Identification of Pneumococcal Serotypes by PCR–Restriction Fragment Length Polymorphism

• Main Authors: María del Mar García-Suárez, Irene González-Rodríguez, María Dolores Cima-Cabal, Jose Enrique Yuste, Fernando Vazquez, Enrique Santiago
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Diagnostics
• Subjects: <i>streptococcus pneumoniae</i>; serotype; pcr-rflp
• Online Access: https://www.mdpi.com/2075-4418/9/4/196

<i>Streptococcus pneumoniae</i> shows more than 90 capsular serotypes that can be distinguished by their reactivity against antisera. The main objective of this work was the development of a molecular method for serotyping without the use of antisera. A computer program containing an algorithm was used to search in a database for potentially useful enzymes for Restriction Fragment Length Polymorphism-RFLP typing, in order to maximize the discrimination between different serotypes. DNA sequences of 90 serotypes for the region between <i>dex</i>B and <i>ali</i>A genes were compiled, and a computer screening of restriction enzymes was performed. The<i> </i><i>wzg</i><i>&#8722;</i><i>wzh</i><i>&#8722;</i><i>wzd</i><i>&#8722;</i><i>wze</i><i> </i>region and <i>Sse</i>9I restriction predicted unique PCR-RFLP patterns for 39 serotypes and eight serogroups. A second restriction enzyme resolved fragment specific patterns for 25 serotypes. The method was tested with 98 serotype-unknown clinical isolates. PCR-RFLP analysis deduced correct serotypes that were confirmed by Quellung reaction for 78.5% of the isolates.