Dabernat H, Delmas C, Lareng M B
Pathol Biol (Paris). 1984 May;32(5):378-80.
Mecillinam, an antibiotic of the beta-lactam group, is active against Gram negative bacilli, with the exception of a few species such as Haemophilus influenzae. The activities of ampicillin, mecillinam, and ampicillin-mecillinam combinations at ratios of 1/1, 2/1, 4/1, 1/2 and 1/4, on 21 Haemophilus influenzae strains, were studied by agar dilution and determination of minimal inhibitory concentrations (MIC). Ampicillin at concentrations of 0.12 to 0.25 mg/l was active on susceptible strains. Beta-lactamase-producing strains were inhibited by 4 and 8 mg/l ampicillin. MICs of mecillinam were above 128 mg/l for 19 strains; two strains were susceptible to 2 mg/l. In every case, antibacterial activity was greater with the ampicillin-mecillinam combination than with either one of the antibiotics alone. The maximum antibacterial effect was obtained at ratios of 1/1 and 1/2; in this case, susceptible strains were inhibited by 0.06 mg/l ampicillin. Kinetic evaluation (killing curves) showed that ampicillin has a bactericidal effect at concentrations under the MIC when it is combined with mecillinam at a 1/1 ratio.
美西林是一种β-内酰胺类抗生素，对革兰氏阴性杆菌有活性，但对少数菌种如流感嗜血杆菌除外。通过琼脂稀释法和最小抑菌浓度（MIC）测定，研究了氨苄西林、美西林以及氨苄西林与美西林以1/1、2/1、4/1、1/2和1/4比例组合对21株流感嗜血杆菌菌株的活性。浓度为0.12至0.25mg/L的氨苄西林对敏感菌株有活性。产β-内酰胺酶的菌株被4mg/L和8mg/L的氨苄西林抑制。19株菌株的美西林MIC高于128mg/L；两株菌株对2mg/L敏感。在每种情况下，氨苄西林与美西林组合的抗菌活性均高于单独使用任何一种抗生素。在1/1和1/2的比例下获得最大抗菌效果；在这种情况下，敏感菌株被0.06mg/L的氨苄西林抑制。动力学评估（杀菌曲线）表明，当氨苄西林与美西林以1/1比例组合时，在低于MIC的浓度下具有杀菌作用。
