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Serotype-specific invasiveness and colonization prevalence in Streptococcus pneumoniae correlate with the lag phase

Patrick Bättig1, Lucy J Hathaway, Sandra Hofer

  • 1Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, CH-3010 Bern, Switzerland.

Microbes and Infection
|August 30, 2006
PubMed

Insights

Streptococcus pneumoniae serotypes with higher invasive potential had longer lag phases in vitro. Fetal calf serum (FCS) shortened this lag phase, suggesting a link between growth and disease severity.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Bacterial Pathogenesis

Background:

  • Streptococcus pneumoniae serotypes exhibit varying colonization and disease-causing potentials.
  • Understanding the factors influencing pneumococcal virulence is crucial for public health.

Purpose of the Study:

  • To investigate the relationship between in vitro growth characteristics and the in vivo invasiveness and colonization prevalence of Streptococcus pneumoniae serotypes.
  • To determine if fetal calf serum (FCS) supplementation affects pneumococcal growth in a manner related to serotype invasiveness.

Main Methods:

  • Compared in vitro growth (lag phase duration) of 47 clinical isolates of Streptococcus pneumoniae (15 serotypes) in brain heart infusion broth with or without 5% FCS.
  • Correlated in vitro growth data with epidemiological data on serotype-specific colonization prevalence and invasive potential.
  • Assessed the impact of antioxidants (manganese, Tiron, mannitol, catalase) on lag phase duration.

Main Results:

  • Lag phase duration was positively associated with serotype invasiveness and inversely associated with colonization prevalence.
  • FCS supplementation significantly shortened the lag phase, particularly for serotypes linked to invasive disease (P=0.007).
  • Antioxidant supplementation did not significantly alter lag phase duration.

Conclusions:

  • In vitro lag phase duration is a potential indicator of Streptococcus pneumoniae serotype invasiveness and colonization prevalence.
  • FCS may play a role in promoting the growth of more invasive pneumococcal serotypes.
  • These findings suggest a correlation between in vitro growth dynamics and in vivo serotype selection.

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