Factors affecting anti-microbial activity in vitro
PH of the environment
some drugs more active at acidic or alkaline PH
Components of medium
media composition components enhance or inhibit bacterial growth.
Stability of drug
Size of inoculum: the larger the bacterial inoculum, the lower the apparent sensitivity of the organisms.
Length of incubation: short exposure of moisture to the drug inhibits their growth but does not kill them; longer exposure of moisture to a drug gives a chance for resistant motants to emerge.
Metabolic activity of moistures
actively and rapidly growing micro-organisms are more susceptible to drug action than those in the resting phase.
Techniques of routinely used antimicrobial sensitivity testing (disc diffusion tests)
sensitivity testing media