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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
04:25

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

Published on: February 24, 2014

Impact of new Clinical Laboratory Standards Institute Streptococcus pneumoniae penicillin susceptibility testing

Robertino M Mera1, Linda A Miller, Heather Amrine-Madsen

  • 1Research Statistics Unit, GlaxoSmithKline, Research Triangle Park, North Carolina 27709, USA. robertino.mera@gsk.com

Microbial Drug Resistance (Larchmont, N.Y.)
|December 2, 2010
PubMed

Insights

Penicillin resistance in Streptococcus pneumoniae showed a complex pattern influenced by vaccine introduction. New criteria reveal shifts in resistance, with potential loss of vaccine serotype resistance and gain in non-vaccine types.

Area of Science:

  • Microbiology
  • Epidemiology
  • Infectious Diseases

Background:

  • Penicillin resistance in Streptococcus pneumoniae is a significant public health concern.
  • Changes in resistance patterns can be influenced by antimicrobial use and vaccination strategies.
  • Evolving breakpoints for resistance detection necessitate re-evaluation of historical trends.

Purpose of the Study:

  • To analyze trends in penicillin resistance of Streptococcus pneumoniae in the U.S. from 1996-2008.
  • To evaluate the impact of changing Clinical Laboratory Standards Institute (CLSI) breakpoints on resistance detection.
  • To assess the influence of pneumococcal conjugate vaccine introduction on resistance patterns.

Main Methods:

  • Analysis of 97,843 U.S. Streptococcus pneumoniae isolates from the Surveillance Network database (1996-2008).
  • Comparison of penicillin resistance rates using old (≥2 μg/ml) and new CLSI breakpoints (≥8 μg/ml for blood/bronchial, ≥0.12 μg/ml for meningitis).
  • Examination of resistance trends in relation to the introduction of the conjugate pneumococcal vaccine.

Main Results:

  • Using the old breakpoint (≥2 μg/ml), penicillin resistance rose, fell, and rebounded (15.6% to 16.9%).
  • New breakpoints showed minimal change for blood/bronchial isolates (0.24% to 1.52%) but high prevalence for meningitis (34.8%).
  • Post-vaccine, resistance at 1-2 μg/ml declined, while resistance at 0.12-0.5 μg/ml increased, suggesting serotype replacement.

Conclusions:

  • The introduction of the conjugate pneumococcal vaccine likely influenced penicillin resistance trends.
  • New CLSI criteria reveal different resistance profiles, particularly for meningitis isolates.
  • Observed shifts indicate potential loss of vaccine serotype resistance and acquisition by non-vaccine serotypes, warranting continued surveillance.

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