Detection of Streptococcus pneumoniae in sterile liquids using real-time PCR (qPCR) in hospitalized patients with suspected invasive pneumococcal disease.

Abstract

The standard for diagnosing invasive pneumococcal disease (IPD) is to isolate pneumococcus in culture. However, the etiological agent cannot be identified in some patients, especially those who received empirical antibiotic therapy. This study aimed to detect pneumococcus in normally sterile fluids by qPCR in patients with suspected IPD hospitalized in Lima. qPCR had a detection limit of 1.2 x 101 genome copies/uL. Of the 71 clinical samples (51 were pleural fluid [PF] and 20 were cerebrospinal fluid [CSF]), 29.4% (28/71) were positive for pneumococcus by culture and 71.8% (51/71) were positive by qPCR, including 78.4% (40/51) in PF and 55.0% (11/20) in CSF. Of the positive samples, 13/51 were serotype 19A. The detection of pneumococcus was almost double by qPCR compared to the conventional microbiological method. Therefore, molecular methods such as qPCR should be implemented to improve the identification and timely treatment of IPD in Peru and in the region. Motivation for the study. Invasive pneumococcal disease (IPD) is usually diagnosed by microbiological culture to detect pneumococcus. However, this is sometimes not possible, particularly in patients who have previously received antibiotics. This study sought to detect pneumococcus using a molecular technique such as qPCR in hospitalized patients in Lima with suspected IPD. Main findings. qPCR detected a higher frequency of pneumococcus than the standard microbiological technique. Implications for public health. These findings suggest that the implementation of qPCR could significantly improve the identification and treatment of IPD in Peru.