Topics: COVID-19; Coinfection; Humans; Pneumocystis carinii; Pneumonia, Pneumocystis; SARS-CoV-2
PubMed: 34059997
DOI: 10.1007/s15010-021-01630-9