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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

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[Streptococcus pneumoniae growth based on drug resistance genotype]

Katsuhito Miyashita1

  • 1Department of Bacteriology, Kanazawa University Graduate School of Medical Science, Division of Environmental Science.

Kansenshogaku Zasshi. the Journal of the Japanese Association for Infectious Diseases
|August 14, 2008
PubMed

Insights

Penicillin and macrolide resistance in Streptococcus pneumoniae strains impacts their growth rates. Some resistant strains, particularly those with macrolide resistance genotypes, exhibit earlier and faster proliferation, influencing clinical prevalence.

Area of Science:

  • Microbiology
  • Bacterial genetics
  • Antimicrobial resistance

Context:

  • Streptococcus pneumoniae exhibits tolerance attributed to penicillin and macrolide resistance genotypes.
  • Clinical prevalence of S. pneumoniae is influenced by these resistance genotypes, potentially due to strain-specific growth characteristics.
  • Limited comparative data exists on the growth dynamics of S. pneumoniae strains with distinct resistance profiles.

Purpose:

  • To compare the in vitro growth capabilities of Streptococcus pneumoniae strains possessing different penicillin and macrolide resistance genotypes.
  • To identify specific growth parameters (e.g., doubling time, peak attainment) that differentiate resistant strains.
  • To elucidate the relationship between genotypic resistance and phenotypic growth rate in S. pneumoniae.

Summary:

  • Growth curves of S. pneumoniae strains, including ATCC6303, a penicillin-susceptible strain (PSSP8), and a penicillin-intermediate/macrolide-resistant strain (PISP), were analyzed using spectrophotometry.
  • Significant differences in dullness time, doubling time (D.B.T.), and peak attainment were observed between PSSP8 and PISP strains.
  • Growth rate priorities varied: PSSP > PISP > PRSP for penicillin resistance, and mefA > non-mefA, non-ermB > ermB for macrolide resistance, with some PISP strains showing immediate proliferation.

Impact:

  • Findings reveal that genotypic resistance influences S. pneumoniae growth dynamics, with certain macrolide-resistant strains proliferating earlier and faster.
  • These growth differences may explain the varying clinical distribution of resistant S. pneumoniae strains.
  • Understanding strain-specific growth rates is crucial for predicting the epidemiological behavior of antibiotic-resistant bacteria.

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