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Transposon-916-like elements in clinical isolates of Enterococcus faecium
H M Fletcher1, L Marri, L Daneo-Moore
1Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140.
Journal of General Microbiology
|November 1, 1989
Summary
Most Enterococcus faecium clinical isolates show tetracycline resistance. Resistance is often linked to Tn916-like elements, but unidentified genes also contribute to lower resistance levels.
Area of Science:
- Microbiology
- Genetics
- Antimicrobial Resistance
Background:
- Tetracycline (Tc) resistance is a significant concern in clinical settings.
- Enterococcus faecium is a common cause of hospital-acquired infections.
Purpose of the Study:
- To investigate the genetic basis of tetracycline resistance in clinical isolates of Enterococcus faecium.
- To identify the mechanisms conferring high and low levels of Tc resistance.
Main Methods:
- Analysis of clinical isolates of Enterococcus faecium for Tc resistance.
- Molecular characterization of resistance determinants, including transposons and plasmids.
- Comparison of Tc resistance levels in isolates with and without specific genetic elements.
Main Results:
- Nine out of ten Enterococcus faecium isolates exhibited Tc resistance.
- Conjugative transposons (Tn5031, Tn5032, Tn5033) homologous to Tn916 were found in three isolates.
- A plasmid with Tn916 homology was identified in a fourth isolate, both associated with higher Tc resistance.
- Unidentified Tc-resistance genes likely responsible for lower resistance in remaining isolates.
Conclusions:
- Tn916-like elements are a major contributor to high-level tetracycline resistance in Enterococcus faecium.
- Novel Tc resistance genes may be present in clinical isolates with lower resistance levels.
- Understanding these resistance mechanisms is crucial for infection control.