Mutation in 23S rRNA responsible for resistance to 16-membered macrolides and streptogramins in Streptococcus...

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Streptococcus pneumoniae is a leading cause of bacterial infections.
• Antibiotic resistance in S. pneumoniae is a significant public health concern.
• Macrolides and streptogramins are important classes of antibiotics used to treat S. pneumoniae infections.

Purpose of the Study:

• To investigate the molecular basis of an unusual antibiotic resistance phenotype in a clinical isolate of Streptococcus pneumoniae.
• To identify the genetic mutation responsible for resistance to 16-membered macrolides and streptogramins.

Main Methods:

• Phenotypic characterization of Streptococcus pneumoniae clinical isolate BM4455 for antibiotic susceptibility.
• Genetic analysis to identify mutations in ribosomal RNA genes, specifically 23S rRNA.

Main Results:

• The clinical isolate BM4455 displayed resistance to 16-membered macrolides and streptogramins.
• A specific mutation, A2062C (using Escherichia coli numbering), was identified in domain V of all four copies of the 23S rRNA gene.
• This mutation is strongly associated with the observed resistance phenotype.

Conclusions:

• The A2062C mutation in 23S rRNA is responsible for the dual resistance to macrolides and streptogramins in Streptococcus pneumoniae BM4455.
• This finding highlights the importance of monitoring specific rRNA mutations for understanding and combating antibiotic resistance.
• The study provides insights into the mechanisms of resistance to these important antibiotic classes.