The Relevance of a Novel Quantitative Assay to Detect up to 40 Major Streptococcus pneumoniae Serotypes Directly in Clinical Nasopharyngeal and Blood Specimens

• Authors: Melina Messaoudi, Centre International de Recherche en Infectiologie (CIRI); Milen Milenkov, Centre International de Recherche en Infectiologie (CIRI); Werner C. Albrich, Kantonsspital St. Gallen; Mark P. G. van der Linden, University Hospital RWTH Aachen; Thomas Bénet, Hôpital Edouard Herriot - Hospices Civils de Lyon; Monidarin Chou, University of Health Sciences, Cambodia; Mariam Sylla, Centre hospitalo-universitaire Gabriel Touré; Patricia Barreto Costa, Instituto Oswaldo Cruz/Fiocruz; Nathalie Richard, Hôpitaux Est - Hospices Civils de Lyon; Keith Klugman, Emory University; Hubert P. Endtz, Centre International de Recherche en Infectiologie (CIRI); Gláucia Paranhos-Baccalà, Centre International de Recherche en Infectiologie (CIRI); Jean-Noël Telles, Centre International de Recherche en Infectiologie (CIRI)
• Journal Title: PLoS ONE
• Volume: Volume 11, Number 3
• Publisher: Public Library of Science | 2016-03-17, Pages e0151428-e0151428
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1371/journal.pone.0151428
• Subjects: Health Sciences, Pathology; Health Sciences, Public Health; Biology, Microbiology
• Keywords: Science & Technology; Multidisciplinary Sciences; Science & Technology - Other Topics; INVASIVE PNEUMOCOCCAL DISEASE; REAL-TIME PCR; CAPSULAR SEROTYPES; MULTIPLEX PCR; LATEX AGGLUTINATION; CARRIAGE; ADULTS; IDENTIFICATION; Polymerase chain reaction; Blood; Children; Pediatrics; Bacterial pathogens; Conjugate vaccines; Infectious disease epidemiology

Abstract

For epidemiological and surveillance purposes, it is relevant to monitor the distribution and dynamics of Streptococcus pneumoniae serotypes. Conventional serotyping methods do not provide rapid or quantitative information on serotype loads. Quantitative serotyping may enable prediction of the invasiveness of a specific serotype compared to other serotypes carried. Here, we describe a novel, rapid multiplex real-time PCR assay for identification and quantification of the 40 most prevalent pneumococcal serotypes and the assay impacts in pneumonia specimens from emerging and developing countries. Eleven multiplex PCR to detect 40 serotypes or serogroups were optimized. Quantification was enabled by reference to standard dilutions of known bacterial load. Performance of the assay was evaluated to specifically type and quantify S. pneumoniae in nasopharyngeal and blood samples from adult and pediatric patients hospitalized with pneumonia (n = 664) from five different countries. Serogroup 6 was widely represented in nasopharyngeal specimens from all five cohorts. The most frequent serotypes in the French, South African, and Brazilian cohorts were 1 and 7A/F, 3 and 19F, and 14, respectively. When both samples were available, the serotype in blood was always present as carriage with other serotypes in the nasopharynx. Moreover, the ability of a serotype to invade the bloodstream may be linked to its nasopharyngeal load. The mean nasopharyngeal concentration of the serotypes that moved to the blood was 3 log-fold higher than the ones only found in the nasopharynx. This novel, rapid, quantitative assay may potentially predict some of the S. pneumoniae serotypes invasiveness and assessment of pneumococcal serotype distribution.