Pneumocystis pneumonia suspected cases in 604 non-HIV and HIV patients

Description of a Murine Model of Pneumocystis Pneumonia

Pneumocystis pneumonia is a serious lung infection caused by an original ubiquitous fungus with opportunistic behavior, referred to as Pneumocystis jirovecii. P. jirovecii is the second most common fungal agent among invasive fungal infections after Candida spp. Unfortunately, there is still an inability to culture P. jirovecii in vitro, and so a great impairment to improve knowledge on the pathogenesis of Pneumocystis pneumonia. In this context, animal models have a high value to address complex interplay between Pneumocystis and the components of the host immune system. Here, we propose a protocol for a murine model of Pneumocystis pneumonia. Animals become susceptible to Pneumocystis by acquiring an immunocompromised status induced by iterative administration of steroids within drinking water. Thereafter, the experimental infection is completed by an intranasal challenge with homogenates of mouse lungs containing Pneumocystis murina. The onset of clinical signs occurs within 5 weeks following the infectious challenge and immunosuppression can then be withdrawn. At termination, lungs and bronchoalveolar lavage (BAL) fluids from infected mice are analyzed for fungal load (qPCR) and immune response (flow cytometry and biochemical assays). The model is a useful tool in studies focusing on immune responses initiated after the establishment of Pneumocystis pneumonia.

Comparison of the outcomes of Pneumocystis jirovecii pneumonia in rheumatoid arthritis patients treated with and without biologics

BACKGROUND

To investigate the outcomes of Pneumocystis jirovecii pneumonia (PCP) between patients with rheumatoid arthritis (RA) treated with and without biologics before PCP onset.

PATIENTS AND METHODS

We retrospectively included rheumatoid arthritis (RA) patients with PCP treated with and without biologics before PCP onset. The primary endpoints were 30-day and 180-day survival rates, and the secondary endpoint was severe PCP, including in-hospital death, intensive care unit admission, and requirement of respiratory support during hospitalization.

RESULTS

Eighty-two patients were enrolled in this study, including the Biologics group (n = 39) and Non-Biologics group (n = 43). There were no significantly differences in the 30-day and 180-day survival rates and severe PCP rate in the Biologics group and the Non-Biologics group before and after adjusting the patient characteristics. Kaplan-Meier survival curves for death showed no significantly differences between the Biologics and Non-Biologics groups. Cox regression hazard analysis revealed that the average daily prednisolone dose within 90 days before PCP onset was weakly associated with mortality after PCP.

CONCLUSIONS

Biologic use before PCP onset did not increase the severity and mortality of PCP compared to non-biologics use in patients with RA.

Pneumocystis pneumonia in HIV-positive and non-HIV patients: a retrospective comparative study from a lower-middle income country

In this study, we compared the predisposing factors, key demographic and clinical characteristics, clinical outcomes, and factors associated with poor prognosis in pneumocystis pneumonia (PCP) infection among the human immunodeficiency virus (HIV)-positive and non-HIV patient populations. This retrospective analysis was conducted at the Aga Khan University Hospital, Karachi, via the collection and analysis of patient records with a diagnosis of "pneumocystosis" between January 2015 and October 2020. Additionally, the laboratory database was evaluated, and patients with a laboratory-confirmed diagnosis of PCP were included. During the study period, 52 laboratory-confirmed hospitalized PCP patients were identified. Of these, 23 and 29 patients were diagnosed using microscopy and polymerase chain reaction, respectively. 34.6% of our patients were HIV positive, with a median CD4 count of 20.5 cells/mm3 (range: 10.7-50.5). Other conditions identified were corticosteroid use, autoimmune diseases, malignancy, radiation, and chemotherapy. On chest imaging, consolidation was found in 30%, ground-glass opacities in 24%, and nodular infiltrates in 20% of the cases. HIV-positive patients had a lower hemoglobin level and a higher level of β-D-glucan at the time of admission, whereas non-HIV patients were found to have more co-morbid conditions than HIV patients. We observed no difference in clinical outcomes between the two populations. Factors associated with a poor prognosis among our patients included concomitant infections at the time of diagnosis, the need for invasive mechanical ventilation, and a longer duration of stay in the hospital as well as the intensive care unit.

Adjunctive glucocorticoid therapy for Pneumocystis jirovecii pneumonia in solid organ transplant recipients: A multicenter cohort, 2015-2020

Solid organ transplant recipients (SOTRs) frequently receive adjunctive glucocorticoid therapy (AGT) for Pneumocystis jirovecii pneumonia (PJP). This multicenter cohort of SOTRs with PJP admitted to 20 transplant centers in Canada, the United States, Europe, and Australia, was examined for whether AGT was associated with a lower rate of all-cause intensive care unit (ICU) admission, 90-day death, or a composite outcome (ICU admission or death). Of 172 SOTRs with PJP (median [IQR] age: 60 (51.5-67.0) years; 58 female [33.7%]), the ICU admission and death rates were 43.4%, and 20.8%, respectively. AGT was not associated with a reduced risk of ICU admission (adjusted odds ratio [aOR] [95% CI]: 0.49 [0.21-1.12]), death (aOR [95% CI]: 0.80 [0.30-2.17]), or the composite outcome (aOR [95% CI]: 0.97 [0.71-1.31]) in the propensity score-adjusted analysis. AGT was not significantly associated with at least 1 unit of the respiratory portion of the Sequential Organ Failure Assessment score improvement by day 5 (12/37 [32.4%] vs 39/111 [35.1%]; P = .78). We did not observe significant associations between AGT and ICU admission or death in SOTRs with PJP. Our findings should prompt a reevaluation of routine AGT administration in posttransplant PJP treatment and highlight the need for interventional studies.

Global prevalence, mortality, and main characteristics of HIV-associated pneumocystosis: A systematic review and meta-analysis

The epidemiology of Human Immunodeficiency Virus (HIV)-associated pneumocystosis (HAP) is poorly described on a worldwide scale. We searched related databases between January 2000 and December 2022 for studies reporting HAP. Meta-analysis was performed using StatsDirect (version 2.7.9) and STATA (version 17) according to the random-effects model for DerSimonian and Laird method and metan and metaprop commands, respectively. Twenty-nine studies with 38554 HIV-positive, 79893 HIV-negative, and 4044 HAP populations were included. The pooled prevalence of HAP was 35.4% (95% CI 23.8 to 47.9). In contrast, the pooled prevalence of PCP among HIV-negative patients was 10.16% (95% CI 2 to 25.3). HIV-positive patients are almost 12 times more susceptible to PCP than the HIV-negative population (OR: 11.710; 95% CI: 5.420 to 25.297). The mortality among HAP patients was 52% higher than non-PCP patients (OR 1.522; 95% CI 0.959 to 2.416). HIV-positive men had a 7% higher chance rate for PCP than women (OR 1.073; 95% CI 0.674 to 1.706). Prophylactic (OR: 6.191; 95% CI: 0.945 to 40.545) and antiretroviral therapy (OR 3.356; 95% CI 0.785 to 14.349) were used in HAP patients six and three times more than HIV-positive PCP-negatives, respectively. The control and management strategies should revise and updated by health policy-makers on a worldwide scale. Finally, for better management and understanding of the epidemiology and characteristics of this coinfection, designing further studies is recommended.

Pneumocystis jirovecii pneumonia in people living with HIV: a review

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.

Pneumocystis jirovecii pneumonia mortality risk associated with preceding long-term steroid use for the underlying disease: A multicenter, retrospective cohort study

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.

The microbiome, resistome, and their co-evolution in sewage at a hospital for infectious diseases in Shanghai, China

The emergence of antibiotic-resistant bacteria (ARB) caused by the overuse of antibiotics severely threatens human health. Hospital sewage may be a key transmission hub for ARB. However, the complex link between the microbiome and resistomeresistance in hospital sewage remains unclear. In this study, metagenomic assembly and binning methods were used to investigate the microbial community, resistome, and association of antibiotic resistance genes (ARGs) with ARB in sewage from 10 representative sites (outpatient building, surgery building, internal medicine buildings [IMB1-4], staff dormitory, laboratory animal building, tuberculosis building [TBB], and hospital wastewater treatment plant) of a hospital in Shanghai from June 2021 to February 2022. A total of 252 ARG subtypes, belonging to 17 antibiotic classes, were identified. The relative abundance of KPC-2 was higher at IMBs and TBB than at other sites. Of the ARG-carrying contigs, 47.3%-62.6% were associated with mobile genetic elements, and the proportion of plasmid-associated ARGs was significantly higher than that of chromosome-associated ARGs. Although a similar microbiome composition was shared, certain bacteria were enriched at different sites. Potential pathogens Enterococcus B faecium and Klebsiella pneumoniae were primarily enriched in IMB2 and IMB4, respectively. The same ARGs were identified in diverse bacterial hosts (especially pathogenic bacteria), and accordingly, the latter possessed multiple ARGs. Furthermore, gene flow was frequently observed in the sewage of different buildings. The results provide crucial information on the characterization profiles of resistomes in hospital sewage in Shanghai.IMPORTANCEEnvironmental antibiotic resistance genes (ARGs) play a critical role in the emergence and spread of antimicrobial resistance, which poses a global health threat. Wastewater from healthcare facilities serves as a significant reservoir for ARGs. Here, we characterized the microbial community along with the resistome (comprising all antibiotic resistance genes) in wastewater from a specialized hospital for infectious diseases in Shanghai. Potential pathogenic bacteria (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus B faecium) were frequently detected in hospital wastewater and carried multiple ARGs. A complex link between microbiome and resistome was observed in the wastewater of this hospital. The monitoring of ARGs and antibiotic-resistant bacteria (ARB) in hospital wastewater might be of great significance for preventing the spread of ARB.

Pneumocystis Pneumonia After Allogeneic Hematopoietic Cell Transplantation: A Case-Control Study on Epidemiology and Risk Factors on Behalf of the Infectious Diseases Working Party of the European Society for Blood and Marrow Transplantation

Pneumocystis pneumonia (PCP) is a life-threatening complication after allogeneic hematopoietic cell transplantation (allo-HCT). However, allo-HCT procedures have evolved toward older patients, unrelated donors, and reduced-intensity conditioning, possibly modifying the risks. Polymerase chain reaction (PCR), widely used nowadays, is more sensitive than microscopy diagnostic methods. This study aimed to assess the factors associated with PCP in allo-HCT recipients within 2 years of HCT and managed according to current procedures. This multicenter, nested case-control study included PCP cases diagnosed by PCR, cytology, or immunofluorescence on bronchoalveolar lavage fluid between 2016 and 2018. Two controls per case were selected from the ProMISe registry and matched for the center, transplant date, and underlying disease. Fifty-two cases and 104 controls were included among the 5452 patients who underwent allo-HCT in the participating centers. PCP occurred at a median of 11.5 months after transplantation. The mortality rate was 24% on day 30 after the PCP diagnosis and 37% on day 90. The clinical presentation and mortality rates of the 24 patients diagnosed using only PCR were not different from those diagnosed with microscopy methods. Our study demonstrates a substantial incidence of, and mortality from, PCP, after allogeneic HCT despite well-established prophylactic approaches. In our experience, PCP nowadays occurs later after transplant than previously reported, justifying the prolongation of prophylaxis after six months in many cases. Allo-HCT recipients diagnosed with PCR as the only PCP marker should benefit from specific treatment as for other patients.

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.

Negative serum (1,3) -β-D-glucan has a low power to exclude Pneumocystis jirovecii pneumonia (PJP) in HIV-uninfected patients with positive qPCR

OBJECTIVE

The current study evaluated the diagnostic performance of serum (1,3)-beta-D Glucan (BDG) in differentiating PJP from P. jirovecii-colonization in HIV-uninfected patients with P. jirovecii PCR-positive results.

METHODS

This was a single-center retrospective study between 2019 and 2021. The diagnosis of PJP was based on the following criteria: detection of P. jirovecii in sputum or BAL specimen by qPCR or microscopy; Meet at least two of the three criteria: (1) have respiratory symptoms of cough and/or dyspnea, hypoxia; (2) typical radiological picture findings; (3) receiving a complete PJP treatment. After exclusion, the participants were divided into derivation and validation cohorts. The derivation cohort defined the cut-off value of serum BDG. Then, it was verified using the validation cohort.

RESULTS

Two hundred and thirteen HIV-uninfected patients were enrolled, with 159 PJP and 54 P. jirovecii-colonized patients. BDG had outstanding specificity, LR, and PPV for PJP in both the derivation (90.00%, 8.900, and 96.43%) and the validation (91.67%, 9.176, and 96.30%) cohorts at ≥ 117.7 pg/mL. However, it had lower sensitivity and NPV in the derivation cohort (89.01% and 72.97%), which was even lower in the validation cohort (76.47% and 57.89%). Of note, BDG ≥ 117.7 pg/mL has insufficient diagnostic efficacy for PJP in patients with lung cancer, interstitial lung disease (ILD) and nephrotic syndrome. And although lymphocytes, B cells, and CD4+ T cells in PJP patients were significantly lower than those in P. jirovecii-colonized patients, the number and proportion of peripheral blood lymphocytes did not affect the diagnostic efficacy of serum BDG.

CONCLUSIONS

Serum BDG ≥ 117.7 pg/mL could effectively distinguish P. jirovecii-colonization from infection in qPCR-positive HIV-uninfected patients with infectious diseases, solid tumors (excluding lung cancer), autoimmune or inflammatory disorders, and hematological malignancies. Of note, for patients with lung cancer, ILD, and nephrotic diseases, PJP should be cautiously excluded at BDG < 117.7 pg/mL.

Machine Learning Models for Prediction of Severe Pneumocystis carinii Pneumonia after Kidney Transplantation: A Single-Center Retrospective Study

BACKGROUND

The objective of this study was to formulate and validate a prognostic model for postoperative severe Pneumocystis carinii pneumonia (SPCP) in kidney transplant recipients utilizing machine learning algorithms, and to compare the performance of various models.

METHODS

Clinical manifestations and laboratory test results upon admission were gathered as variables for 88 patients who experienced PCP following kidney transplantation. The most discriminative variables were identified, and subsequently, Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF), K-Nearest Neighbor (KNN), Light Gradient Boosting Machine (LGBM), and eXtreme Gradient Boosting (XGB) models were constructed. Finally, the models' predictive capabilities were assessed through ROC curves, sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and F1-scores. The Shapley additive explanations (SHAP) algorithm was employed to elucidate the contributions of the most effective model's variables.

RESULTS

Through lasso regression, five features-hemoglobin (Hb), Procalcitonin (PCT), C-reactive protein (CRP), progressive dyspnea, and Albumin (ALB)-were identified, and six machine learning models were developed using these variables after evaluating their correlation and multicollinearity. In the validation cohort, the RF model demonstrated the highest AUC (0.920 (0.810-1.000), F1-Score (0.8), accuracy (0.885), sensitivity (0.818), PPV (0.667), and NPV (0.913) among the six models, while the XGB and KNN models exhibited the highest specificity (0.909) among the six models. Notably, CRP exerted a significant influence on the models, as revealed by SHAP and feature importance rankings.

CONCLUSIONS

Machine learning algorithms offer a viable approach for constructing prognostic models to predict the development of severe disease following PCP in kidney transplant recipients, with potential practical applications.

Trends in the Epidemiology of Pneumocystis Pneumonia in Immunocompromised Patients without HIV Infection

The increasing morbidity and mortality of life-threatening Pneumocystis pneumonia (PCP) in immunocompromised people poses a global concern, prompting the World Health Organization to list it as one of the 19 priority invasive fungal diseases, calling for increased research and public health action. In response to this initiative, we provide this review on the epidemiology of PCP in non-HIV patients with various immunodeficient conditions, including the use of immunosuppressive agents, cancer therapies, solid organ and stem cell transplantation, autoimmune and inflammatory diseases, inherited or primary immunodeficiencies, and COVID-19. Special attention is given to the molecular epidemiology of PCP outbreaks in solid organ transplant recipients; the risk of PCP associated with the increasing use of immunodepleting monoclonal antibodies and a wide range of genetic defects causing primary immunodeficiency; the trend of concurrent infection of PCP in COVID-19; the prevalence of colonization; and the rising evidence supporting de novo infection rather than reactivation of latent infection in the pathogenesis of PCP. Additionally, we provide a concise discussion of the varying effects of different immunodeficient conditions on distinct components of the immune system. The objective of this review is to increase awareness and knowledge of PCP in non-HIV patients, thereby improving the early identification and treatment of patients susceptible to PCP.

Detection of Opportunistic Fungi from the Bronchoalveolar Lavage Specimens of Patients with Pulmonary Diseases

Background

Opportunistic fungi are a constantly evolving group of pathogens that become active when the immune system is compromised, begin to multiply, and soon overwhelm the weakened immune system. This study was performed to evaluate the number of opportunistic fungi in bronchoalveolar lavage (BAL) samples of patients with pulmonary diseases.

Materials and Methods

After receiving patients' consent and demographic forms, a total of 120 BAL samples were taken by a pulmonary physician. The etiologic agents were identified by standard morphological and molecular methods. Yeast cells were counted on culture media, and direct smears were precisely examined for the presence of yeasts elements, Pneumocystis, and filamentous fungi.

Results

In this study, 29 (24.1%) patients showed positive direct smears for yeast elements in their BAL samples. The mean colony count of yeasts was 42,000 (CFU/mL) on culture media. Six (5%) species of filamentous fungi, including three (2.5%) isolates of Penicillium species (P. variabile, P. glabrum, and P. thomii), two (1.67%) Aspergillus species (A. flavus and A. fumigatus), 1 case (0.83%) Pseudallescheria boydii were detected. Seven cases (5.83%) of Pneumocystis cysts were observed in the direct smears stained with Giemsa. Identification of all fungi confirmed by molecular or sequencing methods.

Conclusions

Due to the presence of a large number of fungi in the BAL samples and possible physical interference with the selected drugs for treatment, we draw the attention of pulmonologists to this important issue. Rapid diagnosis of fungal infections is essential to optimize treatments and outcomes.

How to diagnose and treat a non-HIV patient with Pneumocystis jirovecii pneumonia (PCP)?

BACKGROUND

Pneumocystis jirovecii Pneumonia (PCP) incidence is increasing in non-HIV infected patients. In contrast to PCP in patients infected with HIV, diagnosis is often delayed, and illness is associated with an increased mortality.

OBJECTIVE

To provide a comprehensive review of clinical presentation, risk factors, diagnostic strategies, and treatment options of PCP in non-HIV-infected patients.

SOURCES

Web-based literature review on PCP for trials, meta-analyses and systematic reviews using PubMed. Restriction to English language was applied.

CONTENT

Common underlying conditions in non-HIV-infected patients with PCP are haematological malignancies, autoimmune and inflammatory diseases, solid organ or haematopoietic stem cell transplant and prior exposure to corticosteroids. New risk groups include patients receiving monoclonal antibodies and immunomodulating therapies. Non-HIV-infected patients with PCP present with rapid onset and progression of pneumonia, increased duration of hospitalization and a significantly higher mortality rate than patients infected with HIV. PCP is diagnosed by a combination of clinical symptoms, radiological and mycological features. Immunofluorescence microscopy from bronchoalveolar lavage (BAL) or PCR testing CT imaging and evaluation of the clinical presentation are required. The established treatment regime consists of trimethoprim and sulfamethoxazole.

IMPLICATIONS

While the number of patients immunosuppressed for other causes than HIV is increasing, a simultaneous rise in PCP incidence is observed. In the group of non-HIV-infected patients, a rapid onset of symptoms, a more complex course, and a higher mortality rate are recorded. Therefore, time to diagnosis must be as short as possible to initiate effective therapy promptly. This review aims to raise awareness of PCP in an increasingly affected at-risk group and provide clinicians with a practical guide for efficient diagnosis and targeted therapy. Furthermore, it intends to display current inadequacies in research on the topic of PCP.

Clinical features and diagnostic value of metagenomic next -generation sequencing in five cases of non-HIV related Pneumocystis jirovecii pneumonia in children

Background

Pneumocystis jirovecii (PJ) is an opportunistic pathogenic fungus, and PJ pneumonia (PJP) is a commonly problem in HIV-positive patients. While PJP is not caused by HIV, it generally advances rapidly and can quickly lead to severe respiratory failure. To improve pediatricians’ understanding of the condition and aid early accurate diagnoses and therapy, we examined the clinical characteristics of five instances of non-HIV related PJP (NH-PJP) in children and the efficacy of metagenomic next-generation sequencing (mNGS) in its diagnosis.

Methods

From January 2020 to June 2022, five children with NH-PJP were admitted to the PICU of the First Affiliated Hospital of Zhengzhou University. We retrospectively summarize the clinical presentation, previous histories, routine laboratory findings, treatment, outcome of regression, and results of mNGS in these five children.

Results

Five male children between the ages of 11 months and 14 years had an acute onset on NH-PJP, three of the children had chest tightness after activity, shortness of breath and paroxysmal dry cough, — and two had high fever and dry cough. All five of the children had several flocculent high-density pictures in both lungs at the beginning of the disease, and lung auscultation revealed coarse breath sounds in both lungs, one of which was accompanied by a modest quantity of dry rales. PJ nuclear sequences were found in one patient and four patients’ blood and alveolar lavage fluid. All five children were treated with Trimethoprim-sulfamethoxazole (TMP-SMX) in combination with Caspofungin and corresponding symptomatic treatment. Four patients were cured and one patient died.

Conclusion

Children commonly encounter an initial exposure to NH-PJP, which manifests as a high fever, dry cough, chest discomfort, dyspnea that worsens over time, fast disease progression, and a high death rate. The clinical presentation of children with PJ infection should be taken into consideration along with the results for diagnose. mNGS has higher sensitivity and a shorter detection period compared to identification of PJP.

Detection of Pneumocystis jirovecii by PCR in patients with lung cancer: A preliminary study

INTRODUCTION

Infection complications in lung cancer (LC), one of the most common cancers in the world, are still among the most important causes of death. Of them, P. jirovecii, which is as an opportunistic infection, causes a life-threatening type of pneumonia in cancer patients. This preliminary study aimed to determine the incidence and clinical status of P. jirovecii by PCR in lung cancer patients compared to the conventional method.

MATERIAL AND METHODS

Sixty-nine lung cancer patients and fSorty healthy individuals were included in the study. After sociodemographical and clinical features were recorded, sputum samples were collected from attenders. Firstly, microscopic examination was made with Gomori's methenamine silver stain and then PCR was performed.

RESULTS

P. jirovecii was detected in three of 69 lung cancer patients by PCR (4.3%), but not by microscopy. However, healthy individuals were negative for P. jirovecii by both methods. Based on clinical and radiological findings, P. jirovecii was evaluated as probable infection in one patient and colonization in the other two patients. Although PCR is more sensitive than conventional staining methods, it cannot distinguish probable and proven infections from pulmonary colonization.

DISCUSSION

It is important to evaluate the decision of infection together with laboratory, clinical and radiological findings. Moreover, PCR may enable to know the colonization and to take precautions such as prophylaxis, due to the risk of colonization turning into an infection in immunocompromised patient groups. Further studies involving larger populations and evaluating the colonization-infection relationship in patients with solid tumors are needed.

Targeting β-glucans, vital components of the Pneumocystis cell wall

β-glucan is the most abundant polysaccharide in the cell wall of Pneumocystis jirovecii, which has attracted extensive attention because of its unique immunobiological characteristics. β-glucan binds to various cell surface receptors, which produces an inflammatory response and accounts for its immune effects. A deeper comprehension of the processes by Pneumocystis β-glucan recognizes its receptors, activates related signaling pathways, and regulates immunity as required. Such understanding will provide a basis for developing new therapies against Pneumocystis. Herein, we briefly review the structural composition of β-glucans as a vital component of the Pneumocystis cell wall, the host immunity mediated by β-glucans after their recognition, and discuss opportunities for the development of new strategies to combat Pneumocystis.

Emerging and re-emerging fungal threats in Africa

The emergence of deadly fungal infections in Africa is primarily driven by a disproportionately high burden of human immunodeficiency virus (HIV) infections, lack of access to quality health care, and the unavailability of effective antifungal drugs. Immunocompromised people in Africa are therefore at high risk of infection from opportunistic fungal pathogens such as Cryptococcus neoformans and Pneumocystis jirovecii, which are associated with high morbidity, mortality, and related socioeconomic impacts. Other emerging fungal threats include Emergomyces spp., Histoplasma spp., Blastomyces spp., and healthcare-associated multi-drug resistant Candida auris. Socioeconomic development and the Covid-19 pandemic may influence shifts in epidemiology of invasive fungal diseases on the continent. This review discusses the epidemiology, clinical manifestations, and current management strategies available for these emerging fungal diseases in Africa. We also discuss gaps in knowledge, policy, and research to inform future efforts at managing these fungal threats.

Prognostic Analysis of Pneumocystis Jirovecii Pneumonia in Interstitial Lung Disease Patients: A Retrospective Clinical Study

(1) Background: The clinical characteristics and the prognostic factors of HIV-negative Pneumocystis jirovecii pneumonia (PJP) patients (non-HIV-PJP) with interstitial lung disease (ILD) remain unclear. Our objectives were to describe the clinical characteristics and to explore the prognostic factors of non-HIV-ILD-PJP patients. (2) Methods: The enrolled patients in this retrospective study were stratified based on the presence or absence of ILD and fibrotic ILD (FILD). The log-rank test and Cox regression models were used to analyze the prognostic factors. (3) Results: Among 378 non-HIV-PJP patients, there were 133 patients with ILD-PJP, and 70 patients were classified as having FILD-PJP. The all-cause mortality rate for the ILD-PJP group is higher than that of the ILD-PJP group (57.9% vs. 38.4%, p < 0.001). However, the all-cause mortality is similar between the FILD-PJP group and non-FILD-PJP group. Preexisting ILD (HR: 2.156, p = 0.003) and honeycomb appearance on the chest HRCT (HR = 16.3, p < 0.001) are independent survival risk factors for ILD-PJP. Non-invasive ventilation is an independent survival risk factor for ILD-PJP patients (HR = 928.56, p < 0.01) and FILD-PJP patients (HR = 33.86, p < 0.001). (4) Conclusions: Pre-existing ILD and honeycomb appearance on the chest HRCT are independent survival risk factors for PJP patients. Non-invasive ventilation is associated with poor survival for both ILD-PJP and FILD-PJP patients.

Risk factors of in-hospital mortality in patients with pneumocystis pneumonia diagnosed by metagenomics next-generation sequencing

Objectives

The metagenomic next-generation sequencing (mNGS) test is useful for rapid and accurate detection and identification of pathogenic microorganisms. The aim of the present study was to investigate the factors associated with in-hospital mortality in pneumocystis pneumonia (PCP) patients with mNGS-assisted diagnosis.

Methods

Our study enrolled 154 patients with mNGS-positive PCP from August 2018 to February 2022 at the First Affiliated Hospital of Zhengzhou University respectively. Patients were divided into the survivor group (n=98) and the death group (n=56) according to whether in-hospital death occurred. Baseline characteristics, patients’ pre-hospital symptoms and patients’ CT imaging performance during hospitalization were carefully compared between the two groups. Risk factors for the occurrence of in-hospital death were sought by selecting indicators that were significantly different between the two groups for modelling and performing multiple logistic regression analysis.

Results

Compared with the in-hospital death patients, the survivors were younger and had higher levels of albumin (ALB) (age: 50.29 ± 14.63 years vs 59.39 ± 12.27 years, p<0.001; ALB: 32.24 ± 5.62 g/L vs 29.34 ± 5.42g/L, p=0.002; respectively), while the levels of lactate dehydrogenase (LDH) and C-reactive protein CRP were lower (LDH: 574.67 ± 421.24 U/L vs 960.80 ± 714.94 U/L, p=0.001; CRP: 54.97 ± 55.92 mg/L vs80.45 ± 73.26 mg/L, p=0.018; respectively). Multiple logistic regression analysis revealed that age, the baseline LDH and CRP levels were all positively associated with high in-hospital mortality [age: OR(95%CI): 1.115 (1.062-1.172), p<0.001; LDH: OR(95%CI): 1.002 (1.001-1.003), p<0.001; CRP: OR(95%CI): 1.008 (1.000-1.017), p=0.045; respectively] while the platelet counts was negatively associated with it [OR(95%CI): 0.986 (0.979-0.992), p<0.001].

Conclusions

Old age, high baseline levels of LDH and CRP and low platelet counts were risk factors of the in-hospital mortality in mNGS positive PCP patients.

Exploring the Differences in Pneumocystis Pneumonia Infection Between HIV and Non-HIV Patients

Pneumocystis pneumonia (PCP) is one of the most common opportunistic infections worldwide that affects the lung. Pneumocystis leads to pneumonia, caused by Pneumocystis jirovecii, formerly known as Pneumocystis carinii. In recent decades, PCP has been a major health problem for human immunodeficiency virus (HIV) patients and is responsible for most of mortality and morbidity. However, the increasing number of immunosuppressive-related diseases has led to outbreaks in other patient populations, raising the concern for PCP as it becomes a major concern among those patients. These changes led to marked changes in the prevalence and mortality rates of PCP. Huge variations in those parameters among HIV and non-HIV patients have been seen also. Historically, the diagnosis was made by staining and direct visualization of the organism within the bronchoalveolar lavage (BAL) fluid. The diagnosis is now made by microscopic examination and a real-time polymerase chain reaction (PCR) of BAL. Serum (1,3)-β-D-glucan, which is a component of the Pneumocystis jirovecii cell wall that distinguishes it from other fungi, has become an important diagnostic tool. Early diagnosis and treatment play a vital role in the patient’s survival and in the infection outcome; hence, empirical PCP therapy should be started immediately when the infection is suspected without waiting for the results of the diagnostic test. Steroids play an important role in the treatment of HIV patients, especially patients who present with hypoxia and respiratory failure. Prophylaxis is very effective and should be given to all patients at high risk of PCP. Antiretroviral therapy (ART) should be started as soon as possible in newly diagnosed HIV-infected patients with PCP, and the immune status of immunocompromised patients with PCP should be improved by temporarily withholding immunosuppressive drugs or reducing their doses.

Metagenomic Next-Generation Sequencing Is Highly Efficient in Diagnosing Pneumocystis Jirovecii Pneumonia in the Immunocompromised Patients

Purposes

To explore the value of metagenomic next-generation sequencing (mNGS) in diagnosing pneumocystis jiroveciipneumonia (PJP) in the immunocompromised patients.

Methods

Data of 122 patients with PJP in an immunosuppressed state and 67 non-PJP patients were collected. The diagnostic efficacy of mNGS was compared with the conventional methods, including Gomori methenamine silver (GMS) staining and serum (1,3)-β-D-glucan (BDG). Changes of anti-microbial therapy for patients with PJP based on mNGS results were also reviewed.

Results

The diagnostic sensitivity of mNGS to PJP was higher than that of GMS and BDG (100% vs. 15 and 74.5%, p < 0.001). The diagnostic specificity (91.%) was lower than that of GMS (100%), and similar with BDG (89.6%). In addition to P. jirovecii, mNGS revealed co-pathogens like human β-herpesvirus 5, human γ-pesvirus 4, and some other opportunistic pathogens. The reads of mNGS were remarkably higher in BALF than in blood samples. Initial antimicrobial treatment was modified in 89.3% patients based on the mNGS results, and 74 cases (60.7%) were treated with anti-P. jirovecii therapy.

Conclusion

mNGS is highly efficient in diagnosing PJP and good at identifying pathogens in mixed infections.

Analysis of lncRNA and mRNA Repertoires in Lung From BAFF-R-Deficient Pneumocystis-Infected Mice

Background

Pneumocystis pneumonia (PCP) is a common medical issue in immunosuppressive patients. Increasing evidence supports that B cells may play an essential role in PCP individuals. The present study aims to integrate lncRNA and mRNA expression profiles and further investigate the molecular function of mature B cells in PCP.

Methods

The lung tissue of wild-type (WT) mice and B-cell-activating factor receptor–deficient (mature B-cell deficiency, BAFF-R–/–) mice were harvested at 3 weeks after being infected with pneumocystis. After total RNAs were extracted, transcriptome profiling was performed following the Illumina HiSeq 3000 protocol. lncRNA-targeted miRNA pairs were predicted using the online databases. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment pathways were analyzed to functionally annotate these differentially expressed genes. Additionally, the immune-related lncRNA–miRNA–mRNA–ceRNA network was subsequently performed. The quantitative real-time PCR (RT-PCR) analysis was conducted to evaluate the lncRNA and mRNA expression profiles in WT-PCP mice and BAFF-R–/– PCP mice.

Results

Compared with the control group, 166 mRNAs were observed to be aberrantly expressed (fold change value ≥2; P &lt;0.05) in the BAFF-R–/– PCP group, including 39 upregulated and 127 downregulated genes, while there were 69 lncRNAs differently expressed in the BAFF-R–/– PCP group, including 15 upregulated and 54 downregulated genes. In addition, GO and KEGG pathway analyses showed that BAFF-R deficiency played an important role in the primary and adaptive immune responses in PCP. Furthermore, the lncRNA and mRNA co-expression network was established. We noted that the core network of lncRNA-TF (transcription factor) pairs could be classified into the categories including infection and immunity pathways.

Conclusion

In summary, in this study, we further explored the role of mature B cells in the pathogenesis and progression of PCP and the data demonstrated that BAFF-R deficiency could play a significant role in immune regulation in the PCP population.

Efficacy of Trimethoprim–Sulfamethoxazole in Combination with an Echinocandin as a First-Line Treatment Option for Pneumocystis Pneumonia: A Systematic Review and Meta-Analysis

Although combination therapy using trimethoprim–sulfamethoxazole (TMP–SMX) plus echinocandins has been reported to reduce the mortality of patients with pneumocystis pneumonia (PCP), it remains unclear whether it is more effective than TMP–SMX monotherapy, the current first-line treatment for this disease. Hence, we performed a systematic review and meta-analysis to compare the efficacies of these treatment options for PCP. The Scopus, EMBASE, PubMed, CINAHL, and Ichushi databases were searched for studies (up to January 2022) reporting the mortality and positive response rates (fewer clinical symptoms, improved partial pressure of arterial oxygen, and resolution of pneumonitis on chest imaging) of PCP patients receiving monotherapy or combination therapy. Four studies met the inclusion criteria. All four presented mortality data and one had positive response rates. Compared with the monotherapy, the combination therapy resulted in significantly lower mortality and higher positive response rates (mortality: odds ratio (OR) 2.20, 95% confidence interval (CI) 1.46–3.31; positive response rate: OR 2.13, 95%CI 1.41–3.23), suggesting it to be an effective and promising first-line therapy for PCP. However, further safety evaluations are needed to establish this as a fact.

Treatment of Pneumocystis jirovecii pneumonia in non-human immunodeficiency virus-infected patients using a combination of trimethoprim-sulfamethoxazole and caspofungin

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an infectious disease common in immunocompromised hosts. However, the currently, the clinical characteristics of non-HIV patients with PJP infection have not been fully elucidated.

AIM

To explore efficacy of trimethoprim–sulfamethoxazole (TMP-SMX) and caspofungin for treatment of non-human immunodeficiency virus (HIV)-infected PJP patients.

METHODS

A retrospective study enrolled 22 patients with non-HIV-infected PJP treated with TMP-SMX and caspofungin from 2019 to 2021. Clinical manifestations, treatment and prognosis of the patients were analyzed.

RESULTS

Five patients presented with comorbidity of autoimmune diseases, seven with lung cancer, four with lymphoma, two with organ transplantation and four with membranous nephropathy associated with use of immunosuppressive agents. The main clinical manifestations of patients were fever, dry cough, and progressive dyspnea. All patients presented with acute onset and respiratory failure. The most common imaging manifestation was ground glass opacity around the hilar, mainly in the upper lobe. All patients were diagnosed using next-generation sequencing, and were treated with a combination of TMP-SMX and caspofungin. Among them, 17 patients received short-term adjuvant glucocorticoid therapy. All patients recovered well and were discharged from hospital.

CONCLUSION

Non-HIV-infected PJP have rapid disease progression, high risk of respiratory failure, and high mortality. Combination of TMP-SMX and caspofungin can effectively treat severe non-HIV-infected PJP patients with respiratory failure.

Trends in the Epidemiology and Outcomes of Pneumocystis Pneumonia among Human Immunodeficiency Virus (HIV) Hospitalizations

Introduction: Pneumocystis Pneumonia (PCP) is a common opportunistic infection among people living with the human immunodeficiency virus (HIV). This study’s objective was to assess temporal trends in PCP epidemiology among hospitalized patients with HIV/AIDS in the US and to compare data for hospitalizations with HIV with PCP to those without PCP. Methods: The national inpatient sample (NIS) data were analyzed from 2002−2014. The discharge coding identified hospitalized patients with HIV or AIDS and with or without PCP. Results: We identified 3,011,725 hospitalizations with HIV/AIDS during the study period; PCP was present in 5% of the patients with a diagnosis of HIV. The rates of PCP progressively declined from 6.7% in 2002 to 3.5 % in 2014 (p < 0.001). Overall mortality in patients with HIV was 3.3% and was significantly higher in those with PCP than without PCP (9.9% vs. 2.9%; p < 0.001). After adjusting for demographics and other comorbidities, PCP had higher odds of hospital mortality 3.082 (OR 3.082; 95% CI, 3.007 to 3.159; p < 0.001). Conclusion: From 2002 to 2014, the rate of PCP in HIV patients has decreased significantly in the United States but is associated with substantially higher mortality.

Pneumocystis Pneumonia: Pitfalls and Hindrances to Establishing a Reliable Animal Model

Pneumocystis pneumonia is a severe lung infection that occurs primarily in largely immunocompromised patients. Few treatment options exist, and the mortality rate remains substantial. To develop new strategies in the fields of diagnosis and treatment, it appears to be critical to improve the scientific knowledge about the biology of the Pneumocystis agent and the course of the disease. In the absence of in vitro continuous culture system, in vivo animal studies represent a crucial cornerstone for addressing Pneumocystis pneumonia in laboratories. Here, we provide an overview of the animal models of Pneumocystis pneumonia that were reported in the literature over the last 60 years. Overall, this review highlights the great heterogeneity of the variables studied: the choice of the host species and its genetics, the different immunosuppressive regimens to render an animal susceptible, the experimental challenge, and the different validation methods of the model. With this work, the investigator will have the keys to choose pivotal experimental parameters and major technical features that are assumed to likely influence the results according to the question asked. As an example, we propose an animal model to explore the immune response during Pneumocystis pneumonia.

Beta-D-Glucan in Patients with Haematological Malignancies

(1-3)-beta-D-glucan (BDG) is an almost panfungal marker (absent in zygomycetes and most cryptococci), which can be successfully used in screening and diagnostic testing in patients with haematological malignancies if its advantages and limitations are known. The aim of this review is to report the data, particularly from the last 5 years, on the use of BDG in haematological population. Published data report mainly on the performance of the Fungitell™ assay, although several others are currently available, and they vary in method and cut-off of positivity. The sensitivity of BDG for invasive fungal disease (IFD) in haematology patients seems lower than in other populations, possibly because of the type of IFD (lower sensitivity was found in case of aspergillosis compared to candidiasis and pneumocystosis) or the use of prophylaxis. The specificity of the test can be improved by using two consecutive positive assays and avoiding testing in the case of the concomitant presence of factors associated with false positive results. BDG should be used in combination with clinical assessment and other diagnostic tests, both radiological and mycological, to provide maximum information. Good performance of BDG in cerebrospinal fluid (CSF) has been reported. BDG is a useful diagnostic method in haematology patients, particularly for pneumocystosis or initial diagnosis of invasive fungal infections.

Primary prophylaxis for Pneumocystis jirovecii pneumonia in patients receiving rituximab

BACKGROUND

Although previous studies suggested that rituximab increases the risk of Pneumocystis jirovecii pneumonia (PJP), it is uncertain whether its primary prophylaxis for PJP is justified.

RESEARCH QUESTION

Does the benefit of primary prophylaxis for PJP in patients receiving rituximab treatment outweigh the potential risk of the prophylaxis?

STUDY DESIGN AND METHODS

This retrospective study included 3524 patients (hematologic diseases=2500; rheumatic diseases=559; pre/post-solid organ transplantation=465) first exposed to rituximab between 2002 and 2018 in a tertiary referral center in South Korea. Patients were classified into a control group (n=2523) and a prophylaxis group (n=1001) according to the administration of prophylactic TMP-SMX during the first 28 days after the start of rituximab (intention-to-treat analysis). In addition, exposure to TMP-SMX was examined as a time-varying variable (time-varying analysis). Primary outcome was the prophylactic effect of TMP-SMX on the 1-year incidence of PJP. Inverse probability of treatment weights was applied to minimize the baseline imbalance. Secondary outcome included the incidence of adverse drug reactions (ADRs) related to TMP-SMX.

RESULTS

Over 2759.9 person-years, 92 PJP infections occurred, with a mortality rate of 27.2%. The prophylaxis group showed a significantly lower incidence of PJP (adjusted sub-distribution hazard ratio (aSHR), 0.20 [95% CI, 0.10-0.42]) than the control group. This result was consistent with the results of time-varying analysis, in which only one PJP infection occurred during TMP-SMX administration (aSHR, 0.01 [0.003-0.16]). The incidence of adverse drug reactions (ADRs) related to TMP-SMX was 18.1 (14.6-22.2)/100 person-years, and most were of mild-to-moderate severity. Based on ten severe ADRs, the number needed to harm was 101 (61.9-261.1), whereas the number needed to prevent one PJP infection was 32 (24.8-39.4).

INTERPRETATION

TMP-SMX prophylaxis significantly reduces PJP incidence with a tolerable safety profile in patients receiving rituximab treatment.

A novel droplet digital polymerase chain reaction for diagnosis of Pneumocystis pneumonia (PCP)-a clinical performance study and survey of sulfamethoxazole-trimethoprim resistant mutations

Objectives To determine the performance of droplet digital polymerase chain reaction (ddPCR) assays in diagnosing Pneumocystis pneumonia (PCP), and to survey the sulfamethoxazole-trimethoprim (SMX-TMP) resistant mutations in our PCP cohort. Methods A prospective study was conducted from January 2017 to June 2018. Adult immunocompromised subjects with pneumonia were enrolled. Bronchoalveolar lavage fluid samples were obtained for standard microscopic testing and ddPCR to quantify the Pneumocystis MSG gene. DHPS and DHFR gene sequencings were performed to detect SMX-TMP resistance. Results Of 54 subjects, 12 had definite PCP, 7 had probable PCP, and 35 were non-PCP. In the PCP cohort, 10 (53%) had HIV infections. Using a cutoff value of ≥ 1.94 copies/µL, the ddPCR exhibited an overall sensitivity of 91.7% (61.5-99.8%) and specificity of 88.1% (74.4-96%). It showed a better performance when different cutoff values were used in subjects with HIV (≥ 1.80 copies/µL) and non-HIV (≥ 4.5 copies/µL). ROC curves demonstrated an AUC of 0.80 (95% CI, 0.56-1.0) for the HIV group, and 0.99 (95% CI, 0.95-1.0) for the non-HIV group. Of 16 PCP samples tested for DHPS- and DHFR-mutations, only DHPS mutations were detected (2). Most of the subjects, including those with DHPS mutations, demonstrated favorable outcomes. Conclusions The ddPCR exhibited a satisfactory diagnostic performance for PCP. Based on very limited data, the treatment outcomes of PCP did not seem to be affected by the DHPS mutations.

The mycological and molecular study of Pneumocystis jiroveci pneumonia among HIV and non-HIV immunocompromised patients hospitalized in pulmonary units in Guilan, Northern Iran

Background and Objectives

Pneumocystis jirovecii pneumonia (PJP) is a serious infection that usually affects those with a weak immune system. Since the prevalence of this infection in Iran and in the world is not clearly defined, the present study aimed to evaluate the incidence, clinical spectrum, and demographic characteristics of PJP among HIV and non-HIV immunocompromised patients.

Materials and Methods

Bronchoalveolar Lavage (BAL) specimens were obtained from 3 groups of immunocompromised patients, including acquired immunodeficiency syndrome (AIDS) patients, diabetic patients, and patients receiving immunosuppressive therapies. All were hospitalized in pulmonary units. The specimens were examined using microscopic methods (Giemsa and calcofluor white staining) and the nested-PCR technique based on mtLSU-rRNA gene.

Results

A total of 120 BAL samples were collected. From 12.5% (5 from 40) of HIV-infected patients, 5% (2 from 40) of patients receiving immunosuppressive therapies, and 2.5% (1 from 40) of diabetic patients Pneumocystis jiroveci was isolated. There was not any association between the prevalence of PJP and the patient's gender (p= 0.557) and age (p= 0.681). Fever and dyspnea (n=7, 87.5%), nonproductive cough and abnormal auscultation sound (n=5, 62.5%), and also chills and weight loss (n=2, 25%) were the documented clinical symptoms of PJP. Also, the results showed that none of the samples had positive results for P. jiroveci with microscopic tests while using the nested-PCR method 8 samples had positive results.

Conclusion

Since PJP often causes symptoms that are similar to other illnesses, such as the flu or tuberculosis, clinical and laboratory findings should be used simultaneously for making the final decision on drug administration.

Pneumocystis jiroveci pneumonia with cytomegalovirus infection diagnosed by metagenomic next-generation sequencing in a patient with nephrotic syndrome: A case report

INTRODUCTION

Opportunistic infection with multiple pathogens currently has become less uncommon since the application of immunosuppressant or corticosteroid in non- Human immunodeficiency virus patients. However, the clinical diagnosis of the co-infection remains difficult since the uncertainty and deficiency of the microbiologic testing methods.

PATIENT CONCERNS

A 66-year-old male patient was admitted to our hospital with chest stuffiness, shortness of breath and elevated body temperature.

DIAGNOSIS

He was diagnosed with the co-infection of Pneumocystis jiroveci and cytomegalovirus by metagenomic next-generation sequencing of bronchoalveolar lavage fluid after bronchoscopy.

INTERVENTIONS

The patient was empirically treated with broad-spectrum antibiotics, trimethoprim/ sulfamethoxazole and ganciclovir in the beginning of the admission.

OUTCOMES

The condition of this patient was not improved even with the intervention at the early stage of the disease. His family requested discharge after 24 inpatient days.

LESSONS

This case highlights the application of metagenomic next-generation sequencing in the clinical diagnosis of pulmonary co-infection. Suitable prophylaxis, necessary clinical awareness and accurate diagnosis are indispensable for immunocompromised patients with pulmonary infection.

Signatures of B Cell Receptor Repertoire Following Pneumocystis Infection

B cells play vital roles in host defense against Pneumocystis infection. However, the features of the B cell receptor (BCR) repertoire in disease progression remain unclear. Here, we integrated single-cell RNA sequencing and single-cell BCR sequencing of immune cells from mouse lungs in an uninfected state and 1–4 weeks post-infection in order to illustrate the dynamic nature of B cell responses during Pneumocystis infection. We identified continuously increased plasma cells and an elevated ratio of (IgA + IgG) to (IgD + IgM) after infection. Moreover, Pneumocystis infection was associated with an increasing naïve B subset characterized by elevated expression of the transcription factor ATF3. The proportion of clonal expanded cells progressively increased, while BCR diversity decreased. Plasma cells exhibited higher levels of somatic hypermutation than naïve B cells. Biased usage of V(D)J genes was observed, and the usage frequency of IGHV9-3 rose. Overall, these results present a detailed atlas of B cell transcriptional changes and BCR repertoire features in the context of Pneumocystis infection, which provides valuable information for finding diagnostic biomarkers and developing potential immunotherapeutic targets.

Pneumocystis jirovecii pneumonia in autoimmune rheumatic diseases: a nationwide population-based study

OBJECTIVE

To compare Pneumocystis jirovecii pneumonia (PJP) risk between patients with autoimmune rheumatic diseases (ARD) and the general population METHODS: We identified patients with ARD recorded in the National Health Insurance Research Database of Taiwan from 2002 to 2015 and randomly selected a comparison cohort from the general population matched for age and sex. We analyzed PJP risk stratified by sex, age, comorbidities, and medications using Cox proportional hazard model.

RESULTS

We enrolled 103,117 patients with ARD. PJP risk significantly increased in patients with any ARD and with each individual ARD like rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjogren's syndrome (SjS), polymyositis and dermatomyositis (PM/DM), systemic sclerosis (SSc), and systemic vasculitis. Patients with PM/DM showed prominent risk with incidence rate of 12.47/100,000 patient year (95% confidence interval (CI), 32.16-86.70). In a time-dependent Cox proportional hazard model with comorbidities and medications as covariates, PM/DM, SSc, SLE, and SjS significantly increased adjusted hazard ratios (aHR) of 5.40, 5.12, 4.09, and 3.64, respectively (95% CI of 2.82-10.35, 2.16-12.13, 2.41-6.95, and 2.06-6.42, respectively). AHR after adjusting for male sex, cancer, human immunodeficiency virus infection (HIV), and interstitial lung disease also significantly increased. Use of daily oral steroid dose of >10 mg conferred the highest risk followed by mycophenolate. Use of injected steroids, cyclophosphamide, biological agents, methotrexate, and cyclosporine conferred a significantly higher risk.

CONCLUSION

Underlying ARD significantly predisposes patients to PJP, with PM/DM posing the highest threat. In addition to underlying disease, comorbidities and concomitant immunosuppressants are major risks. The strongest risk is recent daily steroid dose of >10 mg. Mycophenolate seems to be a more prominent risk factor than cyclophosphamide. Key Points • Autoimmune rheumatic diseases (ARD) significantly increased the overall risk of PJP, and so did each individual ARD. • Use of steroids, mycophenolate, cyclophosphamide, biological agents, methotrexate, and cyclosporine all significantly increased risk of PJP. • Male, elderly, malignancy, HIV, and interstitial lung disease are also related to increased risk of PJP. • Underlying ARD, comorbidities, and use of immunosuppressant should all be considered in determining the overall risk of PJP.

Host Factors and Outcomes in Hospitalizations for Pneumocystis Jirovecii Pneumonia in the United States

OBJECTIVE

To assess host factors in pneumocystis jirovecii pneumonia (PCP)-related hospitalizations and compare outcomes between HIV and non-HIV patients.

METHODS

Using the National Inpatient Sample database, we identified 3384 hospitalizations with PCP (International Classification of Diseases, Ninth Revision, Clinical Modification code: 136.3) as the primary discharge diagnosis from 2005 to 2014. We evaluated hospitalizations for the following host factors: HIV, malignancies, organ transplantation, rheumatologic diseases, and vasculitides. We compared the prevalence of individual host factors among PCP hospitalizations over time, and compared intervention rates and outcomes between HIV and non-HIV patients with PCP.

RESULTS

Among all hospitalizations for PCP, malignancy was the most prevalent host factor (46.0%, n=1559), followed by HIV (17.8%, n=604); 60.7% (n=946) of malignancies were hematologic. The prevalence of HIV among hospitalizations for PCP decreased from 25.1% in 2005 to 9.2% in 2014 (P<.001), whereas the prevalence of non-HIV immunocompromising conditions increased. Compared with HIV patients, PCP patients without HIV had higher rates of bronchoscopy (52.3% vs 26.7%, P<.001) and endotracheal intubation (17.0% vs 7.9%, P<.001), prolonged hospitalizations (11.5 vs 8.7 days, P<.001), higher hospitalization costs (86.8 vs 48.2×10³ USD, P<.001) and increased in-hospital mortality (16.0% vs 5.0%, P<.001). After adjusting for age, sex, and smoking status, there was no difference in mortality between non-HIV and HIV patients with PCP (adjusted odds ratio, 1.4; 95% CI, 0.9 to 2.3).

CONCLUSION

The epidemiology of PCP has shifted with an increase in the prevalence of non-HIV patients who have higher intubation rates and prolonged hospitalizations compared with matched HIV patients.

A nationwide study on inpatient opportunistic infections in patients with chronic lymphocytic leukemia in the pre-ibrutinib era

OBJECTIVE

Opportunistic infections in chronic lymphocytic leukemia (CLL) have been described in clinical trials, single-center studies, and case reports. We performed a nationwide study to estimate the incidence and impact of inpatient opportunistic infections.

METHODS

The incidence rate (IR) and incidence rate ratio (IRR) for Swedish CLL patients diagnosed 1994-2013, and matched controls were calculated, as well as the case-fatality ratio (CFR).

RESULTS

Among 8989 CLL patients, a total of 829 opportunistic infections were registered (IR 16.6 per 1000 person-years) compared with 252 opportunistic infections in 34 283 matched controls (IR 0.99). The highest incidence in the CLL cohort was for Pneumocystis pneumonia (200 infections, IR 4.03); Herpes zoster (146 infections, IR 2.94), and Pseudomonas (83 infections, IR 1.66) infections. The highest risk relative to matched controls was observed for Pneumocystis pneumonia (IRR 114, 95% confidence interval 58.7-252). The 60-day CFR for CLL patients with opportunistic infections was 23% (188/821), highest for progressive multifocal encephalopathy (5/7, 71%) and aspergillosis (25/60, 42%).

CONCLUSION

We have uniquely depicted the incidence of rare and serious infections in CLL patients and found a relatively high incidence of Pneumocystis pneumonia. Of the most common opportunistic infections, CLL patients with aspergillosis had the poorest prognosis.

Pneumocystis jirovecii Pneumonia in Children with Hematological Malignancies: Diagnosis and Approaches to Management

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection that mostly affects children with suppressed cellular immunity. PJP was the most common cause of infectious death in children with acute lymphoblastic leukemia prior to the inclusion of cotrimoxazole prophylaxis as part of the standard medical care in the late 1980s. Children with acute leukemia, lymphomas, and those undergoing hematopoietic stem cell transplantation, especially allogeneic transplantation, are also at high risk of PJP. Persistent lymphopenia, graft versus host disease, poor immune reconstitution, and lengthy use of corticosteroids are significant risk factors for PJP. Active infection may be due to reactivation of latent infection or recent acquisition from environmental exposure. Intense hypoxemia and impaired diffusing capacity of the lungs are hallmarks of PJP, while computerized tomography of the lungs is the diagnostic technique of choice. Immunofluorescence testing with monoclonal antibodies followed by fluorescent microscopy and polymerase chain reaction testing of respiratory specimens have emerged as the best diagnostic methods. Measurement of (1-3)-β-D-glucan in the serum has a high negative predictive value in ruling out PJP. Oral cotrimoxazole is effective for prophylaxis, but in intolerant patients, intravenous and aerosolized pentamidine, dapsone, and atovaquone are effective alternatives. Ιntravenous cotrimoxazole is the treatment of choice, but PJP has a high mortality even with appropriate therapy.

Diagnosing Pneumocystis jirovecii pneumonia: A review of current methods and novel approaches

Pneumocystis jirovecii can cause life-threatening pneumonia in immunocompromised patients. Traditional diagnostic testing has relied on staining and direct visualization of the life-forms in bronchoalveolar lavage fluid. This method has proven insensitive, and invasive procedures may be needed to obtain adequate samples. Molecular methods of detection such as polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), and antibody-antigen assays have been developed in an effort to solve these problems. These techniques are very sensitive and have the potential to detect Pneumocystis life-forms in noninvasive samples such as sputum, oral washes, nasopharyngeal aspirates, and serum. This review evaluates 100 studies that compare use of various diagnostic tests for Pneumocystis jirovecii pneumonia (PCP) in patient samples. Novel diagnostic methods have been widely used in the research setting but have faced barriers to clinical implementation including: interpretation of low fungal burdens, standardization of techniques, integration into resource-poor settings, poor understanding of the impact of host factors, geographic variations in the organism, heterogeneity of studies, and limited clinician recognition of PCP. Addressing these barriers will require identification of phenotypes that progress to PCP and diagnostic cut-offs for colonization, generation of life-form specific markers, comparison of commercial PCR assays, investigation of cost-effective point of care options, evaluation of host factors such as HIV status that may impact diagnosis, and identification of markers of genetic diversity that may be useful in diagnostic panels. Performing high-quality studies and educating physicians will be crucial to improve the rates of diagnosis of PCP and ultimately to improve patient outcomes.

Characterization of Pneumocystis jirovecii pneumonia at three tertiary comprehensive hospitals in southern China

Due to the increasing use of immunosuppressant therapy, Pneumocystis jirovecii pneumonia (PJP) has become an emerging concern in human immunodeficiency virus (HIV)-negative patients. In this study, we conducted a retrospective study of 96 hospitalized patients with PJP from January 2015 to June 2019 at three tertiary comprehensive hospitals in Southern China. Information was collected regarding patient demographics, clinical manifestations, risk factors, laboratory analyses, radiological images, and treatment outcomes. PJP infection was most commonly found in middle-aged men. Kidney diseases (35.5%) and connective tissue diseases (38.7%) were the predominant risk factors for PJP. About half of the patients (48.4%) received glucocorticoid, immunosuppressant, and/or chemotherapy in a low dose or in a short-term (< 3 months). None of the patients had previously received trimethoprim-sulfamethoxazole (TMP-SMX) for PJP prophylaxis. All patients had two or more clinical manifestations (cough, dyspnea, fever, and chest pain). Biochemical investigations of CRP, ESR, PaO2, LDH, and KL-6 showed that over 90% of the patients exceeded the reference range of indicators. Our analyses revealed the dominant risk factors (HIV, kidney diseases, and connective tissue diseases) and the most consistent biochemical indicators (LDH, BG, and KL-6) for PJP. Moreover, early prophylaxis, diagnosis, and treatment should contribute to improve the survival of these PJP patients.

Lower Mortality Associated With Adjuvant Corticosteroid Therapy in Non-HIV-Infected Patients With Pneumocystis jirovecii Pneumonia: A Single-Institution Retrospective US Cohort Study

Background

Pneumocystis jirovecii pneumonia (PJP) remains a cause of mortality in HIV-negative patients. The clinical benefit of adjuvant corticosteroids in these patients is uncertain. This study aimed to determine if corticosteroids would reduce mortality in a cohort of HIV-negative PJP patients.

Methods

We examined a retrospective case series of patients diagnosed with PJP at the University of Colorado Hospital between 1995 and 2019. Data were collected in 71 PJP-infected patients. Twenty-eight patients were HIV-negative, and 43 were infected with HIV. We performed bivariate and forward, stepwise multivariable logistic regressions to identify mortality predictors.

Results

Common underlying conditions in HIV-negative patients were hematologic malignancies (28.6%), autoimmune disorders (25.9%), and solid organ transplantation (10.7%). HIV-negative patients had higher rates and durations of mechanical ventilation and intensive care unit stay. Survival was significantly increased in HIV-negative patients receiving adjuvant corticosteroids, with 100% mortality in patients not receiving corticosteroids vs 60% mortality in patients receiving corticosteroids (P = .034). In an adjusted multivariable model, no adjuvant corticosteroid use was associated with higher mortality (odds ratio, 13.5; 95% CI, 1.1–158.5; P = .039) regardless of HIV status.

Conclusions

We found substantial mortality among HIV-negative patients with PJP, and adjuvant corticosteroid use was associated with decreased mortality. Response to corticosteroids is best established in HIV-infected patients, but emerging reports suggest a similar beneficial response in PJP patients without HIV infection. Further prospective studies may establish a more definitive role of the addition of corticosteroids among HIV-negative patients with PJP.

Identifying predictors for bacterial and fungal coinfection on chest computed tomography in patients with Pneumocystis pneumonia

BACKGROUND

Pneumocystis pneumonia (PCP) is a common opportunistic infection with high mortality in individuals with decreased immunity. Pulmonary coinfections with PCP are associated with poor prognosis. The study aims to identify radiological predictors for pulmonary coinfections in patients with PCP and risk factors for mortality.

METHODS

This is a retrospective, five-year study was conducted in a medical center, enrolling patients diagnosed with PCP, who received a chest computed tomography (CT) scan. The radiological findings and medical records of all participants were reviewed carefully by 2 independent doctors. Univariable and multivariable analysis was performed to identify radiological predictors for pulmonary coinfection and clinical risk factors for poor prognosis.

RESULTS

A total of 101 participants were included, of which 39 were HIV-infected and 62 were non-HIV-infected. In multivariable analysis, radiologic predictors on chest CT for coinfection with bacteria pneumonia included lack of ground glass opacity (adjusted odds ratio [aOR], 6.33; 95% confidence interval [CI], 2.03-19.77; p = 0.001) and presence of pleural effusion (aOR, 3.74; 95% CI, 1.27-10.99; p = 0.017). Predictors for fungal pneumonia included diffuse consolidation (adjusted OR, 6.27; 95% CI, 1.72-22.86; p = 0.005) and presence of pleural effusion (adjusted OR, 5.26; 95% CI, 1.44-19.17; p = 0.012). A significantly higher in-hospital mortality was associated with older age, recent corticosteroid exposure, cytomegalovirus coinfection, and acute respiratory failure.

CONCLUSION

Early identification of pulmonary coinfections in PCP using radiological features on the CT scans, will enable appropriate treatment which is crucial to improve the prognosis.

Diagnostic accuracy of serum (1-3)-β-D-glucan for Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) can be a life-threatening opportunistic infection in immunocompromised hosts. The diagnosis can be challenging, often requiring semi-invasive respiratory sampling. The serum 1,3-β-D-glucan (BDG) assay has been proposed as a minimally invasive test for the presumptive diagnosis of PJP.

METHOD

We carried out a systematic review and meta-analysis using articles in the English language published between January 1960 and September 2019. We estimated the pooled sensitivity and specificity of BDG testing using a bivariate random effects approach and compared test performance in human immunodeficiency virus (HIV) and non-HIV subgroups with meta-regression. Data from the pooled sensitivity and specificity were transformed to generate pre- and post-test probability curves.

RESULTS

Twenty-three studies were included. The pooled sensitivity and specificity of serum BDG testing for PJP were 91% (95%CI 87-94%) and 79% (95%CI 72-84%) respectively. The sensitivity in patients with HIV was better than in patients without (94%, 95%CI 91-96%) versus 86% (95%CI 78-91%) (p 0.02), with comparable specificity (83%, 95%CI 69-92% versus 83%, 95%CI 72-90%) (p 0.10). A negative BDG was only associated with a low post-test probability of PJP (≤5%) when the pre-test probability was low to intermediate (≤20% in non-HIV and ≤50% in HIV).

CONCLUSIONS

Among patients with a higher likelihood of PJP, the pooled sensitivity of BDG is insufficient to exclude infection. Similarly, for most cases, the pooled specificity is inadequate to diagnose PJP. Understanding the performance of BDG in the population being investigated is therefore essential to optimal clinical decision-making.

Etiologies and outcomes of rheumatology patients with acute respiratory failure requiring intensive care: a single-center medical records review study of 259 patients

OBJECTIVE

The etiologies of acute respiratory failure in patients with systemic rheumatic diseases (SRDs) requiring intensive care remain unknown. This study was undertaken to investigate the etiologies and outcomes.

METHODS

A medical records review study was performed of 259 adult SRDs patients with respiratory failure admitted to medical ICU across a 5-year period. The etiologies were classified as infection, SRD exacerbation, and undetermined. The factors associated with ICU mortality were identified with multivariate logistic regression analysis.

RESULTS

The etiologies of respiratory failure included infection (n = 209, 80.7%), SRD exacerbation (n = 71, 27.4%), and undetermined (n = 21, 8.1%). The most common pathogen was Pneumocystis jirovecii (39.8%), followed by Aspergillus spp. (33.2%), and cytomegalovirus (23.2%). The ICU mortality rate was 59.8%. A high acute physiology and chronic health evaluation II score (OR 1.118, 95% CI 1.054 to 1.186, p < 0.001), a PaO₂/FiO₂ ratio < 100 mmHg (OR 3.918, 95% CI 2.199 to 6.892, p < 0.001), and a diagnosis of dermatomyositis/polymyositis (OR 4.898, 95% CI 1.949 to 12.309, p = 0.001), vasculitis (OR 3.007, 95% CI 1.237 to 7.309, p = 0.015), and Pneumocystis pneumonia (OR 2.345, 95% CI 1.168 to 4.705, p = 0.016) were associated with increased mortality.

CONCLUSIONS

Opportunistic infections and SRD exacerbation were the most common etiologies of acute respiratory failure in patients with SRDs requiring ICU admission, with high ICU mortality. Development of a standard protocol for differential diagnosis in this population might help initiate definitive therapy and improve clinical outcome. Key Points • Infections, especially with opportunistic infections, were the leading cause of acute respiratory failure in critically ill rheumatology patients, with high mortality. • Severity of illness, certain types of rheumatic diseases, and opportunistic fungal infections were associated with increased mortality. • Using a comprehensive diagnostic workup might help to confirm the infective etiology and improve outcome.

Prognostic impact of pre-existing interstitial lung disease in non-HIV patients with Pneumocystis pneumonia

Background

The increasing incidence of life-threatening Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients is a global concern. Yet, no reports have examined the prognostic significance of pre-existing interstitial lung disease (ILD) in non-HIV PCP.

Methods

We retrospectively reviewed the medical records of non-HIV PCP patients with (ILD group) or without (non-ILD group) pre-existing ILD. The clinical features and outcomes of the ILD group were compared with those of the non-ILD group. Cox regression models were constructed to identify prognostic factors.

Results

74 patients were enrolled in this study. The 90-day mortality was significantly higher in the ILD group than in the non-ILD group (62.5% versus 19.0%, p<0.001). In the ILD group, patients with a higher percentage of bronchoalveolar lavage fluid neutrophils had worse outcomes compared to those having a lower percentage (p=0.026). Multivariate analyses revealed that pre-existing ILD (p=0.002) and low levels of serum albumin (p=0.009) were independent risk factors for 90-day mortality. Serum levels of β-d-glucan were significantly reduced after treatment of PCP in both groups, whereas levels of Krebs von den Lungen-6 (KL-6) significantly increased in the ILD group. In the ILD group, the 90-day mortality of patients with increasing KL-6 levels after treatment was significantly higher than those with decreasing levels (78.9% versus 0%, p=0.019).

Conclusion

In non-HIV PCP patients, pre-existing ILD is associated with a poorer prognosis. Prophylaxis for PCP is needed in patients with pre-existing ILD under immunosuppression.

Pre-existing interstitial lung disease (ILD) is an independent prognostic risk factor for non- HIV Pneumocystis pneumonia (PCP). Prophylaxis for PCP is needed in patients with pre-existing ILD under immunosuppression.http://bit.ly/37BGZuK

The Pathogenesis of Fungal-Related Diseases and Allergies in the African Population: The State of the Evidence and Knowledge Gaps

The prevalence of allergic diseases in the African continent has received limited attention with the allergic diseases due to fungal allergens being among the least studied. This lead to the opinion being that the prevalence of allergic disease is low in Africa. Recent reports from different African countries indicate that this is not the case as allergic conditions are common and some; particularly those due to fungal allergens are increasing in prevalence. Thus, there is need to understand both the aetiology and pathogenies of these diseases, particularly the neglected fungal allergic diseases. This review addresses currently available knowledge of fungal-induced allergy, disease pathogenesis comparing findings from human versus experimental mouse studies of fungal allergy. The review discusses the potential role of the gut mycobiome and the extent to which this is relevant to fungal allergy, diagnosis and human health.

Molecular Diagnosis of Pneumocystis jirovecii Pneumonia by Use of Oral Wash Samples in Immunocompromised Patients: Usefulness and Importance of the DNA Target

Pneumocystis jirovecii pneumonia (PJP) is an important cause of pneumonia in the HIV-negative immunocompromised population, for whom the fungal load is low, the differential diagnosis is difficult, and a bronchoalveolar lavage (BAL) sample is often not readily available. Molecular techniques have improved the microbiological diagnosis in this scenario. The usefulness of two real-time PCR techniques targeting nuclear single-copy and mitochondrial multicopy genes, respectively, applied to oral wash specimens (OW) for PJP diagnosis was assessed, and its accuracy was compared to a BAL fluid-based diagnosis. Immunocompromised patients having PJP in the differential diagnosis of an acute respiratory episode, and from whom OW and BAL or lung biopsy specimens were obtained ≤48 h apart, were retrospectively included. PCRs targeting the dihydropteroate synthase gene (DHPS) and the mitochondrial small-subunit (mtSSU) rRNA gene were performed in paired OW-BAL specimens. Thirty-six patients were included (88.6% HIV negative). Fifteen patients (41.7%) were classified as PJP, and a further 8 were considered P. jirovecii colonized. Quantification of DHPS and mtSSU in BAL fluid showed an accuracy of 96.9% and 93.0%, respectively, for PJP diagnosis, whereas a qualitative approach performed better when applied to OW (accuracy, 91.7%) irrespective of the PCR target studied (kappa = 1). Qualitative molecular diagnosis applied to OW showed an excellent performance for PJP diagnosis regardless of the target studied, being easier to interpret than the quantitative approach needed for BAL fluid.

[Pneumocystis jirovecii pneumonia-an opportunistic infection undergoing change]

Pneumocystis jirovecii pneumonia (PcP) has for many years been reported mostly in human immunodeficiency virus-infected patients. Increasingly, it also affects other immunocompromised patients, e.g. after organ or allogeneic stem cell/bone marrow transplantation, patients with hematologic malignancies or autoimmune diseases. The diagnosis of PcP relies on a critical evaluation of clinical symptoms, risk factors, radiologic features and microbiological tests. High dose cotrimoxazole is the most effective therapeutic option. Rapid initiation is essential, since mortality is especially high in patients admitted to intensive care with respiratory failure. This article reviews the current epidemiology of PcP and highlights the diagnostic and therapeutic options. Recommendations for primary and secondary prophylaxis are summarized.