Antibiotics minimum inhibitory concentration

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

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). 

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). 

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 goal of antimicrobial dosing for surgical prophylaxis is to maintain antibiotic concentrations above the minimum inhibitory concentration (MIC) of suspected organisms for the duration of the operation. 

Penicillin G 24 million units/24 h IV in four to six equally divided doses may be used in place of nafcillin or oxacillin if strain is penicillin susceptible (minimum inhibitory concentration 0,1 mcg/mL) and does not produce /5-lactamase vancomycin should be used in patients with immediate-type hypersensitivity reactions to beta-lactam antibiotics (see Table 37-3 for dosing guidelines) cefazolin may be substituted for nafcillin or oxacillin in patients with non-immediate-type hypersensitivity reactions to penicillins... 

Antibiotic concentrations in respiratory secretions in excess of the pathogen minimum inhibitory concentration (MIC) are necessary for successful treatment of pulmonary infections. 

The absorption and excretion of carbenicillin in man has been reported [396]. The antibiotic is not absorbed intact from the gut intramuscular injection (which is painful) often provides adequate serum levels (approximately 20 Mg/ntl) but infections with Pseudomonas strains having minimum inhibitory concentrations up to, or higher than, 100 Mg/ml require intravenous thbrapy to achieve such levels. No evidence of active metabolite formation has been obtained. Marked reductions in the half-life (and serum levels) of carbenicillin follow extracorporeal dialysis or peritoneal dialysis, the former producing the most striking effect [397]. These results were, of course, obtained in patients with severe renal failure. Patients with normal renal function rapidly eliminate the drug but, as with all penicillins, renal tubular secretion can be retarded by concurrent administration of probenecid. 

The plasmid expressing Tet repressor (pcDNA6/TR) has a blas-ticidin-resistance cassette, while the plasmid used for the shRNA conditional expression (pSuperior) confers resistance to puromycin. Therefore, before starting the procedures, these two antibiotics need to be titrated on the selected cell line to find out the minimum inhibitory concentration necessary to kill completely untransfected cells. 

Table 10.2 further shows that the minimum inhibitory concentration may, for some antibiotics and some cultures, be lower than the corresponding detection... 

Table 10.2 Minimum Inhibitory Concentrations of Antibiotics for Common Dairy Starter Cultures and B cillus ste rothermophilus...

The first marine bacterial metabolite to be reported was pentabromopseudiline (89) which is composed of more than 70% bromine by weight. It shows antibiotic properties against Gram-positive bacteria with minimum inhibitory concentrations from 0.0063 to 0.2 pg/ml [80]... 

Figure 10. Microcalorimetric growth experiments with Escherichia coli in the presence of antibiotics (1.6 pg/ml = twice the minimum inhibitory concentration), added at the time indicated by the arrow, a, tetracycline b, doxycycline 0, control experiment. Obviously doxycycline suppressed the growth more efficiently than tetracycline. Adapted from Mcirdh et al. (1976).

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

Resistance to tetracyclines. The tetracyclines Figure 7.3) are a family of closely related antibiotics now numbering at least seven, which are inhibitors of protein synthesis [150]. The tetracyclines are broad spectrum antibiotics, oxytetracycline being the most active against strains of Ps. aeruginosa. In sensitive strains, the range of minimum inhibitory concentrations (MIC values) is 10-30 /xg/ml. However, strains with MIC values of greater than lOp-g/ml are considered clinically resistant. 

Antibiotic Number of strains tested Minimum inhibitory concentration (figlml) ... 

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