Some methods using radioisotope labelled drugs. In contrast dilution methods allow determination of the minimal inhibitory concentration of an agent which can be correlated with blood urine and other body fluid levels of the antimicrobial agent. Laboratory tests that can be helpful in guiding antimicrobial therapy include antimicrobial susceptibility testing determination of bacterial beta lactamase production assay of serum inhibitory and bactericidal activity and assay of specific antibiotic levels in serum. Laboratory tests used to guide antimicrobial therapy. Accurate measurement of serum concentrations of antimicrobial agents is important when the margin between therapeutic and toxic levels is narrow. Soluble agents penetrate to a greater extent 16.
Antimicrobial levels and renal function for most antimicrobial agents renal excretion is the major pathway for elimination from the. Serum and that in lymph from different parts of the body in cluding the kidney. Humanserum pools are prepared. And the relationship between measurable concentrations of the drug in serum and other bodily fluids and concentrations in tissue remain. In human subjects concentrations of drug in body fluids have been reported 4 7 9 11 12. The concentration of an antibiotic in the fluids of the body is generally inferred from measurement of the drug in blood tissue homogenates or lymph stamey et al 1965.
All serum results are referred to standard curves established with serumdiluents. Antimicrobial agents and chemotherapy june 1993 p. Serum protein binding determines the level of free drug available to diffuse across membranes 1 16 18 22. The measurement of antibiotic concentrations in various fluids has been a prominent aspect of the evaluation of new antibiotics and the quality control of their manufacture. With the availability of rapid accurate assays the measurement of antibiotic material in serum and other body fluids is feasible desirable and widely practiced for these purposes. The reference standard concentration is also pre pared in a normal human serum pool.
Chisholm gd waterworth pm calnan js garrod lp. For the other body fluids listed the subjects were generally hospitalized patients table 2. The values given for serum and urine were obtained from normal adults in controlled phar macologic studies table 1. A simple micro agar diffusion method for the determination of antibiotic concentrations in blood and other body fluids. Finally because various body tissues bind antimicrobial agents with different capacities 39 and tissue fluidantibiotic concentration is a combination of bound and unbound drug 40 it is necessary to know the protein binding of an antibiotic to both the tissue or body fluid and plasma or serum in order to interpret correctly the significance of the tissue concentration. Concentration of antibacterial agents in interstitial tissue fluid.
Cockett et aly 1967. A major factor influencing penetration is the scrum protein binding of the antimicrobial drug. Human serum samples containing unknown con centrations ofan antimicrobial are assayed as above but a normal human serum pool is used as diluent. Pmc free article georgopoulos a.
Gallery of Measurement Of Antimicrobial Agents In Serum And Body Fluids
