Serotypes and antibiotic susceptibility of Streptococcus pneumoniae isolates causative of invasive diseases in Mexican children

J Infect Dev Ctries. 2011 Mar 2;5(2):119-22. doi: 10.3855/jidc.1348.


Introduction: Streptococcus pneumoniae is a worldwide leading cause of morbidity and mortality, while susceptibility towards penicillin and macrolides can be less than 50% in many regions.

Methodology: A total of 150 isolates of S. pneumoniae causative of invasive diseases in children were characterized, of which 24.6% had a fatal outcome.

Results: The most prevalent serotypes were 19F, 6B, 23F and 14. Resistance to penicillin, erythromycin (mostly of macrolide-lincosamide-streptogramin resistance phenotype) or trimethoprim-sulfamethoxazole was found in more than 40% of the isolates, but no resistance phenotype appeared linked to lethality. Serotype 3 isolates, which were seldom resistant, had a twofold lethality rate compared to the total sample.

Conclusion: Serotyping could provide a better outcome-predicting tool than susceptibility testing. The seven-valent vaccine does not include the most prevalent serotypes found in Mexico.

MeSH terms

  • Adolescent
  • Anti-Bacterial Agents / pharmacology*
  • Child
  • Child, Preschool
  • Drug Resistance, Bacterial*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Macrolides / pharmacology
  • Male
  • Mexico / epidemiology
  • Microbial Sensitivity Tests
  • Penicillins / pharmacology
  • Pneumococcal Infections / epidemiology*
  • Pneumococcal Infections / microbiology
  • Pneumococcal Infections / mortality
  • Prevalence
  • Serotyping
  • Streptococcus pneumoniae / classification*
  • Streptococcus pneumoniae / drug effects*
  • Streptococcus pneumoniae / isolation & purification
  • Trimethoprim, Sulfamethoxazole Drug Combination / pharmacology


  • Anti-Bacterial Agents
  • Macrolides
  • Penicillins
  • Trimethoprim, Sulfamethoxazole Drug Combination