Rapid Emergence of Resistance to Linezolid during Linezolid Therapy of an Enterococcus faecium Infection

We report the emergence of linezolid resistance (MICs of 16 to 32 mg/liter) in clonally related vancomycin-susceptible and -resistant Enterococcus faecium isolates from an intensive care unit patient after 12 days of linezolid therapy. Only linezolid-susceptible isolates of the same clone were detected at 28 days after termination of linezolid therapy

Evaluation of New Broth Media for Microdilution Antibiotic Susceptibility Testing of Lactobacilli, Pediococci, Lactococci, and Bifidobacteria

Nine pure or mixed broth media were evaluated for their suitabilities to determine MICs in a microdilution test of 19 antibacterial agents for lactic acid bacteria (LAB) of the genera Lactobacillus, Pediococcus, Lactococcus, and Bifidobacterium. A mixed formulation of Iso-Sensitest broth (90%) and deMan-Rogosa-Sharpe broth (10%) with or without supplementation with l-cysteine, referred to as the LAB susceptibility test medium, provided the most optimal medium basis in terms of growth support of nonenterococcal LAB and correct indication of MICs of international control strains