In vitro Antimicrobial Activity of Ampicillin-Ceftriaxone and Ampicillin-Ertapenem Combinations Against Clinical Isolates of Enterococcus faecalis with High Levels of Aminoglycoside Resistance
2008

Antimicrobial Combinations Against Resistant Enterococcus faecalis

Sample size: 5 publication Evidence: moderate

Author Information

Author(s): Pasticci Maria Bruna, Mencacci Antonella, Moretti Amedeo, Palladino Nicola, Maria Lapalorcia Luigi, Bistoni Francesco, Baldelli Franco

Primary Institution: University of Perugia

Hypothesis

The study aims to analyze the in vitro interaction between ampicillin and ceftriaxone, and evaluate the ampicillin-ertapenem combination against high-level aminoglycoside resistant E. faecalis strains.

Conclusion

The study found a bacteriostatic and bactericidal synergism in vitro between ampicillin and ceftriaxone for some strains of E. faecalis, but not for the ampicillin-ertapenem combination.

Supporting Evidence

  • Three of the five strains showed a bacteriostatic synergistic effect with ampicillin and ceftriaxone.
  • The combination of ampicillin and ceftriaxone resulted in a colony reduction of ≥ 3 log10 for some strains.
  • No synergistic effect was observed with the ampicillin-ertapenem combination.

Takeaway

The researchers tested two antibiotic combinations to see if they could work better together against a tough germ, and found that one combination worked well, but the other did not.

Methodology

The study used double disk diffusion tests and time killing curves to evaluate the antimicrobial activity of the combinations against five strains of E. faecalis.

Limitations

The study was limited to only five strains of E. faecalis, which may not represent the broader population.

Participant Demographics

The strains were isolated from bacteremic patients, including those with central line related sepsis, liver abscess, and prosthetic valve endocarditis.

Digital Object Identifier (DOI)

10.2174/1874285800802010079

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