{"id":963,"date":"2009-04-20T19:07:00","date_gmt":"2009-04-21T02:07:00","guid":{"rendered":"http:\/\/wp.onegoodcookie.com\/?p=963"},"modified":"2013-03-07T21:33:45","modified_gmt":"2013-03-08T02:33:45","slug":"minimum-inhibitory-concentration-mic","status":"publish","type":"post","link":"https:\/\/insidesurgery.com\/2009\/04\/minimum-inhibitory-concentration-mic\/","title":{"rendered":"Minimum Inhibitory Concentration (MIC)"},"content":{"rendered":"
Minimum inhibitory concentration should be considered in the care of patients with microbial diseases. Of key importance in selecting an antibiotic to treat a surgical bacterial infection is the susceptibility of the isolate to the administered drug. One way to measure this is calculation of the minimum inhibitory concentration (MIC) of several possible antibiotic choices against the bacterial isolate.<\/p>\n
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Minimum inhibitory concentration is defined as the lowest (i.e., most dilute) concentration of an antibiotic that inhibits the growth of the microbe in specific test media known to be hospital to the organism.<\/p>\n
The minimum inhibitory concentration (MIC) value is reported in microg\/L, not in multiples of dilution. So, the more dilutions a drug can sustain while still having growth retardant ability means a lower mg\/L value. The key point is that the lower MIC in microg\/L (i.e., the more times the antibiotic has been diluted) the more sensitive the bacterial isolate is to the drug.<\/p>\n
There are three general methods of determining minimum inhibitory concentration. These are the serial dilution, disc diffusion, and gradient diffusion methods. In practice, there are commercially available methods that are widely used to make determining the MIC efficient and affordable.<\/p>\n
In this method, the antibiotic is diluted in several two-fold decreasing concentrations. The broth or agar containing the dilution multiples is then inoculated with bacterial isolate of interest and incubated for 18-24 hours at 35 degrees C.<\/p>\n
A media sample without antibiotic is also inoculated with the isolate for control purposes.<\/p>\n
The broth dilution tubes or agar plates are then inspected to determine the lowest concentration of antibiotic that prevents of turbidity (dilution tubes) or colony growth (agar plates.)<\/p>\n