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Ribosomal resistance of clinical enterococcal to streptomycin isolates

Insights

High-level streptomycin resistance in Streptococcus faecalis is often caused by modifying enzymes. However, some strains show resistance due to ribosomal changes, indicating a significant mechanism for enterococcal antibiotic resistance.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Antimicrobial Resistance

Background:

  • Streptococcus faecalis (now Enterococcus faecalis) is a common cause of nosocomial infections.
  • High-level streptomycin resistance (HLSR) is a growing clinical concern, limiting treatment options.
  • Understanding resistance mechanisms is crucial for effective antimicrobial stewardship.

Purpose of the Study:

  • To investigate the mechanisms underlying high-level streptomycin resistance in clinical isolates of Streptococcus faecalis.
  • To differentiate between enzymatic modification and ribosomal alterations as causes of HLSR.

Main Methods:

  • Analysis of 12 clinical isolates of Streptococcus faecalis.
  • Determination of streptomycin-modifying enzyme production in resistant strains.
  • Assessment of ribosomal susceptibility to streptomycin in enzyme-negative strains.

Main Results:

  • Six of the 12 isolates produced streptomycin-modifying enzymes.
  • Three enzyme-negative isolates exhibited resistance attributed to ribosomal alterations.
  • Ribosomal insusceptibility was identified as a key factor in HLSR.

Conclusions:

  • Both streptomycin-modifying enzymes and ribosomal resistance contribute to HLSR in Streptococcus faecalis.
  • Ribosomal insusceptibility is a significant mechanism driving HLSR in clinical enterococcal isolates.
  • These findings highlight the diverse strategies employed by bacteria to resist antibiotics.

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