Gram-positive Organisms Streptococcus pneumoniae, Streptococcus pyogenes. Gram-positive Organisms Streptococcus agalactiae. In addition, most strains of Bacteroides fragilis and Clostridium are resistant to cefixime. Susceptibilty Testing Diffusion Techniques Quantitative methods that require measurement of zone diameters give an estimate of antibiotic susceptibility. One such procedure 1-3 has been recommended for use with disks to test susceptibility to cefixime.
Standardized procedures require the use of laboratory control organisms.
The 5-mcg cefixime disk should be used for all in vitro testing of isolates. As with standard diffusion methods, dilution procedures require the use of laboratory control organisms. In nineteen of these, the clinical course could be assessed and a favorable outcome occurred in 10.