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Updated: Jul 15, 2026

Antibiotic Efficacy Testing in an Ex vivo Model of Pseudomonas aeruginosa and Staphylococcus aureus Biofilms in the Cystic Fibrosis Lung
Published on: January 22, 2021
In vitro activity of linezolid and 12 other antimicrobials against coryneform bacteria
José-Luis Gómez-Garcés1, Juan-Ignacio Alos, Javier Tamayo
1Servicio de Microbiología, Hospital de Móstoles, Instituto Madrileño de la Salud, c/Rio Jucar s/n, 28935 Móstoles, Madrid, Spain. jlgarces@microb.net
Objectives:
To compare the in vitro activity of linezolid with 12 other antimicrobials against 190 strains of the coryneform bacteria, including 60 strains of C. amycolatum, 30 of C. striatum, 30 of C. jeikeium, 10 of C. urealyticum, 20 of B. casei, 20 of D. hominis and 20 of T. otitidis.
Methods:
Minimum inhibitory concentrations (MICs) and time-death curves were carried out according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI).
Results:
Linezolid was very active against the 130 strains of the Corynebacterium species studied. Only the glycopeptides showed similar efficacy. In contrast, penicillin G, ampicillin, macrolides, lincosamides, fluoroquinolones and aminoglycosides showed generally high MICs. Among the beta-lactams, only imipenem was active against the majority of strains of C. striatum and C. amycolatum, and, approximately half of the C. jeikeium and C. urealyticum isolates. Both Dermabacter hominis and Brevibacterium casei showed marked resistance against most of the antimicrobials tested, while Turicella otitidis only showed high MICs against macrolides and clindamycin. For all of them, linezolid, vancomycin and teicoplanin proved effective. The time-death curves showed linezolid to behave as a bacteriostatic agent (approximately 90% death rate). Such activity was more accentuated for C. amycolatum and C. striatum (reduction of 1.3 and 1.7log(10)CFU/mL, respectively) than for C. jeikeium and C. urealyticum (reduction of 1.0 and 0.8log(10), respectively).
Conclusions:
Our results indicate that linezolid is active against coryneform bacteria. The efficacy of linezolid is equal to or even superior to that of the glycopeptides.
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