It is stable in the presence of some bacterial b -lactamases. Loracarbef is inactive against most strains of Acinetobacter, Enterobacter, Morganella morganii, Proteus vulgaris, Providencia, Pseudomonas, and Serratia. Quantitative methods that require measurement of zone diameters give the most precise estimate of the susceptibility of bacteria to antimicrobial agents. One such standardized method 1 has been recommended for use with the 30-mcg loracarbef disk. Interpretation involves the correlation of the diameter obtained in the disk test with MIC for loracarbef.
Standardized procedures require the use of laboratory control organisms.
As with standard diffusion methods, dilution procedures require the use of laboratory control organisms. The majority of these involved the diaper area in young pediatric patients. In a controlled clinical study of acute otitis media performed in Europe, loracarbef was compared to amoxicillin. In a controlled clinical study of acute maxillary sinusitis performed in Europe, loracarbef was compared to doxycycline. In this study there were 210 sinus-puncture evaluable patients.