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Pneumocystis jirovecii (PJ), an opportunistic fungus, can have major consequences in terms of morbidity and mortality. These infections occur mainly in immunocompromised patients and are known for their pulmonary tropism (Pneumocystis pneumonia, PCP). While prevention modalities have been studied in HIV-infected populations, evidence is scarce in non-HIV patients. The decision to prescribe prophylaxis for PJ requires assessment of the clinical context, as well as existing risk factors that may predispose an individual to develop PCP. Few indicators exist that are sufficiently sensitive and specific to predict the occurrence of PCP. The decision to use prophylaxis must be made on a case-by-case basis., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

(1,3)-β-d-Glucan (BG) assay is a non-invasive test commonly used in the diagnostic of invasive fungal diseases. Given its high sensitivity, it was suggested that a negative BG result is sufficient for excluding the diagnosis of Pneumocystis pneumonia (PCP). However, suboptimal performance has been described in human immunodeficiency virus (HIV)-negative patients, particularly those with haematological malignancies. We aimed to assess the sensitivity of the BG assay for diagnosing PCP in HIV-negative patients based on their underlying PCP risk factors. We conducted a single-center, retrospective study (2009-2021) enrolling HIV-negative patients diagnosed with PCP and who underwent BG testing. Patients colonized with Pneumocystis jirovecii were included as a control group. In all, 55 PCP patients and 61 colonized patients met the inclusion criteria. Patients were further categorized according to the underlying condition that exposes patients to PCP. Median BG concentration was significantly higher in the PCP group than in the colonization group (500 vs. 31 pg/ml; P < 10-4, Mann-Whitney test) and the BG assay demonstrated a sensitivity of 85% and a specificity of 82% for PCP diagnosis. Notably, sensitivity was significantly higher in non-cancer patients (100%) compared to those with solid cancer (72%) and haematologic cancer (79%) (P < .05, Fischer's exact test). These findings strengthen the high performance of BG testing for screening PCP in non-cancer patients, comparable to that observed in HIV-infected individuals. In contrast, they highlight its low reliability in patients with malignancies, emphasizing the importance of considering underlying conditions when interpreting BG results and refining the role of the test in PCP diagnosis., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Background: Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection that primarily affects immunocompromised individuals. Typical symptoms of PJP include the subacute onset of dyspnea, nonproductive cough, and low-grade fever. In hematology patients, particularly those who are allogeneic stem cell transplant recipients, the disease often presents with a more aggressive clinical course. While hypercalcemia has been documented as a manifestation of PJP in some solid organ transplant recipients, it has not been reported in hematology or stem cell transplant patients., Case Presentation: Here, we present a case of PJP in a 56-year-old male allogeneic stem cell transplant recipient, who developed hypercalcemia and renal failure during the late post-transplant period. The patient had a history of allogeneic stem cell transplantation due to acute myeloid leukemia. He presented with symptoms of fatigue and weakness. Laboratory tests revealed hypercalcemia (13.8 mg/dL) and elevated serum creatinine levels (2.3 mg/dL). The patient was hospitalized, and despite initial treatment with hydration and furosemide, the hypercalcemia persisted, leading to the administration of denosumab. During follow-up, hypoxia was detected, and a chest CT scan revealed mosaic attenuation and ground-glass opacities. Bronchoscopy was performed, and PCR testing confirmed the presence of Pneumocystis jirovecii. Other causes of hypercalcemia were ruled out, with PTH measured at 13.8 pg/mL (normal range 15-65 pg/mL), albumin at 3.71 g/dL, 1.25-dihydroxy vitamin D3 at 96 ng/dL (normal range 26-95 ng/dL), and 25-hydroxy vitamin D at 32.5 ng/mL (normal range 20-40 ng/mL). A PET-CT scan demonstrated no pathological FDG uptake, with the exception of findings suggestive of a pulmonary infection. Following treatment with trimethoprim-sulfamethoxazole and denosumab, the patient's hypercalcemia and infection resolved., Conclusions:  Although rare, PJP can present with hypercalcemia and kidney injury in allogeneic stem cell transplant recipients. Early diagnosis and treatment can improve both PJP and hypercalcemia., (© 2024. The Author(s).)

Objectives: This study aimed to identify the risk factors and construct the diagnostic model associated with pneumocystis pneumonia (PCP) in pediatric patients., Methods: This retrospective observational study analyzed 34 cases of PCP and 51 cases of other types of pneumonia treated at Children's Hospital Affiliated to Shandong University between January 2021 and August 2023. Multivariate binary logistic regression was used to identify the risk factors associated with PCP. Receiver operating characteristic curves and calibration plots were constructed to evaluate the diagnostic model., Results: Twenty clinical variables significantly differed between the PCP and non-PCP groups. Multivariate binary logistic regression analysis revealed that dyspnea, body temperature>36.5°C, and age<1.46 years old were risk factors for PCP. The area under the curve of the diagnostic model was 0.958, the P -value of Hosmer-Lemeshow calibration test was 0.346, the R 2 of the calibration plot for the actual and predicted probability of PCP was 0.9555 ( P <0.001), and the mean Brier score was 0.069. In addition, metagenomic next-generation sequencing revealed 79.41% (27/34) and 52.93% (28/53) mixed infections in the PCP and non-PCP groups, respectively. There was significantly more co-infection with cytomegalovirus and Streptococcus pneumoniae in the PCP group than that in the non-PCP group (p<0.05)., Conclusions: Dyspnea, body temperature>36.5°C, and age<1.46 years old were found to be independent risk factors for PCP in pediatric patients. The probability of co-infection with cytomegalovirus and S. pneumoniae in the PCP group was significantly higher than that in the non-PCP group., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhang, Li, Chen, Wang, Yang, Xu and Wang.)

Background: Pneumocystis jirovecii infection is an opportunistic infection that mostly affects patients with immunosuppressive conditions like human immunodeficiency virus (HIV) infection or medications, like corticosteroids. This study reports a rare case of Pneumocystis Jiroveci infection in a relatively immunocompetent patient which presented with uncommon radiological findings., Case Presentation: A 46-year-old man with a malnourished appearance and a history of opium dependence presented with dry cough, dyspnea, and weight loss to the hospital. There was no evidence of an immunocompromised condition or use of any immunosuppressive medication in the history of the patient. A lung high-resolution computed tomography (HRCT) scan revealed a crazy-paving appearance and localized infiltration. Methenamine silver staining and the histopathological findings in the transbronchial lung biopsy confirmed the diagnosis of PJP. Antibiotics and bronchodilators were administrated and the patient was discharged after 6 days of hospitalization. HIV testing and immunoglobulin levels were normal in the hospital course as well as his follow-up visits. After a 2-month follow-up, the patient was in good condition despite of mild remaining infiltration in his lung., Conclusions: PJP typically affects HIV-infected patients, but due to excessive use of immunosuppressive medications, its prevalence is increasing in non-HIV-infected patients. Malnutrition may predispose the patients to PJP, even in the absence of immunosuppressive conditions., (© 2024. The Author(s).)

Introduction: While Pneumocystis pneumonia (PcP) remains a major AIDS-defining disease, the majority of cases of PcP now present in the HIV-negative cohort, causing significant mortality. PcP PCR diagnosis is not novel, and the optimal route of diagnosis remains unclear, with an imperfect reference method and complexity in result interpretation for alternative tests., Areas Covered: This extensive review utilizing a literature search underpinning a recent systematic review/meta-analysis discusses the technical and clinical performance of PcP PCR, the added benefits of PCR testing, future aspects/considerations, and how PCR may be best used in clinical algorithms to provide a probability of PcP., Expert Opinion: Given the current imperfect reference test for PcP, an alternative would be beneficial. Concerns over PcP PCR generating false positive results are valid but can be resolved by using positivity thresholds that drive specificity. Unfortunately, the extensive range of PCR assays complicates the provision of a PCR reference method. Combination testing incorporating PCR and B-D-Glucan, along with clinical and host risk factors, is key to understanding the individual probability of PcP. It is critical that access to PcP PCR testing is improved through technical and logistical development. Conversely, syndromic approaches including PcP need to be fully evaluated.

Background: Influenza is an acute respiratory infection caused by influenza viruses, with influenza A virus (IAV) being the most common and most likely to progress to critically ill cases leading to death. Pneumocystis jiroveci is an opportunistic lung-causing fungus that occurs most often in immunocompromised individuals and can cause Pneumocystis jiroveci pneumonia (PJP). It is rare for both diseases to occur in the same patient., Methods: Appropriate laboratory tests, chest computed tomography (CT), bronchoalveolar lavage fluid, second-generation macro gene sequencing, and pathogenetic tests to clarify the diagnosis., Results: G test and LDH were high, and chest CT showed rapidly progressive interstitial pneumonia, which was confirmed by bronchoalveolar lavage fluid and macrogenomic second-generation sequencing (mNGS) to be a mixed infection of H. influenzae type A virus and Pneumocystis jiroveci., Conclusions: In rapidly progressive interstitial pneumonia, bronchoalveolar lavage and mNGS should be done early to clarify the presence of infection with specific pathogenic organisms.

Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: B. G. reports receipt of nonfinancial support from Gilead Sciences, MSD, and Pfizer outside the submitted work. F. R. reports receipt of personal fees from AbbVie, AstraZeneca, Gilead Sciences, Janssen, Merck, Roche, and ViiV Healthcare outside the submitted work. E. C. reports personal fees from GILEAD, SANOFI-GENZYME, and BAXTER outside the submitted work. B. T. reports receipt of nonfinancial support from Gilead Sciences and personal fees from AbbVie, Gilead Sciences, Lilly Oncology, and Incyte outside the submitted work. None declared (R. Lécuyer, N. I., F. C., R. Lavergne, F. G., F. M., D. B., A. C., M. G., Y. C., A. N.).

Pneumocystis jirovecii pneumonia (PJP) is one of the leading opportunistic infections seen in people living with HIV. Bilateral infiltrations characterize PJP and miliary involvement is very rare. In this article, we report a 32-year-old person living with HIV who was followed up with a diagnosis of miliary PJP. Our patient was admitted to the hospital with complaints of cough, sputum, and weight loss. Initially, miliary tuberculosis was considered due to the presence of miliary involvement on chest radiography, but the diagnosis was made with P. jirovecii PCR positivity. This article aims to report a case of miliary PJP, a rare clinical form of PJP., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Nephrotic syndrome (NS) is a common chronic kidney disease that is often accompanied by a state of immunodeficiency. Immunosuppression increases the risk of infections, with Pneumocystis jirovecii and Nocardia brasiliensis being two opportunistic pathogens that can cause severe infections in patients with compromised immune function. This study presents a case of a middle-aged male patient with NS concurrently infected with Pneumocystis jirovecii and Nocardia brasiliensis. It aims to synthesize the pertinent diagnostic approaches and treatment experiences. Notably, there have been no reported cases of NS occurring simultaneously with both Pneumocystis jirovecii pneumonia and Nocardia pneumonia., Case Presentation: A 58-year-old male farmer presented to the hospital with a one-week history of persistent fever, cough, and sputum production. His maximum body temperature was recorded at 39 °C, and he produced yellow viscous sputum. This patient had a one-year history of NS, managed with long-term oral corticosteroid and cyclophosphamide therapy. Admission chest computed tomography displayed interstitial changes in both lungs. After failing to detect any pathogens through routine etiological tests, we successfully identified Nocardia brasiliensis, Pneumocystis jirovecii, and Lodderomyces elongisporus using bronchoscopy-guided sputum samples through metagenomic next-generation sequencing (mNGS) technology. Subsequently, we initiated a combined treatment regimen for the patient using trimethoprim-sulfamethoxazole, meropenem, and moxifloxacin, which yielded remarkable therapeutic outcomes., Conclusion: The adoption and promotion of mNGS technologies have significantly resolved the difficulty in early pathogen detection, guiding clinicians from empirical to genomic diagnosis, achieving prevention before treatment, and thereby enhancing patient survival rates., (© 2024. The Author(s).)

Background: The performance and availability of invasive and non-invasive investigations for the diagnosis of Pneumocystis jirovecii pneumonia (PCP) vary across clinical settings. Estimating the pre-test probability of PCP is essential to the optimal selection and interpretation of diagnostic tests, such as the 1,3-β-D-glucan assay (BDG), for the prioritization of bronchoscopy, and to guide empiric treatment decisions. We aimed to develop a multivariable risk score to estimate the pre-test probability of PCP., Methods: The score was developed from a cohort of 626 individuals who underwent bronchoscopy for the purposes of identifying PCP in a Canadian tertiary-care centre, between 2015 and 2018. We conducted a nested case-control study of 57 cases and 228 unmatched controls. Demographic, clinical, laboratory, and radiological data were included in a multivariable logistic regression model to estimate adjusted odds ratios for PCP diagnosis. A clinical risk score was derived from the multivariable model and discrimination was assessed by estimating the score's receiver operating characteristic curve., Results: Participants had a median age of 60 years (interquartile range [IQR] 49-68) and 115 (40%) were female; 40 (14%) had HIV and 49 (17%) had a solid organ transplant (SOT). The risk score included prior SOT or HIV with CD4 ≤ 200/µL (+ 2), serum lactate dehydrogenase ≥ 265.5 IU/mL (+ 2), radiological pattern typical of PCP on chest x-ray (+ 2) or CT scan (+ 2.5), and PCP prophylaxis with trimethoprim-sulfamethoxazole (-3) or other antimicrobials (-2). The median score was 4 points (IQR, 2-4.5) corresponding to a 28% probability of PCP. The risk prediction model had good discrimination with a c-statistic of 0.79 (0.71-0.84). Given the operating characteristics of the BDG assay, scores ≤ 3 in patients without HIV, and ≤ 5.5 in those with HIV, paired with a negative BDG, would be expected to rule out PCP with 95% certainty., Conclusion: We propose the PCP Score to estimate pre-test probability of PCP. Once validated, it should help clinicians determine which patients to refer for invasive investigations, when to rely on serological testing, and in whom to consider pre-emptive treatment., (© 2024. The Author(s).)

Background: Identification of the opportunistic fungus Pneumocystis jirovecii in respiratory specimens presents challenges, particularly in differentiating between colonization and active infection. The present study assessed a probe-based real time PCR (qPCR) diagnostic effectiveness in patients with diverse underlying conditions, particularly those with COVID-19 and pulmonary insufficiency., Methods: To set up the qPCR, clinical samples from 281 patients with respiratory ailments were tested. Subsequently, a descriptive study was conducted on 112 patients with pulmonary insufficiency with and without COVID-19 suspected of P. jirovecii infection. All specimens were subjected to DNA extraction followed by nested PCR and qPCR targeting the mitochondrial large subunit (mtLSU)-rRNA gene., Results: Based on nested PCR and qPCR, P. jirovecii was identified in 40 out of 281 patients, with slight variations in positive samples observed across dilutions. Three patients who tested positive in nested PCR yielded negative results in probe-based qPCR. Conversely, three patients who tested positive in probe-based qPCR yielded negative results in nested PCR. Considering nested PCR as the golden standard, probe-based qPCR demonstrated good diagnostic performance, with 92.5% sensitivity and 98.7% specificity. Based on cycle threshold (Ct) values, the positive cases were categorized: ≤32 as infection, >35 as colonization, and a grey zone between these values (32 < X ≤ 35). The analysis of 112 PCP-suspected patients revealed a prevalence ranging from 6.25% (nested PCR) to 7% (probe-based qPCR)., Conclusions: This study suggested Ct values to differentiate Pneumocystis pneumonia/colonization in immunocompromised patients. To further augment the diagnostic sensitivity, it is recommended to integrate qPCR results with clinical parameters and biomarkers to offer a more precise understanding of Pneumocystis -related conditions., Competing Interests: The authors declare that the research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Rouhi, Erami, Rastgufar, Jahani, Aboutalebian, Soltani, Fakhim and Mirhendi.)

Background: Serum (1,3)-β-D-glucan (BDG) detection for diagnosis of Pneumocystis jirovecii pneumonia (PJP) in non-human immunodeficiency virus (HIV) immunocompromised patients lacks intensive care unit (ICU)-specific data. We aimed to assess its performance and determine the optimal cutoff for PJP in ICU population., Methods: This retrospective study included critically ill non-HIV immunocompromised patients admitted to a medical ICU with suspected pneumonia, undergoing simultaneous microbiological testing for P. jirovecii on lower respiratory tract specimens and serum BDG. Confounders affecting BDG positivity were explored by multivariable logistic regression. Optimal cut-offs were derived from Youden's index for the entire cohort and subgroups stratified by confounders. Diagnostic performance of serum BDG was estimated at different cutoffs., Results: Of 400 patients included, 42% were diagnosed with PJP and 58.3% had positive serum BDG. Serum BDG's area under the receiver operating characteristic curve was 0.90 (0.87-0.93). At manufacturer's 150 pg/ml cut-off, serum BDG had high sensitivity and negative predictive value (94%), but low specificity and positive predictive value (67%). Confounders associated with a positive serum BDG in PJP diagnosis included IVIG infusion within 3 days (odds ratio [OR] 9.24; 95% confidence interval [CI] 4.09-20.88, p < 0.001), other invasive fungal infections (OR 4.46; 95% CI 2.10-9.49, p < 0.001) and gram-negative bacteremia (OR 29.02; 95% CI 9.03-93.23, p < 0.001). The application of optimal BDG cut-off values determined by Youden's index (252 pg/ml, 390 pg/ml, and 202 pg/ml) specific for all patients and subgroups with or without confounders improved the specificity (79%, 74%, and 88%) and corresponding PPV (75%, 65%, and 85%), while maintaining reasonable sensitivity and NPV., Conclusions: Tailoring serum BDG cutoff specific to PJP and incorporating consideration of confounders could enhance serum BDG's diagnostic performance in the ICU settings., (© 2024. The Author(s).)

This study included 20 patients with hematological diseases who developed Pneumocystis jirovecii pneumonia (PJP) after receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT) from April 2014 to October 2022 at Peking University People's Hospital. The 20 patients comprised 13 males (65.0% ) and seven females (35.0% ), with a median age of 34 (19-60) years. Eleven cases (55.0% ) of acute myeloid leukemia, four cases (20.0% ) of acute lymphocytic leukemia, two cases (10.0% ) of myelodysplastic syndrome, one case (5.0% ) of chronic myelomonocytic leukemia, one case (5.0% ) of non-Hodgkin lymphoma, and one case (5.0% ) of aplastic anemia were analyzed. Three cases (15.0% ) of HLA-identical sibling hematopoietic stem cell transplantation, three cases (15.0% ) of matched unrelated donor hematopoietic stem cell transplantation, and 14 cases (70.0% ) of haploid hematopoietic stem cell transplantation were identified. The median onset time of PJP was 353 (74-1121) days after transplantation. The clinical symptoms mainly included fever, cough, expectoration, and dyspnea. All patients presented signs of infection based on the CT scan, including bilateral diffuse ground-glass opacities, patchy shadows, and solid nodules. Nine patients (45.0% ) required respiratory support via nasal catheter oxygen inhalation, while seven patients (35.0% ) required ventilator-assisted breathing. Seven (35.0% ) severe infections and 13 (65.0% ) mild to moderate infections were recorded. Moreover, eight patients (40.0% ) were complicated with human cytomegalovirus infection, whereas two patients were complicated with EB virus infection. Furthermore, all 20 patients received treatment with compound sulfamethoxazole (standard dose, 11 cases; low dose, 9 cases). Furthermore, 19 patients survived and one patient died.

Pneumocystis jirovecii pneumonia is an opportunistic infection that affects HIV-infected and immunocompromised persons and rarely affects immunocompetent patients. However, after the advent of the COVID-19 pandemic, some COVID-19 patients without immunocompromise or HIV were infected with P. jirovecii. Clinical manifestations were atypical, easily misdiagnosed, and rapidly progressive, and the prognosis was poor.

Seronegative human immunodeficiency virus (HIV) infection, where an HIV-specific antibody response is lacking even in chronic or late-stage HIV infections, is extremely rare. Here, we report the case of a 50-year-old Japanese man presenting with Pneumocystis pneumonia who did not produce antibodies against HIV-1 until the initiation of antiretroviral therapy (ART). Fourth-generation antigen-antibody testing temporarily reverted from weakly positive to negative soon after initiating ART, likely due to a reduction in viral load (assessed by p24 antigen levels). His HIV-1 antibody titers remained low or indeterminate even after four years of ART. A literature review suggested that the absence of HIV-1-specific antibody production may be associated with unimpeded HIV replication and rapid CD4 + T cell decline. Seronegative HIV infection can lead to deferred diagnosis and treatment, thereby increasing the risk of transmitting the virus to others or developing opportunistic illnesses. It is important to combine multiple tests for diagnosis, depending on the medical condition. Further studies are required to investigate the host factors involved in the production of HIV-1-specific antibodies., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

We report a rare case of a patient with Janus kinase 2-positive myelofibrosis on ruxolitinib, presenting with indolent pneumonia and cavitary lung lesions. Initial transthoracic biopsy was non-specific, but thoracoscopic biopsy revealed necrotising granulomatous disease caused by Pneumocystis jirovecii pneumonia (PJP). The patient, initially treated with trimethoprim-sulfamethoxazole, was switched to atovaquone due to gastrointestinal intolerance. Given the patient's immunosuppression and extensive cavitary lesions, an extended course of atovaquone was administered, guided by serial imaging, resulting in clinical and radiological improvement. Unfortunately, the patient later passed away from a severe SARS-CoV-2 infection before complete radiographic resolution was observed. This case highlights the importance of recognising atypical PJP presentations causing granulomatous disease in immunosuppressed patients. While rare, documenting such cases may improve diagnosis using less invasive methods and help determine optimal treatment durations for resolution of these atypical infections., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Pneumocystis jirovecii is a prevalent opportunistic fungal pathogen that can lead to life-threatening Pneumocystis pneumonia in immunocompromised individuals. Given that timely and accurate diagnosis is essential for initiating prompt treatment and enhancing patient outcomes, it is vital to develop a rapid, simple, and sensitive method for P. jirovecii detection. Herein, we exploited a novel detection method for P. jirovecii by combining recombinase polymerase amplification (RPA) of nucleic acids isothermal amplification and the trans cleavage activity of Cas12a. The factors influencing the efficiency of RPA and Cas12a-mediated trans cleavage reaction, such as RPA primer, crRNA, the ratio of crRNA to Cas12a and ssDNA reporter concentration, were optimized. Our RPA-Cas12a-based fluorescent assay can be completed within  30-40 min, comprising a 25-30 min RPA reaction and a 5-10 min trans cleavage reaction. It can achieve a lower detection threshold of 0.5 copies/µL of target DNA with high specificity. Moreover, our RPA-Cas12a-based fluorescent method was examined using 30 artificial samples and demonstrated high accuracy with a diagnostic accuracy of 93.33%. In conclusion, a novel, rapid, sensitive, and cost-effective RPA-Cas12a-based detection method was developed and demonstrates significant potential for on-site detection of P. jirovecii in resource-limited settings., (© 2024. The Author(s).)

Background: Kidney transplantation has emerged as the most effective treatment for patients with uremia. Advances in immunosuppressant medications have significantly reduced the risk of rejection. However, a notable increase in opportunistic infections, such as Pneumocystis jirovecii pneumonia (PJP), demands special attention in clinical practice. Our study aims to evaluate risk factors and identify predictive markers associated with PJP in kidney transplantation recipients., Methods: We conducted a case-control study (1:2 ratio) involving kidney transplant recipients with and without PJP, matched based on the same surgical date. The study was carried out at Zhongnan Hospital of Wuhan University, China., Results: Ninety-three participants were enrolled at Zhongnan Hospital of Wuhan University, comprising 31 with PJP and 62 without PJP. All patients tested negative for HIV. Our findings indicate that PJP patients exhibited lower levels of serum albumin (P = 0.001), reduced counts of total and CD3 + (P < 0.001), CD4 + (P = 0.001), and CD8 + T lymphocytes (P < 0.001), and a lower rate of prophylactic trimethoprim-sulfamethoxazole (TMP-SMZ) usage compared to non-PJP patients (P = 0.02). Conversely, urea levels in PJP patients were significantly higher than in non-PJP controls (P < 0.001). We developed a model combining CD8 + T cell count (< 241.11/μL, P < 0.001) and ALB levels (< 35.2 g/L, P = 0.003), which demonstrated excellent discriminatory power in distinguishing PJP from non-PJP cases, with an area under the curve (AUC) of 0. 920 (95% CI, 0.856-0.989)., Conclusions: Our study suggests that a baseline CD8 + T cell count (< 241.11/μL) and serum ALB levels (< 35.2 g/L) offer robust predictive value for the occurrence of PJP infections in kidney transplant recipients., Competing Interests: Declaration of competing interest There are no conflicts of interest associated with this study., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Kidney transplant recipients (KTR) are at an increased risk of developing Pneumocystis jirovecii pneumonia (PCP), especially during the first year after transplantation. This is the first reported pediatric KTR, with chronic kidney disease (CKD) secondary to kidney dysplasia and vesicoureteral reflux, who developed refractory and symptomatic hypercalcemia 5 years after transplantation. The hypercalcemia was resistant to treatment with intravenous hyperhydration, furosemide, and a low-calcium diet. A respiratory tract infection due to PCP treated with trimethoprim-sulfamethoxazole did not improve calcium levels. Due to the hypercalcemic symptom burden for the patient, a single dose of subcutaneous denosumab was used to achieve sustained clinical and biochemical improvement, without any severe adverse events. This case highlights the potential use of denosumab as a treatment option in pediatric KTR with refractory hypercalcemia related to PCP. Further study of denosumab in young people with CKD or kidney transplants is needed before routine use can be recommended., (© 2024. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Background: This meta-analysis examines the comparative diagnostic performance of polymerase chain reaction (PCR) for the diagnosis of Pneumocystis pneumonia (PCP) on different respiratory tract samples, in both human immunodeficiency virus (HIV) and non-HIV populations., Methods: A total of 55 articles met inclusion criteria, including 11 434 PCR assays on respiratory specimens from 7835 patients at risk of PCP. QUADAS-2 tool indicated low risk of bias across all studies. Using a bivariate and random-effects meta-regression analysis, the diagnostic performance of PCR against the European Organisation for Research and Treatment of Cancer-Mycoses Study Group definition of proven PCP was examined., Results: Quantitative PCR (qPCR) on bronchoalveolar lavage fluid provided the highest pooled sensitivity of 98.7% (95% confidence interval [CI], 96.8%-99.5%), adequate specificity of 89.3% (95% CI, 84.4%-92.7%), negative likelihood ratio (LR-) of 0.014, and positive likelihood ratio (LR+) of 9.19. qPCR on induced sputum provided similarly high sensitivity of 99.0% (95% CI, 94.4%-99.3%) but a reduced specificity of 81.5% (95% CI, 72.1%-88.3%), LR- of 0.024, and LR+ of 5.30. qPCR on upper respiratory tract samples provided lower sensitivity of 89.2% (95% CI, 71.0%-96.5%), high specificity of 90.5% (95% CI, 80.9%-95.5%), LR- of 0.120, and LR+ of 9.34. There was no significant difference in sensitivity and specificity of PCR according to HIV status of patients., Conclusions: On deeper respiratory tract specimens, PCR negativity can be used to confidently exclude PCP, but PCR positivity will likely require clinical interpretation to distinguish between colonization and active infection, partially dependent on the strength of the PCR signal (indicative of fungal burden), the specimen type, and patient population tested., Competing Interests: Potential conflicts of interest. A. A. has received honoraria from Gilead Sciences. S. C.-A. A. has received united educational grants from F2G Ltd and consulted for MSD Australia. T. R. R. has received grants from Pfizer and the Irish Department of Agriculture, Food and the Marine and honoraria from Gilead and Menarini Pharma. P. L. W. has performed diagnostic evaluations and received meeting sponsorship from Associates of Cape Cod, Bruker, Dynamiker, and Launch Diagnostics; speaker fees, expert advice fees, and meeting sponsorship from Gilead; and speaker and expert advice fees from F2G. J. P. D. has received personal fees from F2G, Gilead Sciences, and Pfizer. W. J. H. has received lecture honoraria from AbbVie, Amgen, AstraZeneca, Celgene/BMS, Gilead Sciences, Janssen, MSD, and Pfizer; has received support to attend meetings and travel support from AbbVie, Alexion, Astellas, Janssen, Lilly, MSD, Novartis, and Pfizer; and has participated on advisory boards for AbbVie, Amgen, AstraZeneca, Basilea, Celgene/BMS, Gilead Sciences, Janssen, and Sanofi-Aventis. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Competing Interests: The authors declare no conflict of interest.

Background: Metagenomic next-generation sequencing (mNGS) excels in diagnosis of infection pathogens. We aimed to evaluate the performance of mNGS for the diagnosis of Pneumocystis jirovecii pneumonia (PJP) in non-HIV infected children., Methods: Totally 36 PJP children and 61 non-PJP children admitted to the pediatric intensive care unit from March 2018 to December 2021 were retrospectively enrolled. Clinical features of PJP children were summarized. 1,3-β-D glucan (BDG) test and bronchoalveolar lavage fluid (BALF) mNGS were used for evaluation of PJP diagnostic performance. Antimicrobial management modifications for PJP children after the mNGS results were also reviewed., Results: Pneumocystis jirovecii was detected in all PJP children by mNGS (36/36), and the sensitivity of mNGS was 100% (95% confidence interval [CI]: 90.26-100%). The sensitivity of BDG was 57.58% (95% CI: 39.22-74.52%). Of the 26 (72.2%) PJP patients with mixed infection, twenty-four (66.7%) were detected by BALF-mNGS. Thirteen patients (36.1%) had their antimicrobial management adjusted according to the mNGS results. Thirty-six PJP children included 17 (47.2%) primary immunodeficiency and 19 (52.8%) secondary immunodeficiency, of whom 19 (52.8%) survived and 17 (47.2%) died. Compared to survival subgroup, non-survival subgroup had a higher rate of primary immunodeficiency (64.7% vs. 31.6%, P = 0.047), younger age (7 months vs. 39 months, P = 0.011), lower body weight (8.0 kg vs. 12.0 kg, P = 0.022), and lower T lymphocyte counts., Conclusions: The mortality rate of PJP in immunosuppressed children without HIV infection is high and early diagnosis is challenging. BALF-mNGS could help identify PJP and guide clinical management., (© 2024. The Author(s).)

Persistent inflammatory damage and suppressed immune function play a crucial role in the pathogenesis and progression of the pneumocystis jirovecii pneumonia (PjP). Therefore, we aimed to investigate the correlation between the combined immune and inflammatory indicator: the neutrophil-to-lymphocyte ratio (NLR) and prognosis of non-human immunodeficiency virus (non-HIV) PjP.In the retrospective analysis conducted in ICUs at Beijing Chao-Yang Hospital, we examined data from 157 patients diagnosed with non-HIV PjP. Our findings reveal a concerning hospital mortality rate of 43.3%, with the 28-day mortality rate reaching 47.8%.Through multivariable logistic and Cox regression analyses, we established a significant association between elevated NLR levels and hospital mortality (adjusted odd ratio, 1.025; 95% CI, 1.008-1.043; p = 0.004) or 28-day mortality (adjusted hazard ratio, 1.026; 95% CI, 1.008-1.045; p = 0.005). Specifically, patients with an NLR exceeding 20.3 demonstrated markedly lower overall survival rates, underscoring the biomarker's predictive value for both hospital and 28-day mortality.In conclusion, non-HIV PjP patients in the ICU still have a high rate of mortality and a poor short-term prognosis after discharge. A high level of NLR was associated with an increased risk of hospital mortality and 28-day mortality., (© 2024. The Author(s).)

Background: Pneumocystis jirovecii pneumonia (PcP) remains associated with high rates of mortality, and the impact of immunocompromising underlying disease on the clinical presentation, severity, and mortality of PcP has not been adequately evaluated., Research Question: Does the underlying disease and immunosuppression causing PcP impact the outcome and clinical presentation of the disease?, Study Design and Methods: In this multicenter retrospective observational study, conducted from January 2011 to December 2021, all consecutive patients admitted with a proven or probable diagnosis of PcP according to the European Organisation for Research and Treatment of Cancer consensus definitions were included to assess the epidemiology and impact of underlying immunosuppressive diseases on overall and 90-day mortality., Results: Overall, 481 patients were included in the study; 180 (37.4%) were defined as proven PcP and 301 (62.6%) were defined as probable PcP. Patients with immune-mediated inflammatory diseases (IMIDs) or solid tumors had a statistically poorer prognosis than other patients with PcP at day 90. In multivariate analysis, among the HIV-negative population, solid tumor underlying disease (OR, 5.47; 95% CI, 2.16-14.1; P < .001), IMIDs (OR, 2.19; 95% CI, 1.05-4.60; P = .037), long-term corticosteroid exposure (OR, 2.07; 95% CI, 1.03-4.31; P = .045), cysts in sputum/BAL smears (OR, 1.92; 95% CI, 1.02-3.62; P = .043), and SOFA score at admission (OR, 1.58; 95% CI, 1.39-1.82; P < .001) were independently associated with 90-day mortality. Prior corticotherapy was the only immunosuppressant associated with 90-day mortality (OR, 1.67; 95% CI, 1.03-2.71; P = .035), especially for a prednisone daily dose ≥ 10 mg (OR, 1.80; 95% CI, 1.14-2.85; P = .010)., Interpretation: Among patients who were HIV-negative, long-term corticosteroid prior to PcP diagnosis was independently associated with increased 90-day mortality, specifically in patients with IMIDs. These results highlight both the needs for PcP prophylaxis in patients with IMIDs and to early consider PcP curative treatment in severe pneumonia among patients with IMIDs., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: B. G. reports receipt of nonfinancial support from Gilead Sciences, MSD, and Pfizer, outside the submitted work. F. R. reports receipt of personal fees from Abbvie, Astra Zeneca, Gilead Sciences, Janssen, Merck, Roche, and ViiV Healthcare, outside the submitted work. E. C. reports personal fees from Gilead, Sanofi-Genzyme, and Baxter, outside the submitted work. None declared (R. L., N. I., F. C., R.-a. L., F. G., F. M., D. B., A. C., M. G., Y. C., A. N., B. T.)., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Interstitial lung disease (ILD) is a new risk category for pneumocystis pneumonia (PCP) with a high mortality rate. The definite diagnostic criteria of PCP in ILD patients have not been established until now. The aims of this study were to identify potential risk factors of PCP in patients with ILD, and to evaluate the performance of metagenomic next-generation sequencing (mNGS), CD4 + T cell count, (1-3)-β-D-Glucan (BG) and lactate dehydrogenase (LDH) in the diagnosis of PCP in ILD patients., Methods: This is a retrospective, single-center, case-control study. ILD patients who underwent mNGS from December 2018 to December 2022 were included in the study. Based on the diagnosis criteria of PCP, these patients were divided into PCP-ILD and non-PCP-ILD groups. The potential risk factors for PCP occurrence in ILD patients were analysed via logistic regression. The diagnostic efficacy of mNGS was compared with serological biomarkers., Results: 92 patients with ILD were enrolled, 31 of which had a definite PCP and were assigned to the PCP-ILD group while 61 were to the non-PCP-ILD group. The infection rate of PJ in ILD patients was 33.7% (31/92). The history of glucocorticoid therapy, CD4 + T cell count, BG level and traction bronchiectasis on HRCT were associated with PCP occurrence in ILD patients. LDH level did not reach statistical significance in the logistic regression analysis. mNGS was confirmed as the most accurate test for PCP diagnosis in ILD patients., Conclusion: ILD is a new risk group of PCP with high PCP prevalence. Clinicians should pay close attention to the occurrence of PCP in ILD patients who possess the risk factors of previous glucocorticoid therapy, decreased CD4 + T cell count, increased BG level and absence of traction bronchiectasis on HRCT. mNGS showed the most excellent performance for PCP diagnosis in ILD patients. Peripheral blood CD4 + T cell count and BG level are alternative diagnostic methods for PCP in ILD patients. However, the diagnostic value of serum LDH level was limited in ILD patients., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

A male patient in his 40s who had been unwell for months with fever of unknown origin and clinicopathological features suspicious for haemophagocytic lymphohistiocytosis presented to hospital with worsening subacute shortness of breath. CT pulmonary angiogram demonstrated ground glass changes involving all lung lobes with an apicobasal gradient. These changes, combined with long-term steroid exposure for granulomatous hepatitis without pneumocystis prophylaxis, raised concern for pneumocystis jirovecii pneumonia (PJP). A subsequent bronchoscopic lavage specimen was positive on PCR for PJP and the patient was started on appropriate therapy. Clinical and radiological changes initially improved but after completion of therapy, symptoms and radiological abnormalities returned. Retreatment with second-line treatment resulted again in initial improvement followed by relapse with acute deterioration. Further investigations for an alternate diagnosis were made, with a surgical lung biopsy performed finally revealing immunosuppression-related Epstein-Barr virus positive large B cell lymphoma with lymphomatoid granulomatosis of grade 3 pattern., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

We assessed predictive models (PMs) for diagnosing Pneumocystis jirovecii pneumonia (PCP) in AIDS patients seen in the emergency room (ER), aiming to guide empirical treatment decisions. Data from suspected PCP cases among AIDS patients were gathered prospectively at a reference hospital's ER, with diagnoses later confirmed through sputum PCR analysis. We compared clinical, laboratory, and radiological data between PCP and non-PCP groups, using the Boruta algorithm to confirm significant differences. We evaluated ten PMs tailored for various ERs resource levels to diagnose PCP. Four scenarios were created, two based on X-ray findings (diffuse interstitial infiltrate) and two on CT scans ("ground-glass"), incorporating mandatory variables: lactate dehydrogenase, O2 sat , C-reactive protein, respiratory rate (> 24 bpm), and dry cough. We also assessed HIV viral load and CD4 cell count. Among the 86 patients in the study, each model considered either 6 or 8 parameters, depending on the scenario. Many models performed well, with accuracy, precision, recall, and AUC scores > 0.8. Notably, nearest neighbor and naïve Bayes excelled (scores > 0.9) in specific scenarios. Surprisingly, HIV viral load and CD4 cell count did not improve model performance. In conclusion, ER-based PMs using readily available data can significantly aid PCP treatment decisions in AIDS patients., (© 2024. The Author(s).)

Introduction: Pneumocystis jirovecii pneumonia (PJP) is a well-known and frequent opportunistic infection in HIV patients. However, there has been an increase in the number of reports of PJP in other immunosuppressed patients with autoimmune inflammatory disorders or because of chemotherapy and high doses of steroids, especially when used in combination as part of immunosuppressive therapy., Objective: Despite the increasing importance of PJP in non-HIV patients, there is a lack of comprehensive and updated information on the epidemiology, pathogenesis, diagnosis, microbiology, treatments, and prophylaxis of this infection in this population. Therefore, the objective of this systematic review is to synthesize information on these aspects, from a perspective of evidence-based medicine., Methods: The protocol is prepared following the preferred reporting items for systematic reviews and meta-analyses (PRISMA-P) guidelines. We will perform a systematic review of literature published between January 2010 and July 2023, using the databases PubMed, Google Scholar, ScienceDirect, and Web of Science. In addition, manual searches will be carried out through related articles, and references to included articles. The main findings and clinical outcomes were extracted from all the eligible studies with a standardized instrument. Two authors will independently screen titles and abstracts, review full texts, and collect data. Disagreements will be resolved by discussion, and a third reviewer will decide if there is no consensus. We will synthesize the results using a narrative or a meta-analytic approach, depending on the heterogeneity of the studies., Expected Results: It is expected that this systematic review will provide a comprehensive and up-to-date overview of the state-of-the-art of PJP in non-HIV patients. Furthermore, the study will highlight possible gaps in knowledge that should be addressed through new research., Conclusions: Here, we present the protocol for a systematic review which will consider all existing evidence from peer-reviewed publication sources relevant to the primary and secondary outcomes related to diagnosing and managing PJP in non-HIV patients., Competing Interests: The authors declare that they have no competing interests., (Copyright: © 2024 Orozco-Ugarriza et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: To describe the epidemiology of Pneumocystis jirovecii pneumonia and colonization diagnosed by next-generation sequencing (NGS) and explore the usefulness of the number of P. jirovecii sequence reads for the diagnosis of P. jirovecii pneumonia., Methods: We examined the NGS results for P. jirovecii in respiratory samples collected from patients and analysed their clinical, radiological and microbiological characteristics., Results: Among 285 respiratory samples collected over a 12-month period (January to December 2022), P. jirovecii sequences were detected in 56 samples from 53 patients. Fifty (94.3%) of the 53 patients were HIV-negative. Following our case definitions, 37 (69.8%) and 16 (30.2%) of the 53 patients had P. jirovecii infection and colonization respectively. P. jirovecii infection was associated with presence of underlying disease with immunosuppression (94.6% vs 18.8%, P < 0.05), positive serum 1,3-β-D-glucan (41.2% vs 0%, P < 0.01) and higher number of P. jirovecii sequence reads (P < 0.005). In contrast, P. jirovecii colonization was associated with the male sex (93.8% vs 54.1%, P < 0.01), another definitive infectious disease diagnosis of the respiratory tract (43.8% vs 2.7%, P < 0.001) and higher survival (100% vs 67.6%, P < 0.01). Although P. jirovecii pneumonia was associated with higher number of P. jirovecii reads in respiratory samples, only a sensitivity of 82.14% and a specificity of 68.75% could be achieved., Conclusion: Detection of P. jirovecii sequences in respiratory samples has to be interpreted discreetly. A combination of clinical, radiological and laboratory findings is still the most crucial in determining whether a particular case is genuine P. jirovecii pneumonia., (© 2024. The Author(s).)

This case describes a four-month-old male who was admitted to the pediatric intensive care unit for acute respiratory failure in the setting of a co-infection requiring increased ventilatory support. Immunodeficiency workup demonstrated poor vaccination response and low immunoglobulin titers. mNGS via Karius® test was positive for Pneumocystis jiroveci (PJP), Parvovirus, and Bocavirus. The patient was successfully treated with trimethoprim-sulfamethoxazole and prednisone. Genetic workup via Invitae panel confirmed that the patient had X-linked Hyper-IgM Syndrome. Use of mNGS can help with early identification of pathogens that conventional testing does not detect, even in patients not already identified as immunocompromised., Competing Interests: CONFLICTS OF INTEREST None to report., (Published by Elsevier Inc.)

Background: Pneumocystis jirovecii pneumonia (PJP) is an interstitial pneumonia caused by pneumocystis jirovecii (PJ). The diagnosis of PJP primarily relies on the detection of the pathogen from lower respiratory tract specimens. However, it faces challenges such as difficulty in obtaining specimens and low detection rates. In the clinical diagnosis process, it is necessary to combine clinical symptoms, serological test results, chest Computed tomography (CT) images, molecular biology techniques, and metagenomics next-generation sequencing (mNGS) for comprehensive analysis., Purpose: This study aims to overcome the limitations of traditional PJP diagnosis methods and develop a non-invasive, efficient, and accurate diagnostic approach for PJP. By using this method, patients can receive early diagnosis and treatment, effectively improving their prognosis., Methods: We constructed an intelligent diagnostic model for PJP based on the different Convolutional Neural Networks. Firstly, we used the Convolutional Neural Network to extract CT image features from patients. Then, we fused the CT image features with clinical information features using a feature fusion function. Finally, the fused features were input into the classification network to obtain the patient's diagnosis result., Results: In this study, for the diagnosis of PJP, the accuracy of the traditional PCR diagnostic method is 77.58%, while the mean accuracy of the optimal diagnostic model based on convolutional neural networks is 88.90%., Conclusion: The accuracy of the diagnostic method proposed in this paper is 11.32% higher than that of the traditional PCR diagnostic method. The method proposed in this paper is an efficient, accurate, and non-invasive early diagnosis approach for PJP., (© 2024. The Author(s).)

Background: The prevalence of non-HIV related Pneumocystis jirovecii pneumonia (PJP) is increasing with use of immunosuppressive therapies. There are case reports of solid organ transplant recipients on immunosuppressive therapy presenting with mild hypercalcemia, leading to a diagnosis of PJP. Recent studies have shown efficacy of PJP prophylaxis for patients treated with rituximab with a favourable adverse effect profile., Case Presentation: A 78-year-old male with a history of PR3-ANCA vasculitis, chronic kidney disease and heart failure with reduced ejection fraction presented to our tertiary care hospital with a two-week history of confusion and non-productive cough. Background immunosuppression with rituximab was completed every six months. The patient was found to have hypercalcemia and new infiltrates and ground glass opacities on cross-sectional imaging. Bronchoscopy was performed that was positive for Pneumocystis jirovecii. He was treated with 21 days of trimethoprim-sulfamethoxazole and prednisone with resolution of symptoms and hypercalcemia., Conclusions: Herein, we present a novel case of PJP in a non-transplant recipient preceded by hypercalcemia. Our case demonstrates the importance for a high suspicion for PJP in chronically immunosuppressed patients on rituximab presenting with PTH-independent hypercalcemia., (© 2024. The Author(s).)

Pneumocystis jirovecii pneumonia (PJP) is a serious and sometimes fatal infection occurring in immunocompromised individuals. High-risk patients include those with low CD4 counts due to human immunodeficiency virus infection and transplant recipients. The incidence of PJP is increasing, and rapid detection of PJP is needed to effectively target treatment and improve patient outcomes. A common method used is an immunofluorescent assay (IFA), which has limitations, including labor costs, low sensitivity, and requirement for expert interpretation. This study evaluates the performance of the DiaSorin Molecular Pneumocystis jirovecii analyte-specific reagent (ASR) in a laboratory-developed test (LDT) for the direct detection of P. jirovecii DNA without prior nucleic acid extraction. Respiratory samples ( n = 135) previously tested by IFA from 111 patients were included. Using a composite standard of in-house IFA and reference lab PJP PCR, the percent positive agreement for the LDT using the DiaSorin ASR was 97.8% (90/92). The negative percent agreement was 97.7% (42/43). The lower limit of detection of the assay was determined to be 1,200 copies/mL in bronchoalveolar lavage fluid. Analytical specificity was assessed using cultures of oropharyngeal flora and common respiratory bacterial and fungal pathogens. No cross-reactivity was observed. Our study suggests that the DiaSorin Pneumocystis ASR accurately detects P. jirovecii DNA and demonstrates improved sensitivity compared to the IFA method., Importance: Our study is unique compared to other previously published studies on the DiaSorin analyte-specific reagent (ASR) because we focused on microbiological diagnostic methods commonly used (immunofluorescent assay) as opposed to pathology findings or reference PCR. In addition, in our materials and methods, we describe the protocol for the use of the DiaSorin ASR as a singleplex assay, which will allow other users to evaluate the ASR for clinical use in their lab., Competing Interests: Melissa Miller is a member of the DiaSorin Molecular Scientific Advisory Board

Purpose of Review: This review highlights the epidemiology of Pneumocystis jirovecii pneumonia in solid organ transplant recipients, advancements in the diagnostic landscape, and updates in treatment and prevention., Recent Findings: The increasing use of immune-depleting agents in the context of solid organ transplantation has given rise to P. jirovecii pneumonia in this population. The use of prophylaxis has dramatically reduced risk of infection; however, late-onset infections occur after cessation of prophylaxis and in the setting of lymphopenia, advancing patient age, acute allograft rejection, and cytomegalovirus infection. Diagnosis requires respiratory specimens, with PCR detection of Pneumocystis replacing traditional staining methods. Quantitative PCR may be a useful adjunct to differentiate between infection and colonization. Metagenomic next-generation sequencing is gaining attention as a noninvasive diagnostic tool. Trimethoprim-sulfamethoxazole remains the drug of choice for treatment and prevention of Pneumocystis pneumonia. Novel antifungal agents are under investigation., Summary: P. jirovecii is a fungal opportunistic pathogen that remains a cause of significant morbidity and mortality in solid organ transplant recipients. Early detection and timely treatment remain the pillars of management., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Patients with multiple myeloma (MM) are at high risk for infections, including opportunistic infections such as Pneumocystis jirovecii pneumonia (PJP). We conducted a retrospective analysis of patients with MM developing PJP over a 6-year period between January 2016 and December 2021 at the University Hospital of Würzburg by screening cases of microbiologically documented PJP. A total of 201 positive results for P. jirovecii in respiratory specimens were retrospectively retrieved through our microbiology database. Of these cases, 13 patients with MM fulfilled the definition of probable PJP according to EORTC fungal disease definitions. We observed two peaks in PJP incidence, one after stem cell transplantation during first-line treatment (n = 5) and the other in heavily pretreated patients with six or more prior lines of therapy (n = 6). There was high morbidity with nine (69%) patients admitted to the ICU, seven of whom (78%) required mechanical ventilation, and high mortality (62%, n = 8). Notably, only two of the 13 patients (15%) had received PJP prophylaxis. The main reason for discontinuation of prophylaxis with trimethoprim-sulfamethoxazole was grade IV neutropenia. The observed morbidity and mortality of PJP in MM patients are significant and even higher than reported for patients with other hematologic malignancies. According to most current guidelines, the use of prophylaxis would have been clearly recommended in no more than three (23%) of the 13 patients. This illustrates the need to critically reconsider the indications for PJP prophylaxis, which remain incompletely defined., (© 2023. The Author(s).)

Background: Increasing evidence revealed that lung microbiota dysbiosis was associated with pulmonary infection in lung transplant recipients (LTRs). Pneumocystis jirovecii (P. jirovecii) is an opportunistic fungal pathogen that frequently causes lethal pneumonia in LTRs. However, the lung microbiota in LTRs with P. jirovecii pneumonia (PJP) remains unknow., Methods: In this prospective observational study, we performed metagenomic next-generation sequencing (mNGS) on 72 bronchoalveolar lavage fluid (BALF) samples from 61 LTRs (20 with PJP, 22 with PJC, 19 time-matched stable LTRs, and 11 from LTRs after PJP recovery). We compared the lung microbiota composition of LTRs with and without P. jirovecii, and analyzed the related clinical variables., Results: BALFs collected at the episode of PJP showed a more discrete distribution with a lower species diversity, and microbiota composition differed significantly compared to P. jirovecii colonization (PJC) and control group. Human gammaherpesvirus 4, Phreatobacter oligotrophus, and Pseudomonas balearica were the differential microbiota species between the PJP and the other two groups. The network analysis revealed that most species had a positive correlation, while P. jirovecii was correlated negatively with 10 species including Acinetobacter venetianus, Pseudomonas guariconensis, Paracandidimonas soli, Acinetobacter colistiniresistens, and Castellaniella defragrans, which were enriched in the control group. The microbiota composition and diversity of BALF after PJP recovery were also different from the PJP and control groups, while the main components of the PJP recovery similar to control group. Clinical variables including age, creatinine, total protein, albumin, IgG, neutrophil, lymphocyte, CD3 + CD45 + , CD3 + CD4 + and CD3 + CD8 + T cells were deeply implicated in the alterations of lung microbiota in LTRs., Conclusions: This study suggests that LTRs with PJP had altered lung microbiota compared to PJC, control, and after recovery groups. Furthermore, lung microbiota is related to age, renal function, nutritional and immune status in LTRs., (© 2024. The Author(s).)

Pneumocystis jirovecii is a ubiquitous opportunistic fungus that can cause life-threatening pneumonia. People with HIV (PWH) who have low CD4 counts are one of the populations at the greatest risk of Pneumocystis jirovecii pneumonia (PCP). While guidelines have approached the diagnosis, prophylaxis, and management of PCP, the numerous studies of PCP in PWH are dominated by the 1980s and 1990s. As such, most studies have included younger male populations, despite PCP affecting both sexes and a broad age range. Many studies have been small and observational in nature, with an overall lack of randomized controlled trials. In many jurisdictions, and especially in low- and middle-income countries, the diagnosis can be challenging due to lack of access to advanced and/or invasive diagnostics. Worldwide, most patients will be treated with 21 days of high-dose trimethoprim sulfamethoxazole, although both the dose and the duration are primarily based on historical practice. Whether treatment with a lower dose is as effective and less toxic is gaining interest based on observational studies. Similarly, a 21-day tapering regimen of prednisone is used for patients with more severe disease, yet other doses, other steroids, or shorter durations of treatment with corticosteroids have not been evaluated. Now with the widespread availability of antiretroviral therapy, improved and less invasive PCP diagnostic techniques, and interest in novel treatment strategies, this review consolidates the scientific body of literature on the diagnosis and management of PCP in PWH, as well as identifies areas in need of more study and thoughtfully designed clinical trials., Competing Interests: G.B.-L., T.C.L., T.B., Z.N.S., M.S., and E.G.M. are co-investigators on a proposal for a PCP treatment platform trial for people with and without HIV. T.B. has been the principal investigator of clinical trials sponsored by Shionogi Pharmaceuticals, Atea Pharmaceuticals, and Astra Zeneca Pharmaceuticals; he is currently recruiting to a clinical trial, sponsored by Mundpharma, of rezafungin for PCP. T.B. did not contribute to the rezafungin or echinocandin sections.

We describe the case of a 51-year-old Caucasian man with a background of a cardiac and renal transplant who developed Enterocytozoon bieneusi colitis and pneumocystis jirovecii (PJP) pneumonia following treatment for suspected rejection. The patient developed methemoglobinemia which was attributed to primaquine. He was treated with intravenous methylene blue leading to clinical and biochemical resolution. We describe in detail the pathophysiological mechanism for methemoglobinemia and its treatment, in particular with methylene blue., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Introduction: Pneumocystis jirovecii pneumonia (PJP) is a rare complication of hematopoietic stem cell transplantation (HSCT). Primary prophylaxis for 6-12 months post-HSCT is the standard approach. However, there is no consensus regarding the optimal duration of prophylaxis., Methods: We identified patients who developed PJP more than 1-year post-HSCT. All patients had previously received 12 months of PJP prophylaxis. PJP was diagnosed based on clinical findings and the detection of P. jirovecii in bronchoalveolar lavage (BAL) using polymerase chain reaction (PCR). The CD4 + T-cell percentage was determined using flow cytometry. Data expressed as median (interquartile range)., Results: Ten patients developed PJP at 17.5 months (16-24 months) post-HSCT. PJP diagnosis occurred 5.5 months (3-15 months) after discontinuing prophylaxis. Eight patients received anti-thymocyte globulin (ATG) as graft versus host disease (GVHD) prophylaxis. At diagnosis, only one patient had lymphopenia; all patients had CD4 + T-lymphocyte counts ≥0.2 × 10 9 /L (median 0.337 × 10 9 /L). Three patients had concomitant bacterial infections. The clinical presentation was mild; only three required hospitalization, none of them required intensive care and there were no deaths., Conclusion: There is a need to develop risk-adapted prophylactic strategies in the contemporary era using ATG-based GVHD prophylaxis., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Accurate differentiation between Pneumocystis jirovecii (Pj) infection and colonization is crucial for effective treatment., Methods: From September 2016 to June 2022, 89 immunocompromised patients with unexplained lung infiltrates and clinical suspicion of Pj pneumonia were enrolled at Peking University People's Hospital. Bronchoalveolar lavage fluid (BALF) of these patients were detected by quantitative PCR (qPCR) and droplet digital PCR (ddPCR)., Results: The performance of ddPCR was superior to qPCR in detecting Pj infection. Area under the curve was 0.97 (95 %CI: 0.94-1) for ddPCR of the BALF in all patients. The optimal threshold value for discriminating Pj infection from colonization by ddPCR was 13.98 copies/test, with a sensitivity of 97.96 %, specificity of 85.71 %. No obvious correlation between ddPCR copy number and disease severity was observed., Conclusion: BALF ddPCR exhibits robust potential in detecting Pj and effectively discriminating colonization and infection., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023. Published by Elsevier Inc.)

Introduction and Importance: Pneumocystis jirovecii (PJP) pneumonia is a serious life-threatening condition in immunocompromised individuals and is often associated with human immunodeficiency virus (HIV) + patients. We describe a case of PJP pneumonia which provided a diagnostic challenge in a patient who presented with no known risk factors leading to a delay in initiation of appropriate antibiotic therapy., Case Presentation: A 71-year-old previously healthy white/Caucasian male presented with subacute hypoxic respiratory failure due to multifocal pneumonia with diffuse bilateral ground glass opacities with consolidations despite prior treatment with antibiotics and steroids. He was admitted and started on intravenous broad-spectrum antibiotics but continued to deteriorate, eventually requiring intubation and transfer to the ICU. Bronchoscopy revealed PJP and treatment was initiated, but the patient developed refractory shock and multiorgan failure, and ultimately died. It was later discovered that he was HIV-1 positive., Clinical Discussion: PJP, as a potential cause of his presentation, was not considered given that our patient lacked any overt risk factors for PJP pneumonia. He continued to worsen despite broad spectrum antibiotic therapy and hence bronchoscopy was pursued. His clinical profile, in hindsight, was suspicious for PJP pneumonia and early PJP-directed antibiotic therapy may have prevented a fatal outcome, as in this case. There was an element of cognitive bias across multiple providers which may have contributed to the delay in treatment despite his rapid clinical decline while on conventional pneumonia treatment protocol. His diagnosis was later evident when his BAL-DFA grew PJP in addition to his low levels of CD4 and CD8 cells. He was found to be HIV-1 positive five days after his death; there was a delay in this diagnosis since all positive HIV tests from the hospital are reported as 'pending' until the presumptive positive sample goes to the Connecticut Department of Public Health State laboratory for the confirmatory test. PJP-targeted therapies were initiated later in our patient's hospital course when the infection had progressed to refractory septic shock with multiorgan failure and eventual death., Conclusion: PJP pneumonia is a fatal disease if not recognized early in the course of illness, and the patient usually undergoes multiple antibiotic regimens before they are diagnosed and receive appropriate clinical care. The gold standard of diagnostic testing for PJP is by obtaining bronchial washings through a flexible bronchoscopy and the turnaround time for such results may take a few days to result. A significant proportion of patients may not have any overt risk factors of immunosuppression and early empiric treatment for PJP may be clinically appropriate as the delay in diagnosis may be associated with significant morbidity and mortality risk., (© 2024. The Author(s).)

Objective: Long-term steroid use increases the risk of developing Pneumocystis pneumonia (PcP), but there are limited reports on the relation of long-term steroid and PcP mortality., Methods: Retrospective multicenter study to identify risk factors for PcP mortality, including average steroid dose before the first visit for PcP in non-human immunodeficiency virus (HIV)-PcP patients. We generated receiver operating characteristic (ROC) curves for 90-day all-cause mortality and the mean daily steroid dose per unit body weight in the preceding 10 to 90 days in 10-day increments. Patients were dichotomized by 90-day mortality and propensity score-based stabilized inverse probability of treatment weighting (IPTW) adjusted covariates of age, sex, and underlying disease. Multivariate analysis with logistic regression assessed whether long-term corticosteroid use affected outcome., Results: Of 133 patients with non-HIV-PcP, 37 died within 90 days of initial diagnosis. The area under the ROC curve for 1-40 days was highest, and the optimal cutoff point of median adjunctive corticosteroid dosage was 0.34 mg/kg/day. Past steroid dose, underlying interstitial lung disease and emphysema, lower serum albumin and lower lymphocyte count, higher lactate dehydrogenase, use of therapeutic pentamidine and therapeutic high-dose steroids were all significantly associated with mortality. Underlying autoimmune disease, past immunosuppressant use, and a longer time from onset to start of treatment, were associated lower mortality. Logistic regression analysis after adjusting for age, sex, and underlying disease with IPTW revealed that steroid dose 1-40 days before the first visit for PcP (per 0.1 mg/kg/day increment, odds ratio 1.36 [95% confidence interval = 1.16-1.66], P<0.001), low lymphocyte counts, and high lactate dehydrogenase revel were independent mortality risk factor, while respiratory failure, early steroid, and sulfamethoxazole/trimethoprim for PcP treatment did not., Conclusion: A steroid dose before PcP onset was strongly associated with 90-day mortality in non-HIV-PcP patients, emphasizing the importance of appropriate prophylaxis especially in this population., Competing Interests: K.M. have received personal fees from Nippon Shinyaku Co td and AstraZeneca. N.T. have received grants and personal fees from Eli Lilly Japan, AstraZeneca, Daiichi-Sankyo Pharmaceutical, Chugai Pharmaceutical, Taiho Pharmaceutical, Pfizer Inc. Japan, Boehringer-Ingelheim Japan, and Ono Pharmaceutical; grants from Kyowa Hakko Kirin, Nippon Kayaku Co. Ltd., and Takeda Pharmaceutical Co. Ltd.; and personal fees from MSD and Bristol-Myers Squibb Company Japan outside the submitted work. None declared (S.S., R. S., J. I., G. K., T. K., T. T., K. K., T. K., Y. N., H. H., D. H., N. M.) This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2024 Miyake et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: This manuscript assesses the incidence of Pneumocystis jiroveci pneumonia (PJP) among patients receiving contemporary treatment regimens for antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and adverse events associated with PJP prophylaxis., Methods: Incident users of rituximab or cyclophosphamide for AAV were identified in the TriNetX electronic health records database from 2011 to 2022. The incidence rates (IRs) of PJP in the first 6 months of induction therapy with rituximab and/or cyclophosphamide and during postinduction maintenance therapy with rituximab were calculated. Cox proportional hazard models were used to estimate hazard ratios (HRs) and confidence intervals (CIs) for the risk of adverse events commonly associated with PJP prophylaxis., Results: We identified 1,461 AAV cases who received induction therapy with rituximab (69.7%), cyclophosphamide (18.9%), or both (11.4%). Prophylaxis prescribed within 30 days of induction included trimethoprim-sulfamethoxazole (30.7%), atovaquone (5.4%), dapsone (3.8%), and pentamidine (0.8%). During induction therapy, 10 cases of PJP were identified (IR 15.0 cases per 1,000 patient-years); no deaths occurred. In adjusted analyses, those who received prophylaxis had a higher risk of leukopenia (HR 3.1; 95% CI 1.1-8.6), rash (HR 1.9; 95% CI 1.0-3.6), and nephropathy (HR 2.6; 95% CI 1.3-5.1) than those who did not. During rituximab maintenance therapy (n = 709), five cases of PJP were identified (IR 2.1 cases per 1,000 person-years), one of whom died during the hospitalization associated with a PJP diagnosis., Conclusion: Rates of PJP in patients with AAV were lower than previously observed, and few cases occurred during rituximab maintenance therapy. PJP prophylaxis was associated with adverse events., (© 2023 American College of Rheumatology.)

Pneumocystis jirovecii pneumonia (PJP) is a potentially fatal type of pneumonitis, which may have devastating consequences. Typically, it occurs in immunocompromised patients, with the natural history varying depending on the presence or not of HIV infection. Staining and polymerase chain reaction (PCR) testing in induced sputum or bronchoalveolar lavage (BAL) is the cornerstone of the diagnosis, while trimethoprim-sulfamethoxazole is the treatment of choice. The etiological association of biologic agents with the occurrence of PJP is not entirely clear. Adalimumab is a fully human monoclonal anti-TNF-alpha antibody, which has been introduced relatively recently in the treatment of autoimmune inflammatory diseases, such as rheumatoid arthritis. In contrast to other biologic agents, such as Alemtuzumab or Infliximab, there are a small number of reports that support the drug's ability to trigger the occurrence of PJP. Hereby, we present a 53-year-old female patient with a medical history of rheumatoid arthritis on Adalimumab therapy, who developed PJP and we will discuss the main characteristics of PJP and the possible contribution of biologics to the occurrence of the infection., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)