Intraspecies transfer of a chloramphenicol-resistance plasmid of staphylococcal origin.
OBJECTIVE
The emergence of antibiotic-resistant bacteria is a phenomenon of concern to the clinician as well as to the pharmaceutical industry, because it is the major cause of failure in the treatment of infectious diseases. The genetic exchange of plasmids containing antibiotic resistant determinants (R-plasmids) between organisms of the same or different species is believed to play a crucial role in the evolution of antibiotic resistant bacteria. Staphylococcus aureus is well known for its multi-drug resistance (MDR). This work was undertaken to study the intraspecies transfer of a chloramphenicol (C) resistance staphylococcal R-plasmid among different clinical isolates of S. aureus.


METHODS
From a MDR S. aureus MC524 strain, a small plasmid pMC524/MBM was isolated. Lysostaphin lysis and sucrose mediated detergent lysis were used for plasmid preparation. Agarose gel electrophoresis, transformation experiments, Southern blotting and hybridization were done. Restriction endonuclease (RE) digestions were performed.


RESULTS
pMC524/MBM, which codes for C resistance could be transferred into some C sensitive clinical strains of S. aureus. The size and the RE digestion patterns of the plasmids isolated from the S. aureus transformants were identical to those of pMC524/MBM.


CONCLUSIONS
These results suggest that pMC524/MBM, without any modification is capable of transferring, maintaining, replicating and expressing itself in different clinical strains of S. aureus and hence may be responsible for the spread of C resistance.
Bhakta
Mausumi
M
Section of Microbiology, Department of Physiology, University College of Science & Technology University of Calcutta, Kolkata, India.
Arora
Suranjana
S
Bal
Manjusri
M
D002702:Chloramphenicol Resistance / Q000235:genetics*; D003227:Conjugation, Genetic; D022761:Gene Transfer, Horizontal; D011815:R Factors / Q000235:genetics / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000235:genetics*