Oral colonization of Pneumocystis jirovecii in patients with rheumatoid arthritis and respiratory symptoms: a substudy of the AURORA cohort

OBJECTIVES: (PJ) colonization using oral wash polymerase chain reaction (PCR) in Danish rheumatoid arthritis (RA) patients with respiratory symptoms or recurrent pneumonia, and assessed its diagnostic utility for PCP. METHOD: This secondary analysis of the AURORA study included 76 consenting adults (aged ≥ 18 years) with RA and respiratory symptoms or recurrent pneumonia. Oral wash samples were tested for PJ using a validated PCR assay. All patients underwent pulmonary assessment, including high-resolution computed tomography (HRCT). Medical records were audited for PCP diagnoses after 2 years. RESULTS: The mean age was 65.6 years, 63% were female, 24% received biological disease-modifying anti-rheumatic drug treatment, and 8% had received biological treatment of >3 years' duration. Only one patient (1%), treated with methotrexate and rituximab and presenting with recurrent pneumonia, cough, and dyspnoea, tested positive for PJ. HRCT showed pneumonia, interstitial lung disease (usual interstitial pneumonia pattern), bronchiectasis, and emphysema. PCP was confirmed by a respiratory physician based on clinical presentation. No other patients developed PCP during follow-up. CONCLUSION: Oral colonization with PJ was rare in this cohort of Danish RA patients with respiratory symptoms. The low prevalence of colonization and the absence of PCP in PJ-negative patients suggest that routine screening for oral PJ colonization is not warranted in this population.