AmBisome administration for Candida albicans shunt infections.

1048 tericidal activity of ceftazidime could be correlated with the MIC value for the different strains. Results when the strains were exposed to a concentration of 4 × MIC were comparable to those at 8 × MIC, suggesting that no further bactericidal effect can be achieved by increasing the ceftazidime concentration above 4 × MIC (no concentration effect). At 2 × MIC, bactericidal activity was seen against all isolates; in general, this activity was comparable to that observed with 4 × and 8 × MIC, even on CTZ-R strains, but in one CTZ-R, one CTZ-I and two CTZ-S strains, re-growth at 24 h was observed. CI has been reported to be at least as effective as intermittent administration in severe infections.3–5 β-Lactam clinical efficacy may be optimized using administration by CI providing that serum drug concentrations are in excess of the MIC value of the infecting bacteria. From our results, the use of ceftazidime at a concentration of 4 × MIC gave excellent bactericidal activity within 6–8 h of antibiotic exposure and increasing the drug concentration to 8 × MIC did not increase the bacterial killing. Ceftazidime concentrations of 2 × MIC still demonstrated in vitro bactericidal activity against P. aeruginosa, but at 6–8 h after drug exposure, thus supporting the hypothesis that the 2 × MIC value may be sufficient to achieve bacterial killing over a 24 h period. Should such an assumption be confirmed, a reduction in the ceftazidime daily dosage, or treatment of more resistant bacteria, could be introduced. Before any conclusions can be reached as to clinical validity of our findings, the results of the present time–kill experiments should be integrated with pharmacokinetic/pharmacodynamic findings and confirmed in clinical trials using different patient sub-populations.