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

Diagnostic values of BALF metagenomic next-generation sequencing, BALF real-time PCR and serum BDG for Pneumocystis jirovecii pneumonia in HIV-infected patients

Introduction

This study aimed to assess the diagnostic values of bronchoalveolar lavage fluid (BALF) real-time polymerase chain reaction (PCR) and BALF metagenomic next-generation sequencing (mNGS) for Pneumocystis jirovecii pneumonia (PJP) in patients infected with human immunodeficiency virus (HIV).

Methods

A total of 99 HIV-infected PJP patients and 61 HIV-infected patients diagnosed with non-PJP pneumonia between March 2019 and December 2022 were enrolled. P. jirovecii and multiple other co-pathogens detected in BALF by mNGS were analyzed. The clinical final diagnosis was employed as a benchmark. We compared the diagnostic performance of mNGS in PJP with serum BDG and BALF real-time PCR. The mixed infections detected by mNGS and modifications of antimicrobial treatment were also analyzed.

Results

The sensitivity of mNGS test of BALF samples reached 85.86%, which was significantly higher than serum BDG (39.39%, P < 0.001). The sensitivity of BALF P. jirovecii PCR (84.85%) was similar with mNGS (P > 0.05). The specificity of mNGS (100%) was also same as PCR (100.0%), and superior to serum BDG (88.52%, P < 0.001). Besides, mNGS performs remarkably well in identifying co-pathogens of PJP patients infected with HIV. In addition to P. jirovecii, 82 cases (82.83%) of other co-pathogens were identified based on mNGS. Moreover, thirty-four patients (34.34%) increased therapeutic dose of trimethoprim-sulfamethoxazole (TMP-SMZ) based on BALF P. jirovecii PCR. Based on the mNGS results, initial antimicrobial treatment was modified in 86.87% (86/99) of PJP patients.

Conclusion

BALF mNGS and real-time PCR are two powerful techniques for rapid diagnosis of PJP with high specificity and sensitivity. Moreover, the benefit of mNGS is that it may identify other organisms besides PJP and it may benefit proper and prompt treatment.

Pneumocystis jirovecii Pneumonia in HIV-Negative, Non-transplant Patients: Epidemiology, Clinical Manifestations, Diagnosis, Treatment, and Prevention

Purpose of Review

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that is increasingly seen in HIV-negative patients with immune compromise due to other etiologies. We lack comprehensive clinical recommendations for this population.

Recent Findings

In non-HIV cases, PJP has a mortality rate of up to 50%, which is unacceptable despite the presence of safe and effective prophylaxis and therapy. Steroid use is one of the most common risk factors for disease development. New data suggests that lower doses of the preferred treatment regimen, TMP-SMX, may be equally effective for treatment while limiting side effects. While commonly used, the benefit of corticosteroids for the treatment of PJP has recently been called into question, with a recent multicenter cohort demonstrating no benefit among solid organ transplant recipients.

Summary

A high suspicion of PJP in individuals with pneumonia during immunosuppressant use is crucial. Therapeutic options are evolving to decrease potential side effects while maintaining efficacy in this highly morbid disease.

Protocol for the systematic review of the Pneumocystis jirovecii-associated pneumonia in non-HIV immunocompromised patients

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) is a well-known and frequent opportunistic infection in HIV patients. However, there has been an increase in the number of reports of PJP in other immunosuppressed patients with autoimmune inflammatory disorders or because of chemotherapy and high doses of steroids, especially when used in combination as part of immunosuppressive therapy.

OBJECTIVE

Despite the increasing importance of PJP in non-HIV patients, there is a lack of comprehensive and updated information on the epidemiology, pathogenesis, diagnosis, microbiology, treatments, and prophylaxis of this infection in this population. Therefore, the objective of this systematic review is to synthesize information on these aspects, from a perspective of evidence-based medicine.

METHODS

The protocol is prepared following the preferred reporting items for systematic reviews and meta-analyses (PRISMA-P) guidelines. We will perform a systematic review of literature published between January 2010 and July 2023, using the databases PubMed, Google Scholar, ScienceDirect, and Web of Science. In addition, manual searches will be carried out through related articles, and references to included articles. The main findings and clinical outcomes were extracted from all the eligible studies with a standardized instrument. Two authors will independently screen titles and abstracts, review full texts, and collect data. Disagreements will be resolved by discussion, and a third reviewer will decide if there is no consensus. We will synthesize the results using a narrative or a meta-analytic approach, depending on the heterogeneity of the studies.

EXPECTED RESULTS

It is expected that this systematic review will provide a comprehensive and up-to-date overview of the state-of-the-art of PJP in non-HIV patients. Furthermore, the study will highlight possible gaps in knowledge that should be addressed through new research.

CONCLUSIONS

Here, we present the protocol for a systematic review which will consider all existing evidence from peer-reviewed publication sources relevant to the primary and secondary outcomes related to diagnosing and managing PJP in non-HIV patients.

Evaluation of analyte-specific reagents for the direct detection of Pneumocystis jirovecii

Pneumocystis jirovecii pneumonia (PJP) is a serious and sometimes fatal infection occurring in immunocompromised individuals. High-risk patients include those with low CD4 counts due to human immunodeficiency virus infection and transplant recipients. The incidence of PJP is increasing, and rapid detection of PJP is needed to effectively target treatment and improve patient outcomes. A common method used is an immunofluorescent assay (IFA), which has limitations, including labor costs, low sensitivity, and requirement for expert interpretation. This study evaluates the performance of the DiaSorin Molecular Pneumocystis jirovecii analyte-specific reagent (ASR) in a laboratory-developed test (LDT) for the direct detection of P. jirovecii DNA without prior nucleic acid extraction. Respiratory samples (n = 135) previously tested by IFA from 111 patients were included. Using a composite standard of in-house IFA and reference lab PJP PCR, the percent positive agreement for the LDT using the DiaSorin ASR was 97.8% (90/92). The negative percent agreement was 97.7% (42/43). The lower limit of detection of the assay was determined to be 1,200 copies/mL in bronchoalveolar lavage fluid. Analytical specificity was assessed using cultures of oropharyngeal flora and common respiratory bacterial and fungal pathogens. No cross-reactivity was observed. Our study suggests that the DiaSorin Pneumocystis ASR accurately detects P. jirovecii DNA and demonstrates improved sensitivity compared to the IFA method.

IMPORTANCE

Our study is unique compared to other previously published studies on the DiaSorin analyte-specific reagent (ASR) because we focused on microbiological diagnostic methods commonly used (immunofluorescent assay) as opposed to pathology findings or reference PCR. In addition, in our materials and methods, we describe the protocol for the use of the DiaSorin ASR as a singleplex assay, which will allow other users to evaluate the ASR for clinical use in their lab.