Risk Factors of Pneumocystis jirovecii Pneumonia in Patients with Inflammatory Bowel Disease: A Nationwide Population-Based Study

Background/Aims

: Pneumocystis jirovecii pneumonia (PJP) is a rare but potentially fatal infection. This study was conducted to investigate the risk factors for PJP in inflammatory bowel disease (IBD) patients.

Methods

: This nationwide, population-based study was conducted in Korea using claims data. Cases of PJP were identified in patients diagnosed with ulcerative colitis (UC) or Crohn's disease (CD) between 2010 and 2017, and the clinical data of each patient was analyzed. Dual and triple therapy was defined as the simultaneous prescription of two or three of the following drugs: steroids, calcineurin inhibitors, immunomodulators, and biologics.

Results

: During the mean follow-up period (4.6±2.3 years), 84 cases of PJP were identified in 39,462 IBD patients (31 CD and 53 UC). For CD patients, only age at diagnosis >40 years (hazard ratio [HR], 6.12; 95% confidence interval [CI], 1.58 to 23.80) was significantly associated with the risk of PJP, whereas in UC patients, diagnoses of diabetes (HR, 2.51; 95% CI, 1.19 to 5.31) and chronic obstructive pulmonary disease (HR, 3.41; 95% CI, 1.78 to 6.52) showed significant associations with PJP risk. Triple therapy increased PJP risk in both UC (HR, 3.90; 95% CI, 1.54 to 9.88) and CD patients (HR, 5.69; 95% CI, 2.32 to 14.48). However, dual therapy increased PJP risk only in UC patients (HR, 2.53; 95% CI, 1.36 to 4.70). Additionally, 23 patients (27%) received intensive care treatment, and 10 (12%) died within 30 days.

Conclusions

: PJP risk factors differ in CD and UC patients. Considering the potential fatality of PJP, prophylaxis should be considered for at-risk IBD patients.

Diagnosis model of early Pneumocystis jirovecii pneumonia based on convolutional neural network: a comparison with traditional PCR diagnostic method

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an interstitial pneumonia caused by pneumocystis jirovecii (PJ). The diagnosis of PJP primarily relies on the detection of the pathogen from lower respiratory tract specimens. However, it faces challenges such as difficulty in obtaining specimens and low detection rates. In the clinical diagnosis process, it is necessary to combine clinical symptoms, serological test results, chest Computed tomography (CT) images, molecular biology techniques, and metagenomics next-generation sequencing (mNGS) for comprehensive analysis.

PURPOSE

This study aims to overcome the limitations of traditional PJP diagnosis methods and develop a non-invasive, efficient, and accurate diagnostic approach for PJP. By using this method, patients can receive early diagnosis and treatment, effectively improving their prognosis.

METHODS

We constructed an intelligent diagnostic model for PJP based on the different Convolutional Neural Networks. Firstly, we used the Convolutional Neural Network to extract CT image features from patients. Then, we fused the CT image features with clinical information features using a feature fusion function. Finally, the fused features were input into the classification network to obtain the patient's diagnosis result.

RESULTS

In this study, for the diagnosis of PJP, the accuracy of the traditional PCR diagnostic method is 77.58%, while the mean accuracy of the optimal diagnostic model based on convolutional neural networks is 88.90%.

CONCLUSION

The accuracy of the diagnostic method proposed in this paper is 11.32% higher than that of the traditional PCR diagnostic method. The method proposed in this paper is an efficient, accurate, and non-invasive early diagnosis approach for PJP.

Incidence of Pneumocystis Jiroveci Pneumonia in Patients With ANCA-Associated Vasculitis Initiating Therapy With Rituximab or Cyclophosphamide

OBJECTIVE

This manuscript assesses the incidence of Pneumocystis jiroveci pneumonia (PJP) among patients receiving contemporary treatment regimens for antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and adverse events associated with PJP prophylaxis.

METHODS

Incident users of rituximab or cyclophosphamide for AAV were identified in the TriNetX electronic health records database from 2011 to 2022. The incidence rates (IRs) of PJP in the first 6 months of induction therapy with rituximab and/or cyclophosphamide and during postinduction maintenance therapy with rituximab were calculated. Cox proportional hazard models were used to estimate hazard ratios (HRs) and confidence intervals (CIs) for the risk of adverse events commonly associated with PJP prophylaxis.

RESULTS

We identified 1,461 AAV cases who received induction therapy with rituximab (69.7%), cyclophosphamide (18.9%), or both (11.4%). Prophylaxis prescribed within 30 days of induction included trimethoprim-sulfamethoxazole (30.7%), atovaquone (5.4%), dapsone (3.8%), and pentamidine (0.8%). During induction therapy, 10 cases of PJP were identified (IR 15.0 cases per 1,000 patient-years); no deaths occurred. In adjusted analyses, those who received prophylaxis had a higher risk of leukopenia (HR 3.1; 95% CI 1.1-8.6), rash (HR 1.9; 95% CI 1.0-3.6), and nephropathy (HR 2.6; 95% CI 1.3-5.1) than those who did not. During rituximab maintenance therapy (n = 709), five cases of PJP were identified (IR 2.1 cases per 1,000 person-years), one of whom died during the hospitalization associated with a PJP diagnosis.

CONCLUSION

Rates of PJP in patients with AAV were lower than previously observed, and few cases occurred during rituximab maintenance therapy. PJP prophylaxis was associated with adverse events.

Pneumocystis jirovecii with high probability detected in bronchoalveolar lavage fluid of chemotherapy-related interstitial pneumonia in patients with lymphoma using metagenomic next-generation sequencing technology

BACKGROUND

Previous studies achieved low microbial detection rates in lymphoma patients with interstitial pneumonia (IP) after chemotherapy. However, the metagenomic next-generation sequencing (mNGS) is a comprehensive approach that is expected to improve the pathogen identification rate. Thus far, reports on the use of mNGS in lymphoma patients with chemotherapy-related IP remain scarce. In this study, we summarized the microbial detection outcomes of lymphoma patients with chemotherapy-related IP through mNGS testing of bronchoalveolar lavage fluid (BALF).

METHODS

Fifteen lymphoma patients with chemotherapy-related IP were tested for traditional laboratory microbiology, along with the mNGS of BALF. Then, the results of mNGS and traditional laboratory microbiology were compared.

RESULTS

Of the 15 enrolled patients, 11 received rituximab and 8 were administered doxorubicin hydrochloride liposome. The overall microbial yield was 93.3% (14/15) for mNGS versus 13.3% (2/15) for traditional culture methods (P ≤ 0.05). The most frequently detected pathogens were Pneumocystis jirovecii (12/15, 80%), Cytomegalovirus (4/15, 26.7%), and Epstein-Barr virus (3/15, 20%). Mixed infections were detected in 10 cases. Five patients recovered after the treatment with antibiotics alone without glucocorticoids.

CONCLUSION

Our findings obtained through mNGS testing of BALF suggested a high microbial detection rate in lymphoma patients with IP after chemotherapy. Notably, there was an especially high detection rate of Pneumocystis jirovecii. The application of mNGS in patients with chemotherapy-related IP was more sensitive.

Clinical Characteristics and Outcomes of Pneumocystis jirovecii Pneumonia in Cancer Patients From a Tertiary Care Hospital

Objective To investigate the predisposing factors, disease course, potential complications, role of primary prophylaxis, and overall outcomes of Pneumocystis jirovecii pneumonia (PJP) in cancer patients. Methods The study was conducted at Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan. We analyzed the medical records of cancer patients diagnosed with PJP from January 2018 to December 2022 and collected data about demographic characteristics, clinical presentation, predisposing factors, treatment, complications, and mortality rates. We used SPSS 20 (IBM Corp., Armonk, NY, USA) for data analysis. Results Out of 84 patients, 59.5% (n=50) were males and most of the patients belonged to the age group 41 to 65 years. Sixty-seven point nine percent (67.9%; n=57) of patients had underlying hematological malignancy, including three bone marrow transplant recipients while 32.2% (n=27) of patients had underlying solid organ malignancy. We also observed the use of corticosteroids, rituximab, and fludarabine as predisposing factors in 15% (n=13), 27% (n=23), and 3.7%(n=03) of patients, respectively. The most common symptoms were dyspnea (88%; n=74), followed by fever (69%; n=58) and cough (69%; n=58). The former one was more prevalent in hematological malignancy patients as compared to the solid organ tumor group (p-value 0.001). We noted respiratory failure (45.2%; n=38), ICU stay (52.38%; n=44), death (32%; n=27), and shock (10.7% n=9) as the most common PJP-related complications. Moreover, all these complications were more frequent in hematological malignancy patients. We also observed that only three patients developed PJP while on adequate primary prophylaxis for this condition. The overall all-cause one-month mortality was 32% (n=27). Conclusion Cancer patients, especially those with hematological malignancies presenting with symptoms suggestive of PJP, need careful evaluation and preemptive treatment as PJP-related mortality is higher in cancer patients. Early diagnosis and treatment in this population can be lifesaving. Moreover, all cancer patients should receive PJP prophylaxis when indicated.

Purine antimetabolites associated Pneumocystis jirovecii pneumonia

PURPOSE

To detect the possible safety signal of purine antimetabolites associated with Pneumocystis jirovecii pneumonia through disproportionality analysis in the FDA Adverse Event Reporting System (FAERS) Database.

METHODS

A case/non-case retrospective disproportionality analysis was performed in the publicly available FAERS database using AERSmine (2004Q1-2021Q3). Four models were developed to explore the signal strength of PAs among different populations with possible confounding factors. Reporting odds ratio (ROR) and Proportional reporting ratio (PRR) was used as the data mining algorithm for the analysis. A value of ROR-1.96SE > 1 and PRR ≥ 2 with an associated X2 value of 4 or more was considered the threshold for a signal.

RESULTS

A total of 7073 reports associated with Pneumocystis jirovecii pneumonia were present in the database, of which 899 reports were associated with purine antimetabolites. A crude signal strength of ROR 15.76(14.70-16.91) was obtained for purine antimetabolites associated PJP, with the highest signal strength reported with fludarabine and thioguanine [ROR 19.63(17.42-22.13); 19.45(13.21-28.63)]. Stratifying the cases based on autoimmune disorders and the cancer population revealed an ROR of 3.33(2.46-4.50) and 2.93(2.26-3.79) respectively. The highest risk of PJP with use of PAs was observed amongst children with a higher risk of nearly 2 times than the adult population [ROR 11.57(9.16-14.62)].

CONCLUSIONS

Our study provided evidence on the occurrence of PJP with the use of purine antimetabolites among the autoimmune and cancer population. We identified signals for PJP with azathioprine, mercaptopurine, thioguanine, cladribine, fludarabine, and clofarabine. More research with a superior epidemiological study design of a defined population is required to validate these findings.

Infectious Complications in Patients With Non-small Cell Lung Cancer Treated With Immune Checkpoint Inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICI) are standard treatment for nonsmall cell lung cancer (NSCLC). However, the burden of infectious complications during ICI therapy is poorly described.

MATERIALS AND METHODS

We conducted a retrospective study of patients with NSCLC treated with ICIs between 2007 and 2020 at a tertiary academic center. The incidence, characteristics, and healthcare utilization outcomes of infections during ICI therapy and within 3 months of ICI discontinuation are presented using descriptive statistics. Cox proportional hazard models are used to examine infection-free survival by demographic and treatment factors. Associations between patient or treatment characteristics and hospitalization or ICU admission are analyzed by logistic regression, presented as odds ratios (OR).

RESULTS

Of 298 patients, infections occurred in 54.4% (n = 162). Of these patients, 59.3% (n = 96) required hospitalization and 15.4% (n = 25) required ICU admission. The most common infection was bacterial pneumonia. Fungal infections occurred in 12 patients (7.4%). Patients with chronic obstructive pulmonary disease (COPD) (OR 2.15, 95% CI, 1.01-4.58), corticosteroid treatment within 1 month prior to infection onset (OR 3.04, 95% CI, 1.47-6.30), and concomitant irAE and infection (OR 5.48, 95% CI, 2.15-14.00) had higher odds of hospitalization. Corticosteroid use was associated with higher odds of ICU admission (OR 3.09, 95% CI, 1.29-7.38).

CONCLUSION

In this large single-institution study we identify that more than half of patients with ICI-treated NSCLC develop infectious complications. We identify that patients with COPD, recent corticosteroid use, and concomitant irAE and infection have higher odds of hospitalization, and that unusual infections (eg, fungal) can occur. This highlights clinical awareness of infections as important complications during ICI therapy in patients with NSCLC.

Indication for a Pneumocystis Prophylaxis Therapy in Patients with Vascular Anomalies Treated with PIK3/AKT/mTOR Pathway Inhibitors: Experts' Opinion and Systematic Review from the Literature

BACKGROUND

Vascular anomalies (VAs) are increasingly being treated with PI3K/AKT/mTOR pathway inhibitors. These drugs have immunosuppressive properties and thus theoretically overexpose patients to opportunistic infections, especially Pneumocystis jirovecii pneumonia (PJP). PJP prophylaxis use lacks consensus. We aimed to investigate the prevalence of PJP in patients receiving mTOR/PI3K/AKT inhibitors for VAs and determine any indication for pneumocystis prophylaxis in this population.

METHODS

The study was conducted in 2 parts: (1) we sent a survey to a panel of international experts of VAs asking about their use of pneumocystis prophylaxis drugs and (2) we performed a systematic review of the literature of all published cases of patients receiving these drugs for VA to estimate the prevalence of PJP in this population.

RESULTS

Answers from 68 experts were analyzed: 21 (30.9%) answered they always add PJP prophylaxis when prescribing mTOR inhibitors, 20 (29.4%) case-by-case, and 27 (39.7%) never. For the systematic review, among 3,053 reports screened, 217 were included involving 1,189 patients (1,143 received sirolimus, 38 everolimus, 4 alpelisib, 4 miransertib). Among the 1,189 cases, 2 (0.2%) PJP were reported: one under sirolimus and one under everolimus. Thus, the prevalence of PJP was estimated at 0.88 cases/1,000 patients under sirolimus (95% CI: -0.84 to 2.59) and 26.31 cases/1,000 under everolimus (95% CI: -24.58 to 77.18). Patients with PJP never received prophylaxis drugs. We found no PJP cases under alpelisib and miransertib. PJP prophylaxis was given in 218 (18.3%) cases, more frequently for children (91.3 vs. 77.2% in the non-prophylaxis group, p = 0.012), mostly trimethoprim-sulfamethoxazole (186 patients, 85.3%).

CONCLUSION

Our study shows that even if PJP is a rare event, it may occur in patients with VAs treated with an mTOR inhibitor. Although our results cannot allow for revising guidelines, prophylaxis with TMP-SMX might be appropriate for a subgroup of patients with risk factors for PJP.

A machine learning diagnostic model for Pneumocystis jirovecii pneumonia in patients with severe pneumonia

BACKGROUND

The diagnosis of Pneumocystis jirovecii pneumonia (PCP) in patients presenting with severe pneumonia is challenging and delays in treatment were associated with worse prognosis. This study aimed to develop a rapid, easily available, noninvasive machine learning diagnostic model for PCP among patients with severe pneumonia.

METHODS

A retrospective study was performed in West China Hospital among consecutive patients with severe pneumonia who had undergone bronchoalveolar lavage for etiological evaluation between October 2010 and April 2021. Factors associated with PCP were identified and four diagnostic models were established using machine learning algorithms including Logistic Regression, eXtreme Gradient Boosting, Random Forest (RF) and LightGBM. The performance of these models were evaluated by the area under the receiver operating characteristic curve (AUC).

RESULTS

Ultimately, 704 patients were enrolled and randomly divided into a training set (n = 564) and a testing set (n = 140). Four factors were ultimately selected to establish the model including neutrophil, globulin, β-D-glucan and ground glass opacity. The RF model exhibited the greatest diagnostic performance with an AUC of 0.907. The calibration curve and decision curve analysis also demonstrated its accuracy and applicability.

CONCLUSIONS

We constructed a PCP diagnostic model in patients with severe pneumonia using four easily available and noninvasive clinical indicators. With satisfying diagnostic performance and good clinical practicability, this model may help clinicians to make early diagnosis of PCP, reduce the delays of treatment and improve the prognosis among these patients.

Gaining an Understanding of Pneumocystosis in Wales

Pneumocystis pneumonia (PcP) is a serious complication of many significant immunocompromising conditions. Prior incidence estimates in Wales are based on PcP's presentation in the HIV and transplant populations. The objectives were to describe the incidence of PcP in Wales using laboratory reporting measures and assess the impact of underlying immunosuppression cause on mortality. All positive PCR results for PcP between 2015 and 2018 were identified. The total number of unique positives with clinical and radiological correlation was 159 patients, a mean of 39.75 annually. The healthcare records of these patients were reviewed. The mortality at one month was 35.2% and 49.1% at one year. HIV remains the commonest cause of immunosuppression but has lower mortality than non-HIV conditions (12% vs. 59% at one year, p < 0.00001). Non-HIV conditions were categorised as life-threatening and non-life threatening but had a non-significant mortality (66% vs. 54%; p = 0.149), highlighting the negative impact of PcP. An incidence of PcP in Wales of 1.23-1.26 cases per 100,000 has been identified, 32-35% greater than the upper limit previously estimated. There is high mortality in non-HIV patients regardless of immunosuppression cause. A heightened awareness of PcP in these groups will hasten diagnosis and potentially improve mortality.

Changing Trends in the Incidence and Clinical Features of Pneumocystis jirovecii Pneumonia in Non-HIV Patients before and during the COVID-19 Era and Risk Factors for Mortality between 2016 and 2022

Fungal superinfections have been reported in patients with coronavirus disease 2019 (COVID-19). We analyzed the incidence and clinical characteristics of Pneumocystis jirovecii pneumonia (PCP) in non-human immunodeficiency virus patients at a tertiary hospital between 2016 and 2022 to evaluate the impact of the COVID-19 pandemic on PCP. The study period was divided into pre-COVID-19 and COVID-19 eras based on the pandemic declaration by the World Health Organization. Among the 113 patients included, the incidence of PCP in the COVID-19 era (37/1000 patient-years) was significantly higher than that in the pre-COVID-19 era (13.1/1000 patient-years) (p < 0.001). Co-infection with invasive pulmonary aspergillosis (IPA) also increased (2.4% vs. 18.3%, p = 0.013). Independent risk factors for PCP-related mortality were previous glucocorticoid use, hypoxemia, acute kidney injury, and IPA co-infection. Risk factors for IPA in patients with PCP included previous use of tyrosine kinase inhibitors, COVID-19 infection within 30 days, leukopenia, and intensive care unit admission. In the COVID-19 era, 12 (16.9%) patients with PCP had a history of COVID-19 infection within 90 days; however, infection was not associated with mortality. Active evaluation of patients with suspected PCP and assessment of IPA co-infection risk may help improve the outcomes of patients with PCP.

Case report: A HIV-negative hemodialysis patient positive for pANCA with severe pneumocystis pneumonia: A case report and review of literature

RATIONALE

Pneumocystis pneumonia (PCP) is an opportunistic fungal infection that occurs in people with impaired or suppressed immunity such as patients with human immunodeficiency virus or organ transplant. However, the incidence and characteristics of PCP in the population with long-term hemodialysis is poorly described in the literature.

PATIENT CONCERNS

We present a case of a 50-year-old female patient being transferred to our hospital in February 2022 with a 20-day history of cough and tight breath. She received amoxicillin and cephalosporin anti-infection treatment successively in local hospital but no significant improvement in symptoms. She had a 2-year history of hemodialysis and no relevant transplantation and human immunodeficiency virus infection. She was diagnosed as ANCA associated vasculitis (AAV) and given oral prednisone acetate (20 mg/day) and methotrexate (2.5 mg/week) half a year ago.

DIAGNOSES

Based on the patient's medical history, Lung computerized tomography image, the Next generation sequencing report, the patient was diagnosed with renal failure, anti-neutrophil cytoplasmic antibody associated vasculitis, and Pneumocystis pneumonia.

INTERVENTIONS

The dosage of immunosuppressant was reduced due to leucocyte dripping and fever, and antibiotic and antifungal treatment were also given. The patient's lung condition was getting worse and noninvasive ventilator was required to maintain blood oxygen. Blood filtration is used to remove toxins. Ganciclovir and trimethoprim-sulfamethoxazole was used based on the next generation sequencing report.

OUTCOMES

The patient died of respiratory failure.

LESSONS

The risk of PCP in hemodialysis patients may be higher than that in ordinary population, and the prognosis of patients with immunosuppression may be worse. Dynamic assessment of vasculitis activity is necessary for hemodialysis patients with AAV because infections may obscure lung symptoms of AAV. It is not recommended that hemodialysis patients with long-term immunosuppression should reduce or stop the dosage of immunosuppressive drugs during the treatment because it may aggravate the condition of PCP. There is still no clear conclusion on whether hemodialysis patients need preventive medicine, but the identification of risk factors and early diagnosis and treatment are important for the prognosis of PCP on hemodialysis population.

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.

Pneumocystis jirovecii diagnosed by next-generation sequencing of bronchoscopic alveolar lavage fluid: A case report and review of literature

BACKGROUND

The advent of molecular targeted agents and immune checkpoint inhibitors has greatly improved the treatment of advanced renal cell carcinoma (RCC), thus significantly improving patient survival. The incidence of rare drug-related adverse events has gained increased attention.

CASE SUMMARY

We report a patient with advanced RCC treated with multiple lines of molecular targeted agents and immune checkpoint inhibitors, who developed a pulmonary infection after treatment with everolimus in combination with lenvatinib. Determining the pathogenic organism was difficult, but it was eventually identified as Pneumocystis jirovecii by next-generation sequencing (NGS) of bronchoscopic alveolar lavage fluid (BALF) and successfully treated with trimethoprim-sulfamethoxazole.

CONCLUSION

Rare pulmonary infections caused by molecular targeted agents are not uncommon in clinical practice, but their diagnosis is difficult. Evaluating BALF with NGS is a good method for rapid diagnosis of such infections.

Clinical characteristics of and risk factors for Pneumocystis jirovecii pneumonia in anti-melanoma differentiation-associated gene 5 (Anti-MDA5) antibody-positive dermatomyositis patients: a single-center retrospective study

OBJECTIVE

Pneumocystis jirovecii pneumonia (PJP) is a serious opportunistic infection mainly diagnosed in patients with rheumatic conditions. However, PJP in anti-melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5 + DM) patients remains poorly understood. We aimed to investigate the 6-month PJP risk in newly diagnosed MDA5 + DM patients.

METHODS

A retrospective observational study of 105 inpatients with newly diagnosed MDA5 + DM was conducted at Renji Hospital from January 2018 to November 2019. Demographic information, clinical characteristics, and treatment data were recorded. The primary outcome was PJP incidence within 6 months after a MDA5 + DM diagnosis.

RESULTS

The analysis included 105 patients, including 13 patients diagnosed with PJP during the observation period. The median time from the MDA5 + DM diagnosis to PJP was 89 ± 38 days. Compared with the PJP - patients, the PJP + patients had a significantly greater risk of mortality (69.2% vs. 13.0% P < 0.001). Regarding the baseline comorbidities, hypertension (P = 0.013) and cancer (P = 0.02) were more common in the PJP + group. Additionally, a larger proportion of the PJP + patients received prolonged high-dose steroid therapy (≥ 60 mg/day and ≥ 1 month) (P = 0.022) and double or triple immunosuppressant therapy (P = 0.013). The multivariate analysis showed that PJP was independently associated with lymphopenia (ALC < 500 cells/µl) (OR: 5.434, 95% CI: 2.074-55.155; P = 0.012) and the combined use of cyclophosphamide (CTX) and tacrolimus (TAC) (OR: 10.695, 95% CI: 1.440-20.508; P = 0.005).

CONCLUSION

There was a high incidence and mortality in the MDA5 + DM patients with PJP, with patients on combined immunosuppressive treatments, particularly CTX and TAC, being at a higher risk. Prolonged high-dose steroid therapy (≥ 60 mg/day and ≥ 1 month) was another risk factor for PJP. Key Points • There was a high incidence and mortality in the MDA5 + DM patients with PJP. • Most PJP cases occurred within 3 months after the MDA5 + DM diagnosis. • The 6-month infection risk of PJP increased with the administration of multiagent immunosuppression, especially the combination of CTX and TAC. • Prolonged high-dose steroid therapy (≥ 60 mg/day and ≥ 1 month) was another risk factor for PJP.

Pneumocystis pneumonia in patients with Cushing's syndrome: A French multicenter retrospective study

OBJECTIVE

Pneumocystis pneumonia (PcP) is an opportunistic infection occurring in immunocompromised patients. Cushing's syndrome (CS) impairs the immune system, and several authors have reported PcP in patients with CS. The present study aimed to characterize PcP occurring in a CS context and its management in French tertiary centers, in order to highlight the similarities in clinical presentation and treatment according to whether prophylaxis is implemented or not.

METHODS

This was a multicenter retrospective study conducted in several French University Hospitals and Cancer Centers. Patients with PcP and confirmed CS regardless of etiology were included. We excluded patients with other known causes of acquired immunodeficiency with increased risk of PcP.

RESULTS

Twenty-five patients were included. CS etiology was neoplastic in 84.0% of cases. CS clinical presentation associated predominant catabolic signs (76.0%), hypokalemia (91.7%) and lymphopenia (89.5%). CS was intense in most patients, with mean plasma cortisol levels at diagnosis of 2.424±1.102nmol/L and urinary free cortisol>10× the upper limit of normal in 85.0%. In all patients, PcP onset followed introduction of cortisol blockers, at a median 5.5 days. Patients were treated with 1 to 3 cortisol blockers, mainly metyrapone (88%), which significatively lowered plasma cortisol levels to 667±541nmol/L at the onset of PcP (P<0.001). PcP occurred in 7 patients despite prophylaxis. Finally, 60.0% patients were admitted to intensive care, and 20.0% died of PcP.

CONCLUSION

High mortality in patients with PcP implies that clinicians should be better informed about this rare infectious complication. Prophylaxis remains controversial, requiring comparative studies.

Risk of Pneumocystis jirovecii Pneumonia among Solid Organ Transplant Recipients: A Population-Based Study

Few studies have comprehensively investigated the occurrence of Pneumocystis jirovecii pneumonia (PJP) among solid organ transplant (SOT) recipients. This study investigated the risk of PJP after organ transplantation. Each patient who underwent SOT was propensity-score-matched with four non-SOT individuals in terms of sex, age, insured salary, urbanization of residence, comorbidities, and year of enrollment. When considering the 3-year follow-up, the patients who had undergone SOT were at higher risk of PJP, with the adjusted odds ratio (aOR) being 17.18 (95% confidence interval (CI): 8.80-33.53). Furthermore, SOT recipients were also at higher PJP risk than the patients without SOT at 6 months, 1 year, and 2 years, with the aOR being 22.64 (95% CI: 7.53-68.11), 26.19 (95% CI: 9.89-69.37), and 23.06 (95% CI: 10.23-51.97), respectively. Patients comorbid with HIV infection, hematological malignancies, or vasculitis were at higher risk (aOR = 59.08, 95% CI = 20.30-171.92), (aOR = 11.94, 95% CI = 5.36-26.61), and (aOR = 21.72, 95% CI = 2.41-195.81), respectively. The recipients of SOT were at higher risk of PJP, and PJP can develop at any stage after transplantation. SOT recipients comorbid with HIV, hematologic malignancies, or vasculitis were at higher PJP risk.

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.

Application of metagenomic next-generation sequencing in the diagnosis of pulmonary invasive fungal disease

Background

Metagenomic next-generation sequencing (mNGS) is increasingly being used to detect pathogens directly from clinical specimens. However, the optimal application of mNGS and subsequent result interpretation can be challenging. In addition, studies reporting the use of mNGS for the diagnosis of invasive fungal infections (IFIs) are rare.

Objective

We critically evaluated the performance of mNGS in the diagnosis of pulmonary IFIs, by conducting a multicenter retrospective analysis. The methodological strengths of mNGS were recognized, and diagnostic cutoffs were determined.

Methods

A total of 310 patients with suspected pulmonary IFIs were included in this study. Conventional microbiological tests (CMTs) and mNGS were performed in parallel on the same set of samples. Receiver operating characteristic (ROC) curves were used to evaluate the performance of the logarithm of reads per kilobase per million mapped reads [lg(RPKM)], and read counts were used to predict true-positive pathogens.

Result

The majority of the selected patients (86.5%) were immunocompromised. Twenty species of fungi were detected by mNGS, which was more than was achieved with standard culture methods. Peripheral blood lymphocyte and monocyte counts, as well as serum albumin levels, were significantly negatively correlated with fungal infection. In contrast, C-reactive protein and procalcitonin levels showed a significant positive correlation with fungal infection. ROC curves showed that mNGS [and especially lg(RPKM)] was superior to CMTs in its diagnostic performance. The area under the ROC curve value obtained for lg(RPKM) in the bronchoalveolar lavage fluid of patients with suspected pulmonary IFIs, used to predict true-positive pathogens, was 0.967, and the cutoff value calculated from the Youden index was −5.44.

Conclusions

In this study, we have evaluated the performance of mNGS-specific indicators that can identify pathogens in patients with IFIs more accurately and rapidly than CMTs, which will have important clinical implications.

Low-dose trimethoprim-sulfamethoxazole for the treatment of Pneumocystis jirovecii pneumonia (LOW-TMP): protocol for a phase III randomised, placebo-controlled, dose-comparison trial

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection of immunocompromised hosts with significant morbidity and mortality. The current standard of care, trimethoprim-sulfamethoxazole (TMP-SMX) at a dose of 15-20 mg/kg/day, is associated with serious adverse drug events (ADE) in 20%-60% of patients. ADEs include hypersensitivity reactions, drug-induced liver injury, cytopenias and renal failure, all of which can be treatment limiting. In a recent meta-analysis of observational studies, reduced dose TMP-SMX for the treatment of PJP was associated with fewer ADEs, without increased mortality.

METHODS AND ANALYSIS

A phase III randomised, placebo-controlled, trial to directly compare the efficacy and safety of low-dose TMP-SMX (10 mg/kg/day of TMP) with the standard of care (15 mg/kg/day of TMP) among patients with PJP, for a composite primary outcome of change of treatment, new mechanical ventilation, or death. The trial will be undertaken at 16 Canadian hospitals. Data will be analysed as intention to treat. Primary and secondary outcomes will be compared using logistic regression adjusting for stratification and presented with 95% CI.

ETHICS AND DISSEMINATION

This study has been conditionally approved by the McGill University Health Centre; Ethics approval will be obtained from all participating centres. Results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04851015.

Prognostic factors and clinical efficacy of second-line treatments of Pneumocystis jirovecii pneumonia for non-HIV patients after first-line treatment failure

Background

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening opportunistic infection. In non-HIV immunocompromised patients with PCP, a standard second-line treatment has not been established up to now.

Methods

Non-HIV immunocompromised patients with confirmed PCP between April 2013 and December 2020 were included. Their PCP treatment history was tracked. Factors related to first-line trimethoprim/sulfamethoxazole (TMP/SMX) and second-line treatment failure were identified. Different second-line treatment strategies were compared.

Results

Among the 220 patients, 127 (57.73%) did not respond to first-line TMP/SMX treatment. Risk factors related to treatment failure included symptom triad with breathlessness at rest, persistent fever and cough (85% in the treatment failure group versus 74% in the treatment success group, P = 0.034), treatment with invasive mechanical ventilation (67 vs. 19%, P < 0.001), coinfection with CMV (69 vs. 47%, P = 0.035), and bacteremia (59 vs. 10%, P < 0.001). A total of 49 patients received second-line treatment on the basis of TMP/SMX, and 28 (57.1%) of them responded to the treatment. No clinical parameter, including selection of different therapies, was found to be significantly associated with second-line treatment failure. Further, the prognosis of different second-line therapies showed no drug or drug combination strategy superior to others. The primaquine group had lower 90-day mortality rate (45.9%) but showed no statistically significant difference compared with the non-primaquine group (64.6%). The patients in the clindamycin plus primaquine group had the lowest in-hospital mortality rate (22.2%, P = 0.042) among different second-line therapies, although the in-hospital mortality of the primaquine group was not significantly different from that of the non-primaquine group. The differences in 28 day mortality and overall mortality rates were not statistically significant, too.

Conclusion

CMV infection and bacteremia were risk factors significantly associated with treatment failure of TMP/SMX. The response and survival rates of second-line treatment, including clindamycin, primaquine, and caspofungin, were poor, maybe clindamycin plus primaquine as second line treatment was better than other treatment strategies. These results suggest that clinicians should carefully evaluate whether the treatment of TMP/SMX has failed due to a coinfection rather than hastily changing to a second-line drug when the patient worsens.

Comparison of PneumID real-time PCR assay with Amplex eazyplex LAMP assay for laboratory diagnosis of Pneumocystis jirovecii Pneumonia

We compared PneumID PCR with Amplex eazyplex LAMP assay for the diagnosis of Pneumocystis jirovecii pneumonia (PJP). Both assays enable accurate diagnosis of definite PJP. Cut-off cycle threshold of the PneumID assay was < 26.68 while the cut-off time-to-positivity of the eazyplex assay was 16:02 (minutes:seconds). The positive and negative percentage agreement of eazyplex assay with PneumID assay was 75.0% and 100.0% respectively, while the overall agreement was substantial with kappa = 0.80. For both assays, establishment of cut-off values to differentiate probable PJP from colonization was not feasible as results overlapped.

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.

Pneumocystis pneumonia with respiratory failure in a HIV-negative patient following short course of low-dose to moderate-dose prednisolone for a dermatological condition

A woman in her 80s was admitted with 5 days of progressive dyspnoea and hypoxic respiratory failure, in the setting of receiving a 3-week course of low-dose to moderate-dose prednisolone for a pruritic skin rash. Her medical history was not significant for major medical comorbidities or any other clear risk factors for secondary immunosuppression apart from advanced age. CT revealed widespread small-airway and parenchymal disease with ground-glass opacities consistent with atypical respiratory infection. Sputum PCR confirmed Pneumocystis jirovecii She was diagnosed with Pneumocystis jirovecii pneumonia (PJP) in the context of her clinical presentation, radiological features and PCR result. Her HIV status was negative. The patient was treated with 4 weeks of trimethoprim-sulfamethoxazole and 3 weeks of adjunctive prednisolone. She initially required high-dependency unit support with non-invasive ventilation. In this case report, we review the literature regarding PJP in the dermatology setting.

Pneumocystis jirovecii pneumonia in a patient receiving chemotherapy for advanced prostatic cancer: a case report

Pneumocystis jirovecii pneumonia (PJP) in advanced prostatic cancer patients not receiving high-dose glucocorticoids has been reported rarely. A 73-year-old man underwent chemotherapy with cisplatin and docetaxel for advanced prostatic cancer. After nine cycles of chemotherapy, he developed a high fever, dry cough, shortness of breath, and severe fatigue, with rapid-onset hypoxic respiratory failure. Investigations demonstrated bilateral ground-glass opacities with positive bronchoalveolar lavage fluid (BALF) for Pneumocystis jirovecii by next-generation sequencings (NGS). The patient recovered well with treatment with trimethoprim-sulfamethoxazole, caspofungin, and corticosteroids. This case report describes a case of PJP in a patient with a solid tumor who did not receive high-dose glucocorticoids and emphasizes the importance of early diagnosis and treatment.

Concurrent Infection with SARS-CoV-2 and Pneumocystis jirovecii in Immunocompromised and Immunocompetent Individuals

Coronavirus disease 2019 (COVID-19) may occur with concurrent infections caused by bacterial and fungal microorganisms. This systematic review evaluated studies reporting concomitant COVID-19 and Pneumocystis jirovecii pneumonia (PJP). We found 39 patients (74% male, median age: 56.8 (range: 11–83) years), including 66% immunosuppressed individuals (23% HIV-infected and 41% on long-term corticosteroid therapy). Patients were characteristically severely ill (mechanical ventilation: 70%), associated with 41% mortality. The median lymphocyte count was 527 cells/mm³ (range: 110–2200), and the median CD4+ T cell count was 206 cells/mm³ (range: 8–1021). We identified three patterns of concurrent COVID-19 and P. jirovecii infection. The first pattern (airway colonization with a low burden of P. jirovecii) does not seem to modify the COVID-19 course of illness. However, P. jirovecii superinfection, typically occurring weeks after COVID-19 diagnosis as a biphasic illness, and P. jirovecii coinfection characteristically results in progressive multilobar pneumonia, which is associated with poor outcomes. To support this categorization, we reported three patients with concurrent PJP and COVID-19 identified in our institution, presenting these clinical scenarios. The diagnosis of PJP requires a high index of suspicion, since clinical and radiological characteristics overlap with COVID-19. Observational studies are necessary to determine the PJP burden in patients with COVID-19 requiring hospitalization.

Pneumocystis jirovecii pneumonia in HIV-negative patients, a frequently overlooked problem. A case series from a large Italian center

BACKGROUND AND OBJECTIVES

Pneumocystis jirovecii pneumonia (PCP) still has substantial morbidity and mortality. For non-HIV patients, the course of infection is severe, and management guidelines are relatively recent. We collected all PCP cases (European Organization for Research and Treatment of Cancer criteria) diagnosed in HIV-negative adult inpatients in 2019-2020 at our center in northern Italy.

RESULTS

Of 20 cases, nine had microbiologic evidence of probable (real-time polymerase chain reaction, RT-PCR) and 11 proven (immunofluorescence) PCP on respiratory specimens. Half were female; the median age was 71.5 years; 14 of 20 patients had hematologic malignancies, five had autoimmune/hyperinflammatory disorders, and one had a solid tumor. RT-PCR cycle threshold (Ct) was 24-37 for bronchoalveolar lavage (BAL) and 32-39 for sputum; Ct was 24-33 on BAL proven cases. Of 20 cases, four received additional diagnoses on BAL. At PCP diagnosis, all patients were not on anti-pneumocystis prophylaxis. We retrospectively assessed prophylaxis indications: 9/20 patients had a main indication, 5/9 because of prednisone treatment ≥ 20 mg (or equivalents) for ≥4 weeks. All patients underwent antimicrobial treatment according to guidelines; 18/20 with concomitant corticosteroids. A total of 4/20 patients died within 28 days from diagnosis.

CONCLUSION

Despite appropriate treatment, PCP is still associated to high mortality (20%) among non-HIV patients. Strict adherence to prophylaxis guidelines, awareness of gray areas, and prompt diagnosis can help manage this frequently overlooked infection.

Bendamustine and pneumocystis pneumonia: A systematic review

Background

Bendamustine, a bifunctional mechlorethamine alkylating agent, is used in the treatment of patients with hematologic malignancies. Myelosuppression and cytotoxic effect arises quite often after bendamustine treatment. To date, there have been no recommendations for routine chemoprophylaxis for Pneumocystis carinii pneumonia (PCP) in patients under treatment with this agent. The present systematic review aimed to evaluate the existing data on bendamustine effects on pneumocystis pneumonia.

Method

English papers were systematically reviewed using Web of Science, Embase, Google Scholar, PubMed, and Cochrane library. There was no time constraint for the paper search. The used keywords included “Pneumonia, Pneumocystis”or “Pneumocystis Pneumonia”or “Pneumocystis jirovecii” and “Bendamustine hydrochloride or Bendamustine. “Through our search, 113 papers were found, 26 of which were chosen following a review of the titles and abstracts; ultimately, 10 were included in the research.

Result

A total of 10 studies (out of 113 studies) were retrieved. The papers were classified into seven case reports, two clinical trials, and one retrospective analysis study. The case reports included 14 patients diagnosed with PCP after bendamustine administration between 2003 and 2019. The patients' mean age was with a range of 66.8. Non‐Hodgkin's lymphoma (including diffuse large B‐cell lymphoma and mantle cell lymphoma) (n = 9, 60%), chronic lymphocytic leukemia (n = 4, 26.6%), and breast cancer (n = 2, 13.4%) were the most prevalent types of malignancy. Bendamustine, along with rituximab, were the most commonly prescribed chemotherapy regimens during the treatments. Finally, the mortality rate among the patients whose results were reported (n = 9) was 44.44% (n = 4).

Conclusion

The present review described PCP infection in patients with malignancies after the treatment with bendamustine, a chemotherapeutic agent associated with lymphopenia. Further research is required to determine the PCP risk in patients with bendamustine treatment and identify individuals who may benefit from prophylaxis.

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.

Nomograms for Death from Pneumocystis jirovecii Pneumonia in HIV-Uninfected and HIV-Infected Patients

Purpose

Pneumocystis jirovecii pneumonia (PCP) is a major cause of death in immunocompromised patients. Many risk factors for poor prognosis have been reported, but few studies have created predictive models with these variables to calculate the death rate accurately. This study created nomogram models for the precise prediction of mortality risk in human immunodeficiency virus (HIV) uninfected and HIV-infected patients with PCP.

Patients and Methods

A retrospective study was performed over a 10-year period to evaluate the clinical characteristics and outcomes of PCP in HIV-uninfected and HIV-infected adults treated in Beijing, China from 2010 to 2019. Univariate and multivariate logistic regression analyses were used to identify mortality risk factors to create the nomograms. Nomogram models were evaluated by using a bootstrapped concordance index, calibration plots and receiver operating characteristic (ROC) curves.

Results

A total of 167 HIV-uninfected and 193 HIV-infected PCP patients were included in the study. Pneumothorax, duration of fever after admission, CD4+ T cells ≤100/µL and trimethoprim-sulfamethoxazole (TMP-SMX) combined with caspofungin (CAS) treatment were independent risk factors for death in HIV-uninfected PCP patients. We derived a well calibrated nomogram for mortality by using these variables. The area under the curve was 0.865 (95% confidence interval 0.799–0.931). Independent risk factors for death in HIV-infected PCP patients were pneumothorax, platelet (PLT) ≤80×10⁹/L, haemoglobin (HGB) ≤90 g/L, albumin (ALB), cytomegalovirus (CMV) coinfection and TMP-SMX combined with CAS treatment. The nomogram showed good discrimination, with a C-index of 0.904 and excellent calibration.

Conclusion

The nomograms which were derived may be useful tools for the precise prediction of mortality in HIV-uninfected and HIV-infected patients, but require validation in clinical practice.

VV-ECMO combined with prone position ventilation in the treatment of Pneumocystis jirovecii pneumonia: A case report

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) occurs in immunocompromised hosts. It is classified as PJP with human immunodeficiency virus (HIV) infection (HIV-PJP) and PJP without HIV infection (non-HIV PJP). Compared with HIV-PJP, non-HIV PJP is more likely to develop rapidly into respiratory failure, with difficult diagnosis and high mortality.

PATIENT CONCERNS

A 46-year-old male with membranous nephropathy was treated with oral corticosteroids and tacrolimus. He was admitted to our hospital for fever and dyspnea which developed 4 days ago. Laboratory data revealed that leukocytes were 10.99 × 109/L, neutrophils 87.7%, lymphocytes 9.6%, C-reactive protein 252.92 mg/L, New coronavirus nucleic acid detection negative. CT scan of chest revealed ground-glass opacity in both lungs. He was admitted to the respiratory department of our hospital, and then transferred to ICU because of his critical condition.

DIAGNOSIS

High throughput gene detection of pathogenic microorganisms in alveolar lavage fluid showed that the detection sequence of Pneumocystis yersiniae increased significantly. The serum HIV-antibody was negative. Therefore, the patient was diagnosed as non-HIV PJP.

INTERVENTIONS

After admission, the patient was assisted by noninvasive ventilator and treated with compound trimethoprim-sulfamethoxazole (SMX-TMP) and caspofungin. The patient's condition continued to deteriorate, and then underwent endotracheal intubation and veno-venous extracorporeal membrane oxygenation (VV-ECMO) combined with prone position ventilation until the lung lesion improved.

OUTCOMES

VV-ECMO was stopped on day 12, tracheal intubation was removed after 2 days. The patient was transferred to the respiratory department on day 15, discharged after 12 days without complications. Two months later, the follow-up showed that the patient was in good condition.

CONCLUSION

VV-ECMO combined with prone position ventilation could be a useful choice for respiratory assistance in non-HIV PJP patients.

Clinical Utilization of DiaSorin Molecular Polymerase Chain Reaction in Pneumocystis Pneumonia

BACKGROUND

Pneumocystis jirovecii polymerase chain reaction (PCR) testing is a sensitive diagnostic tool but does not distinguish infection from colonization. Cycle threshold (CT) may correlate with fungal burden and could be considered in clinical decision making. Clinical use of PCR and significance of CT values have not previously been examined with the DiaSorin Molecular platform.

METHODS

Retrospective review of P jirovecii PCR, CT values and clinical data from 18 months in a multihospital academic health system. The diagnostic performance of PCR with respect to pathology and correlation of CT with severity were examined.

RESULTS

Ninety-nine of 1006 (9.8%) assays from 786 patients in 919 encounters were positive. Among 91 (9.9%) encounters in which P jirovecii pneumonia (PJP) was treated, 41 (45%) were influenced by positive PCR. Negative PCR influenced discontinuation of therapy in 35 cases. Sensitivity and specificity of PCR were 93% (95% CI, 68%-100%) and 94% (95% CI, 91%-96%) with respect to pathology. CT values from deep respiratory specimens were significantly different among treated patients (P = .04) and those with positive pathology results (P < .0001) compared to patients not treated and those with negative pathology, respectively, and was highly predictive of positive pathology results (area under the curve = 0.92). No significant difference was observed in comparisons based on indicators of disease severity.

CONCLUSIONS

Pneumocystis jirovecii PCR was a highly impactful tool in the diagnosis and management of PJP, and use of CT values may have value in the treatment decision process in select cases. Further investigation in a prospective manner is needed.

Identification of Pneumocystis jirovecii with Fluorescence In-Situ Hybridization (FISH) in Patient Samples-A Proof-of-Principle

In resource-limited settings, where pneumocystosis in immunocompromised patients is infrequently observed, cost-efficient, reliable, and sensitive approaches for the diagnostic identification of Pneumocystis jirovecii in human tissue samples are desirable. Here, an in-house fluorescence in situ hybridization assay was comparatively evaluated against Grocott’s staining as a reference standard with 30 paraffin-embedded tissue samples as well as against in-house real-time PCR with 30 respiratory secretions from immunocompromised patients with clinical suspicion of pneumocystosis. All pneumocystosis patients included in the study suffered from HIV/AIDS. Compared with Grocott’s staining as the reference standard, sensitivity of the FISH assay was 100% (13/13), specificity was 41% (7/17), and the overall concordance was 66.7% with tissue samples. With respiratory specimens, sensitivity was 83.3% (10/12), specificity was 100% (18/18), and the overall concordance was 93.3% as compared with real-time PCR. It remained unresolved to which proportions sensitivity limitations of Grocott’s staining or autofluorescence phenomena affecting the FISH assay accounted for the recorded reduced specificity with the tissue samples. The assessment confirmed Pneumocystis FISH in lung tissue as a highly sensitive screening approach; however, dissatisfying specificity in paraffin-embedded biopsies calls for confirmatory testing with other techniques in case of positive FISH screening results. In respiratory secretions, acceptable sensitivity and excellent specificity were demonstrated for the diagnostic application of the P. jirovecii-specific FISH assay.

No Change of Pneumocystis jirovecii Pneumonia after the COVID-19 Pandemic: Multicenter Time-Series Analyses

Consolidated infection control measures imposed by the government and hospitals during COVID-19 pandemic resulted in a sharp decline of respiratory viruses. Based on the issue of whether Pneumocystis jirovecii could be transmitted by airborne and acquired from the environment, we assessed changes in P. jirovecii pneumonia (PCP) cases in a hospital setting before and after COVID-19. We retrospectively collected data of PCP-confirmed inpatients aged ≥18 years (N = 2922) in four university-affiliated hospitals between January 2015 and June 2021. The index and intervention dates were defined as the first time of P. jirovecii diagnosis and January 2020, respectively. We predicted PCP cases for post-COVID-19 and obtained the difference (residuals) between forecasted and observed cases using the autoregressive integrated moving average (ARIMA) and the Bayesian structural time-series (BSTS) models. Overall, the average of observed PCP cases per month in each year were 36.1 and 47.3 for pre- and post-COVID-19, respectively. The estimate for residuals in the ARIMA model was not significantly different in the total PCP-confirmed inpatients (7.4%, p = 0.765). The forecasted PCP cases by the BSTS model were not significantly different from the observed cases in the post-COVID-19 (−0.6%, 95% credible interval; −9.6~9.1%, p = 0.450). The unprecedented strict non-pharmacological interventions did not affect PCP cases.

A Microbial World: Could Metagenomic Next-Generation Sequencing Be Involved in Acute Respiratory Failure?

Background

The usefulness of metagenomic next-generation sequencing (mNGS) in identifying pathogens is being investigated. We aimed to compare the power of microbial identification between mNGS and various methods in patients with acute respiratory failure.

Methods

We reviewed 130 patients with respiratory failure, and 184 specimens including blood, bronchoalveolar lavage fluid (BALF), sputum, pleural effusion, ascitic fluid, and urine were tested by mNGS and conventional methods (culture, PCR). We also enrolled 13 patients to evaluate the power of mNGS and pathogen targets NGS (ptNGS) in microbial identifications. Clinical features and microbes detected were analyzed.

Results

mNGS outperformed the conventional method in the positive detection rate of Mycobacterium tuberculosis (MTB) (OR, ∞; 95% CI, 1–∞; P < 0.05), bacteria (OR, 3.7; 95% CI, 2.4–5.8; P < 0.0001), fungi (OR, 4.37; 95% CI, 2.7–7.2; P < 0.0001), mycoplasma (OR, 10.5; 95% CI, 31.8–115; P = 0.005), and virus (OR, ∞; 95% CI, 180.7–∞; P < 0.0001). We showed that 20 patients (28 samples) were detected with Pneumocystis jirovecii (P. jirovecii) by mNGS, but not by the conventional method, and most of those patients were immunocompromised. Read numbers of Klebsiella pneumoniae (K. pneumoniae), Acinetobacter baumannii (A. baumannii), Pseudomonas aeruginosa (P. aeruginosa), P. jirovecii, cytomegalovirus (CMV), and Herpes simplex virus 1 (HSV1) in BALF were higher than those in other sample types, and the read number of Candida albicans (C. albicans) in blood was higher than that in BALF. We found that orotracheal intubation and type 2 diabetes mellitus (T2DM) were associated with a higher detection rate of bacteria and virus by mNGS, immunosuppression was associated with a higher detection rate of fungi and virus by mNGS, and inflammatory markers were associated with mNGS-positive detection rate of bacteria. In addition, we observed preliminary results of ptNGS.

Conclusion

mNGS outperformed the conventional method in the detection of MTB, bacteria, fungi, mycoplasma, and virus. Orotracheal intubation, T2DM, immunosuppression, and inflammatory markers were associated with a higher detection rate of bacteria, fungi, and virus by mNGS. In addition, ptNGS results were consistent with the detection of abundant bacteria, fungi, and mycoplasma in our specimens.

Semiquantitative Real-Time PCR to Distinguish Pneumocystis Pneumonia from Colonization in a Heterogeneous Population of HIV-Negative Immunocompromised Patients

Pneumocystis jirovecii is a threat to iatrogenically immunosuppressed individuals, a heterogeneous population at rapid growth. We assessed the ability of an in-house semiquantitative real-time PCR assay to discriminate Pneumocystis pneumonia (PCP) from colonization and identified risk factors for infection in these patients. Retrospectively, 242 PCR-positive patients were compared according to PCP status, including strata by immunosuppressive conditions, human immunodeficiency virus (HIV) infection excluded. Associations between host characteristics and cycle threshold (CT) values, semiquantitative real-time PCR correlates of fungal loads in lower respiratory tract specimens, were investigated. CT values differed significantly according to PCP status. Overall, a CT value of 36 allowed differentiation between PCP and colonization with sensitivity and specificity of 71.3% and 77.1%, respectively. A CT value of less than 31 confirmed PCP, whereas no CT value permitted exclusion. A considerable diversity was uncovered; solid organ transplant (SOT) recipients had significantly higher fungal loads than patients with hematological malignancies. In SOT recipients, a CT cutoff value of 36 resulted in sensitivity and specificity of 95.0% and 83.3%, respectively. In patients with hematological malignancies, a higher CT cutoff value of 37 improved sensitivity to 88.5% but reduced specificity to 66.7%. For other conditions, assay validity appeared inferior. Corticosteroid usage was an independent predictor of PCP in a multivariable analysis and was associated with higher fungal loads at PCP expression. Semiquantitative real-time PCR improves differentiation between PCP and colonization in immunocompromised HIV-negative individuals with acute respiratory syndromes. However, heterogeneity in disease evolution requires separate cutoff values across intrinsic and iatrogenic predisposition for predicting non-HIV PCP. IMPORTANCE Pneumocystis jirovecii is potentially life threatening to an increasing number of individuals with compromised immune systems. This microorganism can cause severe pneumonia in susceptible hosts, including patients with cancer and autoimmune diseases and people undergoing solid organ transplantation. Together, these patients constitute an ever-diverse population. In this paper, we demonstrate that the heterogeneity herein has important implications for how we diagnose and assess the risk of Pneumocystis pneumonia (PCP). Specifically, low loads of microorganisms are sufficient to cause infection in patients with blood cancer compared to those in solid organ recipients. With this new insight into host versus P. jirovecii biology, clinicians can manage patients at risk of PCP more accurately. As a result, we take a significant step toward offering precision medicine to a vulnerable patient population. One the one hand, these patients have propensity for adverse effects from antimicrobial treatment. On the other hand, this population is susceptible to life-threatening infections, including PCP.

Epidemiological and clinical characteristics of immunocompromised patients infected with Pneumocystis jirovecii in a twelve-year retrospective study from Norway

Background

Pneumocystis pneumonia (PCP) severely menaces modern chemotherapy and immunosuppression. Detailed description of the epidemiology of Pneumocystis jirovecii today is needed to identify candidates for PCP-prophylaxis.

Methods

We performed a 12-year retrospective study of patients with P. jirovecii detected by polymerase chain reaction in Central Norway. In total, 297 patients were included. Comprehensive biological, clinical and epidemiological data were abstracted from patients’ medical records. Regional incidence rates and testing trends were also assessed.

Results

From 2007 to 2017 we found a 3.3-fold increase in testing for P. jirovecii accompanied by a 1.8-fold increase in positive results. Simultaneously, regional incidence rates doubled from 5.0 cases per 100,000 person years to 10.8. A majority of the study population had predisposing conditions other than human immunodeficiency virus (HIV). Hematological (36.0%) and solid cancers (25.3%) dominated. Preceding corticosteroids were a common denominator for 72.1%. Most patients (74.4%) presented with at least two cardinal symptoms; cough, dyspnea or fever. Main clinical findings were hypoxia, cytopenias and radiological features consistent with PCP. A total of 88 (29.6%) patients required intensive care and 121 (40.7%) suffered at least one complication. In-hospital mortality was 21.5%. Three patients (1.0%) had received prophylaxis.

Conclusions

P. jirovecii is re-emerging; likely due to increasing immunosuppressants use. This opportunistic pathogen threatens the life of heterogenous non-HIV immunosuppressed populations currently at growth. Corticosteroids seem to be a major risk factor. A strategy to increase prophylaxis is called for.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06144-1.

Clinical-epidemiological characteristics of Pneumocystis jirovecii pneumonia in a tertiary hospital in Spain

INTRODUCTION

HIV infection was the main risk of suffering Pneumocystis jirovecii pneumonia (PJP). The clinical-epidemiological characteristics of PJP have currently changed, with there being few studies on this.

METHODS

A retrospective observational study was carried out on paediatric patients diagnosed with PJP over a 17 year period in a third level hospital in Spain.

RESULTS

A total of 23 patients were included, of whom 7/23 (47.8%) suffered a haematological disease, 5/23 (21.7%) a primary immunodeficiency, and 4/23 (17.4%) an HIV infection. Prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) was received by 11/23 (47.8%) patients. All were treated with TMP-SMX and 18/23 (78.3%) with systemic glucocorticoids. There were six (26.1%) deaths, of which one of them (16.7%) suffered an HIV infection. A higher mortality was seen in the non-HIV patients with greater leucocytosis, greater CO2 retention, and a higher heart rate at onset, differences not observed in HIV patients. No differences were found in mortality in relation to the predisposing factor, use of pTMP-SMX, or treatment with glucocorticoids.

CONCLUSIONS

Paediatric patients with haematological cancers are currently the main risk group of developing PJP in this age group. No differences were found in mortality between patients with or without HIV infection as predisposing factor. The mortality among non-HIV patients was higher in those that had greater leucocytosis, greater CO2 retention, and increased heart rate at onset. A better prognosis was not seen in patients that received prophylaxis with TMP-SMX prior to the development of the PJP, or in those that received glucocorticoids as part of the treatment.

Pneumocystis Jirovecii Pneumonia as a Sequela of COVID-19

A 71 years old male came to the hospital with the complaint of cough and fever since 7 days. He was diagnosed with severe COVID pneumonia and was managed with steroids and tocilizumab. He was discharged on steroids and came after 20 days with complaints of worsening shortness of breath and hypoxia. Bronchoscopy and bronchoalveolar lavage was done which showed positive PCR for Pneumocystis Jirovecii Pneumonia (PCP). Patient was started on co-trimoxazole and steroids after which he showed remarkable improvement. This is one of the rare cases in which patient developed PCP as a sequelae of COVID-19.

Doctor-Should I get the COVID-19 vaccine? Infection and immunization in individuals with neuromuscular disorders

The clinical course of neuromuscular disorders (NMDs) can be affected by infections, both in immunocompetent individuals, and in those with reduced immunocompetence due to immunosuppressive/immunomodulating therapies. Infections and immunizations may also trigger NMDs. There is a potential for reduced efficacy of immunizations in patients with reduced immunocompetence. The recent vaccination program for coronavirus disease-2019 (COVID-19) raises several questions regarding the safety and efficacy of this vaccine in individuals with NMDs. In this Practice Topic article, we address the role of vaccine-preventable infections in NMDs and the safety and efficacy of immunization in individuals with NMDs, with emphasis on vaccination against COVID-19.

Pneumocystis jirovecii pneumonia in systemic lupus erythematosus: a nationwide cohort study in Taiwan

OBJECTIVES

To evaluate PJP infection risk in patients with SLE in Taiwan.

METHODS

We identified 24,367 patients with SLE from the National Health Insurance research database between 1997 and 2012 and compared the PJP incidence rates (IRs) with those in 243,670 age- and sex-matched non-SLE controls. PJP risk in the patients was evaluated using a Cox multivariate proportional hazards model.

RESULTS

The patients exhibited a significantly higher PJP risk than the controls, with an IR of 2.63 per 10,000 person-years and IR ratio of 27.65 (95% CI 17.2-45.3, p < 0.001). Male sex (hazard ratio [HR] 2.42, p < 0.01), end-stage renal disease (ESRD; HR 1.74, p = 0.01), recent use of mycofenolate mofetil (MMF; HR 4.43, P < 0.001), intravenous steroid pulse therapy (HR 108.73, p < 0.001), and average oral dose of >7.5 mg/day prednisolone or equivalent (HR 4.83, p < 0.001) were associated with PJP in SLE, whereas hydroxychloroquine use reduced its risk (HR 0.51, p = 0.01). Of note, cyclophosphamide was not associated with PJP infection in the multivariate Cox proportional hazard model.

CONCLUSIONS

Patients with SLE have a considerably high PJP risk. Cyclophosphamide does not increase PJP risk. Male sex, ESRD, MMF use, intravenous steroid pulse therapy, oral prednisolone or equivalent (>7.5 mg/day) are risk factors for PJP, whereas hydroxychloroquine use reduces PJP risk.

The risk factor analysis and treatment experience in pneumocystis jirovecii pneumonia after kidney transplantation

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection among solid organ transplantation. The occurrence of PJP is dangerous and fatal if there is no early identification and sufficient treatment.

OBJECTIVE

The aim of this study was to evaluate the risk factors and provide appropriate strategies of prophylaxis and treatment for PJP after kidney transplantation in our centre.

PATIENTS/METHODS

From January 2009 to December 2018, a total of 167 kidney transplantation recipients with pneumonia were enrolled, including 47 PJP patients as PJP group and 120 non-PJP patients as control group. The clinical characteristics of the two groups were analysed retrospectively.

RESULTS

Multivariate analysis showed that high total dosage of ATG [OR, 2.03; 95% CI, 1.12-3.68] and cytomegalovirus (CMV) infection were independent risk factors for PJP. Trimethoprim-sulfamethoxazole (TMP-SMX) (1.44 g q6h)-based treatment was used for 2 weeks, and its dosage and course were adjusted according to the therapeutic effect and side effects. Forty-five cases were recovered after 3 months of follow-up, and two patients died of respiratory failure. TMP-SMX (0.48 g/day) prophylaxis was used for 3-6 months and prolonged to 7-8 months after treatment for acute rejection, which reduced the incidence of PJP compared with those without prophylaxis.

CONCLUSION

Our study suggests that the high total dosage of ATG and CMV infection indicate the increased risk of PJP. The strategies of prophylaxis and treatment for PJP after kidney transplantation in our centre were effective.

Advances in Supportive Care for Acute Lymphoblastic Leukemia

PURPOSE OF REVIEW

Tremendous advances have been made in the treatment armamentarium for acute lymphoblastic leukemia in recent years, which have substantially improved outcomes for these patients. At the same time, unique toxicities have emerged, and without early intervention, are life-threatening. This article will review the novel therapies in acute leukemias and highlight the clinically relevant supportive care advances.

RECENT FINDINGS

The American Society for Transplantation and Cellular Therapy (ASTCT) has put forth the most recent recommendations in managing the cytokine release syndrome and neurotoxicity after chimeric antigen receptor T cells (CAR-T) and blinatumomab. The hepatic injury incurred by inotuzumab, and the vascular toxicity of tyrosine kinase inhibitors, other relatively novel agents, require subspecialist intervention and multidisciplinary care. Asparaginase, a long-established and key element of pediatric regimens, has made a comeback in the young adult leukemia population. Updated guidelines have been outlined for management of asparaginase thrombotic complications. Lastly, although there have been few changes in the applications of growth factor, antimicrobial prophylaxis, and management of neuropathy, these encompass exceedingly important aspects of care. While the rapidly changing treatment paradigms for acute lymphoblastic leukemia have transformed leukemia-specific outcomes, treatment emergent toxicities have forced much necessary attention to better definitions of these toxicities and on improving supportive care guidelines in acute lymphoblastic leukemia.

Differences and similarities of high-resolution computed tomography features between pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients

BACKGROUND

Accurately differentiating pneumocystis from cytomegalovirus pneumonia is crucial for correct therapy selection in AIDS patients. Hence, the goal of this study was to compare the computerized tomography (CT) features of pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients and identify clinical hallmarks to accurately distinguish these two pathologies.

METHODS

A total of 112 AIDS patients (78 with pneumocystis pneumonia and 34 cytomegalovirus pneumonia) at Beijing Ditan Hospital from January 2017 to May 2019 were included in this study. Two experienced chest radiologists retrospectively reviewed CT images for 17 features including ground-glass opacity, consolidation, nodules, and halo sign. Binary logistic regression analyses were conducted to identify the significant parameters that distinguished pneumocystis pneumonia from cytomegalovirus pneumonia. Correlations were analyzed by Pearson or Spearman correlation analyses. Result were considered significant if P < 0.05.

RESULTS

The presence of consolidation, halo signs, and nodules (all P < 0.05) were significantly more frequent in patients with cytomegalovirus pneumonia than in those with pneumocystis pneumonia. Small nodules (32.5% in cytomegalovirus pneumonia, 6.41% in pneumocystis pneumonia, P < 0.001) without perilymphatic distribution were particularly common in patients with cytomegalovirus pneumonia. Large nodules were not found in any of patients with cytomegalovirus pneumonia. The presence of ground-glass opacity, reticulation, and bronchial wall thickening (all P > 0.05) were common in both groups.

CONCLUSIONS

Analysis of consolidation, nodules, and halo signs may contribute to the differential diagnosis of pneumocystis pneumonia or cytomegalovirus pneumonia. However, some CT features considered typical in one or other diseases appear with similar frequency in both cohorts of AIDS patients. CT features are potentially useful for the differential diagnosis of pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients.

Diagnosis and management of community-acquired pneumonia in children: South African Thoracic Society guidelines

BACKGROUND

Pneumonia remains a major cause of morbidity and mortality amongst South African children. More comprehensive immunisation regimens, strengthening of HIV programmes, improvement in socioeconomic conditions and new preventive strategies have impacted on the epidemiology of pneumonia. Furthermore, sensitive diagnostic tests and better sampling methods in young children improve aetiological diagnosis.

OBJECTIVES

To produce revised guidelines for pneumonia in South African children under 5 years of age.

METHODS

The Paediatric Assembly of the South African Thoracic Society and the National Institute for Communicable Diseases established seven expert subgroups to revise existing South African guidelines focusing on: (i) epidemiology; (ii) aetiology; (iii) diagnosis; (iv) antibiotic management and supportive therapy; (v) management in intensive care; (vi) prevention; and (vii) considerations in HIV-infected or HIVexposed, uninfected (HEU) children. Each subgroup reviewed the published evidence in their area; in the absence of evidence, expert opinion was accepted. Evidence was graded using the British Thoracic Society (BTS) grading system. Sections were synthesized into an overall guideline which underwent peer review and revision.

RECOMMENDATIONS

Recommendations include a diagnostic approach, investigations, management and preventive strategies. Specific recommendations for HIV infected and HEU children are provided.

VALIDATION

The guideline is based on available published evidence supplemented by the consensus opinion of SA paediatric experts. Recommendations are consistent with those in published international guidelines.

Validation of the Pneumocystis pneumonia score in haematology patients with acute respiratory failure

Background

Pneumocystis pneumonia (PCP) is an important cause of acute respiratory failure (ARF) in immunocompromised patients, yet no actual clinical tool suitably identifies patients at risk. Recently, a multivariable prediction model has been proposed for haematology patients with ARF requiring intensive care unit (ICU) admission to assess the risk of PCP (PCP score). However, it has not yet been validated externally.

Methods

To validate the PCP score, a retrospective cohort study was conducted in two large designated haematology centres in Korea. One-hundred and forty haematology patients with ARF were admitted to ICU. They underwent aetiologic evaluations between July 2016 and June 2019. The predictive ability of the score was assessed with the receiver operating characteristic (ROC) curve analysis for both the discrimination and calibration of the score.

Results

Among the 141 patients, 13 (9.2%) were finally diagnosed of PCP. Although the median of PCP score in PCP group was higher than in non-PCP group (3.0 [interquartile range 0.0–4.0] vs. 2.0 [0.5–4.0]), the difference was not statistically significant (P = 0.679). The area under the ROC curve of the PCP score in our cohort was 0.535 (95% CI, 0.449–0.620), indicating no discriminatory ability. When using a cut-off of 3.0 the score, the result was 38.5% (95% CI, 13.9–68.4) sensitive and 7.03% (95% CI, 61.6–78.1) specific. The negative predictive value was 58.8% and positive predictive value was 59.8% for a 10% prevalence of PCP.

Conclusions

In this study, the PCP score was not useful to predict the risk of PCP in haematology patients with ARF. Further prospective validation studies are needed to validate the score’s use in routine clinical practice for the early diagnosis of PCP in haematology patients.

Dihydrofolate Reductase Is a Valid Target for Antifungal Development in the Human Pathogen Candida albicans

The folate biosynthetic pathway is a promising and understudied source for novel antifungals. Even dihydrofolate reductase (DHFR), a well-characterized and historically important drug target, has not been conclusively validated as an antifungal target. Here, we demonstrate that repression of DHFR inhibits growth of Candida albicans, a major human fungal pathogen. Methotrexate, an antifolate, also inhibits growth but through pH-dependent activity. In addition, we show that C. albicans has a limited ability to take up or utilize exogenous folates as only the addition of high concentrations of folinic acid restored growth in the presence of methotrexate. Finally, we show that repression of DHFR in a mouse model of infection was sufficient to eliminate host mortality. Our work conclusively establishes DHFR as a valid antifungal target in C. albicans.

While the folate biosynthetic pathway has provided a rich source of antibacterial, antiprotozoal, and anticancer therapies, it has not yet been exploited to develop uniquely antifungal agents. Although there have been attempts to develop fungal-specific inhibitors of dihydrofolate reductase (DHFR), the protein itself has not been unequivocally validated as essential for fungal growth or virulence. The purpose of this study was to establish dihydrofolate reductase as a valid antifungal target. Using a strain with doxycycline-repressible transcription of DFR1 (P_TETO-DFR1 strain), we were able to demonstrate that Dfr1p is essential for growth in vitro. Furthermore, nutritional supplements of most forms of folate are not sufficient to restore growth when Dfr1p expression is suppressed or when its activity is directly inhibited by methotrexate, indicating that Candida albicans has a limited capacity to acquire or utilize exogenous sources of folate. Finally, the P_TETO-DFR1 strain was rendered avirulent in a mouse model of disseminated candidiasis upon doxycycline treatment. Collectively, these results confirm the validity of targeting dihydrofolate reductase and, by inference, other enzymes in the folate biosynthetic pathway as a strategy to devise new and efficacious therapies to combat life-threatening invasive fungal infections.

IMPORTANCE The folate biosynthetic pathway is a promising and understudied source for novel antifungals. Even dihydrofolate reductase (DHFR), a well-characterized and historically important drug target, has not been conclusively validated as an antifungal target. Here, we demonstrate that repression of DHFR inhibits growth of Candida albicans, a major human fungal pathogen. Methotrexate, an antifolate, also inhibits growth but through pH-dependent activity. In addition, we show that C. albicans has a limited ability to take up or utilize exogenous folates as only the addition of high concentrations of folinic acid restored growth in the presence of methotrexate. Finally, we show that repression of DHFR in a mouse model of infection was sufficient to eliminate host mortality. Our work conclusively establishes DHFR as a valid antifungal target in C. albicans.