Comparison of Molecular and Conventional Methods Used for The Identification of Streptococcus pneumoniae in Upper and Lower Respiratory Tract Samples

This study aimed to determine whether Streptococcus pneumoniae detected by molecular methods in upper respiratory tract samples could be cultured from lower respiratory tract samples and to compare the diagnostic performance of molecular and conventional methods. This retrospective descriptive study included nasopharyngeal swab and sputum samples obtained from patients with suspected pneumonia between January 1, 2024, and September 1, 2025. A total of 311 adult and 230 pediatric nasopharyngeal swab samples were analyzed using Real-Time PCR with the Bosphore Respiratory Pathogens Panel Kit v5. Additionally, sputum cultures from 96 PCR-positive adult patients were evaluated using conventional culture methods. Statistical analyses were performed using SPSS version 23.0. S. pneumoniae positivity was detected by PCR in 193 of 311 adult samples (62.1%). In the pediatric group aged ≤2 years, PCR positivity was 91.2%. PCR positivity was significantly higher in patients aged 18–65 years and in patients diagnosed with pneumonia (p<0.05). A significant association was observed between pulmonary disease groups and PCR positivity (p=0.007). Patients with solid organ malignancy had significantly lower PCR positivity rates (p=0.014). No S. pneumoniae growth was detected in the sputum cultures of the 96 PCR-positive patients. Although molecular methods are highly sensitive for pneumococcal diagnosis, they are insufficient alone for distinguishing colonization from infection. Clinical, radiological, and culture findings should be evaluated together.