Summary
To quantify the relative antibacterial efficacy of β-lactam antibiotics in vitro, a mathematical description of bacterial growth was developed. Curves of growth in the presence of the antibiotic are expressed as quadratic functions of time, with initial growth rate (ko) and rate of change of growth (a) as concentration dependant variables. For these variables the concentration-effect slopes were not parallel; therefore the potency ratio varied between 1 (at about 2 mg/l) and 2 (at higher concentrations). The relative efficacy in vivo was expressed as a potency ratio with regard to the number of bacteria in an infected thigh muscle in mice. The potency ratio was 1.5, which is between the limits of the in vitro results.
Zusammenfassung
Um die relative antibakterielle Wirksamkeit von beta-lactam Antibiotika in vitro zu quantifizieren, wurde eine mathematische Methode zur Beschreibung des bakteriellen Wachstums entwickelt. Die Wachstumskurven in Anwesenheit eines Antibiotikums wurden ausgedrückt als quadratische Funktion der Zeit mit einer initialen Wachstumsrate (ko) und einer Wachstumsänderungsrate (a) ais Konzentrations-abhängige Variable. Für die Variablen waren die Konzentrations-Wirkkurven nicht parallel, deshalb variierte der Wirksamkeitsfaktor zwischen 1 (bei ungefähr 2 mg/l) und 2 (bei höheren Konzentrationen). Die relative Wirksamkeit in vivo wurde als Wirksamkeitsfaktor in bezug auf die Anzahl der Bakterien in einem infizierten Oberschenkelmuskel der Maus ausgedrückt. Der Wirksamkeitsfaktor betrug 1,5. Er liegt zwischen den Grenzen der In-vitro-Ergebnisse.
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Mattie, H., van der Voet, G.B. Influence of aminopenicillins on bacterial growth kinetics in vitro in comparison with the antibacterial effect in vivo. Infection 7 (Suppl 5), S434–S437 (1979). https://doi.org/10.1007/BF01659765
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DOI: https://doi.org/10.1007/BF01659765