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Drug resistance and plasmid profiles in Staphylococcus epidermidis in 1964 and 1986
1Institute of Medical Microbiology, University of Aarhus, Denmark.
Abstract:
An examination has been made of drug resistance and plasmid content of Staphylococcus epidermidis isolated from hospital patients in 1964 and 1986. Drug resistance was much more prevalent in isolates from 1986 than in isolates from 1964. Plasmids were demonstrated in 50 of 52 strains from 1964 and in 102 of 111 strains from 1986. The majority of both drug-sensitive and drug-resistant strains harboured more than one plasmid. Of five plasmids obtained from a multiply-drug-resistant S. epidermidis, four were shown to mediate drug resistance.
Insights
Drug resistance in Staphylococcus epidermidis significantly increased from 1964 to 1986. Most strains carried multiple plasmids, with four of five tested plasmids mediating drug resistance in this bacterium.
Area of Science:
- Microbiology
- Medical Science
- Molecular Biology
Background:
- Staphylococcus epidermidis is a common cause of hospital-acquired infections.
- Understanding the evolution of antibiotic resistance in bacteria is crucial for public health.
- Plasmids are known to play a significant role in the dissemination of antibiotic resistance genes.
Purpose of the Study:
- To compare the prevalence of drug resistance and plasmid content in Staphylococcus epidermidis isolates from two distinct time periods (1964 and 1986).
- To investigate the role of plasmids in mediating drug resistance in Staphylococcus epidermidis.
Main Methods:
- Bacterial isolation and identification of Staphylococcus epidermidis from clinical samples.
- Antimicrobial susceptibility testing to determine drug resistance patterns.
- Plasmid DNA extraction and analysis (e.g., gel electrophoresis).
- Plasmid curing experiments or transformation assays to assess the role of plasmids in drug resistance.
Main Results:
- A notable increase in drug resistance was observed in Staphylococcus epidermidis isolates from 1986 compared to those from 1964.
- Plasmids were frequently detected in both years, present in 50/52 strains in 1964 and 102/111 strains in 1986.
- The majority of both drug-sensitive and drug-resistant strains harbored multiple plasmids.
- Experiments with a multiply-drug-resistant strain demonstrated that four out of five isolated plasmids were responsible for mediating drug resistance.
Conclusions:
- Hospital-acquired Staphylococcus epidermidis strains have shown a significant increase in drug resistance over time.
- Plasmids are prevalent in Staphylococcus epidermidis and are key mediators of antibiotic resistance.
- These findings highlight the dynamic nature of bacterial resistance and the importance of plasmid-mediated gene transfer in its evolution.