[Evaluation of an automated procedure determining the minimum inhibitory concentrations (MIC). ]

The ABAC system allows to distribute simultaneously and automatically a standardized inoculum into microtube-cuvettes containing in lyophilized broth medium twofold serial dilutions of the antibiotics. After an 18 hours incubation time, The system prints automatically the MIC. We have compared the MIC of beta-lactam antibiotics (ampicillin, carbenicillin, cephalothin, cefoxitin, cefamandole, cefuroxime and cefotaxime) and 6 aminoglycoside (gentamicin, tobramycin, netilmycin, amikacin, kanamycin, lividomycin) obtained by the ABAC system and by the Agar dilution method for 302 gram negative bacilli. We also made a comparison of the MIC of 8 antibiotics (oxacillin, oleandomycin, spiramycin, erythromycin, clindamycin, pristinamycin, doxycycline, vancomycin) obtained by the 2 methods for 117 Staphylococcus aureus strains. The evaluation shows that the reproducibility of the results obtained by the ABAC system is good. The statistical analysis shows that the correlation between the MIC obtained with the 2 methods is excellent and that there is no significant discrepancy.