Evaluation of pneumococcal urinary antigen testing for respiratory tract infection investigations

Abstract

Objective: The pneumococcal urinary antigen test enables rapid bacteriological diagnosis in respiratory tract infections. The objective was to identify factors associated with a positive pneumococcal urinary antigen test result.

Patients and methods: This seven-year retrospective monocentric study was performed on consecutive patients presenting with respiratory tract infections reported as pneumococcal-positive. Epidemiological, biological, and radiological factors were analyzed, and severity scores were calculated.

Results: A total of 223 patients were included. Significant associations were observed between positive test results and age over 65years (P=0.01), positive test results and immunosuppression factors (blood disease [25% Ag+ group vs. 4% Ag- group, P=0.001], immunosuppressive therapy [10% Ag+ group vs. 0% Ag- group, P=0.02]). Clinically, fever (64% Ag+ group vs. 42% Ag- group, P=0.01) and cough (46% Ag+ group vs. 19% Ag- group, P<0.01) were associated with a positive result, as were radiological alveolar opacities (67% Ag+ group vs. 44% Ag- group, P=0.01). High PSI score was associated with the Ag+ group (79% vs. 56% Ag- group, P=0.001).

Conclusion: Age, immunosuppressive factors, typical pneumococcal symptoms, and PSI scores were associated with a positive pneumococcal urinary antigen result.

Keywords: Antigénurie pneumocoque; Infection respiratoire; Pneumococcal urinary antigen; Pneumocoque; Respiratory tract infection; Streptococcus pneumoniae.