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Characterization of R-plasmids coding for ampicillin resistance in Salmonella typhi-murium
Abstract:
Eight Salmonella typhi-murium strains coding resistance to ampicillin were chosen from 38 strains isolated in different counties of Hungary in 1981, and their plasmids were characterized by agarose gel electrophoresis. Incompatibility groups and molecular weights of transferable R-plasmids coding resistance to ampicillin were determined and restriction enzyme analyses were done. The studies showed that among R-plasmids coding for ampicillin resistance in S. typhi-murium strains IncI alpha group plasmids with a molecular weight of 66 Mdal were dominant in Hungary. According to their cleavage patterns, the examined plasmids formed two groups. Both types contained some fragments identical in size, and they are supposed to be connected evolutionarily.
Insights
Ampicillin-resistant Salmonella typhi-murium strains in Hungary predominantly carried IncI alpha R-plasmids. These transferable plasmids, common in 1981, showed evolutionary links based on restriction enzyme analysis.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Antibiotic resistance in bacterial pathogens is a growing global concern.
- Salmonella typhi-murium is a significant cause of foodborne illness.
- The emergence of ampicillin resistance in S. typhi-murium necessitates understanding the genetic basis of resistance.
Purpose of the Study:
- To characterize ampicillin resistance plasmids in Salmonella typhi-murium strains isolated in Hungary.
- To determine the types and prevalence of transferable R-plasmids responsible for ampicillin resistance.
Main Methods:
- Isolation and selection of ampicillin-resistant S. typhi-murium strains.
- Plasmid DNA extraction and characterization using agarose gel electrophoresis.
- Determination of incompatibility groups and molecular weights of plasmids.
- Restriction enzyme analysis of plasmid DNA.
Main Results:
- Eight ampicillin-resistant S. typhi-murium strains were analyzed.
- IncI alpha group plasmids with a molecular weight of 66 Mdal were dominant among the characterized R-plasmids.
- Restriction enzyme analysis revealed two distinct plasmid groups, suggesting an evolutionary relationship.
Conclusions:
- IncI alpha plasmids are a major vehicle for ampicillin resistance in Hungarian S. typhi-murium strains.
- The identified plasmid groups share common fragments, indicating a potential evolutionary connection.
- Understanding plasmid epidemiology is crucial for combating antibiotic resistance.