Plates were incubated at 37 C for 48 h under microaerobic conditions and inhibitory concentrations were read at the point where the elliptical zone of inhibition intersected the E-test strip. Plates were inoculated with a multipoint replicator delivering spots of 4 l of the diluted bacterial suspensions, starting from the lowest to the highest concentration of each antimicrobial drug. At the beginning of each series a Mueller-Hinton agar plate without antibiotics was inoculated as a viability control of the strains under study. The inoculated plates were incubated under the same conditions described above. The antimicrobial agents tested in this study were erythromycin, tetracycline, gentamicin, ciprofloxacin, ampicillin and aztreonam.
Table shows the MICs of the six antimicrobial agents tested.
Similar observations were reported previously by Baker et al. With the exception of two strains that appeared to be resistent to ampicillin with the E-test and susceptible with the double dilution agar method, no other major discrepancies were observed between both methods. The MICs obtained by both methods were very similar. In this study, no strain of C. jejuni subsp. In a previous study, using C. jejuni subsp.