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Characterization of a macrolide, lincosamide, and streptogramin resistance plasmid in Staphylococcus epidermidis
Abstract:
A strain of Staphylococcus epidermidis was transduced to erythromycin resistance, and all of the transductants exhibited the macrolide, lincosamide, streptogramin B resistance phenotype. Curing and antibiotic disk studies also indicated that these resistances were controlled by a single plasmid determinant and were constitutive. Agarose gel electrophoresis of plasmid deoxyribonucleic acid (DNA) from donor, cured, and transduced strains showed that a single plasmid was responsible. This plasmid, designated pNE131, was examined for sequence homology to two other plasmids, pE194 and p1258, from Staphylococcus aureus, which also code for erythromycin resistance. DNA from plasmids pNE131 and pE194 hybridized with one another, but no extensive homology to pI258 with either pNE131 or pE194 was found. Restriction endonuclease digests of pNE131 and pE194 showed no common fragments. However, sequence homology was localized to the nucleotides in pE194 that code for the 29,000-dalton protein responsible for erythromycin resistance. pNE131 was calculated to have 2,220 base pairs and is the smallest naturally occurring plasmid with a known function yet reported in S. epidermidis.
Insights
Researchers identified a small plasmid, pNE131, in Staphylococcus epidermidis conferring erythromycin resistance. This discovery advances understanding of antibiotic resistance mechanisms in bacteria.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Antibiotic resistance is a growing global health concern.
- Plasmids are key genetic elements mediating antibiotic resistance in bacteria.
- Staphylococcus epidermidis is an opportunistic pathogen frequently associated with nosocomial infections.
Purpose of the Study:
- To characterize the genetic basis of erythromycin resistance in a strain of Staphylococcus epidermidis.
- To identify and analyze the plasmid responsible for conferring resistance.
- To compare the resistance plasmid with other known erythromycin resistance plasmids.
Main Methods:
- Bacterial conjugation and transduction experiments were performed.
- Antibiotic disk diffusion assays were used to determine resistance phenotypes.
- Plasmid DNA was isolated and analyzed using agarose gel electrophoresis.
- DNA hybridization and restriction endonuclease digestion were employed to assess sequence homology.
Main Results:
- A single plasmid, pNE131, was identified as responsible for erythromycin, macrolide, lincosamide, and streptogramin B resistance.
- pNE131 exhibited sequence homology with plasmid pE194 from Staphylococcus aureus, specifically in the region encoding the erythromycin resistance protein.
- pNE131 has a size of 2,220 base pairs, making it the smallest known naturally occurring functional plasmid in S. epidermidis.
Conclusions:
- The study identified and characterized pNE131, a novel plasmid conferring broad-spectrum antibiotic resistance in S. epidermidis.
- pNE131 represents a significant finding due to its small size and potential implications for the rapid spread of antibiotic resistance.
- Further research into pNE131 could provide insights into plasmid evolution and the development of new strategies to combat antibiotic resistance.