Prevalence of Pneumocystis jirovecii Colonization in Non-Critical Immunocompetent COVID-19 Patients: A Single-Center Prospective Study (JiroCOVID Study)

Abstract

Background: Pneumocystis jirovecii pneumonia (PJP) is an invasive fungal infection (IFI) that occurs mainly in immunocompromised hosts. After observing a high prevalence of PJP as a complication of COVID-19 in immunocompetent patients, we conducted a study to evaluate the prevalence of P. jirovecii colonization with PCR on oral washing samples (OWS) among non-immunocompromised and non-critical patients admitted with COVID-19 pneumonia at our university hospital.

Methods: All patients over 18 years of age admitted to the Infectious Diseases Unit for SARS-CoV-2 pneumonia between July 2021 and December 2022 were included. Patients undergoing invasive mechanical ventilation or ECMO, those with risk factors for developing PJP, and those receiving prophylaxis for P. jirovecii were excluded. Samples were collected by gargling with 10 mL of 0.9% NaCl on day 14 of the hospital stay or at discharge.

Results: Of 290 screened patients, 59 (20%) met the inclusion criteria and were enrolled. Only 1 of 59 patients (1.7%) tested positive for P. jirovecii detection with PCR, and the same patient was the only one to develop PJP in the follow-up period.

Conclusions: Our results are in line with the previous findings of other studies that confirmed a very low prevalence of P. jirovecii colonization on OWS in the immunocompetent population. Despite the limitations of the study, the fact that the only patient who tested positive for P. jirovecii was the only one in our cohort to develop PJP leads us to reflect on the role of this non-invasive sample in predicting the risk of PJP in patients with COVID-19.

Keywords: COVID-19; Pneumocystis jirovecii; SARS-CoV-2; immunocompromised; pneumonia.

Figure 1

Patient’s chest CT scan at PJP diagnosis. A: anterior; P: posterior. Scale bar = 5 cm.