Evaluation of Modified Sequential Multiplex PCR for <i>Streptococcus pneumoniae</i> Serotyping

Abstract

INTRODUCTION Streptococcus pneumoniae is an important bacterial pathogen causing acute otitis media, pneumonia, and invasive pneumococcal diseases (IPD), including bacteremia and meningitis (1-4). It carries high rates of morbidity and mortality, with approximately 1.6 million deaths each year, especially in children, the elderly, and immunocompromised patients (5). More than 93 streptococcal serotypes have been identified on the basis of antigenic differences in their capsular polysaccharides (6). Determination of serotype is essential because only a limited number of serotypes are associated with IPD, with approximately 80 of IPD infections caused by about 20 predominant serotypes (7,8). The Quellung reaction (Statens Serum Institut, Copenhagen, Denmark) has been considered the gold standard for S. pneumoniae serotyping. However, it has limitations, particularly its high cost, labor intensiveness, and the need for a trained technician (9). Sequential multiplex PCR (SM-PCR) has proven to be sensitive and efficient for S. pneumoniae serotyping and has been used extensively in several countries as a replacement for the Quellung reaction (10,11).

Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Causing Invasive Pneumococcal Disease in Korea Between 2017 and 2019 After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

“…Serotyping was performed using modified sequential multiplex (SM)-PCR, as previously described [8]. We carried out an additional multiplex PCR set for serotypes 2, 10F/10C/33C, 31, 35F/ 47F, and 38/25F/25A.…”