Minimum inhibitory concentration determination

Cryptococcus neoformans (1.56 pg/ml) and Mycobacterium intracellularae (1.56 pg/ml). However, berberine chloride did not exhibit sufficient qualitative activity against bacteria to warrant the determination of minimum inhibitory concentration determinations [231]. 

Graded doses ofthe test substance are incorporated into broth dispensed in McCartney boules and the bottles inoculated with the test organism and incubated. The point at which no growth occurs is taken as the bacteriostatic concentration (minimum inhibitory concentration, MIC). It is essential when performing these tests to determine the size of the inoculum as the position of the end-point varies considerably with inoculum size, which should always be defined in any description of result. 

Infective endocarditis caused by these streptococci typically has a subacute clinical course. The current cure rate is often over 90% unless complications occur, which is the case in more than 30% of patients.17 The majority of viridans streptococci remain very susceptible to penicillin, with most strains having a minimum inhibitory concentration (MIC) of less than 0.125 mcg/mL.15,18 Organisms with decreased susceptibilities are increasing. Therefore, antibiotic susceptibilities need to be assessed in order to determine the most appropriate treatment regimen. 

The microdilution method was employed for antibacterial and antifungal activity tests. Media were placed into each well of the 96 well-microplate. Extract solutions at 1,024 pg/ml were added into first raw of microplates and twofold dilutions of the compounds (512-0.25 pg/ml) were made by dispensing the solutions to the remaining wells. Ten microliters of culture suspensions were inoculated into all the wells. The sealed microplates were incubated at 35°C for 24 and 48 h in humid chamber. The lowest concentration of the extracts that completely inhibit macroscopic growth was determined and minimum inhibitory concentrations (MICs) were... 

More recent investigations on the antimycobacterial activity of pamamycin-607 (lb) on 25 independent M. tuberculosis clinical isolates (either susceptible, mono-, or multiresistant to the first line antituberculous drugs) established minimum inhibitory concentrations MICjoo in the range of 1.5-2.0 pg/ml, while the MICjoo of lb for a bioluminescent laboratory strain of M. tuberculosis (H37Rv) was determined as 0.55 pg/ml [3a]. Parallel studies on the effect of lb on the cell cycle distribution of human (HL-60) cells by flow cytometry indicated no... 

The degree of resistance of the mutant clones to the relevant PRP may be assayed by a number of methods. The broth microdiluition susceptibility test, a reference method for determination of the Minimum Inhibitory Concentration (MIC), may be performed according to the guidelines of the National Committee for Clinical Laboratory Standard (NCCLS) as described (20). An example of the increase in the MIC values for Bac7(l-35) in mutagenized HB101 is shown in Table 1. Another suitable and simple method, here described, is the count of bacterial viable cells after incubation with the peptide. 

The variation in the determined minimum inhibitory concentrations (MICs) against E. coli could be explained by the variation in size or molar refractivity of the substituents in o-position, MR0, of the phenyl ring, and the MW. 

Determination of the Minimum Inhibitory Concentration (MIC) of Different Phenothiazines with Respect to Various Bacteria... 

Table 7 Determination of minimum inhibitory concentration (MIC) of promethazine against various bacterial strains...

Determination of Minimum Inhibitory Concentration of Antibiotics and Non-Antibiotics by Tube Dilution of Different Strains of Mycobacteria... 

Candida albicans cells were prepared and used immediately to determine the minimum inhibitory concentration (MIC). RPMI-1640 was used as medium with L-glutamine buffered to pH 7 with 0.15 M 3-(Ar-morpholino)propane sulphonic acid solution. Candida albicans cells, 1.5 x 103 cells/ml, were added to the wells of a 96-well plate containing RPMI-1640 and treated with selected experimental... 

Hexetidine has been quantitatively determined in both commercial formulations and saliva using a reversed-phase HPLC method, with determination being possible at concentrations below the published minimum inhibitory concentrations for a selection of microorganisms. 

Berberine chloride was evaluated for in vitro activity against Candida albicans, Cryptococcus neoformans, Mycobacterium intracellularae, Trichophyton mentagrophytes, and Saccharomyces cerevasiae, as well as representative Gram-positive and Gram-negative bacteria. The alkaloid was found to exhibit moderate to good antifungal activity, and the minimum inhibitory concentrations were determined as follows Candida albicans (0.39 pg/ml) ... 

Matsuda, T., Yano, T., Maruyama, A., and Kumagai, H. 1994. Antimicrobial activities of organic acids determined by minimum inhibitory concentrations at different pH ranged from 4.0 to 7.0. Japan Society for Food Science and Technology 41 687-701. 

---