Abstract
In vitro susceptibility tests were performed with 350 selected strains ofStreptococcus pneumoniae to evaluate disk diffusion tests with 30 μg and 1 μg cefotaxime disks. Zones were compared to MICs of cefotaxime with and without its desacetyl metabolite. Cefotaxime was two to eight times more active than desacetyl cefotaxime, but the two compounds were additive when combined in vitro. For 30 μg disks, zone size breakpoints were ≤27 mm, 28–30 mm and ≥31 mm for resistant, intermediate and susceptible, respectively. For 1 μg disks, those zone size criteria were reduced to ≤13 mm, 14–16 mm and ≥17 mm. The 30 μg disk that is currently available for testing other species can be used for testing pneumococci; however, the 1 μg disk has some important advantages.
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Barry, A.L., Brown, S.D. & Novick, W.J. Criteria for testing the susceptibility ofStreptococcus pneumoniae to cefotaxime and its desacetyl metabolite using 1 μg or 30 μg cefotaxime disks. Eur. J. Clin. Microbiol. Infect. Dis. 14, 724–726 (1995). https://doi.org/10.1007/BF01690885
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DOI: https://doi.org/10.1007/BF01690885