Related Experiment Videos
Bacteriophages associated with multiresistant Staphylococcus aureus in Australia
Abstract:
Nineteen multiresistant strains of Staphylococcus aureus from Australian hospitals were examined for lysogenic bacteriophage. Thirteen strains contained prophage inducible with mitomycin C. Three of these lysed completely on induction producing a phage referred to as type 1; this phage plated on S. aureus propagating strains 6, 53 and 77, which are hosts for phages of serogroup-lysogroup A III, B III and F III respectively. Type-1 phage did not plate on other propagating strains representative of the other serogroup-lysogroup combinations in the International Typing Set for S. aureus. Ten strains of S. aureus lysed incompletely when treated with mitomycin C, yielding phage type 2, that plated only on propagating strain 6. The virions of phage types 1 and 2 had isometric heads and flexible tails, and the genome consisted of c. 40 kilobases of double stranded DNA. The DNA from the two phage types was different, as shown by endonuclease digestion and by hybridisation to reference phage DNAs. The remaining six S. aureus strains contained no phage inducible with either mitomycin C or ultraviolet irradiation. However, all contained type 2 DNA, as shown by Southern blotting, present presumably in a defective prophage state. Moreover, the three strains yielding type-1 phage on induction also contained type-2 DNA. Thus, type-2 DNA was found in all 19 strains of multiresistant S. aureus from geographically diverse Australian hospitals.
Insights
Multiresistant Staphylococcus aureus strains from Australian hospitals were analyzed for bacteriophage. All 19 strains contained type 2 DNA, indicating its widespread presence in these bacteria.
Area of Science:
- Microbiology
- Virology
- Bacteriology
Background:
- Multiresistant Staphylococcus aureus poses a significant threat in hospital settings.
- Lysogenic bacteriophages can influence bacterial virulence and antibiotic resistance.
- Understanding phage carriage in S. aureus is crucial for infection control.
Purpose of the Study:
- To investigate the presence and characteristics of lysogenic bacteriophages in multiresistant Staphylococcus aureus strains from Australian hospitals.
- To determine the genetic relatedness of induced phages and their DNA.
- To identify the prevalence of specific phage DNA sequences in these strains.
Main Methods:
- Induction of prophages using mitomycin C and ultraviolet irradiation.
- Phage typing and characterization of induced phages (type 1 and type 2).
- Analysis of phage DNA using endonuclease digestion, hybridization, and Southern blotting.
Main Results:
- Thirteen of 19 strains yielded inducible prophages (type 1 and type 2).
- Type 1 phage plated on specific S. aureus propagating strains, while type 2 plated only on strain 6.
- All 19 strains contained type 2 DNA, detected by Southern blotting, suggesting its presence in a defective prophage state.
Conclusions:
- Type 2 DNA is universally present in the examined multiresistant Staphylococcus aureus strains from Australian hospitals.
- The widespread presence of type 2 DNA suggests a potential role in the characteristics of these bacterial strains.
- Further research is warranted to elucidate the functional significance of type 2 DNA in S. aureus.