Metagenomic next-generation sequencing assists in diagnosing Pneumocystis Jirovecii pneumonia in non-HIV patients: a case report

Background

Pneumocystis jirovecii Pneumonia (PJP) is a pulmonary opportunistic fungal infection with an incompletely elucidated pathogenesis. In recent years, non-human immunodeficiency virus (HIV) -infected PJP patients have exhibited rapid progression, poor prognosis, and a greater mortality rate compared to their HIV equivalents, necessitating timely detection and management, which are both critical and problematic.

Case report

We report a young patient admitted with diabetic ketoacidosis characterized by rapidly progressing acute respiratory failure with negative pathogen blood cultures, serum antibodies and polymerase chain reaction results, and a normal CD4⁺ lymphocyte count. Anti-HIV antibody were negative. A computed tomography scan of the chest revealed patchy opacities in both lower lungs, a nonspecific manifestation. However, metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid detected high Pneumocystis jiroveci sequence counts and a markedly elevated 1,3-β-D-glucan test titer. Following the diagnosis of non-HIV-infected PJP, the patient was discharged after 13 days with a positive outcome, attained through systematic management involving Trimethoprim-sulfamethoxazole anti-infective medication and stringent glycemic control.

Conclusion

Insufficient glucose management may be an important susceptibility factor for immunocompetent persons with non-HIV-infected PJP patients. MNGS serves as an effective method for rapid diagnosis and medication adjustment when signs, symptoms, and imaging findings of PJP are nonspecific.