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Detection and characterization of IS256, an insertion sequence in Staphylococcus aureus
B R Lyon1, M T Gillespie, R A Skurray
1Department of Microbiology, Monash University, Clayton, Victoria, Australia.
Journal of General Microbiology
|November 1, 1987
Summary
The insertion sequence IS256, found in Australian Staphylococcus aureus strains, mediates aminoglycoside resistance. Tandem duplication of IS256 with Tn4001 enhances resistance, suggesting IS256 has strong promoter activity and may cause genomic rearrangements.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Aminoglycoside resistance is a significant challenge in treating Staphylococcus aureus infections.
- The transposon Tn4001 is identified as the primary mediator of gentamicin, tobramycin, and kanamycin resistance in Australian S. aureus strains.
Purpose of the Study:
- To characterize the insertion sequence IS256, an inverted repeat of Tn4001.
- To investigate the role of IS256 in aminoglycoside resistance levels and potential genomic alterations in S. aureus.
Main Methods:
- Molecular characterization of the Tn4001 transposon and its inverted repeat, IS256.
- Analysis of IS256's genomic location (contiguous with Tn4001 or independent insertions).
- Assessment of aminoglycoside resistance levels in relation to IS256 duplication.
Main Results:
- The 1.35 kb inverted repeat of Tn4001 was identified and designated IS256.
- Tandem duplication of IS256 adjacent to Tn4001 led to increased gentamicin, tobramycin, and kanamycin resistance.
- IS256 was observed in both contiguous and independent insertions within the staphylococcal chromosome.
Conclusions:
- IS256 possesses strong promoter sequences, contributing to elevated aminoglycoside resistance.
- Independent insertions of IS256 suggest its potential involvement in the genome's molecular rearrangements.
- Understanding IS256's function is crucial for combating aminoglycoside resistance in Staphylococcus aureus.