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[Transmissible resistance factor in Pseudomonas aeruginosa: arguments in favor of it being a plasmid]
Abstract:
The transmissible Carbenicillin resistance factor R (56 BE) was isolated in Pseudomonas aeruginosa. It was not cured by usual agents and not isolated by ultra-centrifugation. So the plasmidic nature may be doubtful. We demonstrate in this paper that it is possible: 1) to transduce this factor into bacteria which is then able to conjugate and to transfer resistance to another bacteria, 2) to transfer carbenicillin resistance to arginine deficient strains without bringing chromosomic genes, 3) to obtain the carbenicillin resistance maintenance in Rec deficient strains. All these results are in favour of a plasmid.
Insights
A transmissible Carbenicillin resistance factor in Pseudomonas aeruginosa was confirmed as plasmid-mediated. This factor can be transferred between bacteria and maintained even in deficient strains, supporting its extrachromosomal nature.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Carbenicillin resistance in Pseudomonas aeruginosa is a significant clinical concern.
- The nature of the transmissible resistance factor R (56 BE) was initially uncertain due to difficulties in isolation.
Purpose of the Study:
- To definitively establish the plasmidic nature of the Carbenicillin resistance factor R (56 BE) in Pseudomonas aeruginosa.
- To investigate the mechanisms of resistance transfer and maintenance.
Main Methods:
- Bacterial conjugation experiments to assess resistance transfer.
- Transduction assays to move the resistance factor between bacterial strains.
- Analysis of resistance maintenance in Rec-deficient strains.
Main Results:
- The Carbenicillin resistance factor was successfully transduced into recipient bacteria, which then became capable of conjugation and further resistance transfer.
- Carbenicillin resistance was transferred to arginine-deficient strains without the co-transfer of chromosomal genes.
- The resistance factor demonstrated stable maintenance in Rec-deficient strains, indicating extrachromosomal inheritance.
Conclusions:
- The collective evidence strongly supports the plasmidic nature of the Carbenicillin resistance factor R (56 BE).
- The findings highlight the mobile genetic element's role in disseminating antibiotic resistance within bacterial populations.