Next-generation sequencing technology for the diagnosis of Pneumocystis pneumonia in an immunocompetent female: A case report

Abstract

BACKGROUND

Pneumocystis pneumonia (PCP) is a serious fungal infection usually seen in patients with human immunodeficiency virus, and it is more frequently found and has a high fatality rate in immunocompromised people. Surprisingly, it rarely occurs in immunocompetent patients. However, the clinical diagnosis of this pathogen is made more difficult by the difficulty of obtaining accurate microbiological evidence with routine tests. This case reports a PCP patient with normal immune function who was diagnosed through next-generation sequencing (NGS).

CASE SUMMARY

A 23-year-old female who had no special disease in the past was admitted to the hospital with a persistent fever and cough. Based on the initial examination results, the patient was diagnosed with bipulmonary pneumonia, and empirical broad-spectrum antibiotic therapy was administered. However, due to the undetermined etiology, the patient's condition continued to worsen. She was transferred to the intensive care unit because of acute respiratory failure. After the diagnosis of Pneumocystis jirovecii infection through NGS in bronchoalveolar lavage fluid and treatment with trimethoprim/sulfamethoxazole and caspofungin, the patient gradually recovered and had a good prognosis.

CONCLUSION

This case emphasizes that, for patients with normal immune function the possibility of PCP infection, although rare, cannot be ignored. NGS plays an important role in the diagnosis of refractory interstitial pneumonia and acute respiratory failure.

Keywords: Pneumocystis pneumonia; Pneumocystis jirovecii; Next-generation sequencing; Immunocompetent; Trimethoprim/Sulfamethoxazole; Case report

Core Tip: Although Pneumocystis pneumonia (PCP) in immunocompetent patients is rare, it should be considered in infected patients with sudden onset of respiratory failure. However, using routine clinical examination, it can be challenging to differentiate between colonizing bacteria and subclinical infections. Instead of traditional laboratory techniques, next-generation sequencing (NGS) was used to make the diagnosis in the current case report. Early diagnosis and fast treatment helped to avoid ineffective treatments and improve the prognosis. This case emphasized that PCP can arise in immunocompetent patients, and NGS may be an effective test method for the quick and accurate diagnosis of PCP.