16S rRNA mutations that confer tetracycline resistance in Helicobacter pylori decrease drug binding in Escherichia...

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Tetracycline resistance in Helicobacter pylori is linked to specific mutations in the 16S rRNA gene.
• Understanding these mutations is crucial for effective H. pylori treatment.

Purpose of the Study:

• To investigate the impact of nucleotide substitutions at positions 965-967 in the 16S rRNA gene on tetracycline resistance.
• To determine how these substitutions affect tetracycline binding to ribosomes.

Main Methods:

• Constructed Escherichia coli mutants with varying sequences at positions 965-967 in the 16S rRNA gene.
• Determined Minimum Inhibitory Concentrations (MICs) for tetracycline.
• Measured tetracycline binding to ribosomes from resistant and wild-type strains.

Main Results:

• Mutants with substitutions at positions 965-967 exhibited higher tetracycline MICs compared to wild-type.
• A triple substitution (965TTC967) resulted in a 32-fold increase in MIC compared to the wild-type H. pylori sequence.
• Tetracycline binding to ribosomes was reduced by 40% in the resistant variant.

Conclusions:

• Sequence patterns at ribosomal positions 965-967 directly influence tetracycline binding to the Tet-1 site.
• These findings provide molecular insights into tetracycline resistance mechanisms in H. pylori.