Related Experiment Videos
Abstract:
159 strains of group D streptococci isolated from clinical specimens were examinated for plasmids content. Our objective was to study some characters carried by plasmids: drug-resistance, hemolysins and bacteriocin activity. 73,6% of the strains were antibiotic resistant and in 69% of these, the drug-resistance was transferable by conjugation. In mating of S. faecalis subsp. zymogenes strains we could also isolate three different types of transconjugants in hemolytic activity. The interpretation of this observation was facilitated by the research of bacteriocin activity. We also classified the bacteriocins found in our strains into different types.
Insights
Group D streptococci often carry plasmids conferring antibiotic resistance, which can be transferred between bacteria. These plasmids also influence hemolytic and bacteriocin activities, impacting bacterial interactions.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Group D streptococci are significant human pathogens.
- Plasmids are extrachromosomal DNA elements that can carry virulence factors and antibiotic resistance genes.
- Understanding plasmid-mediated traits in streptococci is crucial for clinical management.
Purpose of the Study:
- To investigate the plasmid content of clinical isolates of Group D streptococci.
- To characterize plasmid-associated drug resistance, hemolytic activity, and bacteriocin production.
- To explore the transferability of these traits via conjugation.
Main Methods:
- Isolation and characterization of 159 Group D streptococci strains from clinical specimens.
- Plasmid DNA extraction and analysis.
- Antibiotic susceptibility testing.
- Bacterial conjugation experiments to assess trait transferability.
- Hemolytic activity assays.
- Bacteriocin typing.
Main Results:
- 73.6% of strains exhibited antibiotic resistance.
- Drug resistance was transferable by conjugation in 69% of resistant strains.
- Three distinct types of transconjugants with varying hemolytic activity were identified in S. faecalis subsp. zymogenes.
- Bacteriocin activity was detected and classified into different types.
Conclusions:
- Plasmids in Group D streptococci frequently carry transferable antibiotic resistance genes.
- Plasmid-borne genes influence hemolytic activity and bacteriocin production.
- These findings highlight the role of plasmids in streptococcal virulence and adaptability.