Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6116507 | Diagnostic Microbiology and Infectious Disease | 2011 | 9 Pages |
Abstract
Noncapsulated pneumococci are atypical Streptococcus pneumoniae that lack a capsule and therefore do not react with any available antisera. These isolates, which are often referred as nontypeable pneumococci (NTPn), are difficult to identify as their differentiation from closely related species such as Streptococcus pseudopneumoniae and other streptococcus of the mitis group is not always straightforward. We developed a low-cost and easy assay to detect and quantify NTPn in primary samples (which may contain multiple species) obtained from nasopharyngeal swabs. The strategy is based on a multiplex polymerase chain reaction targeting lytA, cpsA, aliB-like ORF2, and 16S rDNA genes, plus a restriction fragment length polymorphism assay to differentiate typical from atypical lytA. The application of the proposed methodology to over 500 nasopharyngeal samples found that the prevalence of NTPn in colonization was 3-fold higher than that estimated by routine methods (from 2.9% to 8.6% in the study collection). The international clone NorwayNTST344 was the major clone identified.
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Authors
Alexandra S. Simões, Carina Valente, HermÃnia de Lencastre, Raquel Sá-Leão,