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Increase in pneumococcus macrolide resistance, United States

Stephen G Jenkins1, David J Farrell

  • 1Weill Cornell Medical College, New York, NY 10065, USA. stj2005@med.cornell.edu

Emerging Infectious Diseases
|September 16, 2009
PubMed

Insights

Macrolide resistance in Streptococcus pneumoniae significantly increased in 2005-2006, reaching 35.3%. High-level resistance is growing, particularly in children and the southern US.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Epidemiology

Background:

  • Macrolide resistance in Streptococcus pneumoniae has been a growing concern.
  • Previous surveillance data showed a stable resistance rate of approximately 30%.

Purpose of the Study:

  • To monitor macrolide resistance trends in Streptococcus pneumoniae during year 6 (2005-2006) of the Prospective Resistant Organism Tracking and Epidemiology (PROTECT) study.
  • To compare current resistance data with previous years and analyze resistance mechanisms.

Main Methods:

  • Collection of 6,747 Streptococcus pneumoniae isolates from 119 centers across the United States.
  • Susceptibility testing to macrolides and comparison with historical data.
  • Genotypic analysis of resistance mechanisms, including mef(A) and erm(B).

Main Results:

  • Macrolide resistance in Streptococcus pneumoniae significantly increased to 35.3% in year 6, up from a stable rate of ~30%.
  • Resistance increased across all US regions and age groups, with highest rates in the South and for children aged 0-2 years.
  • Prevalence of lower-level mef(A)-mediated resistance decreased, while highly resistant erm(B) + mef(A) strains increased to 25%.

Conclusions:

  • Pneumococcal macrolide resistance in the US experienced its first significant rise since 2000.
  • High-level macrolide resistance is increasing, necessitating continued surveillance and potential treatment strategy adjustments.
  • Telithromycin and levofloxacin maintained high susceptibility rates (>99% and >98%, respectively), indicating continued efficacy against these resistant strains.

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