Blood (1->3)-beta-D-glucan as a diagnostic test for HIV-related Pneumocystis jirovecii pneumonia

Pneumocystis jirovecii Pneumonia after Heart Transplantation: Two Case Reports and a Review of the Literature

Post-transplant Pneumocystis jirovecii pneumonia (PcP) is an uncommon but increasingly reported disease among solid organ transplantation (SOT) recipients, associated with significant morbidity and mortality. Although the introduction of PcP prophylaxis has reduced its overall incidence, its prevalence continues to be high, especially during the second year after transplant, the period following prophylaxis discontinuation. We recently described two cases of PcP occurring more than one year after heart transplantation (HT) in patients who were no longer receiving PcP prophylaxis according to the local protocol. In both cases, the disease was diagnosed following the diagnosis of a viral illness, resulting in a significantly increased risk for PcP. While current heart transplantation guidelines recommend Pneumocystis jirovecii prophylaxis for up to 6-12 months after transplantation, after that period they only suggest an extended prophylaxis regimen in high-risk patients. Recent studies have identified several new risk factors that may be linked to an increased risk of PcP infection, including medication regimens and patient characteristics. Similarly, the indication for PcP prophylaxis in non-HIV patients has been expanded in relation to the introduction of new medications and therapeutic regimens for immune-mediated diseases. In our experience, the first patient was successfully treated with non-invasive ventilation, while the second required tracheal intubation, invasive ventilation, and extracorporeal CO2 removal due to severe respiratory failure. The aim of this double case report is to review the current timing of PcP prophylaxis after HT, the specific potential risk factors for PcP after HT, and the determinants of a prompt diagnosis and therapeutic approach in critically ill patients. We will also present a possible proposal for future investigations on indications for long-term prophylaxis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A Rare Case of Co-Infection with Nocardia farcinica, Pneumocystis jirovecii, and Aspergillus fumigatus Due to Tooth Extraction in a Mildly Immunosuppressed Patient

We report a case of co-infection with Nocardia farcinica, Pneumocystis jirovecii, and Aspergillus fumigatus due to tooth extraction in a mildly immunosuppressed patient. This patient did not respond well to a meropenem-based regimen, and the number of lesions was significantly reduced after switching to imipenem. The patient's trough concentration was insufficient when using conventional doses of voriconazole for the treatment of pulmonary aspergillosis. After adding omeprazole, the concentration reached standard levels and symptoms improved. The patient eventually made a full recovery.

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.

Accuracy of Pneumocystis jirovecii Plasma Cell-Free DNA PCR for Noninvasive Diagnosis of Pneumocystis Pneumonia

Pneumocystis pneumonia (PCP) caused by Pneumocystis jirovecii is a serious infection in immunocompromised hosts which requires prompt diagnosis and treatment. The recommended specimen for diagnosis of PCP is bronchoalveolar lavage (BAL) fluid, which is invasive and may not be possible in unstable patients. The aim of this study was to evaluate the accuracy of noninvasive P. jirovecii plasma cell-free DNA (cfDNA) PCR using recently optimized preanalytical and analytical methods. Adult patients undergoing clinical testing for PCP with direct fluorescent antibody stain (DFA), respiratory PCR, and/or β-d-glucan were included in this study. Sensitivity and specificity P. jirovecii plasma cfDNA PCR was determined in PCP suspects categorized as proven and probable. A total of 149 patients were included in this study, of which 10 had proven and 27 had probable PCP. Most patients (95.9%, 143/149) were immunocompromised, including hematological malignancies (30.1%), bone marrow transplant (11.2%), solid organ transplantation (47.6%), and HIV/AIDS (4.2%). P. jirovecii plasma cfDNA PCR showed sensitivity and specificity of 100% (10/10; 95% confidence interval [CI], 69.2 to 100) and 93.4% (127/136; 95% CI, 87.8 to 96.9), and 48.6% (18/37; 95% CI, 31.9 to 65.6) and 99.1% (108/109; 95% CI, 94.9 to 100) in proven and proven/probable cases, respectively. P. jirovecii cell-free DNA PCR was similar in sensitivity but with substantially improved specificity over β-d-glucan (sensitivity, 60.0% [18/30; 95% CI, 40.6 to 77.3]); specificity, 66.7% [22/33; 95% CI, 48.2 to 82.0]) in patients with proven/probable PCP. Plasma cfDNA PCR offers a noninvasive testing option for early and accurate diagnosis of PCP, particularly in patients who cannot tolerate bronchoscopy.

Clinical Performance of BAL Metagenomic Next-Generation Sequence and Serum (1,3)-β-D-Glucan for Differential Diagnosis of Pneumocystis jirovecii Pneumonia and Pneumocystis jirovecii Colonisation

Background

Differentiating Pneumocystis jirovecii infection from colonisation is crucial for appropriate therapy administration. In this study, we evaluated the performance of bronchoalveolar lavage fluid (BAL) metagenomic next-generation sequencing (mNGS) and serum 1,3-β-D-glucan (BDG) tests in differentiating colonisation and infection with P. jirovecii.

Methods

From January 2018 to March 2021, 47 patients were enrolled in this study at the Hunan Provincial People’s Hospital. The final diagnosis was used as a reference, and cases were classified into the P. jirovecii pneumonia (PJP) group or the P. jirovecii colonisation (PJC) group. Clinical data were recorded. The performances of mNGS and BDG were compared.

Result

The fungal load significantly differed between patients with PJP and PJC, with median reads of 3,215.79 ± 1,797 vs. 5.61 ± 0.88 in the PJP and PJC groups, respectively (P < 0.0001). BDG also significantly differed between the two groups, with a median titre of 233.60 ± 39.65 pg/ml in the PJP group and 68.48 ± 19.21 pg/ml in the PJC group (P = 0.0006). The area under the curve was 0.973 (95%CI: 0.868–1.007) for mNGS of the BAL and 0.879 (95%CI: 0.769–0.989) for the serum BDG. The optimal threshold value for discriminating P. jirovecii infection from colonisation appeared to be 14 reads (sensitivity, 83.3%; specificity, 95.7%; positive likelihood ratio, 19.2) and BDG = 88.6 pg/ml (sensitivity, 79.2%; specificity, 92.9%; positive likelihood ratio, 18.2). No correlation between mNGS reads and the BDG titre was found in mNGS-positive patients (r² = 0.0076, P = 0.583). The levels of lactate dehydrogenase and C-reactive protein were significantly higher in the PJP group than in the PJC group.

Conclusion

BAL mNGS and serum BDG are useful adjunct tests that can assist with differentiating between colonisation and infection of P. jirovecii.

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.

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.

Comparative effectiveness of trimethoprim-sulfamethoxazole versus atovaquone for the prophylaxis of pneumocystis pneumonia in patients with connective tissue diseases receiving prolonged high-dose glucocorticoids

We compared the prophylactic effect of trimethoprim-sulfamethoxazole (TMP-SMX) with atovaquone for pneumocystis pneumonia (PCP) in patients with connective tissue diseases (CTDs) receiving high-dose glucocorticoids. Patients with CTDs aged ≥ 18 years who were treated with a prolonged course (≥ 4 weeks) of glucocorticoids (≥ 20 mg/day prednisone) in a Japanese tertiary center between 2013 and 2017 were included. The patients were categorized into two groups: TMP-SMX and atovaquone group. Adjusted cumulative incidence of PCP was compared between the two groups after propensity score weighting for differences in confounding factors. A total of 480 patients with a prolonged high-dose glucocorticoid treatment were identified. Out of 383 patients with TMP-SMX prophylaxis, 102 (26.8%) patients experienced adverse events leading to discontinuation within 4 weeks of initiation, while no patient in the atovaquone discontinued the therapy. Two hundred eighty-one patients received TMP-SMX, while 107 received atovaquone for PCP prophylaxis. During a total of 397.0 person-years, 7 PCP cases (2 in the TMP-SMX, 5 in the atovaquone) occurred with a mortality rate of 54.5%. After adjusting for differences in baseline characteristics, the adjusted cumulative incidence of PCP was similar between the two group (HR 0.97, 95% CI 0.19-5.09, p = 0.97). Prophylactic effects for PCP in CTDs patients receiving prolonged high-dose glucocorticoids were similar between TMP-SMX and atovaquone. Atovaquone was well-tolerated with no side effects.

Use of β-D-glucan in diagnosis of suspected Pneumocystis jirovecii pneumonia in adults with HIV infection

OBJECTIVES

An elevated serum (1-3)-β-D-glucan (BDG) concentration has high sensitivity for a diagnosis of Pneumocystis pneumonia (PCP) in people with HIV (PWH). At the current manufacturer-recommended positive threshold of 80 pg/mL (Fungitell), specificity for PCP is variable and other diagnostic tests are required. We evaluated the utility of serum BDG for diagnosis of suspected PCP in PWH at three inner-London hospitals to determine BDG concentrations for diagnosis and exclusion of PCP.

METHODS

From clinical case records, we abstracted demographic and clinical information and categorised patients as having confirmed or probable PCP, or an alternative diagnosis. We calculated sensitivity, specificity and positive predictive value (PPV) of serum BDG concentrations >400 pg/mL and negative predictive value (NPV) of BDG <80 pg/mL.

RESULTS

76 patients were included; 29 had laboratory-confirmed PCP, 17 had probable PCP and 30 had an alternative diagnosis. Serum BDG >400 pg/mL had a sensitivity of 83%, specificity of 97% and PPV 97% for diagnosis of PCP; BDG <80 pg/mL had 100% NPV for exclusion of PCP.

CONCLUSIONS

In PWH with suspected PCP, BDG <80 pg/mL excludes a diagnosis of PCP, whereas BDG concentrations >400 pg/mL effectively confirm the diagnosis. Values 80-400 pg/mL should prompt additional diagnostic tests.

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.

Pneumocystis jirovecii: a review with a focus on prevention and treatment

Introduction: Pneumocystis jirovecii (PJ) is an opportunistic fungal pathogen that can cause severe pneumonia in immunocompromised hosts. Risk factors for Pneumocystis jirovecii pneumonia (PJP) include HIV, organ transplant, malignancy, certain inflammatory or rheumatologic conditions, and associated therapies and conditions that result in cell-mediated immune deficiency. Clinical signs of PJP are nonspecific and definitive diagnosis requires direct detection of the organism in lower respiratory secretions or tissue. First-line therapy for prophylaxis and treatment remains trimethoprim-sulfamethoxazole (TMP-SMX), though intolerance or allergy, and rarely treatment failure, may necessitate alternate therapeutics, such as dapsone, pentamidine, atovaquone, clindamycin, primaquine and most recently, echinocandins as adjunctive therapy. In people living with HIV (PLWH), adjunctive corticosteroid use in treatment has shown a mortality benefit.Areas covered: This review article covers the epidemiology, pathophysiology, diagnosis, microbiology, prophylaxis indications, prophylactic therapies, and treatments.Expert opinion: TMP-SMX has been first-line therapy for treating and preventing pneumocystis for decades. However, its adverse effects are not uncommon, particularly during treatment. Second-line therapies may be better tolerated, but often sacrifice efficacy. Echinocandins show some promise for new combination therapies; however, further studies are needed to define optimal antimicrobial therapy for PJP as well as the role of corticosteroids in those without HIV.

Comparison of Blood (1->3)-β-D-Glucan Levels in AIDS-Related Pneumocystis jirovecii Pneumonia and AIDS-Related Progressive Disseminated Histoplasmosis

In this retrospective study, (1->3)-β-D-glucan (B-glucan) was an unreliable marker for AIDS-related Pneumocystis jirovecii pneumonia (PCP) because a high percentage of participants with progressive disseminated histoplasmosis and respiratory symptoms had a positive B-glucan result. Where histoplasmosis is common attributing B-glucan positivity to PCP without further testing risks misdiagnosis.

Care of Critically Ill Patients with Human Immunodeficiency Virus

Care of patients with human immunodeficiency virus (HIV) infection in the intensive care unit (ICU) has changed dramatically since the infection was first recognized in the United States in 1981. The purpose of this review is to describe the current important aspects of care of patients with HIV infection in the ICU, with a primary focus on the United States and developed countries. The epidemiology and initial approach to diagnosis and treatment of HIV (including the newest antiretroviral guidelines), common syndromes and their management in the ICU, and typical comorbidities and opportunistic infections of patients with HIV infection are discussed.

Circulating (1→3)-β-D-glucan Is Associated With Immune Activation During Human Immunodeficiency Virus Infection

BACKGROUND

Microbial translocation from the gut to systemic circulation contributes to immune activation during human immunodeficiency virus (HIV) infection and is usually assessed by measuring plasma levels of bacterial lipopolysaccharide (LPS). Fungal colonization in the gut increases during HIV-infection and people living with HIV (PLWH) have increased plasma levels of fungal polysaccharide (1→3)-β-D-Glucan (βDG). We assessed the contribution of circulating DG to systemic immune activation in PLWH.

METHODS

Cross-sectional and longitudinal assessments of plasma βDG levels were conducted along with markers of HIV disease progression, epithelial gut damage, bacterial translocation, proinflammatory cytokines, and βDG-specific receptor expression on monocytes and natural killer (NK) cells.

RESULTS

Plasma βDG levels were elevated during early and chronic HIV infection and persisted despite long-term antiretroviral therapy (ART). βDG increased over 24 months without ART but remained unchanged after 24 months of treatment. βDG correlated negatively with CD4 T-cell count and positively with time to ART initiation, viral load, intestinal fatty acid-binding protein, LPS, and soluble LPS receptor soluble CD14 (sCD14). Elevated βDG correlated positively with indoleamine-2,3-dioxygenase-1 enzyme activity, regulatory T-cell frequency, activated CD38+Human Leukocyte Antigen - DR isotype (HLA-DR)+ CD4 and CD8 T cells and negatively with Dectin-1 and NKp30 expression on monocytes and NK cells, respectively.

CONCLUSIONS

PLWH have elevated plasma βDG in correlation with markers of disease progression, gut damage, bacterial translocation, and inflammation. Early ART initiation prevents further βDG increase. This fungal antigen contributes to immune activation and represents a potential therapeutic target to prevent non-acquired immunodeficiency syndrome events.

Clinical Performance of (1,3) Beta-D Glucan for the Diagnosis of Pneumocystis Pneumonia (PCP) in Cancer Patients Tested With PCP Polymerase Chain Reaction

BACKGROUND

Serum (1,3)-beta-D glucan (BDG) is increasingly used to guide the management of suspected Pneumocystis pneumonia (PCP). BDG lacks specificity for PCP, and its clinical performance in high-risk cancer patients has not been fully assessed. Polymerase chain reaction (PCR) for PCP detection is highly sensitive, but cannot differentiate between colonization and infection. We evaluated the diagnostic performance of serum BDG in conjunction with PCP PCR on respiratory samples in patients with cancer and unexplained lung infiltrates.

METHODS

We performed a retrospective analysis of adult patients evaluated for PCP at our institution from 2012 to 2015, using serum BDG and PCP PCR. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the serum BDG at different thresholds were evaluated using PCP PCR alone or in conjunction with clinical presentation in PCP PCR-positive patients.

RESULTS

With PCP PCR alone as the reference method, BDG (≥80 pg/mL) had a sensitivity of 69.8%, specificity of 81.2%, PPV of 34.6%, and NPV of 95.2% for PCP. At ≥200 pg/mL in patients with a positive PCR and a compatible PCP clinical syndrome, BDG had a sensitivity of 70%, specificity of 100%, PPV of 100%, and NPV of 52.0% for PCP.

CONCLUSIONS

Patients negative by both BDG and PCR were unlikely to have PCP. In patients with a compatible clinical syndrome for PCP, higher BDG values (>200 pg/mL) were consistently associated with clinically-significant PCP infections among PCP PCR-positive oncology patients.

(1→3)-β-D-glucan testing for the detection of invasive fungal infections in immunocompromised or critically ill people

BACKGROUND

Invasive fungal infections (IFIs) are life-threatening opportunistic infections that occur in immunocompromised or critically ill people. Early detection and treatment of IFIs is essential to reduce morbidity and mortality in these populations. (1→3)-β-D-glucan (BDG) is a component of the fungal cell wall that can be detected in the serum of infected individuals. The serum BDG test is a way to quickly detect these infections and initiate treatment before they become life-threatening. Five different versions of the BDG test are commercially available: Fungitell, Glucatell, Wako, Fungitec-G, and Dynamiker Fungus.

OBJECTIVES

To compare the diagnostic accuracy of commercially available tests for serum BDG to detect selected invasive fungal infections (IFIs) among immunocompromised or critically ill people.

SEARCH METHODS

We searched MEDLINE (via Ovid) and Embase (via Ovid) up to 26 June 2019. We used SCOPUS to perform a forward and backward citation search of relevant articles. We placed no restriction on language or study design.

SELECTION CRITERIA

We included all references published on or after 1995, which is when the first commercial BDG assays became available. We considered published, peer-reviewed studies on the diagnostic test accuracy of BDG for diagnosis of fungal infections in immunocompromised people or people in intensive care that used the European Organization for Research and Treatment of Cancer (EORTC) criteria or equivalent as a reference standard. We considered all study designs (case-control, prospective consecutive cohort, and retrospective cohort studies). We excluded case studies and studies with fewer than ten participants. We also excluded animal and laboratory studies. We excluded meeting abstracts because they provided insufficient information.

DATA COLLECTION AND ANALYSIS

We followed the standard procedures outlined in the Cochrane Handbook for Diagnostic Test Accuracy Reviews. Two review authors independently screened studies, extracted data, and performed a quality assessment for each study. For each study, we created a 2 × 2 matrix and calculated sensitivity and specificity, as well as a 95% confidence interval (CI). We evaluated the quality of included studies using the Quality Assessment of Studies of Diagnostic Accuracy-Revised (QUADAS-2). We were unable to perform a meta-analysis due to considerable variation between studies, with the exception of Candida, so we have provided descriptive statistics such as receiver operating characteristics (ROCs) and forest plots by test brand to show variation in study results.

MAIN RESULTS

We included in the review 49 studies with a total of 6244 participants. About half of these studies (24/49; 49%) were conducted with people who had cancer or hematologic malignancies. Most studies (36/49; 73%) focused on the Fungitell BDG test. This was followed by Glucatell (5 studies; 10%), Wako (3 studies; 6%), Fungitec-G (3 studies; 6%), and Dynamiker (2 studies; 4%). About three-quarters of studies (79%) utilized either a prospective or a retrospective consecutive study design; the remainder used a case-control design. Based on the manufacturer's recommended cut-off levels for the Fungitell test, sensitivity ranged from 27% to 100%, and specificity from 0% to 100%. For the Glucatell assay, sensitivity ranged from 50% to 92%, and specificity ranged from 41% to 94%. Limited studies have used the Dynamiker, Wako, and Fungitec-G assays, but individual sensitivities and specificities ranged from 50% to 88%, and from 60% to 100%, respectively. Results show considerable differences between studies, even by manufacturer, which prevented a formal meta-analysis. Most studies (32/49; 65%) had no reported high risk of bias in any of the QUADAS-2 domains. The QUADAS-2 domains that had higher risk of bias included participant selection and flow and timing.

AUTHORS' CONCLUSIONS

We noted considerable heterogeneity between studies, and these differences precluded a formal meta-analysis. Because of wide variation in the results, it is not possible to estimate the diagnostic accuracy of the BDG test in specific settings. Future studies estimating the accuracy of BDG tests should be linked to the way the test is used in clinical practice and should clearly describe the sampling protocol and the relationship of time of testing to time of diagnosis.

Serum (1,3)-Beta-d-Glucan has suboptimal performance for the diagnosis of Pneumocystis jirovecii pneumonia in cancer patients and correlates poorly with respiratory burden as measured by quantitative PCR

OBJECTIVE

Non-HIV immunocompromised patients with Pneumocystis jirovecii pneumonia (PCP) have lower fungal load than those with AIDS, potentially affecting the accuracy of diagnostic biomarkers. Therefore, we investigated the performance of serum (1,3)-Beta-d-Glucan (BDG) in conjunction with quantitative Pneumocystis jirovecii PCR (qPCR) in non-HIV cancer patients.

METHODS

We reviewed records of non-HIV cancer patients and classified them as definite, probable, or possible PCP cases, according to clinicoradiological features, microscopy findings, and qPCR results in bronchoscopy specimens. We evaluated the diagnostic performance of serum BDG and its correlation with qPCR results.

RESULTS

We identified 101 PCP patients (73 definite/probable, 28 possible) and 74 controls. Correlation of BDG and qPCR was low among all 101 qPCR-positive patients (Spearman's = 0.38) and in definite/probable PCP cases (Spearman's = 0.18). Considering all qPCR-positive patients, BDG showed consistently low sensitivity at different cutoffs. Among definite/probable cases, the diagnostic accuracy of BDG remained poor, yet slightly improved with high qPCR thresholds (AUC = 0.86 at ≥2000 DNA copies/mL). BDG had a low PPV but excellent NPV across different qPCR and BDG cutoffs.

CONCLUSIONS

BDG and qPCR levels correlate poorly in non-HIV cancer patients with PCP. BDG diagnostic performance is suboptimal but a negative test may be useful to rule out PCP in this population.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Diagnostic accuracy of (1→3)-β-D-glucan to predict Pneumocystis jirovecii pneumonia in non-HIV-infected patients

Background

Pneumocystis jirovecii pneumonia (PCP) is a common and potentially fatal opportunistic infection in immunocompromised non-HIV individuals. There are problems with clinical and diagnostic protocols for PCP that lack sensitivity and specificity. We designed a retrospective study to compared several methods that were used in diagnostics of PCP.

Patients and methods

One hundred and eight immunocompromised individuals with typical clinical picture for PCP and suspicious radiological findings were included in the study. Serum samples were taken to measure the values of (1→3)-β-D-glucan (Fungitell, Associates of Cape Cod, USA). Lower respiratory tract samples were obtained to perform direct immunofluorescence (DIF, MERIFLUOR® Pneumocystis, Meridian, USA) stain and real-time PCR (qPCR).

Results

Fifty-four (50%) of the 108 patients in our study had (1→3)-β-D-glucan > 500 pg/ml. Patients that had (1→3)-β-D-glucan concentrations < 400 pg/ml in serum, had mean threshold cycles (Ct) 35.43 ± 3.32 versus those that had (1→3)-β-D-glucan concentrations >400 pg/mL and mean Ct of 28.97 ± 5.27 (P < 0.001). If we detected P. jirovecii with DIF and qPCR than PCP was proven. If the concentration of (1→3)-β-D-glucan was higher than 400 pg/ml and Ct of qPCR was below 28.97 ± 5.27 than we have been able be certain that P. jirovecii caused pneumonia (odds ratio [OR] 2.31, 95% confidence interval [CI] 1.62–3.27, P < 0.001).

Conclusions

Measurement of (1→3)-β-D-glucan or qPCR alone could not be used to diagnose PCP. Diagnostic cut-off value for (1→3)-β-D-glucan > 400pg/ml and qPCR below 30 Ct, allow us to conclude that patient has PCP. If the values of (1→3)-β-D-glucan are < 400 pg/ml and qPCR is above 35 Ct than colonization with P. jirovecii is more possible than PCP.

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.

Serum-based diagnosis of Pneumocystis pneumonia by detection of Pneumocystis jirovecii DNA and 1,3-β-D-glucan in HIV-infected patients: a retrospective case control study

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is one of the most common HIV-related opportunistic infections. The diagnosis of PCP is based on analyses from respiratory tract specimens which may require the invasive procedure of a diagnostic bronchoscopy. The objective of this study was to evaluate the diagnostic potential of Pneumocystis jirovecii PCR in serum combined with the 1,3-β-D-glucan (betaglucan) test for the diagnosis of PCP in HIV-infected patients.

METHODS

This was a retrospective case-control study including serum samples from 26 HIV-infected patients with PCP collected within 5 days prior to the start of PCP treatment, 21 HIV-infected control subjects matched by blood CD4⁺ cell counts, and 18 blood donors. The serum samples were analyzed for Pneumocystis jirovecii PCR and betaglucan. The reference standard for PCP was based on previously described microbiological and clinical criteria.

RESULTS

All patients with PCP had detectabe Pneumocystis jirovecii DNA in serum yielding a sensitivity for the Pneumocystis jirovecii PCR assay in serum of 100%. All blood donors had negative Pneumocystis PCR in serum. The specificity when testing HIV-infected patients was 71%, but with a PCR Cycle threshold (Ct) value of 34 as cut-off the specificity was 90%. At a putative pretest probaility of 20%, the negative and positive predictive value for the Pneumocystis PCR assay in serum was 0.99 and 0.71, respectively. Betaglucan with cut-off level 200 pg/ml combined with a positive Pneumocystis jirovecii PCR result had sensitivity and specificity of 92 and 90%, respectively. The concentration of Pneumocystis jirovecii DNA in serum samples, expressed by the PCR Ct values, correlated inversely to the betaglucan levels in serum.

CONCLUSION

In this case-control study including 70% of all HIV-infected patients with PCP treated at Sahlgrenska University Hospital during a time period of 13 years, Pneumocystis PCR analysis on serum samples had a very high sensitivity and negative predictive value for the diagnosis of PCP in HIV-infected patients. A serum-based diagnostic procedure either based on Pneumocystis jirovecii PCR alone or in combination with betaglucan analysis may thus be feasible and would facilitate the care of HIV-infected patients with suspected PCP.

Management of Advanced HIV Disease

Great progress has been made in caring for persons with human immunodeficiency virus. However, a significant proportion of individuals still present to care with advanced disease and a low CD4 count. Careful considerations for selection of antiretroviral therapy as well as close monitoring for opportunistic infections and immune reconstitution inflammatory syndrome are vitally important in providing care for such individuals.

HIV adult with fever and shortness of breath: Influenza B misdiagnosed as Pneumocystis (carinii) jiroveci pneumonia (PCP)

Clinical correlation is essential in assessing the relevance of the patient's history and physical findings in making a clinical presumptive diagnosis. False diagnostic associations may result in misdiagnosis. We present a case of an elderly female with HIV on HAART who presented with shortness of breath assumed to have Pneumocystis (carinii) jiroveci pneumonia (PCP) even though she had a clinical diagnosis of influenza B. She was thought to have PCP only because she had HIV. Tests for PCP were negative including BAL staining. Influenza B present in her respiratory secretions by PCR and was also cultured from BAL fluid. Diagnostic associations are helpful in suggesting diagnostic possibilities but must be supported by clinical correlation of characteristic clinical features.

Pneumocystis pneumonia in HIV-1-infected patients

Pneumocystis pneumonia (PCP) is an opportunistic disease that mainly affects patients with a deficiency of cell-mediated immunity, especially acquired immunodeficiency syndrome (AIDS). The incidence of PCP in these patients has declined substantially owing to the widespread use of antiretroviral therapy and PCP prophylaxis. However, PCP is still a major AIDS-related opportunistic infection, particularly in patients with advanced immunosuppression in whom human immunodeficiency virus type 1 (HIV-1) infection remains undiagnosed or untreated. The clinical manifestations, diagnosis, treatment, and prevention of PCP in patients with HIV-1 infection are addressed in this review.

A Model to Predict In-Hospital Mortality in HIV/AIDS Patients with Pneumocystis Pneumonia in China: The Clinical Practice in Real World

We aimed to develop and validate a predictive model to evaluate in-hospital mortality risk in HIV/AIDS patients with PCP in China. 1001 HIV/AIDS patients with PCP admitted in the Beijing Ditan hospital from August 2009 to January 2018 were included in this study. Multivariate Cox proportional hazard model was used to identify independent risk factors of death, and a predictive model was devised based on risk factors. The overall in-hospital mortality was 17.3%. The patients were randomly assigned into derivation cohort (801cases) and validation cohort (200 cases) in 8:2 ratio, respectively, in which in derivation cohort we found that 7 predictors, including LDH >350U/L, HR>130 times/min, room air PaO₂ <70mmHg, later admission to ICU, Anemia (HGB≤90g/L), CD4<50cells/ul, and development of a pneumothorax, were associated with poor prognosis in HIV/AIDS patients with PCP and were included in the predictive model. The model had excellent discrimination with AUC of 0.904 and 0.921 in derivation and validation cohort, respectively. The predicted scores were divided into two groups to assess the in-hospital mortality risk: low-risk group (0-11 points with mortality with 2.15-12.77%) and high-risk group (12-21 points with mortality with 38.78%-81.63%). The cumulative mortality rate also indicated significant difference between two groups with Kaplan-Meier curve (p<0.001). A predictive model to evaluate mortality in HIV/AIDS patients with PCP was constructed based on routine laboratory and clinical parameters, which may be a simple tool for physicians to assess the prognosis in HIV/AIDS patients with PCP in China.

Use of (1→3)-β-d-glucan for diagnosis and management of invasive mycoses in HIV-infected patients

People living with HIV (PLHIV) are highly vulnerable to invasive fungal infections (IFIs) due to their immune dysfunction. Diagnosis and treatment of IFIs remain challenging due to the requirement of deep tissue sampling to visualise and culture fungi before initiating treatment. Such techniques are less practical in resource‐limited settings due to their cost and requirement of relatively invasive procedures. Hence, identification of surrogate markers for the early diagnosis and therapeutic monitoring of IFIs is required. Recent studies have shown that (1→3)‐β‐d‐glucan (BDG), a major fungal cell wall antigen, represents a promising soluble marker for the presumptive diagnosis and therapeutic monitoring of IFIs in HIV‐infected patients. Herein, we review findings on the merits of BDG assays in the diagnosis of IFIs and monitoring of antifungal therapies for PLHIV. Conversely to other types of immunocompromised patients, HIV infection is associated with gut damage and subsequent bacterial and fungal translocation leading to elevated BDG plasma levels.

Evaluation of a Turbidimetric β-d-Glucan Test for Detection of Pneumocystis jirovecii Pneumonia

Currently, diagnosis of Pneumocystis jirovecii pneumonia (PJP) relies on analysis of lower respiratory specimens, either by microscopy or quantitative real-time PCR (qPCR). Thus, bronchoscopy is required, which is associated with increased risk of respiratory failure. We assessed the value of noninvasive serologic β-d-glucan (BDG) testing for laboratory diagnosis of PJP using a newly available turbidimetric assay. We identified 73 cases of PJP with positive qPCR results from lower respiratory specimens for Pneumocystis and serology samples dating from 1 week before to 4 weeks after qPCR. In addition, 25 sera from controls with suspected PJP but specimens negative for Pneumocystis by qPCR were identified. Sera were tested with a turbidimetric BDG assay (Fujifilm Wako Chemicals Europe GmbH, Neuss, Germany), using an 11-pg/ml cutoff. Sensitivity and specificity were calculated based on qPCR test results as a reference. The turbidimetric BDG assay identified 63/73 patients with positive or slightly positive qPCR tests for an overall sensitivity of 86%; after exclusion of cases with only slightly positive qPCR results, sensitivity was 91%. No correlation between serum BDG levels and respiratory specimen DNA levels was found. Serologic BDG testing was negative in 25/25 controls with negative qPCR for a specificity of 100% using the predefined cutoff. In 22/25 samples (88%), no BDG was detected. Serologic BDG testing using the turbidimetric assay showed high sensitivity and specificity compared to qPCR of lower respiratory specimens for the diagnosis of PJP. Both turnover time and test performance will allow clinicians to delay or in some cases forego bronchoscopy.

Clinical, Diagnostic, and Treatment Disparities between HIV-Infected and Non-HIV-Infected Immunocompromised Patients with Pneumocystis jirovecii Pneumonia

The substantial decline in the Pneumocystis jirovecii pneumonia (PCP) incidence in HIV-infected patients after the introduction of antiretroviral therapy (ART) in resource-rich settings and the growing number of non-HIV-infected immunocompromised patients at risk leads to considerable epidemiologic changes with clinical, diagnostic, and treatment consequences for physicians. HIV-infected patients usually develop a subacute course of disease, while non-HIV-infected immunocompromised patients are characterized by a rapid disease progression with higher risk of respiratory failure and higher mortality. The main symptoms usually include exertional dyspnea, dry cough, and subfebrile temperature or fever. Lactate dehydrogenase may be elevated. Typical findings on computed tomography scans of the chest are bilateral ground-glass opacities with or without cystic lesions, which are usually associated with the presence of AIDS. Empiric treatment should be initiated as soon as PCP is suspected. Bronchoalveolar lavage has a higher diagnostic yield compared to induced sputum. Immunofluorescence is superior to conventional staining. A combination of different diagnostic tests such as microscopy, polymerase chain reaction, and (1,3)-β-D-glucan is recommended. Trimeth-oprim/sulfamethoxazole for 21 days is the treatment of choice in adults and children. Alternative treatment regimens include dapsone with trimethoprim, clindamycin with primaquine, atovaquone, or pentamidine. Patients with moderate to severe disease should receive adjunctive corticosteroids. In newly diagnosed HIV-infected patients with PCP, ART should be initiated as soon as possible. In non-HIV-infected immunocompromised patients, improvement of the immune status should be discussed (e.g., temporary reduction of immunosuppressive agents). PCP prophylaxis is effective and depends on the immune status of the patient and the underlying immunocompromising disease.

Venovenous extracorporeal life support in patients with HIV infection and Pneumocystis jirovecii pneumonia

AIM

As experience with extracorporeal life support (ECLS) increases, indications for its use have expanded to diverse patient populations, including those with HIV infection. Pneumocystis jirovecii pneumonia (PJP) is a particularly devastating complication of HIV infections. The objective of this study was to review ECLS use in HIV-positive patients, with particular emphasis on those with concomitant PJP infection.

METHODS

All patients were treated by the same ECLS team, consisting of an ECLS specialist intensivist, cardiothoracic surgeon and allied medical professionals at three healthcare institutions. The same ECLS protocol was utilized for all patients during the study period. A retrospective review was performed for all HIV-positive patients placed on ECLS from May 2011 to October 2014. Demographic, clinical, ECLS and complication data were reviewed to identify risk factors for death.

RESULTS

A total of 22 HIV-positive patients received ECLS therapy during the study period. All patients were supported with venovenous ECLS and overall survival to hospital discharge was 68%. Survival amongst the PJP positive cohort was 60%. Non-survivors were more likely to require inotropic medications on ECLS (100% non-survivors vs. 46.7% survivors, p=0.022) and had a longer total duration of ECLS (13 days non-survivors vs. 7 days survivors, p=0.011). No difference was observed between PJP-positive and PJP-negative patients with regard to demographic data, complication rates or survival.

CONCLUSION

ECLS is a viable treatment option in carefully selected HIV-positive patients, including those with severe disease as manifested by PJP infection.

Concurrent Pneumocystis jirovecii and pulmonary histoplasmosis in an undiagnosed HIV patient

Concurrent Pneumocystis jirovecii (PJ) and pulmonary histoplasmosis (PHP) are rare in a single HIV individual. We present a challenging case of concomitant PJ and PHP in a young HIV individual. A 44-year-old man presented to the emergency department with progressive pulmonary symptoms. He was hypoxic with bilateral pulmonary opacities on chest radiograph. CT of the chest showed a geographical pattern of ground-glass attenuation. He started receiving intravenous antibiotics in addition to oral Bactrim for suspected PJ. He also began receiving itraconazole, given suspected PHP with recent bat-droppings exposure. HIV test was positive, though history was negative; the CD4 count was 5 cells/mm³ Later, he developed respiratory failure without clinical improvement. First bronchoalveolar lavage (BAL) failed to confirm opportunistic pathogens. Repeat BAL revealed PJ but no Histoplasma. Histoplasma antigens were positive, confirming histoplasmosis. The patient died despite aggressive treatment with intravenous Bactrim and amphotericin B.

Diagnostic performance of the (1-3)-β-D-glucan assay in patients with Pneumocystis jirovecii compared with those with candidiasis, aspergillosis, mucormycosis, and tuberculosis, and healthy volunteers

BACKGROUND

Diagnosis of pneumocystis pneumonia (PCP) relies on microscopic visualization of P. jirovecii, or detection of Pneumocystis DNA in respiratory specimens, which involves invasive procedures such as bronchoalveolar lavage. The (1-3)-β-D-glucan (BG) assay has been proposed as a less invasive and less expensive diagnostic test to rule out PCP. We therefore compared blood levels of BG in patients with PCP with those of patients with candidemia, chronic disseminated candidiasis (CDC), invasive aspergillosis, mucormycosis, and tuberculosis and those of healthy volunteers.

METHODS

Adult patients who were diagnosed with PCP, candidemia, CDC, invasive aspergillosis, mucormycosis, and tuberculosis whose blood samples were available, and healthy volunteers were enrolled in a tertiary hospital in Seoul, South Korea, during a 21-month period. The blood samples were assayed with the Goldstream Fungus (1-3)-β-D-glucan test (Gold Mountain River Tech Development, Beijing, China).

RESULTS

A total of 136 individuals including 50 patients P. jirovecii,15 candidemia, 6 CDC, 15 invasive aspergillosis, 10 mucormycosis, and 40 controls (20 TB and 20 healthy volunteers) were included. The mean±SD of the concentration of 1-3-β-D-glucan in the patients with PCP (290.08 pg/mL±199.98) were similar to those of patients with candidemia (314.14 pg/mL±205.60, p = 0.90 at an α = 0.005) and CDC (129.74 pg/mL±182.79, p = 0.03 at an α = 0.005), but higher than those of patients with invasive aspergillosis (131.62 pg/mL±161.67, p = 0.002 at an α = 0.005), mucormycosis (95.08 pg/mL±146.80, p<0.001 at an α = 0.005), and tuberculosis (103.31 pg/mL±140.81, p<0.001 at an α = 0.005) as well as healthy volunteers (101.18 pg/mL±197.52, p<0.001 at an α = 0.005). At a cut-off value > 31.25 pg/mL, which is highly sensitive for PCP versus tuberculosis plus healthy volunteers at the expense of specificity, the BG assay had a sensitivity of 92% (95% CI 81%-98%) and a specificity of 55% (95% CI 39%-71%).

CONCLUSIONS

The BG assay appears to be a useful adjunct test for PCP.

Case of undiagnosed pneumocystis pneumonia (PCP)

Pneumocystis pneumonia (PCP) is an opportunistic fungal infection that is usually seen in immunocompromised patients, especially those with HIV, malignancies, organ transplants and on drug therapies like chemotherapy and steroids. PCP has subacute presentation in patients with AIDS which if left untreated gets worse and is a significant cause of morbidity and mortality. Here we present a case of PCP went undiagnosed, partially due to the patient being unaware of his HIV positive status and partially because no organism could be found under the microscope.

Serum markers as an aid in the diagnosis of pulmonary fungal infections in AIDS patients

Introduction

The etiology of pulmonary infections in HIV patients is determined by several variables including geographic region and availability of antiretroviral therapy.

Materials and methods

A cross-sectional prospective study was conducted from 2012 to 2016 to evaluate the occurrence of pulmonary fungal infection in HIV-patients hospitalized due to pulmonary infections. Patients’ serums were tested for (1–3)-β-D-Glugan, galactomannan, and lactate dehydrogenase. The association among the variables was analyzed by univariate and multivariate regression analysis.

Results

60 patients were included in the study. The patients were classified in three groups: Pneumocystis jirovecii pneumonia (19 patients), community-acquired pneumonia (18 patients), and other infections (23 patients). The overall mortality was 13.3%. The time since diagnosis of HIV infection was shorter in the pneumocystosis group (4.94 years; p = 0.001) than for the other two groups of patients. The multivariate analysis showed that higher (1-3)-β-D-Glucan level (mean: 241 pg/mL) and lactate dehydrogenase (mean: 762 U/L) were associated with the diagnosis of pneumocystosis. Pneumocystosis was the aids-defining illness in 11 out of 16 newly diagnosed HIV-infected patients.

Conclusion

In the era of antiretroviral therapy, PJP was still the most prevalent pulmonary infection and (1-3)-β-D-Glucan and lactate dehydrogenase may be suitable markers to help diagnosing pneumocystosis in our HIV population.

Approach to Fungal Infections in Human Immunodeficiency Virus-Infected Individuals: Pneumocystis and Beyond

Many fungi cause pulmonary disease in patients with human immunodeficiency virus (HIV) infection. Pathogens include Pneumocystis jirovecii, Cryptococcus neoformans, Aspergillus spp, Histoplasma capsulatum, Coccidioides spp, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Talaromyces marneffei, and Emmonsia spp. Because symptoms are frequently nonspecific, a high index of suspicion for fungal infection is required for diagnosis. Clinical manifestations of fungal infection in HIV-infected patients frequently depend on the degree of immunosuppression and the CD4⁺ helper T cell count. Establishing definitive diagnosis is important because treatments differ. Primary and secondary prophylaxes depend on CD4⁺ helper T cell counts, geographic location, and local prevalence of disease.

Evaluation of the automated Becton Dickinson MAX real-time PCR platform for detection of Pneumocystis jirovecii

AIM

We evaluated the performance of the automated quantitative BD MAX (Becton Dickinson) real-time PCR platform for detecting Pneumocystis jirovecii.

MATERIALS & METHODS

A total of 34 retrospective and 137 prospective samples were included.

RESULTS

Retrospectively, all (100%) positive samples were correctly detected by this platform compared with a nested PCR. Among prospective samples, the overall sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were 92.6%, 94.5%, 17.0 and 0.1, respectively. All bronchoalveolar lavage fluid (BALF)/bronchial washing samples were correctly identified by this platform. Samples from patients with colonization had significantly higher median amplification cycle threshold values than patients with P. jirovecii pneumonia.

CONCLUSION

The quantitative BD MAX real-time PCR is a rapid and highly sensitive modality for detecting P. jirovecii, especially in samples from bronchoalveolar lavage fluid/bronchial washing fluid.

Lower Respiratory Tract Infections

This review will focus on the infectious etiologies and more common noninfectious causes of lower respiratory tract syndromes among major immunosuppressed populations. The changing epidemiology of infections in the era of highly active antiretroviral therapy (HAART) in the case of HIV-positive patients and the impacts of both newer immune-suppressant therapies and anti-infective prophylaxis for other immunocompromised hosts will be discussed, with emphasis on diagnostic approaches and practice algorithms.

ECIL guidelines for the diagnosis of Pneumocystis jirovecii pneumonia in patients with haematological malignancies and stem cell transplant recipients

The Fifth European Conference on Infections in Leukaemia (ECIL-5) convened a meeting to establish evidence-based recommendations for using tests to diagnose Pneumocystis jirovecii pneumonia (PCP) in adult patients with haematological malignancies. Immunofluorescence assays are recommended as the most sensitive microscopic method (recommendation A-II: ). Real-time PCR is recommended for the routine diagnosis of PCP ( A-II: ). Bronchoalveolar lavage (BAL) fluid is recommended as the best specimen as it yields good negative predictive value ( A-II: ). Non-invasive specimens can be suitable alternatives ( B-II: ), acknowledging that PCP cannot be ruled out in case of a negative PCR result ( A-II: ). Detecting β-d-glucan in serum can contribute to the diagnosis but not the follow-up of PCP ( A-II: ). A negative serum β-d-glucan result can exclude PCP in a patient at risk ( A-II: ), whereas a positive test result may indicate other fungal infections. Genotyping using multilocus sequence markers can be used to investigate suspected outbreaks ( A-II: ). The routine detection of dihydropteroate synthase mutations in cases of treatment failure is not recommended ( B-II: ) since these mutations do not affect response to high-dose co-trimoxazole. The clinical utility of these diagnostic tests for the early management of PCP should be further assessed in prospective, randomized interventional studies.

Short Communication: Diagnosis of Pneumocystis jirovecii Pneumonia by Detection of DNA in Blood and Oropharyngeal Wash, Compared with Sputum

Molecular diagnostic methods on lower respiratory specimens for Pneumocystis pneumonia (PCP) are recommended, but specimens can be difficult to obtain. This study examined the diagnostic use of PCP polymerase chain reaction (PCR) on oropharyngeal wash (OPW) and blood versus sputum (spontaneous and induced) to find faster, simpler, and less invasive diagnostic methods. We prospectively recruited consenting adults with symptoms consistent with PCP. Real-time PCR targeted the Pneumocystis mitochondrial large subunit ribosomal RNA gene, using the aforementioned specimens. Clinical data were collected from routine records. Forty-five participants provided 45 sputa, 31 OPW, and 41 blood samples. Median age was 39 years and 41 (91%) were male, with median CD4 count being 64 cells/μL. Sputum PCR was positive in 27/45 (60%) participants. Comparative sensitivity of OPW was 9/19 (47%, 95% confidence interval [CI] 23-71) and blood 12/24 (50%, 95% CI 29-71) participants, both with specificity 100%. Including only samples obtained ≤2 days after start of treatment, sensitivity of OPW was 80% (8/10, 95% CI 51-100), that of blood was 57% (8/14, 95% CI 29-86), and that of combined tests was 88% (14/16, 95% CI 70-100). In 14/16 individuals with PCP and specimens obtained ≤2 days after start of treatment, diagnosis was possible using nonrespiratory samples. Despite moderate sensitivity of individual tests, combined PCP PCR on early blood and OPW specimens had high sensitivity and could reduce the need for invasive procedures. There were no false-positive results on nonrespiratory samples. Sampling and laboratory methods use routine technology and so require few additional resources.

Pneumocystis pneumonia associated with human immunodeficiency virus infection without elevated (1 → 3)-β-D glucan: A case report

Pneumocystis pneumonia (PCP) caused by Pneumocystis jirovecii is one of the most common opportunistic infections in immunosuppressed patients, particularly in patients with acquired immunodeficiency syndrome (AIDS). (1 → 3)-β-D-glucan is a component of the cell wall of P. jirovecii and other fungi such as Candida sp., Aspergillus sp. and Histoplasma sp. The measurement of serum (1 → 3)-β-D-glucan has been reported to be a highly sensitive test for PCP related to human immunodeficiency virus (HIV-PCP). We report a case of HIV-PCP not associated with elevated serum (1 → 3)-β-D glucan and highlight how HIV-PCP cannot be completely ruled out if (1 → 3)-β-D glucan is negative.

(1→3)-β-D-Glucan Levels Correlate With Neurocognitive Functioning in HIV-Infected Persons on Suppressive Antiretroviral Therapy: A Cohort Study

Microbial translocation from the gut is associated with immune dysfunction, persistent inflammation, and likely plays a role in the pathogenesis of neurocognitive dysfunction during HIV infection. (1→3)-β-D-Glucan (BDG) is a component of most fungal cell walls and might be a useful indicator of gut mucosal barrier impairment. The objective of this study was to evaluate whether higher blood BDG levels correlate with impaired neurocognitive functioning in a cohort of HIV-infected adults with suppressed levels of HIV RNA in blood plasma. In this cross-sectional cohort study, we measured levels of BDG in blood plasma and cerebrospinal fluid (CSF) supernatant samples in a cohort of adults with acute/early HIV infection, who initiated antiretroviral therapy (ART) during the earliest phase of infection and achieved suppressed levels of HIV RNA in blood plasma (<50 copies/mL) thereafter. We compared BDG with established biomarkers of microbial translocation, immune activation, and cognitive dysfunction (evaluated by global deficit score). We found that higher blood BDG levels were significantly related to higher global deficit scores, reflecting worse neurocognitive performance (Spearman r = 0.47; P = 0.042) among HIV-infected adults with suppressed viral loads who initiated ART early in infection. Two CSF samples presented elevated BDG levels. Interestingly, these 2 samples originated from the 2 subjects with the highest global deficit scores of the cohort. BDG may be a promising independent biomarker associated with neurocognitive functioning in virologically suppressed HIV-infected individuals.

Diagnosis of pneumocystis pneumonia using serum (1-3)-β-D-Glucan: a bivariate meta-analysis and systematic review

BACKGROUND

The (1-3)-β-D-Glucan (BG) assay has been approved for making a diagnosis of invasive fungal disease. However, the role of serum-BG assay for the diagnosis of pneumocystis pneumonia (PCP) is controversial, especially between patients with human immunodeficiency virus (HIV) and non-HIV. We conducted a meta-analysis to determine the difference of the overall accuracy of serum-BG assay for the diagnosis of PCP in immunocompromised patients with and without HIV.

METHODS

After a systematic review of English-language studies and manual researching, sensitivity (Se), specificity (Sp), and other measures of accuracy of serum-BG for the diagnosis of PCP were pooled using random-effects models for bivariate meta-analysis. Summary receiver operating characteristic (SROC) curve was used to summarize overall test performance. Subgroup analyses were performed to explore the heterogeneity in Se and Sp.

RESULTS

Thirteen studies met our inclusion criteria. The summary estimates for serum-BG assay for definite PCP were as follows: Se, 0.91 [95% confidence interval (CI), 0.88-0.93]; Sp, 0.75 (95% CI, 0.68-0.81). As for the patients with and without HIV, the Se and Sp were 0.92 and 0.78, 0.85 and 0.73, respectively. Significant heterogeneity between Se was presented (P=0.04).

CONCLUSIONS

Contrary to the results of the previous meta-analysis, a negative result of serum-BG determination is sufficient for ruling out PCP only in HIV cases. For non-HIV patients, the results should be interpreted in parallel with clinical and radiological findings. Besides, further prospective studies with larger sample size are needed to confirm the diagnosis strategy of BG detection.

Correlation of (1→3)-β-D-glucan with other inflammation markers in chronically HIV infected persons on suppressive antiretroviral therapy

We evaluated associations between levels of BDG and other biomarkers of inflammation in blood from 41 virologically suppressed persons with chronic HIV-infection. We found a significant correlation between BDG and neopterin levels (r=0.68), and trends to significance for correlations with other inflammation markers (tumor-necrosis-factor-α: r=0.30; interleukin-8: r=0.30; interleukin-6: r=0.28). In conclusion, BDG levels correlated with inflammation markers in a cohort of virologically suppressed individuals with chronic HIV infection. Future studies are needed to evaluate whether BDG may be a marker for morbidity in chronic HIV infection.

β-Glucan-Activated Human B Lymphocytes Participate in Innate Immune Responses by Releasing Proinflammatory Cytokines and Stimulating Neutrophil Chemotaxis

B lymphocytes play an essential regulatory role in the adaptive immune response through Ab production during infection. A less known function of B lymphocytes is their ability to respond directly to infectious Ags through stimulation of pattern recognition receptors expressed on their surfaces. β-Glucans are carbohydrates present in the cell wall of many pathogenic fungi that can be detected in the peripheral blood of patients during infection. They have been shown to participate in the innate inflammatory response, as they can directly activate peripheral macrophages and dendritic cells. However, their effect as direct stimulators of B lymphocytes has not been yet fully elucidated. The aim of this study was to examine the molecular mechanisms and cytokine profiles generated following β-glucan stimulation of B lymphocytes, compared with the well-established TLR-9 agonist CpG oligodeoxynucleotide (CpG), and study the participation of β-glucan-stimulated B cells in the innate immune response. In this article, we demonstrate that β-glucan-activated B lymphocytes upregulate proinflammatory cytokines (TNF-α, IL-6, and IL-8). Of interest, β-glucan, unlike CpG, had no effect on B lymphocyte proliferation or IgM production. When compared with CpG (TLR9 agonist), β-glucan-activated cells secreted significantly higher levels of IL-8. Furthermore, IL-8 secretion was partially mediated by Dectin-1 and required SYK, MAPKs, and the transcription factors NF-κB and AP-1. Moreover, we observed that conditioned media from β-glucan-stimulated B lymphocytes elicited neutrophil chemotaxis. These studies suggest that β-glucan-activated B lymphocytes have an important and novel role in fungal innate immune responses.

Simultaneous detection of four common oral Candida species from blood samples by the fluorescence polarization assay

The genus Candida is both the commensal microbe and the opportunistic pathogen, containing approximately 200 species inhabiting in oral cavity of 53 % of the general population. Candida species can cause the diseases from local mucosal infections to systemic mycoses, even life-threatening infections in immunocompromised individuals. The timely differentiation of Candida species is important for the guidance of clinical medication. Four common Candida species in Chinese population (Candida albicans, Candida tropicalis, Candida glabrata, Candida krusei) were chosen as the targets to develop the rapid screening method in this work. Combined with amplification by asymmetric PCR, this parallel fluorescence polarization (FP) immunoassay is carried out in homogeneous solution phase. The limit of detection of the assay was shown to be 50 copies/mL in blood samples. The evaluation in multicenter manner showed excellent reproducibility and stability. The comparison between DNA sequencing and the FP immunoassay indicated that there was no significant difference between these methods. This molecular strategy-based method is simple, rapid, and feasible for identifying common Candida species and thereby holding great potential in the application of clinical laboratories.

Pneumocystis jiroveci pneumonia (PCP) in patients receiving neoadjuvant and adjuvant anthracycline-based chemotherapy for breast cancer: incidence and risk factors

Opportunistic infection with Pneumocystis jiroveci pneumonia (PCP) has not been recognized as a significant complication of early-stage breast cancer treatment. However, we have observed an increase in PCP incidence among patients receiving chemotherapy for early-stage breast cancer. Herein we identify risk factors for and calculate incidence of PCP in this population. We identified all cases of PCP at Dana-Farber Cancer Institute/Brigham and Women's Hospital (DFCI/BWH) from 1/1/2000 to 12/31/2013 in patients with stage I-III breast cancer treated with an adriamycin/cyclophosphamide (AC)-containing regimen. Nineteen cases of PCP in non-metastatic breast cancer patients were identified. All patients with PCP were diagnosed after receipt of either three or four cycles of AC chemotherapy on a dose-dense schedule. Patients who developed PCP were treated with median 16.4 mg prednisone equivalents/day as nausea prophylaxis for a median 64 days. The overall incidence of PCP among 2057 patients treated with neoadjuvant or adjuvant dose-dense AC for three or more cycles was 0.6 % (95 % confidence interval 0.3-1.0 %). No PCP was diagnosed in 1001 patients treated with non-dose-dense AC. There was one death from PCP. Women receiving dose-dense AC chemotherapy for early-stage breast cancer are at risk for PCP. Administering the same chemotherapy and corticosteroid dose over an 8-week versus 12-week non-dose-dense schedule appears to have created a novel infectious vulnerability. Replacing dexamethasone with alternative anti-emetics may mitigate this risk.

Pneumocystis jirovecii pneumonia in patients receiving tumor-necrosis-factor-inhibitor therapy: implications for chemoprophylaxis

Pneumocystis jirovecii pneumonia (PJP) is an important opportunistic infection that has been increasingly reported in patients with rheumatic disease. Reported incidence among patients taking TNF inhibitors (TNFi) has varied, but has usually been low. Still, disease causes significant mortality among those affected and must be considered in patients with rheumatological disease presenting with dyspnea and cough. Diagnosis can be difficult in the non-HIV population, and our understanding of the epidemiology and natural history after exposure is changing. Trimethoprim-sulfamethoxazole is believed to be the most effective agent for treatment and prophylaxis, but is associated with significant adverse effects. Given the low incidence reported in most studies of patients on TNFi, prophylaxis is probably not beneficial for this patient population as a whole.