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Emerging Trends in Antimicrobial Resistance and Serotype Patterns of Streptococcus pneumoniae

Strategic Insights

— 1 min read

Researchers have published new findings on the comparison of antimicrobial resistance and serotype patterns in Streptococcus pneumoniae collected from blood cultures and respiratory specimens in Canadian hospitals from 2007 to 2023. The study aimed to understand the differences in antimicrobial susceptibility testing and serotype identification between blood culture and respiratory specimen isolates. The research found that serotypes 3, 19A, 22F, and 11A were the most common overall, while serotypes 4, 5, 7F, 8, 12F, 14, 19A, and 22F were more frequently identified in blood culture isolates. Conversely, serotypes 6C, 7C, 11A, 19F, 21, 23A, 23B, 23F, 31, 34, 35B, 35F, and non-typeable strains were more commonly recognized in respiratory isolates.

Key Takeaways:

  • The study analyzed 3,111 S. pneumoniae isolates collected from Canadian hospitals from 2007 to 2023.
  • Serotypes 3, 19A, 22F, and 11A were the most common serotypes overall.
  • Serotypes 4, 5, 7F, 8, 12F, 14, 19A, and 22F were more frequently identified in blood culture isolates (P 0.01).
  • Serotypes 6C, 7C, 11A, 19F, 21, 23A, 23B, 23F, 31, 34, 35B, 35F, and non-typeable strains were more commonly recognized in respiratory isolates (P 0.03).
  • Susceptibility rates were significantly lower in respiratory isolates than blood culture isolates for penicillin, ceftriaxone, clarithromycin, clindamycin, and doxycycline (P 0.03).
  • MDR/XDR rates increased over the course of the study (P = 0.004) and were higher in respiratory isolates (10.5%) than in blood culture isolates (5.8%) (P < 0.05).
  • A greater proportion of isolates from blood cultures were serotypes covered by current pneumococcal vaccines.

Statistics:

  • 3,111 S. pneumoniae isolates were analyzed in the study.
  • 35.5% of isolates were from blood cultures.
  • 64.5% of isolates were from respiratory specimens.
  • 8.3% of isolates were MDR/XDR.
  • MDR/XDR rates increased from 2007 to 2023 (P = 0.004).
  • Respiratory isolates had a higher MDR/XDR rate than blood culture isolates (10.5% vs. 5.8%, P < 0.05).

Sources:

  • "Comparison of antimicrobial resistance and serotype patterns in Streptococcus pneumoniae from blood cultures and respiratory specimens in Canadian hospitals from the CANWARD study (2007-23)." Journal of Antimicrobial Chemotherapy, 2025;80.
  • Public Health Agency of Canada, National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, Manitoba, Canada R3E 3M4.
  • Alyssa R. Golden, Heather J. Adam, Irene Martin, Melanie R. Baxter, Ross J. Davidson, James A. Karlowsky, and George G. Zhanel.

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