Prevalence of Pneumocystis jirovecii Colonization in Non-critical Immunocompetent COVID-19 Patients: A Single Center Prospective Study

Abstract

BACKGROUND Pneumocystis jirovecii pneumonia (PJP) is an invasive fungal infection (IFI) that occurs mainly in immunocompromised hosts. As we observed a high prevalence of PCP 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 for COVID-19 pneumonia at our University Hospital. METHODS All patients over 18 years of age admitted to 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 PCP, and those receiving prophylaxis for P. jirovecii were excluded. Samples were collected by gargling with 10mL of 0.9% NaCl on day 14 of hospital stay or at discharge. RESULTS Of 290 screened patients, 59 (20%) met the inclusion criteria and were enrolled. Only one of 59 patients (1.7%) resulted positive for P. jirovecii detection with PCR and the same patient was the only one to develop PCP in the follow up period. CONCLUSION 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 limitation of the study, the fact that the only patient who tested positive P. jirovecii was the only one in our cohort to develop PCP leads us to reflect on the role of this non-invasive sample in predicting the risk of PCP in patients with COVID-19.