A chromosomally located transposon in Pseudomonas aeruginosa
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Abstract:
A new transposon, Tn2521, coding for carbenicillin, streptomycin, spectinomycin, and sulfanilamide resistance, has been identified in Pseudomonas aeruginosa. The transposon occurs naturally in the chromosome of clinical strains of P. aeruginosa isolated in geographically separated hospitals. This has been demonstrated by its transductional linkage to the pur-136 marker and also by Southern hybridization. Tn2521 is 6.8 kilobases, can transpose from the chromosome to both IncP-1 and IncP-2 plasmid genomes, and has a pattern of restriction endonuclease sites unlike that of any previously described transposon. The carbenicillin resistance carried by Tn2521 is due to the PSE-4 type of beta-lactamase.
Insights
A novel transposon, Tn2521, conferring resistance to multiple antibiotics including carbenicillin, streptomycin, spectinomycin, and sulfanilamide, was discovered in Pseudomonas aeruginosa clinical strains. This transposon is naturally present in bacterial chromosomes and can transfer to plasmids.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen frequently associated with hospital-acquired infections.
- Antibiotic resistance in P. aeruginosa poses a significant challenge in clinical settings.
- Transposable elements play a crucial role in the dissemination of antibiotic resistance genes.
Purpose of the Study:
- To identify and characterize a novel transposon responsible for multiple drug resistance in clinical isolates of P. aeruginosa.
- To investigate the genetic properties and mobility of the newly identified transposon.
Main Methods:
- Isolation and characterization of antibiotic-resistant P. aeruginosa strains.
- Transduction experiments to assess genetic linkage.
- Southern hybridization to confirm transposon presence and integration.
- Restriction endonuclease digestion to analyze transposon structure.
Main Results:
- Identification of a new transposon, Tn2521, conferring resistance to carbenicillin, streptomycin, spectinomycin, and sulfanilamide.
- Tn2521 is naturally present in the chromosomes of geographically dispersed clinical P. aeruginosa strains.
- Tn2521 is 6.8 kilobases in size and capable of transposition to IncP-1 and IncP-2 plasmids.
- The carbenicillin resistance is mediated by the PSE-4 beta-lactamase enzyme.
Conclusions:
- Tn2521 represents a significant new mobile genetic element contributing to multidrug resistance in P. aeruginosa.
- The natural occurrence and mobility of Tn2521 highlight its potential role in the spread of antibiotic resistance.
- Understanding Tn2521's characteristics is crucial for developing strategies to combat P. aeruginosa infections.