Recent Advances in the Diagnosis and Management of Pneumocystis Pneumonia

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.

Clinical Manifestations of Human Exposure to Fungi

Biological particles, along with inorganic gaseous and particulate pollutants, constitute an ever-present component of the atmosphere and surfaces. Among these particles are fungal species colonizing almost all ecosystems, including the human body. Although inoffensive to most people, fungi can be responsible for several health problems, such as allergic fungal diseases and fungal infections. Worldwide fungal disease incidence is increasing, with new emerging fungal diseases appearing yearly. Reasons for this increase are the expansion of life expectancy, the number of immunocompromised patients (immunosuppressive treatments for transplantation, autoimmune diseases, and immunodeficiency diseases), the number of uncontrolled underlying conditions (e.g., diabetes mellitus), and the misusage of medication (e.g., corticosteroids and broad-spectrum antibiotics). Managing fungal diseases is challenging; only four classes of antifungal drugs are available, resistance to these drugs is increasing, and no vaccines have been approved. The present work reviews the implications of fungal particles in human health from allergic diseases (i.e., allergic bronchopulmonary aspergillosis, severe asthma with fungal sensitization, thunderstorm asthma, allergic fungal rhinosinusitis, and occupational lung diseases) to infections (i.e., superficial, subcutaneous, and systemic infections). Topics such as the etiological agent, risk factors, clinical manifestations, diagnosis, and treatment will be revised to improve the knowledge of this growing health concern.

A Case of Severe Pneumocystis Pneumonia in an HIV-Negative Patient Successfully Treated with Oral Atovaquone

Currently, atovaquone is not recommended for treating severe Pneumocystis jirovecii pneumonia (PCP) due to insufficient evidence in clinical studies. This report describes a case of severe PCP in a human immunodeficiency virus (HIV)-negative immunosuppressed patient who was successfully treated with oral atovaquone and corticosteroids. A 63-year-old Japanese woman complained of fever and dyspnea for 3 days. She had been treated with oral prednisolone (30 mg/day) for interstitial pneumonia for 3 months without PCP prophylaxis. Although we could not confirm P. jirovecii from the respiratory specimen, a diagnosis of PCP was indicated by marked elevation of serum beta-D-glucan levels and bilateral ground-glass opacities in the lung fields. Based on the arterial blood gas test results (alveolar-arterial oxygen difference >45 mmHg), the disease status of PCP was defined as severe. Trimethoprim-sulfamethoxazole (SXT) is the first-line drug for treating severe PCP. However, given the patient's history of SXT-induced toxic epidermal necrolysis, she was administered atovaquone instead of SXT. Her clinical symptoms and respiratory condition gradually improved, with a 3-week treatment showing a good clinical course. Previous clinical studies on atovaquone have only been conducted in HIV-positive patients with mild or moderate PCP. Accordingly, the clinical efficacy of atovaquone for severe PCP cases or PCP in HIV-negative patients remains unclear. There is a rising incidence of PCP among HIV-negative patients, given the increasing number of patients receiving immunosuppressive medications; moreover, atovaquone has less severe side effects than SXT. Therefore, there is a need for further clinical investigation to confirm the efficacy of atovaquone in cases of severe PCP, especially among HIV-negative patients. In addition, it also remains unclear whether corticosteroids are beneficial for severe PCP in non-HIV patients. Thus, the use of corticosteroids in cases of severe PCP in non-HIV patients should also be investigated.

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.

A comprehensive clinical guide for Pneumocystis jirovecii pneumonia: a missing therapeutic target in HIV-uninfected patients

INTRODUCTION

Pneumocystis jirovecii is an opportunistic, human-specific fungus that causes Pneumocystis pneumonia (PCP). PCP symptoms are nonspecific. A patient with P. jirovecii and another lung infection faces a diagnostic challenge. It may be difficult to determine which of these agents is responsible for the clinical symptoms, preventing effective treatment. Diagnostic and treatment efforts have been made more difficult by the rising frequency with which coronavirus 2019 (COVID-19) and PCP co-occur.

AREAS COVERED

Herein, we provide a comprehensive review of clinical and pharmacological recommendations along with a literature review of PCP in immunocompromised patients focusing on HIV-uninfected patients.

EXPERT OPINION

PCP may be masked by identifying co-existing pathogens that are not necessarily responsible for the observed infection. Patients with severe form COVID-19 should be examined for underlying immunodeficiency, and co-infections must be considered as co-infection with P. jirovecii may worsen COVID-19's severity and fatality. PCP should be investigated in patients with PCP risk factors who come with pneumonia and suggestive radiographic symptoms but have not previously received PCP prophylaxis. PCP prophylaxis should be explored in individuals with various conditions that impair the immune system, depending on their PCP risk.

Pneumocystis jirovecii pneumonia and deep vein thrombosis in a patient with glioblastoma multiforme

We present a case of disseminated Pneumocystis jirovecii pneumonia in a patient with a medical history of glioblastoma multiforme associated with acute deep-vein thrombosis. The patient presented to the emergency department with clinical features of pulmonary infection, and the chest images showed pneumonia. Antibiotics were initiated (azithromycin, cefepime, and vancomycin) and the patient was transferred to the ward for further management, where the condition of the patient continued to worsen over the second day. The patient developed bilateral lower extremity swelling and the doppler ultrasound revealed bilateral lower extremity acute deep vein thrombosis. Laboratory results showed pancytopenia and transaminitis. However, a repeated chest X-ray showed ground-glass changes and interstitial infiltrates, suggestive of atypical infection. We indeed identified D-glucan which hints to a disseminated form of Pneumocystis jirovecii pneumonia infection in this patient. We further confirmed the Pneumocystis jirovecii pneumonia by polymerase chain reaction test from the fluid obtained via bronchoalveolar lavage. We, therefore, initiated intravenous trimethoprim/ sulfamethoxazole treatment with an anticoagulant, and the patient's condition improved. Our findings strongly suggest a possible link between Pneumocystis jirovecii pneumonia infection and thrombogenesis, with impact in medical practice.

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

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

Prognostic implication of bronchoalveolar lavage fluid analysis in patients with Pneumocystis jirovecii pneumonia without human immunodeficiency virus infection

Background

The prognostic value of bronchoalveolar lavage (BAL) fluid analysis in non-human immunodeficiency virus (HIV)-infected patients with Pneumocystis jirovecii pneumonia (PJP) has not been well elucidated. We aimed to investigate the prognostic implication of BAL fluid analysis in non-HIV patients with PJP.

Methods

The data of 178 non-HIV patients diagnosed with PJP based on the results of the polymerase chain reaction assay of BAL fluid specimens between April 2018 and December 2020 were retrospectively reviewed. The clinical characteristics, laboratory findings, and BAL fluid analysis results of patients who died within 90 days after hospital admission were compared.

Results

Twenty patients (11.2%) died within 90 days from admission. The neutrophil count in BAL fluid was significantly higher (median 22.0%, interquartile range [IQR] 2.0–46.0% vs. median 6.0%, IQR 2.0–18.0%, P = 0.044), while the lymphocyte count was significantly lower (median 24.0%, IQR 7.0–37.0% vs. median 41.0%, IQR 22.5–60.5%, P = 0.001) in the non-survivor group compared with that in the survivor group. In the multivariate analysis, the C-reactive protein level (odds ratio [OR] 1.093, 95% confidence interval [CI] 1.020–1.170, P = 0.011) and a BAL fluid lymphocyte count of ≤ 30% (OR 3.353, 95% CI 1.101–10.216, P = 0.033) were independently associated with mortality after adjusting for albumin and lactate dehydrogenase levels.

Conclusion

A low lymphocyte count in BAL fluid may be a predictor of mortality in non-HIV patients with PJP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02041-8.

Usefulness of ß-d-Glucan Assay for the First-Line Diagnosis of Pneumocystis Pneumonia and for Discriminating between Pneumocystis Colonization and Pneumocystis Pneumonia

According to the immunodepression status, the diagnosis of Pneumocystis jirovecii pneumonia (PjP) may be difficult. Molecular methods appear very sensitive, but they lack specificity because Pj DNA can be detected in Pneumocystis-colonized patients. The aim of this study was to evaluate the value of a serum ß-d-Glucan (BDG) assay for the diagnosis of PjP in a large cohort of HIV-negative and HIV-positive patients, either as a first-line diagnostic test for PjP or as a tool to distinguish between colonization and PjP in cases of low fungal load. Data of Pj qPCR performed on bronchopulmonary specimens over a 3-year period were retrieved retrospectively. For each result, we searched for a BDG serum assay performed within ±5 days. Among the 69 episodes that occurred in HIV-positive patients and the 609 episodes that occurred in immunocompromised HIV-negative patients, we find an equivalent sensitivity of BDG assays compared with molecular methods to diagnose probable/proven PjP, in a first-line strategy. Furthermore, BDG assay can be used confidently to distinguish between infected and colonized patients using a 80 pg/mL cut-off. Finally, it is necessary to search for causes of false positivity to increase BDG assay performance. BDG assay represents a valuable adjunctive tool to distinguish between colonization and 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.

Characteristics and Prognostic Factors of Non-HIV Immunocompromised Patients With Pneumocystis Pneumonia Diagnosed by Metagenomics Next-Generation Sequencing

Objective

The aim of this study was to evaluate the potential of metagenomic next-generation sequencing (mNGS) for the diagnosis of pneumocystis pneumonia (PCP) in patients with non-human immunodeficiency virus-infection and to discuss the clinical characteristics and identify prognostic factors associated with patients with non-HIV PCP.

Methods

Forty-six patients with PCP who were admitted in respiratory intensive care unit (ICU) between May 2018 and May 2020 were retrospectively reviewed. The subjects were divided into survivor and non-survivor groups according to the patients' outcome. Conventional methods and mNGS for detecting Pneumocystis jirovecii (P. jirovecii) were analyzed. The patients' demographics, comorbidities, laboratory parameters, and treatments were compared and evaluated in both groups to identify risk factors for mortality by using univariate and multivariate logistic regression.

Results

Metagenomic next-generation sequencing (mNGS) showed a satisfying diagnostic performance of 100% positive of detecting P. jirovecii from bronchoalveolar lavage (BAL) specimens in forty-six patients with non-HIV PCP, compared to only 15.2% for Gomori Methenamine silver (GMS) staining and 84.8% for Serum 1,3-beta-D-glucan (BDG). Among them, the mean age was 46.4-year-old (range 18–79-year-old) and mortality rate was 43.5%. The dominant underlying conditions were connective tissue diseases (34.8%), autoimmune kidney diseases (30.4%), followed by hematologic malignancies (10.9%), and solid organ transplantation (6.5%). A total of 38 cases (82.6%) received glucocorticoid and 19 cases (41.3%) used immunosuppressant within 3 months before diagnosed PCP. Multiple infections were very common, over two thirds' cases had mixed infections. Compared with survivors, non-survivors had a higher acute physiology and chronic health evaluation II (APACHE II) score (14.4 ± 4.8 vs. 10 ± 3.4), Procalcitonin (PCT) [ng/ml: 0.737 (0.122–1.6) vs. 0.23 (0.095–0.35)], lactic dehydrogenase (LDH) [U/L: 1372 (825.5–2150) vs. 739 (490.5–956)], and neutrophil-lymphocyte ratio (NLR) [21.6 (15.67–38.2) vs. 11.75 (5.1–15.52)], but had a lower PaO₂/FiO₂ ratio (mmHg:108.8 ± 42.4 vs. 150.5 ± 47.5), lymphocytes [×10⁹/L: 0.33 (0.135–0.615) vs. 0.69 (0.325–1.07)] and CD4+ T cells [cell/μl: 112 (53.5–264) vs. 255 (145–303.5)], all P < 0.05. Furthermore, we found non-survivors' PaO₂/FiO₂ ratio of day 3 and day 7 had not improved when compared with that of day one, and platelet level and NLR became worse. Multivariate analysis showed that other pathogens' co-infection (OR = 9.011, 95% CI was 1.052–77.161, P = 0.045) and NLR (OR = 1.283, 95% CI was 1.046–1.547, P = 0.017) were the independent risk factors of poor prognosis.

Conclusion

mNGS is a very sensitive diagnostic tool for identifying P. jirovecii in patients who are non-HIV immunocompromised. PCP in patients who are non-HIV infected is associated with a high rate of multiple infections and severe condition. Mixed infection and elevation of NLR were the independent risk factors of poor prognosis.

Pneumocystis jirovecii Pneumonia in Three Patients With Breast Cancer Receiving Neoadjuvant Dose-Dense Chemotherapy

We report three cases of Pneumocystis jirovecii pneumonia (PJP) during dose-dense neoadjuvant chemotherapy for breast cancer. All patients presented with symptoms (e.g., fever), and computed tomography showed diffuse ground-glass shadows. Bronchoalveolar lavage was performed, and the diagnosis was confirmed by polymerase chain reaction for Pneumocystis jirovecii. All patients had completed three or four courses of dose-dense epirubicin-cyclophosphamide chemotherapy and received prednisolone for preventing chemo-induced nausea and vomiting. Moreover, lymphocytopenia was observed in all patients. Since the onset of PJP in preoperative neoadjuvant chemotherapy can be life-threatening and leads to delayed surgery, careful consideration of prophylaxis for PJP is required.

Pneumocystis Pneumonia in a Patient with Ovarian Cancer Receiving Olaparib Therapy

We herein report a case of pneumocystis pneumonia (PCP) in a 77-year-old woman with ovarian cancer who was receiving olaparib therapy. After the patient's second relapse of ovarian cancer, she was administered olaparib as maintenance therapy following successful completion of docetaxel and carboplatin therapy. On receiving olaparib, she showed symptoms of a fever and malaise. Based on laboratory and imaging findings, she was diagnosed with PCP. After treatment with corticosteroids and trimethoprim/sulfamethoxazole followed by atovaquone, the patient's general condition improved. The lymphocytopenia observed after olaparib administration may have been associated with the development of PCP.

Effectiveness of a real-time PCR for diagnosis of Pneumocystis pneumonia in immunocompromised patients - Experience from a tertiary care center, India

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening fungal infection in immunocompromised patients. Traditionally, the laboratory diagnosis of PCP relied on the visualization of organisms by microscopy as Pneumocystis cannot be readily cultured in the laboratory. The polymerase chain reaction (PCR) method is preferred over the conventional microscopic methods as PCR is rapid and found to have higher sensitivity. This retrospective study aimed to analyze the diagnostic value of a real-time PCR (qPCR) for routine diagnosis of PCP in immunocompromised patients with various underlying conditions. The qPCR targets a 121 bp fragment of P.jirovecii mitochondrial large subunit rRNA gene. The study was conducted in a 2600-bed tertiary care hospital between January and December 2019. All patients whose respiratory samples were tested for PCP by qPCR were included. The clinical diagnosis was made for each patient and categorized into PCP and non-PCP based on multi-component clinical criteria by a multi-disciplinary team. The performance characteristics of qPCR were analyzed using clinical diagnosis as the reference. A total of 339 respiratory samples from 289 patients were tested for PCP by qPCR during the study period. The overall sensitivity and specificity of qPCR were 84.75% (95% CI, 73.01% to 92.78%) and 96.1% (95% CI, 92.7 to 98.2), respectively. The sensitivity was slightly higher among HIV-infected patients (91%) than the non- HIV group (81%). The PCR exhibited higher sensitivity in bronchoalveolar lavage (BAL) (94%) than in sputum samples (81%). The colonization can be ruled out with the cycle threshold (C_T) value of below 34 with a sensitivity and specificity of 100% and 78%, respectively. The real-time PCR showed good sensitivity and specificity for routine diagnosis of PCP in patients with various underlying conditions. In addition, a cut-off C_T value (≤ 34) was determined to exclude colonization from active pneumonia.

Low cut-off value of serum (1,3)-beta-D-glucan for the diagnosis of Pneumocystis pneumonia in non-HIV patients: a retrospective cohort study

Background

Non-human immunodeficiency virus (HIV) Pneumocystis pneumonia (PCP) is a fulminant disease with an increasing incidence. The serum beta-d-glucan (BDG) assay is used as an adjunct to the diagnosis of PCP; however, the cut-off value for this assay is not well-defined, especially in the non-HIV PCP population. Therefore, we aimed to identify the assay cut-off value for this population.

Methods

In this retrospective observational study, we reviewed the medical records of all patients (≥ 18 years old) with clinical suspicion of PCP who underwent evaluation of respiratory tract specimens between December 2008 and June 2014 at Kameda Medical Center. We created a receiver operating characteristic curve and calculated the area under the curve to determine the cut-off value for evaluating the inspection accuracy of the BDG assay.

Results

A total of 173 patients were included in the study. Fifty patients showed positive results in specimen staining, loop-mediated isothermal amplification assay, and polymerase chain reaction test, while 123 patients showed negative results. The receiver operating characteristic analyses suggested that the BDG cut-off level was 8.5 pg/mL, with a sensitivity and specificity of 76% and 76%, respectively.

Conclusions

The Wako-BDG cut-off value for the diagnosis of non-HIV PCP is 8.5 pg/mL, which is lower than the classical cut-off value from previous studies. Clinicians should potentially consider this lower BDG cut-off value in the diagnosis and management of patients with non-HIV PCP.

Trial registration: The participants were retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06895-x.

High incidence and mortality of Pneumocystis jirovecii infection in anti-MDA5-antibody-positive dermatomyositis: experience from a single center

BACKGROUND

Idiopathic inflammatory myopathies (IIM) are associated with a significantly higher risk of opportunistic infections including Pneumocystis jirovecii pneumonia (PJP), a potentially fatal opportunistic infection. However, no prior studies have evaluated PJP infection in subtypes of IIM.

OBJECTIVES

To investigate the prevalence and mortality rate of PJP infection in subgroups of IIM patients stratified according to myopathy-specific antibodies.

METHODS

In the first part of the study, 463 consecutive patients with IIM were prospectively followed for a period of at least 1 year to analyze the incidence of PJP. In the second part of the study, we enrolled 30 consecutive PJP patients with any rheumatic disease in order to identify the mortality rate and risk factors by Cox regression analysis. The Kaplan-Meier method with log-rank testing was used to assess differences in survival.

RESULTS

The prevalence of PJP in IIM patients was found to be 3.0/100 person-years, while in MDA5+ DM patients it was 7.5/100 person-years and in MDA5- IIM patients 0.7/100 person-years (P < 0.05). PJP typically occurred in the first 2 months in the case of MDA5+ DM patients who had a significant decrease in their CD4+ T cell counts and lymphocyte counts (P < 0.05). In PJP patients, 3-month mortality was higher for MDA5+ DM patients than in those with other rheumatic diseases (83.3% vs 38.9%, P < 0.05). Alarmingly, MDA5+ DM patients seemed not to benefit from prompt anti-PJP treatment, unlike patients with other rheumatic diseases whose survival improved when anti-PJP treatment was started within 6 days (P < 0.05).

CONCLUSION

PJP has an alarming high incidence and mortality in MDA5+ DM patients. Timely treatment for PJP seems not to improve the prognosis of patients with this particular subtype. Hence, there remains a crucial unmet need to develop PJP prophylaxis for MDA5+ DM patients.

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.

Pneumocystis Pneumonia: Immunity, Vaccines, and Treatments

For individuals who are immunocompromised, the opportunistic fungal pathogen Pneumocystis jirovecii is capable of causing life-threatening pneumonia as the causative agent of Pneumocystis pneumonia (PCP). PCP remains an acquired immunodeficiency disease (AIDS)-defining illness in the era of antiretroviral therapy. In addition, a rise in non-human immunodeficiency virus (HIV)-associated PCP has been observed due to increased usage of immunosuppressive and immunomodulating therapies. With the persistence of HIV-related PCP cases and associated morbidity and mortality, as well as difficult to diagnose non-HIV-related PCP cases, an improvement over current treatment and prevention standards is warranted. Current therapeutic strategies have primarily focused on the administration of trimethoprim-sulfamethoxazole, which is effective at disease prevention. However, current treatments are inadequate for treatment of PCP and prevention of PCP-related death, as evidenced by consistently high mortality rates for those hospitalized with PCP. There are no vaccines in clinical trials for the prevention of PCP, and significant obstacles exist that have slowed development, including host range specificity, and the inability to culture Pneumocystis spp. in vitro. In this review, we overview the immune response to Pneumocystis spp., and discuss current progress on novel vaccines and therapies currently in the preclinical and clinical pipeline.

Clinical characteristics and prognosis of patients with Pneumocystis jirovecii pneumonia without a compromised illness

Objective

Pneumocystis jirovecii pneumonia (PCP) is a fatal respiratory infection, mostly associated with immunocompromised conditions. Several reports have described PCP development in patients who were not immunocompromised, but the clinical course and prognosis of PCP are not well understood. We compared the clinical characteristics and prognoses between patients with and without immunocompromised conditions who developed PCP.

Methods

We retrospectively analyzed patients who had been treated for PCP from three hospitals. We defined immunocompromised (IC) status as following: human immunodeficiency virus (HIV) infection; hematological malignancy; solid organ tumor under chemotherapy; rheumatic disease; medication with immunosuppressive agents. Patients without immunocompromised status were defined as being non-immunocompromised (non-IC).

Results

The IC and non-IC groups comprised 173 and 14 patients. The median ages were 62.0 and 74.0 years in the IC and the non-IC group, respectively. The median interval between admission and anti-PCP treatment was significantly longer for patients in the non-IC group than that for patients in the IC group (7 vs. 2 days). The in-hospital mortality rates were significantly higher for patients in the non-IC group than that for patients in the IC group (71.4% vs. 43.9%; P = 0.047). A longer interval between admission and anti-PCP therapy was associated with increased 90-day mortality rate in patients with PCP (hazard ratio, 1.082; 95% confidence interval, 1.015–1.153; P = 0.016).

Conclusions

Patients with PCP with no predisposing illnesses were older and had higher mortality rates than IC patients with PCP. Delayed anti-PCP treatment was associated with increased 90-day mortality.

Pneumocystis Jirovecii Pneumonia in a Kidney Transplant Recipient 13 Months after Transplantation: A Case Report and Literature Review

Summary. Background.

Pneumocystis jirovecii pneumonia (PCP) is an opportunistic and prevalent fungal infection in immunocompromised hosts, including patients after kidney transplantation (KTx). It is a life threatening infection. While with effective prophylaxis it became less common, it still remains an issue among solid organ transplant (SOT) recipients during the first year. There are no specific clinical signs for PCP. Computed tomography (CT) is a better method for detecting PCP, but definite diagnosis can only be made by identification of the microorganism either by a microscopy or by a polymerase chain reaction (PCR).

Clinical case.

We present a case of a 17 year old with severe PCP 13 months after KTx followed by reduction in kidney function and respiratory compromise. The pathogen was detected by PCR from bronchoalveolar lavage fluid (BALF) and patient was treated successfully with trimethoprim-sulfamethoxazole (TMPSMX). Patient’s condition, respiratory status and kidney function gradually improved. Our presented case is unusual because patient had no known risk factors for PCP and he was more than one year after KTx, what is considered rare. In addition patient and his parents delayed in notifying the treating physician about ongoing symptoms because did not deem them important enough.

Conclusions.

Clinicians treating patients in risk groups for PCP must always remain vigilant even in era of effective prophylaxis. The vigilance should also extend to the patient and patient’s family.

Clinical characteristics and prevalence of dihydropteroate synthase gene mutations in Pneumocystis jirovecii-infected AIDS patients from low endemic areas of China

Pneumocystis pneumonia (PCP) is an opportunistic and potentially life-threatening infection of AIDS patients caused by the fungus Pneumocystis jirovecii (P. jirovecii). Trimethoprim-sulfamethoxazole (TMP-SMX) is the most commonly used drug combination in the treatment and prophylaxis of PCP. However, with long-term use of this combination, mutations in the dihydropteroate synthase (DHPS) gene of P. jirovecii bring about the development of resistance. Data on the prevalence of P. jirovecii and its DHPS mutants in China, especially in low endemic areas, are still limited. Thus, in the present study, we measured the P. jirovecii infection rate among HIV-positive and AIDS (HIV/AIDS) patients with suspected PCP and investigated the relationship between CD4+ T cell count and PCP occurrence. As well as the polymerase chain reaction (PCR) analysis and sequencing, the restriction fragment length polymorphism (RFLP) method was used to analyze DHPS point mutation in P. jirovecii strains. P. jirovecii was detected in 40.82% of cases. The clinical symptoms and signs of PCP were not typical; with decreasing CD4+ T cell counts, PCP infection in HIV/AIDS patients increased. In only one case (1.67%), the patients' DHPS gene could not be cut by the Acc I restriction enzyme. Furthermore, mutation at codon 171 was detected in 11 cases and no mutation was found at codon 57. Patients treated with sulfamethoxazole combined with Voriconazole or Caspofungin exhibited favorable results. After treatment, the symptoms of dyspnea were alleviated, and chest computed tomography findings showed the improvement of lung shadows. These indicated that the prevalence of DHPS mutations in P. jirovecii isolates in AIDS-PCP patients in the region was low. Thus, the contribution of gene mutations to treatment failure requires further research.

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.