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The minimum inhibitory concentration (MIC) and minimum bactericidal concentration are used to measure in vitro activity of antimicrobial agents. They are good indicators of antimicrobial potency, but don't give any information relating to time-dependent antimicrobial killing (the so-called post antibiotic effect).
A selectivity factor higher than 10 is optimal. This means the concentration of antibiotic is sufficient to kill untransfected cells but not toxic enough to kill transfected cells. A selectivity factor lower than 10 means the concentration of antibiotic needed for selection is too close to the toxic concentration for the transfected cells.
The minimum bactericidal concentration (MBC) is the lowest concentration of an antibacterial agent required to kill a particular bacterium. [1] It can be determined from broth dilution minimum inhibitory concentration (MIC) tests by subculturing to agar plates that do not contain the test agent.
Bactericidal antibiotics kill bacteria; bacteriostatic antibiotics slow their growth or reproduction. Bactericidal antibiotics that inhibit cell wall synthesis: the beta-lactam antibiotics ( penicillin derivatives ( penams ), cephalosporins ( cephems ), monobactams , and carbapenems ) and vancomycin .
Depending on the pathogen and antibiotics being tested, the media can be changed and/or adjusted. The antimicrobial concentration is adjusted into the correct concentration by mixing stock antimicrobial with media. The adjusted antimicrobial is serially diluted into multiple tubes (or wells) to obtain a gradient. The dilution rate can be ...
Antimicrobial use has been common practice for at least 2000 years. Ancient Egyptians and ancient Greeks used specific molds and plant extracts to treat infection. [5]In the 19th century, microbiologists such as Louis Pasteur and Jules Francois Joubert observed antagonism between some bacteria and discussed the merits of controlling these interactions in medicine. [6]
Half maximal effective concentration (EC 50) is a measure of the concentration of a drug, antibody or toxicant which induces a biological response halfway between the baseline and maximum after a specified exposure time. [1] More simply, EC 50 can be defined as the concentration required to obtain a 50% [...] effect [2] and may be also written ...
IC 50 values are typically expressed as molar concentration. IC 50 is commonly used as a measure of antagonist drug potency in pharmacological research. IC 50 is comparable to other measures of potency, such as EC 50 for excitatory drugs. EC 50 represents the dose or plasma concentration required for obtaining 50% of a maximum effect in vivo. [1]