Non-HIV-infected patients with Pneumocystis pneumonia in the intensive care unit: A bicentric, retrospective study focused on predictive factors of in-hospital mortality

Identifying optimal serum 1,3-β-D-Glucan cut-off for diagnosing Pneumocystis Jirovecii Pneumonia in non-HIV patients in the intensive care unit

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.

Elevated serum lactate dehydrogenase aids prediction of mortality in Pneumocystis jirovecii pneumonia without underlying human immunodeficiency virus infection - Derivation of a clinical risk score

Pneumocystis jirovecii pneumonia (PCP) is associated with significant mortality amongst patients without underlying human immunodeficiency virus infection (HIV). We sought to develop a risk score to predict mortality in this population. We reviewed patients with a presumed or confirmed PCP and a negative HIV test from 2006-2023. We constructed a multivariable model to identify parameters independently associated with mortality and the adjusted odds ratios were converted to weights to derive a risk score. Subsequently, we compared the performance of our score to the CURB-65 score by means of area under receiver operating characteristic curve (AUC). In total, we examined 93 patients with PCP without HIV. Mortality was 31.2%. Risk factors for mortality included older age, male sex and high serum lactate dehydrogenase levels (LDH) and C-reactive protein levels. A risk score was derived comprising age> 65 years (2 points), male sex (2 points) and LDH> 770 U/L (3 points). Our risk score (AUC 0.71, 95%CI 0.60-0.82) performed better than the CURB-65 score (AUC 0.53, 95%CI 0.41-0.66). A low-risk score of 0-1 had excellent negative predictive value for mortality (97.5%). In conclusion, a risk score comprising age, sex and LDH can predict mortality in PCP without underlying HIV and help with prognostication.

Metabolic modulation: Pneumocystis phosphoglucomutase is a target influencing host recognition

Herein, this manuscript explores the significance of the phosphoglucomutase (PGM) enzyme in Pneumocystis spp., focusing on its role in fungal surface mannoprotein formation. Through expression of the Pneumocystis murina Pmpgm2 in a Saccharomyces cerevisiae pgm2Δ strain, we demonstrate restoration of binding to the mannose receptor (MR) and macrophages to wildtype yeast levels in this complemented strain. Gas Chromatography-Mass Spectroscopy (GC-MS) confirmed reduced mannose content in the pgm2Δ yeast strain compared to the wild-type and complemented Pmpgm2 cDNA-expressing strains. This study underscores fungal PGM function in dolichol glucosyl phosphate biosynthesis, crucial for proper cell wall mannoprotein formation. Furthermore, highlighting the conservation of targetable cysteine residues across fungal pathogens, PGM inhibition maybe a potential therapeutic strategy against a broad spectrum of fungal infections.

Characterization of the Pneumocystis jirovecii and Pneumocystis murina phosphoglucomutases (Pgm2s): a potential target for Pneumocystis therapy

Pneumocystis 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 Pneumocystis. Herein, we surveyed the Pneumocystis jirovecii and Pneumocystis murina genomes, which predicted a homolog of the Saccharomyces cerevisiae major PGM enzyme. Furthermore, we show that PjPgm2p and PmPgm2p function similarly to the yeast counterpart. When both Pneumocystis pgm2 homologs are heterologously expressed in S. cerevisiae pgm2Δ cells, both genes can restore growth and sedimentation rates to wild-type levels. Additionally, we demonstrate that yeast pgm2Δ cell lysates expressing the two Pneumocystis pgm2 transcripts individually can restore PGM activities significantly altered in the yeast pgm2Δ strain. The addition of lithium, a competitive inhibitor of yeast PGM activity, significantly reduces PGM activity. Next, we tested the effects of lithium on P. murina viability ex vivo and found the compound displays significant anti-Pneumocystis activity. Finally, we demonstrate that a para-aryl derivative (ISFP10) with known inhibitory activity against the Aspergillus fumigatus PGM protein and exhibiting 50-fold selectivity over the human PGM enzyme homolog can also significantly reduce Pmpgm2 activity in vitro. Collectively, our data genetically and functionally validate phosphoglucomutases in both P. jirovecii and P. murina and suggest the potential of this protein as a selective therapeutic target for individuals with Pneumocystis pneumonia.

The Development and Evaluation of a Prediction Model for Kidney Transplant-Based Pneumocystis carinii Pneumonia Patients Based on Hematological Indicators

BACKGROUND

This study aimed to develop a simple predictive model for early identification of the risk of adverse outcomes in kidney transplant-associated Pneumocystis carinii pneumonia (PCP) patients.

METHODS

This study encompassed 103 patients diagnosed with PCP, who received treatment at our hospital between 2018 and 2023. Among these participants, 20 were categorized as suffering from severe PCP, and, regrettably, 13 among them succumbed. Through the application of machine learning techniques and multivariate logistic regression analysis, two pivotal variables were discerned and subsequently integrated into a nomogram. The efficacy of the model was assessed via receiver operating characteristic (ROC) curves and calibration curves. Additionally, decision curve analysis (DCA) and a clinical impact curve (CIC) were employed to evaluate the clinical utility of the model. The Kaplan-Meier (KM) survival curves were utilized to ascertain the model's aptitude for risk stratification.

RESULTS

Hematological markers, namely Procalcitonin (PCT) and C-reactive protein (CRP)-to-albumin ratio (CAR), were identified through machine learning and multivariate logistic regression. These variables were subsequently utilized to formulate a predictive model, presented in the form of a nomogram. The ROC curve exhibited commendable predictive accuracy in both internal validation (AUC = 0.861) and external validation (AUC = 0.896). Within a specific threshold probability range, both DCA and CIC demonstrated notable performance. Moreover, the KM survival curve further substantiated the nomogram's efficacy in risk stratification.

CONCLUSIONS

Based on hematological parameters, especially CAR and PCT, a simple nomogram was established to stratify prognostic risk in patients with renal transplant-related PCP.

Molecular Analysis of Dihydropteroate Synthase Gene Mutations in Pneumocystis jirovecii Isolates among Bulgarian Patients with Pneumocystis Pneumonia

Pneumocystis jirovecii pneumonia (PCP) is a significant cause of morbidity and mortality in immunocompromised people. The widespread use of trimethoprim-sulfamethoxazole (TMP-SMZ) for the treatment and prophylaxis of opportunistic infections (including PCP) has led to an increased selection of TMP-SMZ-resistant microorganisms. Sulfa/sulfone resistance has been demonstrated to result from specific point mutations in the DHPS gene. This study aims to investigate the presence of DHPS gene mutations among P. jirovecii isolates from Bulgarian patients with PCP. A total of 326 patients were examined via real-time PCR targeting the P. jirovecii mitochondrial large subunit rRNA gene and further at the DHPS locus. P. jirovecii DNA was detected in 50 (15.34%) specimens. A 370 bp DHPS locus fragment was successfully amplified in 21 samples from 19 PCP-positive patients, which was then purified, sequenced, and used for phylogenetic analysis. Based on the sequencing analysis, all (n = 21) P. jirovecii isolates showed DHPS genotype 1 (the wild type, with the nucleotide sequence ACA CGG CCT at codons 55, 56, and 57, respectively). In conclusion, infections caused by P. jirovecii mutants potentially resistant to sulfonamides are still rare events in Bulgaria. DHPS genotype 1 at codons 55 and 57 is the predominant P. jirovecii strain in the country.

Early application of awake extracorporeal membrane oxygenation in pneumocystis jirovecii pneumonia complicated with severe acute respiratory distress syndrome: a case report

Introduction

Patients suffering from severe acute respiratory distress syndrome (ARDS) are usually treated with mechanical ventilation. Extracorporeal membrane oxygenation (ECMO) has traditionally been considered a life-saving therapy and was reserved as a last resort when other treatment options were exhausted. However, this report outlines our successful initial experience with early implementation of awake venovenous extracorporeal membrane oxygenation (VV-ECMO) in a case of pneumocystis jirovecii pneumonia complicated by severe acute respiratory distress syndrome (ARDS), offering a promising new approach for recovery.

Case presentation

We present a case report of the effective application of awake VV-ECMO in a 29 years-old man with severe ARDS caused by pneumocystis jirovecii pneumonia. The patient initially received antibiotic treatment and non-invasive ventilation (NIV) for respiratory distress, but these interventions failed to improve the worsening dyspnea that occurred in the patient. Following the combined antifungal therapy, high-flow nasal cannula (HFNC) oxygen therapy, and VV-ECMO for a duration of 7 days, the patient's symptoms improved, showing relief.

Conclusion

Awake VV-ECMO proved to be an effective treatment for critically ill patients with ARDS, avoiding the need for invasive mechanical ventilation. However, increased clinical evidence is needed to verify whether awake ECMO could be widely used in severe ARDS caused by other diseases or conditions.

Pneumocystis jirovecii pneumonia in intensive care units: a multicenter study by ESGCIP and EFISG

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic, life-threatening disease commonly affecting immunocompromised patients. The distribution of predisposing diseases or conditions in critically ill patients admitted to intensive care unit (ICU) and subjected to diagnostic work-up for PJP has seldom been explored.

MATERIALS AND METHODS

The primary objective of the study was to describe the characteristics of ICU patients subjected to diagnostic workup for PJP. The secondary objectives were: (i) to assess demographic and clinical variables associated with PJP; (ii) to assess the performance of Pneumocystis PCR on respiratory specimens and serum BDG for the diagnosis of PJP; (iii) to describe 30-day and 90-day mortality in the study population.

RESULTS

Overall, 600 patients were included in the study, of whom 115 had presumptive/proven PJP (19.2%). Only 8.8% of ICU patients subjected to diagnostic workup for PJP had HIV infection, whereas hematological malignancy, solid tumor, inflammatory diseases, and solid organ transplants were present in 23.2%, 16.2%, 15.5%, and 10.0% of tested patients, respectively. In multivariable analysis, AIDS (odds ratio [OR] 3.31; 95% confidence interval [CI] 1.13-9.64, p = 0.029), non-Hodgkin lymphoma (OR 3.71; 95% CI 1.23-11.18, p = 0.020), vasculitis (OR 5.95; 95% CI 1.07-33.22, p = 0.042), metastatic solid tumor (OR 4.31; 95% CI 1.76-10.53, p = 0.001), and bilateral ground glass on CT scan (OR 2.19; 95% CI 1.01-4.78, p = 0.048) were associated with PJP, whereas an inverse association was observed for increasing lymphocyte cell count (OR 0.64; 95% CI 0.42-1.00, p = 0.049). For the diagnosis of PJP, higher positive predictive value (PPV) was observed when both respiratory Pneumocystis PCR and serum BDG were positive compared to individual assay positivity (72% for the combination vs. 63% for PCR and 39% for BDG). Cumulative 30-day mortality and 90-day mortality in patients with presumptive/proven PJP were 52% and 67%, respectively.

CONCLUSION

PJP in critically ill patients admitted to ICU is nowadays most encountered in non-HIV patients. Serum BDG when used in combination with respiratory Pneumocystis PCR could help improve the certainty of PJP diagnosis.

Cotrimoxazole as a Preventative Intervention for Pneumocystis Pneumonia in Pemphigus Patients Treated with Rituximab: A Retrospective Study

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) is a severe, life-threatening complication in patients treated with rituximab. However, there is no consensus on the primary prophylaxis for it in rituximab-treated pemphigus patients. Therefore, we sought to investigate the prophylactic efficacy and safety profile of cotrimoxazole for reducing the risk of developing PJP in pemphigus patients receiving rituximab.

METHODS

This single-center retrospective study investigated 148 pemphigus patients undergoing a first cycle of rituximab between 2008 and 2021 at a tertiary referral center in northern Taiwan. Patients were divided into the prophylaxis group (N = 113) and the control group (N = 35) according to whether or not cotrimoxazole was administered. The primary outcome was the 1-year incidence of PJP in the two groups, while the secondary outcome was the incidence of cotrimoxazole-related adverse events.

RESULTS

Of the 148 patients enrolled in this study, three patients, all in the control group, developed PJP during the 1-year follow-up. The incidence of PJP (8.6%) in the control group was significantly higher than that in the prophylaxis group (0%) (p = 0.012). The incidence of cotrimoxazole-related adverse events was 2.7%, and none of the cases were associated with life-threatening conditions. In addition, the cumulative prednisolone dose was associated with a trend of a higher risk of PJP (p = 0.0483).

CONCLUSIONS

Prophylactic cotrimoxazole significantly reduces the risk of PJP in a certain high-risk population and has a tolerable safety profile.

Trimethoprim/sulfamethoxazole desensitization in an HIV-positive patient with previous Stevens-Johnson syndrome; a failed study

Drug-induced Stevens-Johnson syndrome (SJS) is a rare but life-threatening hypersensitivity reaction. Drug desensitization might be considered in drug-allergic patients with no therapeutic alternative. A 29-year-old man with a recent diagnosis of HIV and HBV (CD4 count: 4 cells/mm3) who has been receiving Trimethoprim/sulfamethoxazole (TMP/SMX) for Pneumocystis pneumonia (PCP) prophylaxis was admitted at Imam Khomeini hospital complex affiliated to Tehran University of Medical Sciences, with the diagnosis of SJS due to TMP/SMX. After 45 days of supportive care, the patient was a candidate for TMP/SMX desensitization due to our region's unavailability of alternative agents. A 9-day desensitization protocol was used, but the patient complained about diarrhea with severe pain in the rectal mucosa, and macules developed over his lips again on the third day. As a result, the desensitization process immediately stopped, and after the signs and symptoms were resolved, the patient was discharged with Clindamycin tablet 600 mg TDS. Unfortunately, two weeks after discharge, the patient experienced acute kidney injury (AKI) and expired after two dialysis sessions.

Supplementary Role of Immunological Indicators in the Diagnosis and Prognosis of Pneumocystis Pneumonia in Non-HIV Immunocompromised Patients

Background

Pneumocystis pneumonia (PCP) has a high mortality in HIV-negative immunocompromised patients. The occurrence and development of PCP are believed to be correlated with the level of lymphocytes and their subsets. The aim of this study was to determine if the levels of lymphocyte subpopulations and immunoglobulin are associated with PCP.

Methods

A total of 74 immunocompromised patients were enrolled in this single-center cohort study. Diagnosis of PCP was based on the relevant pulmonary symptoms and radiological imaging, and the detection of Pneumocystis jirovecii in BAL fluid or biopsy tissue by metagenomic next-generation sequencing (mNGS). All patients were divided into two groups (PCP group and non-PCP group) and the patients in PCP group were then divided into two groupsbased on the outcome of the disease during the hospitalization.

Results

We observed a significant lower level of IgG (p=0.000) and B lymphocyte counts (p=0.017) in the PCP group comparing to that in the non-PCP group. CD4+ T cell counts, as well as the ratio of CD4+/CD8+ T cells in circulation and BAL fluid were also lower in the PCP group comparing to those in the non-PCP group. Lactate dehydrogenase (LDH) in the PCP group was significantly higher than that in the non-PCP group (p=0.029). In the PCP group, a lower level of total lymphocytes (p=0.004), T cells (p=0.001), CD4+ cells (p=0.001), and CD8+ cells (p=0.007), as well as the proportion of lymphocytes in BAL fluid (p=0.000) were found in deceased patients comparing to those in the survived group.

Conclusion

Our study revealed an important role of humoral immunity in the infection of Pneumocystis jirovecii. The level of B cells and IgG could be used as a supplement to predict the occurrence of PCP. The level of CD4+ and CD8+ lymphocytes was significantly correlated with the outcome of PCP.

Non-HIV-infected patients with Pneumocystis pneumonia in the intensive care unit: A bicentric, retrospective study focused on predictive factors of in-hospital mortality

BACKGROUND

The incidence of Pneumocystis pneumonia (PCP) among patients without human immunodeficiency virus (HIV) infection continues to increase. Here, we identified potential risk factors for in-hospital mortality among HIV-negative patients with PCP admitted to the intensive care unit (ICU).

METHODS

We retrospectively analyzed medical records of 154 non-HIV-infected PCP patients admitted to the ICU at Peking Union Medical College Hospital (PUMCH) and China-Japan Friendship Hospital (CJFH) from October 2012 to July 2020. Clinical characteristics were examined, and factors related to in-hospital mortality were analyzed.

RESULTS

A total of 154 patients were enrolled in our study. Overall, the in-hospital mortality rate was 65.6%. The univariate analysis indicated that nonsurvivors were older (58 vs. 52 years, P = 0.021), were more likely to use high-dose steroids (≥1 mg/kg/day prednisone equivalent, 39.62% vs. 55.34%, P = 0.047), receive caspofungin during hospitalization (44.6% vs. 28.3%, P = 0.049), require invasive ventilation (83.2% vs. 47.2%, P < 0.001), develop shock during hospitalization (61.4% vs. 20.8%, P < 0.001), and develop pneumomediastinum (21.8% vs. 47.2%, P = 0.001) and had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores on ICU admission (20.32 vs. 17.39, P = 0.003), lower lymphocyte counts (430 vs. 570 cells/μl, P = 0.014), and lower PaO2/FiO2 values (mmHg) on admission (108 vs. 147, P = 0.001). Multivariate analysis showed that age (odds ratio [OR] 1.03; 95% confidence interval [CI] 1.00-1.06; P = 0.024), use of high-dose steroids (≥1 mg/kg/day prednisone equivalent) during hospitalization (OR 2.29; 95% CI 1.07-4.90; P = 0.034), and a low oxygenation index on admission (OR 0.99; 95% CI 0.99-1.00; P = 0.014) were associated with in-hospital mortality.

CONCLUSIONS

The mortality rate of non-HIV-infected patients with PCP was high, and predictive factors of a poor prognosis were advanced age, use of high-dose steroids (≥1 mg/kg/day prednisone equivalent) during hospitalization, and a low oxygenation index on admission. The use of caspofungin during hospitalization might have no contribution to the prognosis of non-HIV-infected patients with PCP in the ICU.