Sensitivity to detergents and plasmid curing in Enterococcus faecalis.

Area of Science:

• Microbiology
• Molecular Biology
• Antimicrobial Resistance

Background:

• Enterococcus faecalis exhibits intrinsic resistance to various antibiotics.
• Detergents such as sodium N-lauroylsarcosinate (sarkosyl) and sodium dodecyl sulfate (SDS) are known to affect bacterial cell membranes.
• Plasmid curing is a method to eliminate extrachromosomal DNA, potentially restoring antibiotic sensitivity.

Purpose of the Study:

• To determine the sensitivity of a clinical Enterococcus faecalis isolate to sarkosyl and SDS.
• To evaluate the efficacy of sarkosyl and SDS in curing plasmids from Enterococcus faecalis.
• To compare the effects of these detergents on Enterococcus faecalis with those on Escherichia coli.

Main Methods:

• Determination of minimum inhibitory concentrations (MICs) for sarkosyl and SDS against Enterococcus faecalis and Escherichia coli.
• Growth of Enterococcus faecalis and Escherichia coli in the presence of detergents and acridine orange to assess plasmid curing efficiency.
• Phenotypic assessment of plasmid-borne antibiotic resistance (kanamycin, tetracycline).

Main Results:

• Enterococcus faecalis demonstrated significantly higher sensitivity to both sarkosyl and SDS compared to Escherichia coli, with MICs being 100-fold lower.
• Sarkosyl induced 3% plasmid curing in Enterococcus faecalis, while SDS and acridine orange showed no curing effect.
• SDS and acridine orange effectively cured 35% of plasmids in Escherichia coli, whereas sarkosyl was ineffective.

Conclusions:

• The clinical isolate of Enterococcus faecalis is highly susceptible to sarkosyl and SDS.
• Sarkosyl is an effective agent for curing plasmids in this specific Enterococcus faecalis strain.
• Differential responses to detergents highlight species-specific mechanisms in detergent sensitivity and plasmid curing efficacy.