High-level penicillin resistance and penicillin-gentamicin synergy in Enterococcus faecium.

  1. Torres, C. 1
  2. Tenorio, C. 1
  3. Lantero, M. 1
  4. Gastanares, M.-J. 1
  5. Baquero, F. 1
  1. 1 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

Revista:
Antimicrobial Agents and Chemotherapy

ISSN: 0066-4804

Año de publicación: 1993

Volumen: 37

Número: 11

Páginas: 2427-2431

Tipo: Artículo

PMID: 8285628 SCOPUS: 2-s2.0-0027359416 WoS: WOS:A1993ME81900029 GOOGLE SCHOLAR

Otras publicaciones en: Antimicrobial Agents and Chemotherapy

Resumen

Thirty-seven Enterococcus faecium strains with different levels of penicillin susceptibility were studied in time-kill experiments with a fixed concentration (5 μg/ml) of gentamicin combined with different penicillin concentrations (6 to 600 μg/ml). Synergy was defined as a relative decrease in counts of greater than 2 log10 CFU per milliliter after 24 h of incubation when the combination of the antibiotics was compared with its most active component alone. The minimal synergistic penicillin concentrations found were 6 μg/ml for 16 of 16 strains for which penicillin MICs were ≤25 μg/ml, 20 to 100 μg/ml for 14 of 17 strains for which penicillin MICs were 50 to 200 μg/ml, and 200 to 500 μg/ml for 4 of 4 strains for which MICs penicillin were >200 μg/ml. Penicillin-gentamicin synergy was observed even in high-level penicillin-resistant E. faecium strains at penicillin concentrations close to one-half the penicillin MIC. The possibility of treating infections caused by high-level penicillin-resistant E. faecium strains with penicillin-gentamicin combinations in particular cases may depend on the penicillin levels attainable in vivo.