Direct identification of pneumococcal serotypes in blood cultures by a PCR-reverse-hybridisation technique

Abstract

Introduction: The objective of this study was to assess the performance of a technique (S. PneumoStrip test) based on PCR followed by reverse strip hybridisation for the detection of Streptococcus pneumoniae serotypes directly in blood culture vials.

Methods: One hundred and ten (110) pairs of isolated strains and their corresponding original blood cultures vials were studied in parallel. Pure isolated strains were conventionally serotyped using latex agglutination and the Quellung reaction. The S. PneumoStrip test was carried out directly in the original blood culture samples.

Results: In 102 cases (92.7%), results of the serotype obtained by Quellung coincided with their corresponding original blood cultures typed by S. PneumoStrip.

Conclusions: S. PneumoStrip test is a good alternative technique for direct pneumococcal serotyping in blood culture clinical samples.

Keywords: Blood culture; Hemocultivo; PCR; Serotipado; Serotyping; Streptococcus pneumoniae.