Hardisson C, Llaneza J
Chemotherapy. 1977;23 Suppl 1:37-44. doi: 10.1159/000222024.
A study was made of the effect of the inoculum size and the culture conditions on the MIC of a strain of Pseudomonas aeruginosa that was sensitive to fosfomycin. The increase of the inoculum and the conditions which favour the cellular multiplication considerably increase the MIC. Phosphates inhibit the action of the antibiotic. Fosfomycin produces a logarithmic decrease in the number surviving 1 h after being added; the bacterial lysis measured by the decrease in the OD depends on the medium and is hardly noticeable in ordinary broth. In a minimum medium the antibiotic does not affect the growth. The determination of the variation in the consumption of oxygen is a rapid and accurate method of evaluating the effect of fosfomycin. A spontaneous mutant glpT was isolated which was more than 128 times more resistant than the isogenic parental strain. The growth curves of this mutant, the sensitive parental strain and a naturally resistant strain that was isolated in a patient were similar to each other in complex media. In synthetic media the naturally resistant strain shows shorter phases of latency, but the generation times are analogous. This would seem to indicate that the resistance to fosfomycin in P. aeruginosa has no influence on the speed of growth.
对接种量和培养条件对一株对磷霉素敏感的铜绿假单胞菌的最低抑菌浓度（MIC）的影响进行了研究。接种量的增加以及有利于细胞增殖的条件会显著提高最低抑菌浓度。磷酸盐会抑制抗生素的作用。磷霉素添加1小时后，存活菌数呈对数下降；通过光密度（OD）降低来测定的细菌裂解取决于培养基，在普通肉汤中几乎不明显。在基本培养基中，抗生素不影响生长。测定氧气消耗的变化是评估磷霉素效果的一种快速且准确的方法。分离出了一个自发突变体glpT，其抗性比同基因亲本菌株高128倍以上。在复合培养基中，该突变体、敏感亲本菌株以及从一名患者中分离出的天然耐药菌株的生长曲线彼此相似。在合成培养基中，天然耐药菌株的潜伏期较短，但世代时间类似。这似乎表明铜绿假单胞菌对磷霉素的抗性对生长速度没有影响。
