Plasmid mediated silver resistance in Acinetobacter baumannii

Area of Science:

• Microbiology
• Molecular Biology
• Environmental Science

Background:

• Acinetobacter baumannii BL88, an environmental isolate, exhibits resistance to 13 metals and 10 antibiotics.
• Plumbagin, a natural compound, was investigated for its ability to eliminate plasmid-mediated resistance in bacteria.

Purpose of the Study:

• To investigate the curing of metal and antibiotic resistance in Acinetobacter baumannii BL88 using plumbagin.
• To characterize the transfer of resistance and the associated plasmid in Escherichia coli.

Main Methods:

• Treatment of Acinetobacter baumannii BL88 with plumbagin to cure resistance.
• Conjugation experiments to transfer resistance to Escherichia coli K12.
• Plasmid isolation, transformation into E. coli DH5 alpha, and stability studies.
• Analysis of silver ion accumulation and efflux in host bacteria.

Main Results:

• Plumbagin cured resistance to silver, cadmium, antimony, streptomycin, and ampicillin in A. baumannii BL88.
• Silver resistance was transferred to E. coli K12 via conjugation, associated with a 54 kb plasmid (pUPI199).
• The plasmid transformed E. coli DH5 alpha cells and resulted in slower growth rates.
• Plasmid pUPI199 showed differential stability in A. baumannii BL88 under selection pressure.
• A. baumannii BL88 accumulated silver, while E. coli DH5 alpha (pUPI199) effluxed a significant portion of accumulated silver ions.

Conclusions:

• Plasmid pUPI199 mediates silver resistance in Acinetobacter baumannii and can be transferred to Escherichia coli.
• The presence of pUPI199 affects the growth rate and silver ion handling in E. coli.
• Understanding plasmid-mediated resistance mechanisms is crucial for managing bacterial infections and environmental contamination.