Cidal activity of oral third generation cephalosporins against Streptococcus pneumoniae in relation to cefotaxime intrinsic activity
Abstract number: P1040
Cafini F., Aguilar L., Alou L., Giménez M.J., Sevillano D., Torrico M., González N., Granizo J.J., Martín-Herrero J.E., Prieto J.
Objective: To explore killing kinetics within 12 h of oral versus parenteral third generation cephalosporins against ten S. pneumoniae strains exhibiting cefotaxime MICs from 0.03 to 2 mg/l.
Methods: Killing curves were performed following CLSI recommendations with double dilution concentrations ranging from 0.015 mg/l to 4 mg/l (concentrations achievable in serum after standard doses) and a final inoculum of 12 106 cfu/ml. Colony counts were performed at 0, 2, 4, 6, 8, 10, 12 and 24 h. The killing kinetic profile of each antibiotic was defined as the figure resulting when concentrations needed to obtain 90%, 99% or 99.9% reductions in initial inocula within 12 h (dosing interval for oral cephalosporins) are plotted against strains distributed by increasing cefotaxime MICs.
Results: The Figure shows the concentrations needed to obtain 90% reduction in initial inocula within 12 h for the 10 study strains (white columns: cefotaxime; gray columns: cefditoren; diagonal stripes: cefpodoxime; black squares: cefdinir; black columns: cefixime).
Conclusion: The similarity of the killing kinetic profiles of cefditoren and cefotaxime may be important when choosing an oral third generation cephalosporin as initial or sequential therapy in areas with high penicillin resistance prevalence
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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