Grey D, Hamilton-Miller J M
J Med Microbiol. 1977 Aug;10(3):273-9. doi: 10.1099/00222615-10-3-273.
The activities of three sulphonamides and trimethoprim against strains of Pseudomonas aeruginosa have been studied. Sulphadiazine had most activity, sulphadimidine had little, and the activity of sulphamethoxazole was intermediate. According to their sensitivity to sulphamethoxazole, strains were divided into two groups: "highly resistant" (16%, MIC greater than 1000 microgram per ml) and "moderately resistant" (84%, MIC less than or equal to 1000 microgram per ml). The former were resistant on disk testing to Sulphatriad 300 microgram. Sulphamethoxazole and trimethoprim did not act in synergy against them. The moderately resistant strains were sensitive to Sulphatriad; trimethoprim and sulphamethoxazole showed marked synergy against them in agar-plate dilution tests. The concentrations of trimethoprim and sulphamethoxazole necessary for synergy lay for each drug within the range of concentrations at which they have been found in urine, and the ratio of their MICs when acting in synergy was similar to the ratio of their concentrations in urine. It is suggested that a disk containing trimethoprim and sulphamethoxazole in a ratio of 1 : 2 rather than 1 : 20 would be more appropriate when testing strains from urine for their sensitivity to co-trimoxazole.
对三种磺胺类药物和甲氧苄啶针对铜绿假单胞菌菌株的活性进行了研究。磺胺嘧啶活性最强，磺胺二甲嘧啶活性较弱，磺胺甲恶唑的活性居中。根据对磺胺甲恶唑的敏感性，菌株被分为两组：“高度耐药”（16%，最低抑菌浓度大于1000微克/毫升）和“中度耐药”（84%，最低抑菌浓度小于或等于1000微克/毫升）。前者在纸片试验中对300微克的复方磺胺耐药。磺胺甲恶唑和甲氧苄啶对它们没有协同作用。中度耐药菌株对复方磺胺敏感；在琼脂平板稀释试验中，甲氧苄啶和磺胺甲恶唑对它们显示出明显的协同作用。协同作用所需的甲氧苄啶和磺胺甲恶唑浓度，每种药物都在尿液中发现的浓度范围内，并且它们协同作用时的最低抑菌浓度之比与尿液中的浓度之比相似。有人建议，当检测尿液中的菌株对复方新诺明的敏感性时，含甲氧苄啶与磺胺甲恶唑比例为1:2而非1:20的纸片会更合适。
