in example experiments miconazole nitrate , econazole nitrate and clotrimazole were dissolved in dmso . colistin , d - cycloserine , fosfomycin and polymixin b were dissolved in water . nisin was suspended at 10 mg / ml in 0 . 02 m hcl , and the supernatant fraction following centrifugation at 10 , 000 g for 10 mins was used in the following experiments . other solvents that may be used include caster oil , pyridine , and 0 . 9 % saline . for iv administration agents may be solubilised in polyethoxylated caster oil , or cyclodextrins such as sulfobutylether 7 - βcyclodextrin or hydroxypropyl - β - cyclodextrin and lactic acid . minimum inhibitory concentrations ( mics ) of a range of clinical and control bacterial organisms were measured according to bsac ( british society for antimicrobial chemotherapy ) guidelines ( andrews 2001 ), for single agents . the method of determining mics of imidazole with colistin , d - cycloserine , fosfomycin , polymixin b , or nisin is described briefly as follows . mics were measured by agar dilution . kill curves were performed in accordance with the methods of garrison and nuemiller , 2007 . briefly kill profiles were generated by logarithmically plotting mean cfu / ml data over time . total logarithmic reductions in bacterial counts were determined by subtracting 24 h cfu / ml values from starting inocula . p = μg of active compound per mg ( μg / mg ) v = volume required ( ml ) c = final concentration of solution ( mg / l ) w = weight of agent ( mg ) to be dissolved in volume v ( ml ) stock solutions were prepared at concentrations of 1000 mg / l and 100 mg / l . to determine the mic of miconazole , the appropriate amount of each stock solution were added to separate petri dishes give a range of final concentrations ( after the addition of 20 ml molten agar ): from 0 . 12 to 32 mg / l . to determine the mics of miconazole with the specific agent active on a bacterial cell surface , these concentrations of miconazole were used in addition to a fixed sub - inhibitory amount of the agent active on a bacterial cell surface . the amounts of cell membrane or cell wall active agents used were as follows : colistin , 5 mg / l ; d - cycloserine , 10 mg / l ; fosfomycin , 5 mg / l ; polymixin b , 20 mg / l ; nisin , 2 . 5 mg / l . these concentrations were demonstrated to have no inhibitory effect on the growth of the bacterial strains tested , hence any decrease in the mic of miconazole observed in the presence of these cell - surface active agents indicates synergy . volumes ( 20 ml ) of cooled molten ist agar ( oxoid ) was added to each petri dish and mixed by swirling . after drying , the plates were stored at 4 ° c . and protected from light . plates were used on the day of preparation . the test organisms were grown overnight in 5 ml ist broth . using a dilution in 0 . 9 % saline of 1 : 100 , the appropriate agar plates were inoculated using a multipoint inoculator . agar plates and microtitre plates were incubated at 37 ° c . in air for 18 - 20 hours . the mic is the minimum amount of an antibiotic at which there is no visible growth of bacteria . tiny single colonies or faint hazes were not counted as growth . synergy was reported if the inhibitory effect of the drugs in combination were greater than the sum of the inhibitory effects of each drug singly . the concentration of miconazole , with or without the cell membrane or cell wall active agent , capable of inhibiting the growth of 50 % and 90 % of the strains tested is reported as the mic 50 and mic 90 respectively . the range of mics for each group of bacterial strains is also reported . tables 1a , b , c , d , and e , show the mic 50 , mic 90 and range for each combination tested . for each of these combinations , a decrease in the mics for the combination compared to miconazole used singly , demonstrates a synergistic effect . mic 50 , mic 90 and range for polymixin b , used mic 50 , mic 90 and range for nisin b , used at
there is described a composition comprising a therapeutically active imidazole , and derivatives thereof , and an agent active on a bacterial cell surface selected from the group consisting of one or more of colistin , nisin , d - cycloserine , fosfomycin , fosfomycin trometamol , fosfomycin disodium and polymixin b , and derivatives thereof .