Summary
The minimal inhibitory concentrations (MIC) of sulfamethoxazole and trimethoprim against 144 strains of obligately anaerobic bacteria were determined on supplemented Diagnostic Sensitivity Test (Oxoid) agar or broth. 58% of the strains were susceptible to sulfamethoxazole alone (MIC ≤ 16 µg/ml), only 12% were susceptible to trimethoprim alone (≤1 µg/ml), and 85% were susceptible to the combination of sulfamethoxazole plus trimethoprim (≤ 16 µg/ml) at a ratio of 19:1. All 45 strains of theBacteroides fragilis group were susceptible to the combination. At a ratio of 1:1, 78% of the strains showed synergistic activity, at a ratio of 16:1 there was synergism in 54% of the strains. When the strains were tested by a modification of the broth-disc method in Diagnostic Sensitivity Test broth, there was over 98% correlation with the MIC. There was poor correlation between inhibition zone diameters by an agar diffusion method and MIC.
Zusammenfassung
Die minimalen Hemmkonzentrationen (MHK) von Sulfamethoxazol und Trimethoprim gegen 144 obligat anaerobe Bakterienstämme wurden in supplementiertem Diagnostic Sensitivity Test (Oxoid)-Agar und -Bouillon bestimmt. 58% der Stämme waren auf Sulfamethoxazol allein empfindlich (MHK ≤16 µg/ml), nur 12% auf Trimethoprim allein (≤1 µg/ml), aber 85% auf die Kombination von Sulfamethoxazol und Trimethoprim (≤16 µg/ml) in einem Verhältnis von 19:1. Alle 45 Stämme derBacteroides fragilis-Gruppe waren auf die Kombination empfindlich. Bei einem Verhältnis von 1:1 zeigten 78% der Stämme Synergismus, bei einem Verhältnis von 16:1 war dies noch bei 54% der Stämme der Fall. Wurden die Stämme in einer Modifikation der „broth-disc“-Methode in Diagnostic Sensitivity Test-Bouillon geprüft, so betrug die Übereinstimmung mit den MHK-Werten über 98%. Eine sehr schlechte Korrelation war in einem Agardiffusionstest zwischen Hemmhofdurchmesser und den MHK-Werten feststellbar.
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Wüst, J. In vitro susceptibility of anaerobes to co-trimoxazole. Infection 8 (Suppl 2), S187–S189 (1980). https://doi.org/10.1007/BF01639889
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DOI: https://doi.org/10.1007/BF01639889