Inhibitory concentrations

Table 3. Representative Minimum Inhibitory Concentrations for Urinary Tract Organisms by Sulfamethoxazole (SMX), Trimethoprim (TMP), and Their Combination...

Table 1. Minimum Inhibitory Concentration (MIC) of Chloramphenicol and Thiamphenicol Against Sensitive Organisms...

Table 5. Minimum Inhibitory Concentrations (MIC q ) of Florfenicol (2) and Other Antibiotics Against Bacterial Pathogens Isolated from Fish in Japan, Jg/mL...

Tea extracts and tea polyphenols inhibit copper- and peroxide-induced oxidation of LDL in vitro (116,123,124). The inhibitory concentration for 50% reduction (IC q) values for inhibition of copper-induced oxidation of LDL by some phenoHc antioxidants are Hsted in Table 7. The IC q for epigaHocatechin gaHate was found to be 0.075 p.mM, which was the most potent of all the phenoHc antioxidants tested (123,124). Similar results have been reported elsewhere (115,116,125,126). 

One approach to combating antibiotic resistance caused by P-lactamase is to inhibit the enzyme (see Enzyme inhibition). Effective combinations of enzyme inhibitors with P-lactam antibiotics such as penicillins or cephalosporins, result in a synergistic response, lowering the minimal inhibitory concentration (MIC) by a factor of four or more for each component. However, inhibition of P-lactamases alone is not sufficient. Pharmacokinetics, stability, ability to penetrate bacteria, cost, and other factors are also important in determining whether an inhibitor is suitable for therapeutic use. Almost any class of P-lactam is capable of producing P-lactamase inhibitors. Several reviews have been pubUshed on P-lactamase inhibitors, detection, and properties (8—15). 

Minimum Inhibitory Concentration measured by dilution of test compound in agar inoculated with microorganism. 

Minimum inhibitory concentration for 90% of the strains used. jJ-g/ruL All are nonfermentors except the Enterohacteriaceae. 

Although most /3- lactam antibiotics bind covalently to some or all of the same six proteins, there are decided differences among them in terms of their relative affinities. For example, cefoxitin (see Table 1 for structures) fails to bind to protein 2 while cephacetrile binds very slowly to proteins 5 and 6. Cephaloridine binds most avidly to protein 1, the transpeptidase, and inhibits cell elongation and causes lysis at its minimum inhibitory concentration. On the other hand, cephalexin binds preferentially to protein 3 and causes inhibition of cell division and filament formation (75PNA2999, 77MI51002). 

Dichlorophenyl)-2-[2-(perhydropyrido[l,2-u]pyrazin-2-yl)benzyli-dene]thiomorpholin-3-one was claimed as a psychotherapeutic agent (98MIP6). Inhibitory concentration and proportion of high and low affinity... 

Aeration required for aerobic growth removes ethanol (produced by yeast growth) from the medium, keeping ethanol levels below inhibitory concentrations, thus giving a higher yield. 

The minimal inhibitory concentration (MIC) is the concentration which is able to prevent 105cells/mL from growing up to a visable density ( 108cells/mL) under standardized conditions. 

Na+/Ca2+ Exchangers. Figure 5 Chemical structures of amiloride derivatives and their IC50 on NCX and NHX activity. Chemical structure of the two classes of amiloride derivatives and their inhibitory concentrations on NCX and Na+/H+ exchanger activity (Reproduced from Annunziato L, Pignataro G, Di Renzo GF (2004) Pharmacol Rev 56 633-654). 

Activities are expressed as minimum inhibitory concentration (MIC, pg mL ) defined as the lowest concentration required for complete inhibition of growth of bacterial strain. 

Vancomycin is bactericidal to most susceptible bacteria at concentrations near its minimum inhibitory concentration (MIC) and is an inhibitor of bacterial cell wall peptidoglycan synthesis, although at a site different from that of j3-lactam antibiotics (Chapter 9). 

Table 11.2 Effect of inoculum size on the minimum inhibitory concentration (MIC) of three antiseptics against Staphylococcus aureus... 

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. 

Fig. 11.9 Isobologram ( - ) drawn from minimum growth inhibitory concentrations (MIC values) of chlorocresol and phenylmercuric acetate used alone and in combination against Staph, aureus, showing synergy. A, result if combination was merely additive B, result if combination was antagonistic.

The minimum inhibitory concentration (MIC) is the lowest concentration of an antimicrobial agent that prevents growth. The lower the MIC value, the more active the agent. 

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