Diagnosis and management of Pneumocystis jirovecii infection

High prevalence of pneumocystis pneumonia in interstitial lung disease: a retrospective study

BACKGROUND

Interstitial lung disease (ILD) is a new risk category for pneumocystis pneumonia (PCP) with a high mortality rate. The definite diagnostic criteria of PCP in ILD patients have not been established until now. The aims of this study were to identify potential risk factors of PCP in patients with ILD, and to evaluate the performance of metagenomic next-generation sequencing (mNGS), CD4 + T cell count, (1-3)-β-D-Glucan (BG) and lactate dehydrogenase (LDH) in the diagnosis of PCP in ILD patients.

METHODS

This is a retrospective, single-center, case-control study. ILD patients who underwent mNGS from December 2018 to December 2022 were included in the study. Based on the diagnosis criteria of PCP, these patients were divided into PCP-ILD and non-PCP-ILD groups. The potential risk factors for PCP occurrence in ILD patients were analysed via logistic regression. The diagnostic efficacy of mNGS was compared with serological biomarkers.

RESULTS

92 patients with ILD were enrolled, 31 of which had a definite PCP and were assigned to the PCP-ILD group while 61 were to the non-PCP-ILD group. The infection rate of PJ in ILD patients was 33.7% (31/92). The history of glucocorticoid therapy, CD4 + T cell count, BG level and traction bronchiectasis on HRCT were associated with PCP occurrence in ILD patients. LDH level did not reach statistical significance in the logistic regression analysis. mNGS was confirmed as the most accurate test for PCP diagnosis in ILD patients.

CONCLUSION

ILD is a new risk group of PCP with high PCP prevalence. Clinicians should pay close attention to the occurrence of PCP in ILD patients who possess the risk factors of previous glucocorticoid therapy, decreased CD4 + T cell count, increased BG level and absence of traction bronchiectasis on HRCT. mNGS showed the most excellent performance for PCP diagnosis in ILD patients. Peripheral blood CD4 + T cell count and BG level are alternative diagnostic methods for PCP in ILD patients. However, the diagnostic value of serum LDH level was limited in ILD patients.

Prone positioning does not improve outcomes of intubated patients with pneumocystis pneumonia and moderate-severe acute respiratory distress syndrome: a single-center, retrospective, observational, cohort study

BACKGROUND

Pneumocystis pneumonia is an uncommon precipitant of acute respiratory distress syndrome and is associated with high mortality. Prone positioning ventilation has been proven to reduce mortality in patients with moderate-severe acute respiratory distress syndrome. We investigated the effect of prone positioning on oxygenation and mortality in intubated patients with pneumocystis pneumonia comorbid with moderate-severe acute respiratory distress syndrome.

METHODS

In this single-center, retrospective, observational, cohort study, eligible patients were enrolled at West China Hospital of Sichuan University from January 1, 2017, to December 31, 2021. Data on demographics, clinical features, ventilation parameters, arterial blood gas, and outcomes were collected. Patients were assigned to the prone cohort or supine cohort according to whether they received prone positioning ventilation. The main outcome was 28-day mortality.

FINDINGS

A total of 79 patients were included in the study. Sixty-three patients were enrolled in the prone cohort, and 16 patients were enrolled in the supine cohort. The 28-day mortality was 61.9% in the prone cohort and 68.8% in the supine cohort (P = 0.26), and 90-day mortality was 66.7% in the prone cohort and 68.8% in the supine cohort (P = 0.55). Patients in the supine cohort had fewer invasive mechanical ventilation days and more ventilator-free days. The incidence of complications was higher in the prone cohort than in the supine cohort.

CONCLUSIONS

In patients with pneumocystis pneumonia and moderate-severe acute respiratory distress syndrome, prone positioning did not decrease 28-day or 90-day mortality. Trial registration ClinicalTrials.gov number, ChiCTR2200063889. Registered on 20 September 2022, https://www.chictr.org.cn/showproj.html?proj=174886 .

Clinical and Radiological Features of Pneumocystis jirovecii Pneumonia in Children: A Case Series

BACKGROUND

Pneumocytis jirovecii pneumonia (PJP) has high mortality rates in immunocompromised children, even though routine prophylaxis has decreased in incidence. The aim of this case series is to present the radiological and clinical pathway of PJP in a pediatric population.

DESCRIPTION OF CASES

All PJP cases in non-HIV/AIDS patients diagnosed at Istituto Giannina Gaslini Pediatric Hospital in Genoa (Italy) from January 2012 until October 2022 were retrospectively evaluated. Nine cases were identified (median age: 8.3 years), and of these, 6/9 underwent prophylaxis with trimethoprim/sulfamethoxazole (TMP/SMX; five once-a-week schedules and one three times-a-week schedule), while 3/9 did not receive this. PJP was diagnosed by real-time PCR for P. jirovecii-DNA in respiratory specimens in 7/9 cases and two consecutive positive detections of β-d-glucan (BDG) in the serum in 2/9 cases. Most patients (6/8) had a CT scan with features suggestive of PJP, while one patient did not undergo a scan. All patients were treated with TMP/SMX after a median time from symptoms onset of 3 days. In 7/9 cases, empirical TMP/SMX treatment was initiated after clinical suspicion and radiological evidence and later confirmed by microbiological data. Clinical improvement with the resolution of respiratory failure and 30-day survival included 100% of the study population.

DISCUSSION

Due to the difficulty in obtaining biopsy specimens, PJP diagnosis is usually considered probable in most cases. Moreover, the severity of the clinical presentation often leads physicians to start TMP/SMX treatment empirically. BDG proved to be a useful tool for diagnosis, and CT showed good accuracy in identifying typical patterns. In our center, single-day/week prophylaxis was ineffective in high-risk patients; the three-day/week schedule would, therefore, seem preferable and, in any case, should be started promptly in all patients who have an indication of pneumonia.

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.

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 Secondary to Blinatumomab Therapy: A Case Report

INTRODUCTION

With the increasing use of blinatumomab in relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL), including minimal residual disease (MRD)-positive cases, awareness of its adverse effects has gradually improved. Pneumocystis jirovecii pneumonia (PCP) associated with blinatumomab therapy is rare.

CASE PRESENTATION

We present a case of PCP in a patient undergoing blinatumomab therapy. A 70-year-old female diagnosed with Philadelphia-like CRLF2 overexpression B-cell precursor ALL received blinatumomab as consolidation therapy after achieving complete remission with prior induction chemotherapy. On the second day of blinatumomab infusion, she developed intermittent low-grade fever, and chest computed tomography (CT) revealed subtle infiltrates and nodules. Despite empiric trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis, she progressed to significant shortness of breath and type I respiratory failure, with increased lactate dehydrogenase and β-D-glucan assays. Chest CT showed diffuse ground-glass opacities with scattered small nodules. The dry cough prompted next-generation sequencing of peripheral blood, which tested positive for pneumocystis jirovecii without evidence of other pathogens. Consequently, the patient was diagnosed with PCP. The first cycle of blinatumomab had to be discontinued, and therapeutic dosages of TMP-SMX and dexamethasone were administered, resulting in full recovery and stable condition during follow-ups.

CONCLUSION

PCP is rare in B-cell precursor ALL patients receiving blinatumomab therapy but manifests with early onset and rapid disease progression. Despite prophylaxis, PCP infection cannot be ignored during blinatumomab therapy. Therefore, heightened attention is warranted when using blinatumomab therapy.

The SSS revolution in fungal diagnostics: speed, simplicity and sensitivity

INTRODUCTION

Fungal disease has historically presented a diagnostic challenge due to its often non-specific clinical presentations, relative infrequency and reliance on insensitive and time-intensive fungal culture.

SOURCES OF DATA

We present the recent developments in fungal diagnostics in the fields of serological and molecular diagnosis for the most clinically relevant pathogens; developments that have the potential to revolutionize fungal diagnosis through improvements in speed, simplicity and sensitivity. We have drawn on a body of evidence including recent studies and reviews demonstrating the effectiveness of antigen and antibody detection and polymerase chain reaction (PCR) in patients with and without concurrent human immunodeficiency virus infection.

AREAS OF AGREEMENT

This includes recently developed fungal lateral flow assays, which have a low cost and operator skill requirement that give them great applicability to low-resource settings. Antigen detection for Cryptococcus, Histoplasma and Aspergillus spp. are much more sensitive than culture. PCR for Candida spp., Aspergillus spp., Mucorales and Pneumocystis jirovecii is more sensitive than culture and usually faster.

AREAS OF CONTROVERSY

Effort must be made to utilize recent developments in fungal diagnostics in clinical settings outside of specialist centres and integrate their use into standard medical practice. Given the clinical similarities of the conditions and frequent co-infection, further study is required into the use of serological and molecular fungal tests, particularly in patients being treated for tuberculosis.

GROWING POINTS

Further study is needed to clarify the utility of these tests in low-resource settings confounded by a high prevalence of tuberculosis.

AREAS TIMELY FOR DEVELOPING RESEARCH

The diagnostic utility of these tests may require revision of laboratory work flows, care pathways and clinical and lab coordination, especially for any facility caring for the immunosuppressed, critically ill or those with chronic chest conditions, in whom fungal disease is common and underappreciated.

Successful treatment of severe Pneumocystis Jirovecii pneumonia in a diffuse large B-cell lymphoma patient after R-CHOP chemotherapy: A case report

R-CHOP chemotherapy has been established as the first-line standard treatment for elderly patients diagnosed with diffuse large B-cell lymphoma. However, an increased risk of Pneumocystis jirovecii pneumonia in diffuse large B-cell lymphoma patients after the rituximab-based chemotherapy has been reported. We describe a case who developed intermittent cough, fever and shortness of breath after five cycles of R-CHOP treatment for diffuse large B-cell lymphoma. A rapid deterioration in patient's respiratory condition prompted us to adopt an aggressive anti- Pneumocystis jirovecii pneumonia strategy that combined the conventional trimethoprim/sulfamethoxazole and another two antimicrobials, caspofungin and clindamycin. This is the first report mentioning the successful treatment of severe Pneumocystis jirovecii pneumonia with a triple-drug regimen in a HIV-uninfected patient. The aim of our report is also to emphasize that early and correct diagnosis of Pneumocystis jirovecii pneumonia in immunocompromised HIV-uninfected patients is very important. Relevant oncologists should be alert to the risk of Pneumocystis jirovecii pneumonia in patients receiving R-CHOP chemotherapy.

Clinical characteristics and risk factors of in-hospital mortality in patients coinfected with Pneumocystis jirovecii and Aspergillus

OBJECTIVE

To analyze clinical characteristics and risk factors for in-hospital mortality in patients coinfected with P. jirovecii and Aspergillus.

METHODS

This study included 53 patients with coinfection of P. jirovecii pneumonia (PJP) and invasive pulmonary aspergillosis (IPA) in our center from January 2011 to December 2021. All cases were divided into survivor (n=27) and non-survivor groups (n=26). Medical records, laboratory and radiology data were collected. Risk factors for in-hospital mortality were identified by multivariable analyses.

RESULTS

HIV-positive patients accounted for 3.8%. Fever (77.4%), dyspnea (69.8%) and wet cough (24.5%) were common symptoms. Ground-glass opacity (83.0%), consolidation (71.7%), septal thickening (66.0%), and nodules (54.7%) were the most common radiological signs. CD4+ T cell count and serum albumin (ALB) level were significantly lower in non-survival group than in the survival group. Conversely, serum lactate dehydrogenase (LDH) and procalcitonin (PCT) levels were higher in non-survival group than in survival group. Lactic acidosis [odds ratio (OR): 33.999,95% confidential interval (CI): 3.112-371.409; p=0.004], low CD4+ T cell count (<114 cell/µL) [OR: 19.343, 95% CI: 1.533-259.380; p=0.022] and high level of LDH (> 519 U/L) [OR: 11.422, 95% CI: 1.271-102.669; p=0.030] were independent risk factors for mortality.

CONCLUSION

PJP coinfected with IPA incurs high mortality with nonspecific clinical characteristics and is more likely to involve HIV-negative patients. Lactic acidosis, low CD4+ T cell count and high LDH level are independent risk factors for mortality, close monitoring of these parameters is necessary to help distinguish high-risk patients and make appropriate clinical decisions.

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.

Metagenomic next-generation sequencing for the diagnosis of Pneumocystis jirovecii Pneumonia in critically pediatric patients

OBJECTIVE

The aim of this study was to evaluate the effectiveness of metagenomic next-generation sequencing (mNGS) for the diagnosis of Pneumocystis jirovecii Pneumonia (PCP) in critically pediatric patients.

METHODS

Seventeen critically pediatric patients with PCP and sixty patients diagnosed with non-PCP pneumonia who were admitted in pediatric intensive care unit between June 2018 and July 2021 were enrolled. Conventional methods and mNGS for detecting Pneumocystis jirovecii (P. jirovecii) were compared. The patients' demographics, comorbidities, laboratory test results, antibiotic treatment response and 30 day mortality were analyzed.

RESULT

The mNGS showed a satisfying diagnostic performance with a sensitivity of 100% in detecting P. jirovecii compared with Gomori methenamine silver staining (5.9%), serum (1,3)-β-D-glucan (86.7%) and and LDH (55.6%). The diagnostic specificity of mNGS for PCP was higher than that of serum BDG (56.7%) and LDH (71.4%). In PCP group, over one thirds' cases had mixed infections. Compared with survivors, non-survivors had higher stringently mapped read numbers (SMRNs) in bronchoalveolar lavage fluid (BALF) sample (P < 0.05), suggesting SMRNs were closely associated with the severity of response. The detection for P. jirovecii by mNGS both in BALF and blood samples reached a concordance rate of 100%, and the SMRNs in the BALF were remarkably higher than that in blood samples. Initial antimicrobial treatment was modified in 88.2% of PCP patients based on the mNGS results.

CONCLUSION

The mNGS is a potential and efficient technology in diagnosing PCP and shows a satisfying performance in the detection of co-pathogens. Both blood and BALF samples for mNGS are suggested for the presumptive diagnosis of PCP.

The diagnostic value of metagenomic next-generation sequencing for identifying Pneumocystis jirovecii infection in non-HIV immunocompromised patients

Background

Pneumocystis jirovecii pneumonia (PJP) remains an important cause of morbidity and mortality in non-HIV immunocompromised patients especially in transplant recipients. But its diagnosis remains challenging due to the insuffificient performance of conventional methods for diagnosing Pneumocystis jirovecii(P. jirovecii) infection. Therefore, the auxiliary diagnostic function of metagenomics next-generation sequencing (mNGS) in clinical practice is worth of exploring.

Method

34 non-HIV immunocompromised patients who were diagnosed as PJP by clinical manifestations, imaging findings, immune status of the host, and Methenamine silver staining were tested by mNGS from October 2018 to December 2020 in Sichuan Provincial People’s Hospital. The clinical performances of mNGS for P. jirovecii infection diagnosis were also evaluated with genome reads abundance and comparing with other traditional diagnostic methods.

Results

We diagnosed a total of 34 non-HIV PJP patients by the clinical composite diagnosis. Our data shows that, compared with the clinical microbiological test, the detection rate of mNGS for P. jirovecii in non-HIV infected PJP patients is significantly higher than that of Methenamine silver staining and serum 1-3-β-D-glucan. mNGS can be used as an auxiliary diagnostic tool to help diagnosis. The number of reads mapped to the genome of P. jirovecii and the duration of patients from onset to sampling collection were statistically significant between the two groups (Reads>100 and Reads ≤ 100) (8days vs. 23days, p=0.020). In addition, univariate analysis showed that C-reactive protein (15.8mg/L vs.79.56mg/L, p=0.016), lactate dehydrogenase (696U/l vs. 494U/l, p=0.030) and procalcitonin (0.09ng/ml vs. 0.59ng/ml, p=0.028) was also statistically significant between the two groups.

Conclusions

An effective detection rate was achieved in PJP patients using mNGS testing of bronchoalveolar lavage fluid (BALF) or blood. The study also confirmed that the abundance of reads of P. jirovecii is related to the interval between the onset and sample collection. And the inflammation status during simultaneous mNGS detection might determine the abundance of pathogens. Hence, we conclude that the mNGS strategy could benefit disease diagnosis as well as treatment when complicated clinical infections appeared.

Application of Extracorporeal Membrane Oxygenation in Patients With Severe Acute Respiratory Distress Syndrome Caused by Pneumocystis jirovecii Pneumonia Following Kidney Transplantation: A Case Series

Objective: To investigate the application effect of extracorporeal membrane oxygenation (ECMO) in patients with severe acute respiratory distress syndrome (ARDS) caused by Pneumocystis jirovecii pneumonia (PJP) after kidney transplantation.

Methods: This is a case series on 10 kidney transplant recipients with severe ARDS caused by PJP at the People’s Hospital of Zhengzhou, who were enrolled as the case group. A total of 17 cases of PJP diagnosed with severe ARDS without ECMO were selected as the control group. The timing and mode of ECMO support and treatment complications were summarized. The primary aim of this study was mortality and secondary was imaging and complications.

Results: The enrolled patients’ oxygenation index before the start of ECMO ranged from 25 to 92, and the time from admission to the start of ECMO was 1–17 days, with an average of 5.56 days. In the case group, one patient died of hemorrhagic shock due to abdominal hemorrhage, but the other nine patients were successfully weaned from ECMO. Of these patients, one died due to sepsis following weaning. The survival rate in the case group was 80.0% (8/10), and the survival rate in the control group was 35.29% (6/17). The vein–vein ECMO support time in the nine successfully weaned patients in the case group ranged from 131 to 288 h, with an average of 215.5 h. Of the eight patients who survived, deterioration of renal function after transplantation occurred in two patients, but no fatal complications occurred.

Conclusion: Overall, Patients with severe ARDS caused by postoperative PJP infection following kidney transplantation have a poor prognosis. The mortality was lower in patients who were treated with ECMO compared to standard care.

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.

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.

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.

A Clinically Applicable Nomogram for Predicting the Risk of Invasive Mechanical Ventilation in Pneumocystis jirovecii Pneumonia

Objective

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening disease associated with a high mortality rate among immunocompromised patient populations. Invasive mechanical ventilation (IMV) is a crucial component of treatment for PCP patients with progressive hypoxemia. This study explored the risk factors for IMV and established a model for early predicting the risk of IMV among patients with PCP.

Methods

A multicenter, observational cohort study was conducted in 10 hospitals in China. Patients diagnosed with PCP were included, and their baseline clinical characteristics were collected. A Boruta analysis was performed to identify potentially important clinical features associated with the use of IMV during hospitalization. Selected variables were further analyzed using univariate and multivariable logistic regression. A logistic regression model was established based on independent risk factors for IMV and visualized using a nomogram.

Results

In total, 103 patients comprised the training cohort for model development, and 45 comprised the validation cohort to confirm the model’s performance. No significant differences were observed in baseline clinical characteristics between the training and validation cohorts. Boruta analysis identified eight clinical features associated with IMV, three of which were further confirmed to be independent risk factors for IMV, including age (odds ratio [OR] 2.615 [95% confidence interval (CI) 1.110–6.159]; p = 0.028), oxygenation index (OR 0.217 [95% CI 0.078–0.604]; p = 0.003), and serum lactate dehydrogenase level (OR 1.864 [95% CI 1.040–3.341]; p = 0.037). Incorporating these three variables, the nomogram achieved good concordance indices of 0.829 (95% CI 0.752–0.906) and 0.818 (95% CI 0.686–0.950) in predicting IMV in the training and validation cohorts, respectively, and had well-fitted calibration curves.

Conclusions

The nomogram demonstrated accurate prediction of IMV in patients with PCP. Clinical application of this model enables early identification of patients with PCP who require IMV, which, in turn, may lead to rational therapeutic choices and improved clinical outcomes.

Long-Reads-Based Metagenomics in Clinical Diagnosis With a Special Focus on Fungal Infections

Identification of the causative infectious agent is essential in the management of infectious diseases, with the ideal diagnostic method being rapid, accurate, and informative, while remaining cost-effective. Traditional diagnostic techniques rely on culturing and cell propagation to isolate and identify the causative pathogen. These techniques are limited by the ability and the time required to grow or propagate an agent in vitro and the facts that identification based on morphological traits are non-specific, insensitive, and reliant on technical expertise. The evolution of next-generation sequencing has revolutionized genomic studies to generate more data at a cheaper cost. These are divided into short- and long-read sequencing technologies, depending on the length of reads generated during sequencing runs. Long-read sequencing also called third-generation sequencing emerged commercially through the instruments released by Pacific Biosciences and Oxford Nanopore Technologies, although relying on different sequencing chemistries, with the first one being more accurate both platforms can generate ultra-long sequence reads. Long-read sequencing is capable of entirely spanning previously established genomic identification regions or potentially small whole genomes, drastically improving the accuracy of the identification of pathogens directly from clinical samples. Long-read sequencing may also provide additional important clinical information, such as antimicrobial resistance profiles and epidemiological data from a single sequencing run. While initial applications of long-read sequencing in clinical diagnosis showed that it could be a promising diagnostic technique, it also has highlighted the need for further optimization. In this review, we show the potential long-read sequencing has in clinical diagnosis of fungal infections and discuss the pros and cons of its implementation.

Distinct Clinical and Laboratory Patterns of Pneumocystis jirovecii Pneumonia in Renal Transplant Recipients

Late post-transplant Pneumocystis jirovecii pneumonia (PcP) has been reported in many renal transplant recipients (RTRs) centers using universal prophylaxis. Specific features of PcP compared to other respiratory infections in the same population are not well reported. We analyzed clinical, laboratory, administrative and radiological data of all confirmed PcP cases between January 2009 and December 2014. To identify factors specifically associated with PcP, we compared clinical and laboratory data of RTRs with non-PcP. Over the study period, 36 cases of PcP were identified. Respiratory distress was more frequent in PcP compared to non-PcP (tachypnea: 59%, 20/34 vs. 25%, 13/53, p = 0.0014; dyspnea: 70%, 23/33 vs. 44%, 24/55, p = 0.0181). In contrast, fever was less frequent in PcP compared to non-PcP pneumonia (35%, 11/31 vs. 76%, 42/55, p = 0.0002). In both cohorts, total lymphocyte count and serum sodium decreased, whereas lactate dehydrogenase (LDH) increased at diagnosis. Serum calcium increased in PcP and decreased in non-PcP. In most PcP cases (58%, 21/36), no formal indication for restart of PcP prophylaxis could be identified. Potential transmission encounters, suggestive of interhuman transmission, were found in 14/36, 39% of patients. Interhuman transmission seems to contribute importantly to PcP among RTRs. Hypercalcemia, but not elevated LDH, was associated with PcP when compared to non-PcP.

Conditional control of chimeric antigen receptor T-cell activity through a destabilizing domain switch and its chemical ligand

BACKGROUND AIMS

Despite the impressive efficacy of chimeric antigen receptor (CAR) T-cell therapy, adverse effects, including cytokine release syndrome and neurotoxicity, impede its therapeutic application, thus making the modulation of CAR T-cell activity a priority. The destabilizing domain mutated from Escherichia coli dihydrofolate reductase (DHFR) is inherently unstable and degraded by proteasomes unless it is stabilized by its chemical ligand trimethoprim (TMP), a Food and Drug Administration-approved drug. Here the authors reveal a strategy to modulate CAR T-cell activity at the protein level by employing DHFR and TMP as a chemical switch system.

METHODS

First, the system was demonstrated to work in human primary T cells. To introduce the system to CAR T cells, DHFR was genetically fused to the carboxyl terminal of a third-generation CAR molecule targeting CD19 (CD19-CAR), constructing the CD19-CAR-DHFR fusion.

RESULTS

The CD19-CAR-DHFR molecule level was shown to be modulated by TMP. Importantly, the incorporation of DHFR had no impact on the recognition specificity and normal function of the CAR molecule. Little adverse effect on cell proliferation and apoptosis was detected. It was proved that TMP could regulate cytokine secretion and the in vitro cytotoxicity of CD19-CAR-DHFR T cells. Furthermore, the in vivo anti-tumor efficacy was demonstrated to be controllable through the manipulation of TMP administration. The approach to control CD19-CAR also succeeded in 19-BBZ(71), another CD19-targeting CAR with a different structure.

CONCLUSIONS

The proposed approach based on DHFR and TMP provides a facile strategy to bring CAR T-cell therapy under conditional user control, and the strategy may have the potential to be transplantable.

Lessons from an Educational Invasive Fungal Disease Conference on Hospital Antifungal Stewardship Practices across the UK and Ireland

Invasive fungal disease (IFD) is a growing health burden. High mortality rates, increasing numbers of at-risk hosts, and a limited availability of rapid diagnostics and therapeutic options mean that patients are increasingly exposed to unnecessary antifungals. High rates of prescriptions promote patient exposure to undue toxicity and drive the emergence of resistance. Antifungal stewardship (AFS) aims to guide antifungal usage and reduce unnecessary exposure and antifungal consumption whilst maintaining or improving outcomes. Here, we examine several AFS approaches from hospitals across the UK and Ireland to demonstrate the benefits of AFS practices and support the broader implementation of AFS as both a necessary and achievable strategy. Since the accuracy and turnaround times (TATs) of diagnostic tools can impact treatment decisions, several AFS strategies have included the development and implementation of diagnostic-driven care pathways. AFS informed treatment strategies can help stratify patients on a risk basis ensuring the right patients receive antifungals at the optimal time. Using a multidisciplinary approach is also key due to the complexity of managing and treating patients at risk of IFD. Through knowledge sharing, such as The Gilead Antifungal Information Network (GAIN), we hope to drive practices that improve patient management and support the preservation of antifungals for future use.

Multiplex Real-Time Polymerase Chain Reaction on Sputum for the Diagnosis of Pneumocystis jirovecii Pneumonia in Children: A Retrospective Study

Background

Pneumocystis jirovecii pneumonia (PCP) is a serious opportunistic infection in immunocompromised children. Real-time polymerase chain reaction (PCR) is widely used for the diagnosis of PCP due to its good accuracy. However, the diagnostic performance of multiplex real-time PCR on sputum in children with PCP has never been explored.

Methods

Medical records of 63 consecutive pediatric patients were analyzed retrospectively, including 13 cases with PCP and 50 with non-PCP pneumonia. Pneumocystis jirovecii (P. jirovecii) and other co-pathogens detected by multiplex real-time PCR in sputum samples were summarized. Using clinical composite diagnosis as the reference standard, we further compared the diagnostic performance of multiplex real-time PCR to combined serological markers (1,3)-β-D-glucan plus lactate dehydrogenase. Additionally, modifications of antimicrobial treatment for pediatric PCP patients after the report of multiplex real-time PCR results were reviewed.

Results

In children with PCP, nonproductive cough and shortness of breath were more common, lymphocyte count in peripheral blood was markedly lower, and serum levels of (1,3)-β-D-glucan and lactate dehydrogenase were much higher than non-PCP group. Multiplex real-time PCR reached a sensitivity of 100% in diagnosing PCP, which was better than serum (1,3)-β-D-glucan plus lactate dehydrogenase (76.9%). Its specificity (98.0%) significantly surpassed serum (1,3)-β-D-glucan plus lactate dehydrogenase (84.4%). Furthermore, multiplex real-time PCR showed a good performance in identifying co-pathogens in sputum of pediatric PCP patients. Cytomegalovirus, Epstein–Barr virus and Streptococcus pneumoniae were the most common co-pathogens in these patients. Initial antimicrobial treatment was modified in 76.9% of children with PCP after the report of PCR results.

Conclusion

Multiplex real-time PCR on sputum is a diagnostic tool with good performance for the identification of P. jirovecii as well as co-pathogens in children with PCP. Sputum may be an alternative to bronchoalveolar lavage fluid for PCR assay in children when bronchoscopic examination is not feasible.

Metagenomic Next-Generation Sequencing of Bloodstream Microbial Cell-Free Nucleic Acid in Children With Suspected Sepsis in Pediatric Intensive Care Unit

Bloodstream infection is a life-threatening complication in critically ill patients. Multi-drug resistant bacteria or fungi may increase the risk of invasive infections in hospitalized children and are difficult to treat in intensive care units. The purpose of this study was to use metagenomic next-generation sequencing (mNGS) to understand the bloodstream microbiomes of children with suspected sepsis in a pediatric intensive care unit (PICU). mNGS were performed on microbial cell-free nucleic acid from 34 children admitted to PICU, and potentially pathogenic microbes were identified. The associations of serological inflammation indicators, lymphocyte subpopulations, and other clinical phenotypes were also examined. mNGS of blood samples from children in PICU revealed potential eukaryotic microbial pathogens. The abundance of Pneumocystis jirovecii was positively correlated with a decrease in total white blood cell count and immunodeficiency. Hospital-acquired pneumonia patients showed a significant increase in blood bacterial species richness compared with community-acquired pneumonia children. The abundance of bloodstream bacteria was positively correlated with serum procalcitonin level. Microbial genome sequences from potential pathogens were detected in the bloodstream of children with suspected sepsis in PICU, suggesting the presence of bloodstream infections in these children.

A Negative (1,3)-β-D-Glucan Result Alone Is Not Sufficient to Rule Out a Diagnosis of Pneumocystis Pneumonia in Patients With Hematological Malignancies

Background: Serum (1,3)-β-D-glucan (BG) testing is increasingly being used in the diagnostic armamentarium for invasive fungal diseases. Given its high sensitivity, some studies suggest that a negative BG result contributes to rule out a diagnosis of Pneumocystis pneumonia (PCP). However, recent reports described a suboptimal sensitivity in HIV-negative immunocompromised patients. In this study, we evaluated the performance of BG assay for PCP diagnosis in HIV-negative patients with diverse PCP risk factors. We also assessed the correlation between Pneumocystis jirovecii load in pulmonary samples and serum BG levels.

Methods: We retrospectively included HIV-negative patients with microscopically proven PCP and for whom a BG result was available. We also enrolled patients colonized by Pneumocystis as control group. Colonized patients were matched with PCP patients based on their underlying condition that exposed to PCP. Pulmonary fungal loads were determined by an in-house real-time PCR, and BG levels were measured by using the Fungitell® kit (Associates of Cape Cod, Inc.).

Results: Thirty-nine patients were included in each of the two groups. Thirty-four of 39 PCP patients and one of 39 colonized patient had a positive BG test, resulting in a sensitivity of 0.87 (95% CI: 0.73–0.94), a specificity of 0.97 (95% CI: 0.87–0.99), a positive predictive value of 0.97 (95% CI: 0.85–0.99), and a negative predictive value of 0.88 (95% CI: 0.75–0.95) for BG assay. Nonetheless, median BG level differed according to the underlying condition. Among the PCP group, the lowest median level of 211 pg/ml was observed in patients with hematological malignancy (HM) and differed significantly from that observed either in solid organ transplants (3,473 pg/ml) or in patients with autoimmune or inflammatory disorder (3,480 pg/ml). Indeed, the sensitivity of BG assay was estimated at 0.64 (95% CI: 0.35–0.85) in HM patients and was lower than the one observed in the whole PCP group. Furthermore, BG level and fungal burden correlated poorly among all PCP patients.

Conclusion: BG is not a reliable biomarker for ruling out PCP in HIV-negative patients with HM. Interpretation of a negative BG result should take into account, but not be limited to, the underlying condition predisposing to PCP.

Metagenomic Next-Generation Sequencing for the Diagnosis of Pneumocystis jirovecii Pneumonia in Non-HIV-Infected Patients: A Retrospective Study

Introduction

This study aimed to evaluate the utility of metagenomic next-generation sequencing (mNGS) for the diagnosis of Pneumocystis jirovecii pneumonia (PJP) in non-human immunodeficiency virus-infected patients.

Methods

We conducted a retrospective study. A total of 60 non-human immunodeficiency virus-infected PJP patients and 134 patients diagnosed with non-PJP pneumonia were included. P. jirovecii and other co-pathogens identified by mNGS in bronchoalveolar lavage fluid and/or blood samples were analyzed. Using clinical composite diagnosis as the reference standard, we compared the diagnostic performance of mNGS in PJP with conventional methods, including Gomori methenamine silver staining and serum (1,3)-β-d-glucan. Modifications of antimicrobial treatment for PJP patients after the report of mNGS results were also reviewed.

Results

mNGS reached a sensitivity of 100% in diagnosing PJP, which was remarkably higher than Gomori methenamine silver staining (25.0%) and serum (1,3)-β-d-glucan (67.4%). The specificity of mNGS (96.3%) significantly surpassed serum (1,3)-β-d-glucan (81.4%). Simultaneous mNGS of bronchoalveolar lavage fluid and blood samples was performed in 21 out of 60 PJP patients, and it showed a concordance rate of 100% in detecting P. jirovecii. Besides, mNGS showed good performance in identifying co-pathogens of PJP patients, among which cytomegalovirus and Epstein-Barr virus were most commonly seen. Initial antimicrobial treatment was modified in 71.7% of PJP patients after the report of mNGS results.

Conclusion

mNGS is a useful diagnostic tool with good performance for the diagnosis of PJP and the detection of co-pathogens. mNGS of bronchoalveolar lavage fluid and/or blood samples is suggested in patients with presumptive diagnosis of PJP. Blood samples may be a good alternative to bronchoalveolar lavage fluid for mNGS when bronchoscopic examination is not feasible.

Detection of Pneumocystis jirovecii in Hospitalized Children Less Than 3 Years of Age

Few data are available in the literature regarding Pneumocystis jirovecii infection in children under 3 years old. This retrospective cohort study aimed to describe medically relevant information among them. All children under 3 years old treated in the same medical units from April 2014 to August 2020 and in whom a P. jirovecii evaluation was undertaken were enrolled in the study. A positive case was defined as a child presenting at least one positive PCR for P. jirovecii in a respiratory sample. Medically relevant information such as demographical characteristics, clinical presentation, microbiological co-infections, and treatments were collected. The objectives were to describe the characteristics of these children with P. jirovecii colonization/infection to determine the key underlying diseases and risk factors, and to identify viral respiratory pathogens associated. The PCR was positive for P. jirovecii in 32 children. Cardiopulmonary pathologies (21.9%) were the most common underlying disease in them, followed by severe combined immunodeficiency (SCID) (18.8%), hyaline membrane disease (15.6%), asthma (9.4%) and acute leukaemia (6.3%). All SCID children were diagnosed with pneumocystis pneumonia. Co-infection with Pj/Rhinovirus (34.4%) was not significant. Overall mortality was 18.8%. Paediatric pneumocystis is not restricted to patients with HIV or SCID and should be considered in pneumonia in children under 3 years old.

Clinical Impact of Metagenomic Next-Generation Sequencing of Bronchoalveolar Lavage in the Diagnosis and Management of Pneumonia: A Multicenter Prospective Observational Study

Rapid and accurate pathogen identification is necessary for appropriate treatment of pneumonia. Here, we describe the use of shotgun metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage for pathogen identification in pneumonia in a large-scale multicenter prospective study with 159 patients enrolled. We compared the results of mNGS with standard methods including culture, staining, and targeted PCR, and evaluated the clinical impact of mNGS. A positive impact was defined by a definitive diagnosis made using the mNGS results, or change of management because of the mNGS results, leading to a favorable clinical outcome. Overall, mNGS identified more organisms than standard methods (117 versus 72), detected 17 pathogens that consistently were missed in all cases by standard methods, and had an overall positive clinical impact in 40.3% (64 of 159) of cases. mNGS was especially useful in identification of fastidious and atypical organisms causing pneumonia, contributing to detection of definitive pathogens in 45 (28.3%) cases in which standard results were either negative or insufficient. mNGS also helped reassure antibiotic de-escalation in 19 (11.9%) cases. Overall, mNGS led to a change of treatment in 59 (37.1%) cases, including antibiotic de-escalation in 40 (25.2%) cases. This study showed the significant value of mNGS of bronchoalveolar lavage for improving the diagnosis of pneumonia and contributing to better patient care.

Diagnostic accuracy of the 1,3-beta-D-glucan test and lactate dehydrogenase for pneumocystis pneumonia in non-HIV patients

We evaluated the serum levels of (1–3)-beta-d-glucan (BG) and lactate dehydrogenase (LDH) as a tool to support pneumocystis pneumonia (PCP) diagnostic procedures in non-HIV patients. We retrospectively collected non-HIV (human immunodeficiency virus) patients presenting clinical features of PCP between April 1st, 2013, and December 31st, 2018. A total of 225 included patients were tested for Pneumocystis jirovecii by polymerase chain reaction (PCR) and methenamine silver staining. Based on different exclusion criteria, 179 cases were included in the BG group, and 196 cases were included in the LDH group. In each group, cases with positive immunofluorescence (IF) microscopy and PCR were considered proven PCP, while cases with only positive PCR were considered probable PCP. Fifty patients with negative IF and PCR results and proven to be non-PCP infection were chosen randomly as the control group. The cut-off levels of BG and LDH to distinguish non-PCP from probable PCP were 110 pg/mL and 296 U/L with 88% sensitivity and 86% specificity, and 66% sensitivity and 88% specificity, respectively. The cut-off levels of BG and LDH to distinguish non-PCP from proven PCP were 285.8 pg/mL and 379 U/L with 92% sensitivity and 96% specificity, and 85% sensitivity and 77% specificity, respectively. The cut-off levels of BG and LDH to distinguish non-PCP from proven/probable PCP were 144.1 pg/mL and 363 U/L with 90% sensitivity, 86% specificity and 80% sensitivity, 76% specificity respectively. BG and LDH are reliable indicators for detecting P. jirovecii infection in HIV-uninfected immunocompromised patients.

COVID-19 and Pneumocystis jirovecii Pulmonary Coinfection-The First Case Confirmed through Autopsy

Background: Establishing the diagnosis of COVID-19 and Pneumocystisjirovecii pulmonary coinfection is difficult due to clinical and radiological similarities that exist between the two disorders. For the moment, fungal coinfections are underestimated in COVID-19 patients. Case presentation: We report the case of a 52-year-old male patient, who presented to the emergency department for severe dyspnea and died 17 h later. The RT-PCR test performed at his admission was negative for SARS-CoV-2. Retesting of lung fragments collected during autopsy revealed a positive result for SARS-CoV-2. Histopathological examination showed preexisting lesions, due to comorbidities, as well as recent lesions: massive lung thromboses, alveolar exudate rich in foam cells, suprapleural and intra-alveolar Pneumocystisjirovecii cystic forms, and bilateral adrenal hemorrhage. Conclusion: COVID-19 and P.jirovecii coinfection should be considered, particularly in critically ill patients, and we recommend the systematic search for P. jirovecii in respiratory samples.

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.

Critically ill patients with cancer: A clinical perspective

Cancer patients account for 15% of all admissions to intensive care unit (ICU) and 5% will experience a critical illness resulting in ICU admission. Mortality rates have decreased during the last decades because of new anticancer therapies and advanced organ support methods. Since early critical care and organ support is associated with improved survival, timely identification of the onset of clinical signs indicating critical illness is crucial to avoid delaying. This article focused on relevant and current information on epidemiology, diagnosis, and treatment of the main clinical disorders experienced by critically ill cancer patients.

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.

Diagnostic performance of the Sputum Gram Stain in predicting sputum culture results for critically ill pediatric patients with pneumonia

BACKGROUND

The sputum Gram stain is an inexpensive, rapid, and convenient laboratory method that predicts the bacterial pathogens in patients with pneumonia. This study aimed to evaluate the diagnostic performance of this method in predicting sputum culture results for critically ill pediatric patients.

METHODS

From June 2008 to June 2018, patients with pneumonia with an endotracheal or a tracheostomy tube in place in the Pediatric Intensive Care Unit at Changhua Christian Hospital were enrolled retrospectively. Sputum was collected from each patient via the artificial airway for Gram stain and culture evaluations of bacterial pathogens. Mixed culture results were excluded. A successful prediction was defined as a match of the sputum Gram stain and culture results.

RESULTS

A total of 622 records were reviewed, of which 542 were analyzed. Haemophilus influenzae, Pseudomonas aeruginosa, and Streptococcus pneumoniae were the three most common pathogens found. The overall prediction success rate of the sputum Gram stain was 59.23%. The sensitivity of the method in predicting gram-negative bacilli (GNB), gram-negative cocci (GNC), and gram-positive cocci (GPC) was 0.45, 0.67, and 0.61, respectively. Its specificity in predicting GNB, GNC, and GPC was 0.87, 0.98, and 0.87, respectively. Its positive likelihood ratio in predicting GNB, GNC, and GPC was 3.46, 33.50, and 4.69, respectively. The highest prediction success rate among all pathogens was for GNC.

CONCLUSION

The sputum Gram stain had high specificity and relatively low sensitivity in predicting the bacterial pathogens in critically ill pediatric patients. Its high specificity in predicting sputum culture results means that clinicians can confidently use sputum Gram stain results to guide their antibiotic choice for treatment.

Prognosis of pathogen-proven acute respiratory distress syndrome diagnosed from a protocol that includes bronchoalveolar lavage: a retrospective observational study

Background

To treat patients with acute respiratory distress syndrome (ARDS), it is important to diagnose specific lung diseases and identify common risk factors. Our facility focuses on using bronchoalveolar lavage (BAL) to identify precise risk factors and determine the causative pathogen of ARDS within 24 h of intensive care unit (ICU) admission. This study evaluated the prognoses of pathogen-proven ARDS patients who were diagnosed or identified with risk factors using a diagnostic protocol, which included BAL, compared with the prognoses of pathogen-unproven ARDS patients.

Methods

This retrospective observational study was conducted in the ICU at a tertiary hospital from October 2015 to January 2019. We enrolled patients with respiratory distress who were on mechanical ventilation for more than 24 h in the ICU and who were subjected to our diagnostic protocol. We compared the disease characteristics and mortality rates between pathogen-proven and pathogen-unproven ARDS patients.

Results

Seventy ARDS patients were included, of whom, 50 (71%) had pathogen-proven ARDS as per our protocol. Mortality rates in both the ICU and the hospital were significantly lower among pathogen-proven ARDS patients than among pathogen-unproven ARDS patients (10% vs. 50%, p = 0.0006; 18% vs. 55%, p = 0.0038, respectively). Pathogen-proven ARDS patients were independently associated with hospital survival (adjusted hazard ratio, 0.238; 95% confidence interval, 0.096–0.587; p = 0.0021).

Conclusions

Our diagnostic protocol, which included early initiation of BAL, enabled diagnosing pathogen-proven ARDS in 71% of ARDS patients. These patients were significantly associated with higher hospital survival rates. The diagnostic accuracy of our diagnostic protocol, which includes BAL, remains unclear.

Huertas C, Calderón EJ, Eritja R, Lechuga LM. Fast and Accurate Pneumocystis Pneumonia Diagnosis in Human Samples Using a Label-Free Plasmonic Biosensor

Pneumocystis jirovecii is a fungus responsible for human Pneumocystis pneumonia, one of the most severe infections encountered in immunodepressed individuals. The diagnosis of Pneumocystis pneumonia continues to be challenging due to the absence of specific symptoms in infected patients. Moreover, the standard diagnostic method employed for its diagnosis involves mainly PCR-based techniques, which besides being highly specific and sensitive, require specialized personnel and equipment and are time-consuming. Our aim is to demonstrate an optical biosensor methodology based on surface plasmon resonance to perform such diagnostics in an efficient and decentralized scheme. The biosensor methodology employs poly-purine reverse-Hoogsteen hairpin probes for the detection of the mitochondrial large subunit ribosomal RNA (mtLSU rRNA) gene, related to P. jirovecii detection. The biosensor device performs a real-time and label-free identification of the mtLSU rRNA gene with excellent selectivity and reproducibility, achieving limits of detection of around 2.11 nM. A preliminary evaluation of clinical samples showed rapid, label-free and specific identification of P. jirovecii in human lung fluids such as bronchoalveolar lavages or nasopharyngeal aspirates. These results offer a door for the future deployment of a sensitive diagnostic tool for fast, direct and selective detection of Pneumocystis pneumonia disease.

Epidemiology of Pneumocystis jirovecii Pneumonia and (Non-)use of Prophylaxis

Objectives: Pneumocystis jirovecii pneumonia (PCP) is an AIDS-defining illness. In patients with HIV, the benefit of PCP prophylaxis is well-defined when the CD4 T-cell count decreases below 200 cells/μL. In other immunocompromised patients, the value of PCP prophylaxis is not always as well-established. This study aimed to describe the epidemiology of PCP in recent years and assess how many patients with PCP did or did not receive prophylaxis in the month preceding the infection. Material and Methods: A multicenter retrospective study was performed in 3 tertiary care hospital. A list of patients that underwent broncho-alveolar lavage sampling and Pneumocystis jirovecii (PJ) PCR testing was retrieved from the microbiology laboratories. An in-house PJ quantitative PCR (qPCR) was used in each center. A cycle threshold (Ct) value of ≤ 28.5-30 was considered a probable PCP. For patients with a positive PJ qPCR but above this threshold, a predefined case definition of possible PCP was defined as a qPCR Ct value ≤ 34-35 and both of the following criteria: 1. Clinical and radiological features compatible with PCP and 2. The patient died or received PCP therapy and survived. Patient files from those with a qPCR Ct value ≤ 35 were reviewed to determine whether the patient fulfilled the case definition and if PCP prophylaxis had been used in the weeks preceding the PCP. Disease-specific guidelines, as well as hospital-wide guidelines, were used to evaluate if prophylaxis could be considered indicated. Results: From 2012 to 2018, 482 BAL samples were tested. Two hundred and four had a qPCR Ct value ≤ 35 and were further evaluated: 90 fulfilled the definition of probable and 63 of possible PCP while the remaining 51 were considered colonized. Seventy-four percentages of the patients with PCP were HIV-negative. Only 11 (7%) of the 153 patients had received prophylaxis, despite that in 133 (87%) cases prophylaxis was indicated according to guidelines. Conclusion: In regions where HIV testing and treatment is available without restrictions, PCP is mainly diagnosed in non-HIV immunocompromised patients. More than four out of five patients with PCP had not received prophylaxis. Strategies to improve awareness of antimicrobial prophylaxis guidelines in immunocompromised patients are urgently needed.

Ability of quantitative PCR to discriminate Pneumocystis jirovecii pneumonia from colonization

Introduction.

Pneumocystis jirovecii pneumonia (PCP) is a severe disease affecting immunocompromised patients. Diagnosis is difficult due to the low sensitivity of direct examination and inability to grow the pathogen in culture. Quantitative PCR in bronchoalveolar lavage fluid (BAL) has high sensitivity, but limited specificity for distinguishing PCP from colonization.

Aim.

To assess the performance of an in-house quantitative PCR to discriminate between PCP and colonization.

Methodology.

This was a single-centre retrospective study including all patients with a positive PCR result for P. jirovecii in BAL between 2009 and 2017. Irrespective of PCR results, PCP was defined as the presence of host factors and clinical/radiological criteria consistent with PCP and (i) the presence of asci at direct examination of respiratory sample or (ii) anti-PCP treatment initiated with clinical response and absence of alternative diagnosis. Colonization was considered for cases who did not receive anti-PCP therapy with a favourable outcome or an alternative diagnosis. Cases who did not meet the above mentioned criteria were classified as ‘undetermined’.

Results.

Seventy-one patients with positive P. jirovecii PCR were included (90 % non-HIV patients). Cases were classified as follows: 37 PCP, 22 colonization and 12 undetermined. Quantitative PCR values in BAL were significantly higher in patients with PCP versus colonization or undetermined (P<0.0001). The cut-off of 5×10³ copies/ml was able to discriminate PCP cases from colonization with 97 % sensitivity, 82 % specificity, 90 % positive predictive value and 95 % negative predictive value.

Conclusions.

Our quantitative PCR for P. jirovecii in BAL was reliable to distinguish PCP cases from colonization in this predominantly non-HIV population.

A New Age in Molecular Diagnostics for Invasive Fungal Disease: Are We Ready?

Invasive fungal diseases (IFDs) present an increasing global burden in immunocompromised and other seriously ill populations, including those caused by pathogens which are inherently resistant or less susceptible to antifungal drugs. Early diagnosis encompassing accurate detection and identification of the causative agent and of antifungal resistance is critical for optimum patient outcomes. Many molecular-based diagnostic approaches have good clinical utility although interpretation of results should be according to clinical context. Where an IFD is in the differential diagnosis, panfungal PCR assays allow the rapid detection/identification of fungal species directly from clinical specimens with good specificity; sensitivity is also high when hyphae are seen in the specimen including in paraffin-embedded tissue. Aspergillus PCR assays on blood fractions have good utility in the screening of high risk hematology patients with high negative predictive value (NPV) and positive predictive value (PPV) of 94 and 70%, respectively, when two positive PCR results are obtained. The standardization, and commercialization of Aspergillus PCR assays has now enabled direct comparison of results between laboratories with commercial assays also offering the simultaneous detection of common azole resistance mutations. Candida PCR assays are not as well standardized with the only FDA-approved commercial system (T2Candida) detecting only the five most common species; while the T2Candida outperforms blood culture in patients with candidemia, its role in routine Candida diagnostics is not well defined. There is growing use of Mucorales-specific PCR assays to detect selected genera in blood fractions. Quantitative real-time Pneumocystis jirovecii PCRs have replaced microscopy and immunofluorescent stains in many diagnostic laboratories although distinguishing infection may be problematic in non-HIV-infected patients. For species identification of isolates, DNA barcoding with dual loci (ITS and TEF1α) offer optimal accuracy while next generation sequencing (NGS) technologies offer highly discriminatory analysis of genetic diversity including for outbreak investigation and for drug resistance characterization. Advances in molecular technologies will further enhance routine fungal diagnostics.

Point-Counterpoint: Should Serum β-d-Glucan Testing Be Used for the Diagnosis of Pneumocystis jirovecii Pneumonia?

INTRODUCTIONDespite the widespread use of prophylactic antibiotics in high-risk individuals, Pneumocystis jirovecii remains an important cause of pneumonia in immunocompromised patients. During the peak of the AIDS epidemic, many hospitals and outpatient clinics were very proficient at collecting induced sputum specimens for the diagnosis of Pneumocystis jirovecii pneumonia (PJP). With the dramatic reduction in the occurrence PJP in the current era of highly effective antiretroviral therapy, many centers no longer collect induced sputum samples. Thus, the diagnosis of PJP requires bronchoalveolar lavage (BAL) specimens or a decision to treat the patient empirically without a definitive diagnosis. Sputum or BAL specimens are tested for P. jirovecii using special stains or molecular assays, which require highly trained staff that may not be available with a rapid turnaround time. Given the invasive nature of collecting BAL specimens and the expertise needed for interpreting PJP test results, there is interest in using serum 1,3-β-d-glucan (BDG) testing for the diagnosis of PJP. In this point-counterpoint, Luis Ostrosky-Zeichner and Gabriela Corsi-Vasquez discuss the pro view of using BDG testing for the diagnosis of PJP, while Paul E. Sax and Edward F. Pilkington III present the con view of using BDG testing for the diagnosis of PJP.

Non-antibiotic Small-Molecule Regulation of DHFR-Based Destabilizing Domains In Vivo

The E. coli dihydrofolate reductase (DHFR) destabilizing domain (DD), which shows promise as a biologic tool and potential gene therapy approach, can be utilized to achieve spatial and temporal control of protein abundance in vivo simply by administration of its stabilizing ligand, the routinely prescribed antibiotic trimethoprim (TMP). However, chronic TMP use drives development of antibiotic resistance (increasing likelihood of subsequent infections) and disrupts the gut microbiota (linked to autoimmune and neurodegenerative diseases), tempering translational excitement of this approach in model systems and for treating human diseases. Herein, we identified a TMP-based, non-antibiotic small molecule, termed 14a (MCC8529), and tested its ability to control multiple DHFR-based reporters and signaling proteins. We found that 14a is non-toxic and can effectively stabilize DHFR DDs expressed in mammalian cells. Furthermore, 14a crosses the blood-retinal barrier and stabilizes DHFR DDs expressed in the mouse eye with kinetics comparable to that of TMP (≤6 h). Surprisingly, 14a stabilized a DHFR DD in the liver significantly better than TMP did, while having no effect on the mouse gut microbiota. Our results suggest that alternative small-molecule DHFR DD stabilizers (such as 14a) may be ideal substitutes for TMP in instances when conditional, non-antibiotic control of protein abundance is desired in the eye and beyond.

Outbreak-Causing Fungi: Pneumocystis jirovecii

Pneumocystis jirovecii pneumonia (PCP) is an important cause of morbidity in immunocompromised patients, with a higher mortality in non-HIV than in HIV patients. P. jirovecii is one of the rare transmissible pathogenic fungi and the only one that depends fully on the host to survive and proliferate. Transmissibility among humans is one of the main specificities of P. jirovecii. Hence, the description of multiple outbreaks raises questions regarding preventive care management of the disease, especially in the non-HIV population. Indeed, chemoprophylaxis is well codified in HIV patients but there is a trend for modifications of the recommendations in the non-HIV population. In this review, we aim to discuss the mode of transmission of P. jirovecii, identify published outbreaks of PCP and describe molecular tools available to study these outbreaks. Finally, we discuss public health and infection control implications of PCP outbreaks in hospital setting for in- and outpatients.

High initial (1, 3) Beta-d-Glucan concentration may be a predictor of satisfactory response of c aspofungin combined with TMP/SMZ for HIV-negative patients with moderate to severe Pneumocystis jirovecii pneumonia

OBJECTIVES

The aim of this study was to investigate the efficacy of combination therapy of caspofungin and TMP/SMZ (trimethoprim/sulfamethoxazole) in moderate to severe pneumocystis jirovecii pneumonia (PJP) in patients without human immunodeficiency virus infection (HIV) and the relationship between therapeutic effect and plasma (1, 3) Beta-d-Glucan (BDG) levels.

METHODS

We retrospectively reviewed HIV-negative patients with PJP diagnosed in our department, who were treated with combination therapy of caspofungin and TMP/SMZ or monotherapy of TMP/SMZ during a six and a half year period.

RESULTS

A total of 126 moderate to severe PJP patients were enrolled in the study. In the multivariate analysis, low lymphocyte counts, high serum lactate dehydrogenase levels at the diagnosis of PJP and progression to shock were significant risk factors for death. In all patients, there was no significant difference in risk of death at 3 months. In the group of BDG≥800pg/m, patients receiving combination therapy was associated with a significantly decreased risk of death at 3 months, whereas in the group of BDG<800pg/ml, there were no statistically significant difference in survival rate between the two treatment regimens.

CONCLUSION

High initial plasma (1, 3) Beta-d-Glucan concentration may be a predictor of satisfactory caspofungin response to HIV-negative patients with PJP. Based on our findings, we suggest the choice of combination therapy with caspofungin and TMP/SMZ as the initial treatment when BDG≥800pg/ml in moderate to severe HIV-negative patients with PJP.

Comparative Evaluation Between the RealStar Pneumocystis jirovecii PCR Kit and the AmpliSens Pneumocystis jirovecii (carinii)-FRT PCR Kit for Detecting P. jirovecii in Non-HIV Immunocompromised Patients

BACKGROUND

Real-time PCR is more sensitive than microscopic examination for detecting Pneumocystis jirovecii. We compared the performance of two assays for detecting P. jirovecii DNA: the RealStar Pneumocystis jirovecii PCR Kit 1.0 CE (Altona Diagnostics, Hamburg, Germany) and the AmpliSens Pneumocystis jirovecii (carinii)-FRT PCR kit (InterLabService Ltd., Moscow, Russia).

METHODS

We used 159 samples from the lower respiratory tract (112 bronchoalveolar lavage [BAL] fluid, 37 sputum, and 10 endotracheal aspirate [ETA] samples) of non-HIV immunocompromised patients. Nested PCR and sequencing were used to resolve discordant results. The performance of the two assays was evaluated according to clinical categories (clinical Pneumocystis pneumonia [PCP], possible PCP, or unlikely PCP) based on clinical and radiological observations.

RESULTS

The positive and negative percent agreement values were 100% (95% confidence interval [CI], 85.4-100%) and 96.6% (95% CI, 90.9-98.9%), respectively, and kappa was 0.92 (95% CI, 0.84-0.99). P. jirovecii DNA load was significantly higher in the clinical PCP group than in the other groups (P<0.05). When stratified by sample type, the positive rate for BAL fluids from the clinical PCP group was 100% using either assay, whereas the positive rate for sputum/ETA samples was only 20%.

CONCLUSIONS

The two assays showed similar diagnostic performance and detected low P. jirovecii burden in BAL fluids. Both assays may be useful as routine methods for detecting P. jirovecii DNA in a clinical laboratory setting, though their results should be interpreted considering sample type.

Therapy and Management of Pneumocystis jirovecii Infection

The rates of Pneumocystis pneumonia (PcP) are increasing in the HIV-negative susceptible population. Guidance for the prophylaxis and treatment of PcP in HIV, haematology, and solid-organ transplant (SOT) recipients is available, although for many other populations (e.g., auto-immune disorders) there remains an urgent need for recommendations. The main drug for both prophylaxis and treatment of PcP is trimethoprim/sulfamethoxazole, but resistance to this therapy is emerging, placing further emphasis on the need to make a mycological diagnosis using molecular based methods. Outbreaks in SOT recipients, particularly renal transplants, are increasingly described, and likely caused by human-to-human spread, highlighting the need for efficient infection control policies and sensitive diagnostic assays. Widespread prophylaxis is the best measure to gain control of outbreak situations. This review will summarize diagnostic options, cover prophylactic and therapeutic management in the main at risk populations, while also covering aspects of managing resistant disease, outbreak situations, and paediatric PcP.