Source+4

[](resistance and mechanics, why resistance occurs, effective antibiotic systems, combination of antibiotics)
 * Mayer, Gene. "Antibiotics." //Biomedical Sciences Graduate Program//. Web. 05 Apr. 2011.
 * "Cross resistance implies that a single mechanism confers resistance to multiple antimicrobial agents while multiple resistance implies that multiple mechanisms are involved. Cross resistance is commonly seen with closely related antimicrobial agents while multiple resistance is seen with unrelated antimicrobial agents." (section 6)
 * "Altered permeability may be due to the inability of the antimicrobial agent to enter the bacterial cell or alternatively to the active export of the agent from the cell." (section 6)
 * "Resistance is often the result of the production of an enzyme that is capable of inactivating the antimicrobial agent." (section 6)
 * "Resistance can arise due to alteration of the target site for the antimicrobial agent." (section 6)
 * "Resistance can result from the acquisition of a new enzyme to replace the sensitive one" (section 6)
 * "Combination therapy with two or more antibiotics is used in special cases: (section 1)
 * To prevent the emergence of resistant strains
 * T o treat emergency cases during the period when an etiological diagnosis is still in progress
 * To take advantage of antibiotic synergism. "
 * "Antibiotic synergism occurs when the effects of a combination of antibiotics is greater than the sum of the effects of the individual antibiotics. Antibiotic antagonism occurs when one antibiotic, usually the one with the least effect, interferes with the effects of another antibiotic." (section1)
 * "For an antibiotic to be effective the MIC or MBC must be able to be achieved at the site of the infection. The pharmacological absorption and distribution of the antibiotic will influence the dose, route and frequency of administration of the antibiotic in order to achieve an effective dose at the site of infection." (section 1)
 * " Antibiotics are categorized as bactericidal if they kill the susceptible bacteria or bacteriostatic if they reversibly inhibit the growth of bacteria." (section 1)
 * "The basic quantitative measures of the //in vitro// activity of antibiotics are the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC)." (section 1)
 * "The MIC is the lowest concentration of the antibiotic that results in inhibition of visible growth (//i.e.// colonies on a plate or turbidity in broth culture) under standard conditions." (section 1)
 * "The MBC is the lowest concentration of the antibiotic that kills 99.9% of the original inoculum in a given time." (section 1)
 * " For an antibiotic to be effective the MIC or MBC must be able to be achieved at the site of the infection. The pharmacological absorption and distribution of the antibiotic will influence the dose, route and frequency of administration of the antibiotic in order to achieve an effective dose at the site of infection." (section 1)