In vitro pharmacodynamics of ceftazidime against Pseudomonas aeruginosa isolates from cystic fibrosis patients

Abstract

The concentration/MIC (C/MIC) ratio maximizing the bactericidal activity of ceftazidime against 10 Pseudomonas aeruginosa isolates from cystic fibrosis patients was identified. Bactericidal activity was assessed by determining the percent difference in the area under the killing curve at each C/MIC ratio for all of the isolates from that of their growth control. The percent effect at each C/MIC ratio was fitted to a sigmoidal Emax model with maximum bactericidal activity defined as the C/MIC ratio that produced an effect that was 90% of the Emax. Our results suggest that at least some isolates may require higher C/MIC ratios than previously reported for maximal activity.

Low cefpirome levels during twice daily dosing in critically ill septic patients: pharmacokinetic modelling calls for more frequent dosing

“…When antibiotic concentrations fell below this threshold in the in vitro models, bacterial growth was immediately resumed [6,7]. This necessity for a relatively high threshold concentration is supported by a recent in vitro study of isolates obtained from cystic fibrosis patients [33]. It has been suggested by some researchers that concentrations of any b-lactam should be maintained above four to five times the MIC for long periods [2,34,35].…”

Trough serum concentrations of β-lactam antibiotics in cancer patients: inappropriateness of conventional schedules to pharmacokinetic/pharmacodynamic properties of β-lactams

“…In addition, results from in vitro [15,17,19] and in vivo [18,[20][21][22] studies have shown that a serum concentration/MIC ratio of ≥5, at least for CAZ and FEP, may be recommended as a therapeutic goal to ensure the best in vivo antibacterial activity. Increasing drug concentrations above this target concentration provides no added benefit.…”

Consenso español para la prevención y el tratamiento de la infección bronquial por Pseudomonas aeruginosa en el paciente con fibrosis quística

“…Por otra parte, la farmacocinética en sangre de los antimicrobianos en FQ difiere de la de los individuos sin esta enfermedad 17,61-63 ; por ello las dosis utilizadas en caso de emplear la vía sistémica (por ejemplo, en las exacerbaciones) son distintas de las empleadas en los pacientes sin FQ (tabla 4) y repercuten en los valores de los índices PK/PD de los antimicrobianos [58][59][60][64][65][66][67][68][69][70][71][72] .…”