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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

Published on: February 24, 2014

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Evaluation of phenotypic and molecular methods for identification of Streptococcus pneumoniae

Rachid Y Yahiaoui1,2, Casper D J den Heijer1, Petra Wolfs1

  • 1Departement of Medical Microbiology, Maastricht University Medical Centre, Maastricht, The Netherlands.

Future Microbiology
|December 18, 2015
PubMed
Abstract

Insights

Current methods for identifying Streptococcus pneumoniae (S. pneumoniae) are insufficient, with a high rate of optochin resistance observed. Close monitoring of optochin susceptibility is recommended.

Area of Science:

  • Microbiology
  • Clinical Diagnostics
  • Bacterial Pathogenesis

Background:

  • Accurate identification of Streptococcus pneumoniae is crucial for effective treatment and infection control.
  • Existing diagnostic methods and algorithms for S. pneumoniae identification have limitations.
  • Optochin susceptibility testing is a common method for presumptive identification.

Purpose of the Study:

  • To evaluate the performance of various phenotypic and molecular methods for identifying Streptococcus pneumoniae.
  • To assess the accuracy of a widely used S. pneumoniae identification algorithm.
  • To investigate the prevalence of optochin resistance in S. pneumoniae isolates.

Main Methods:

  • Tested 1371 putative S. pneumoniae isolates using three phenotypic methods.
  • Employed a molecular-based method targeting the CpsA virulence factor.
  • Assessed sensitivity, specificity, and performance of a standard S. pneumoniae identification algorithm.

Main Results:

  • No single method or the combined algorithm accurately identified all S. pneumoniae isolates.
  • A significant and high rate of optochin resistance was detected among the isolates.
  • The tested methods and algorithm demonstrated limitations in correctly identifying S. pneumoniae.

Conclusions:

  • Current S. pneumoniae identification methods and optochin susceptibility-based algorithms are unreliable.
  • The high prevalence of optochin resistance necessitates careful consideration in diagnostic strategies.
  • Continuous monitoring of optochin susceptibility in S. pneumoniae is warranted to guide clinical decisions.
Keywords:
PCRStreptococcus pneumoniaebile solubilitycolony morphologyidentificationoptochin

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