Table of Contents
How do you interpret zone of inhibition?
If the observed zone of inhibition is greater than or equal to the size of the standard zone, the microorganism is considered to be sensitive to the antibiotic. Conversely, if the observed zone of inhibition is smaller than the standard size, the microorganism is considered to be resistant.
What is the zone of inhibition in bacterial cultures?
The area around the disk in which the antibiotic concentration is high enough to inhibit bacterial growth is called the zone of inhibition (FIGURE 1 and FIGURE 2). The zone of inhibition is measured in millimeters by a laboratory technician.
What do the diameters of zone of inhibition represent?
The diameter of the zone of inhibition will determine the effectiveness of the antibiotic; the larger the diameter, the greater will be the sensitivity of the bacterium to the antibiotic.
What does it mean if the zone of inhibition is large?
The size of the zone of inhibition is usually related to the level of antimicrobial activity present in the sample or product – a larger zone of inhibition usually means that the antimicrobial is more potent.
What does it mean if the zone of inhibition is larger?
What is the relationship between the size of the zone of inhibition and the effectiveness of the disinfectant?
Although there are other factors that contribute to the sizes of zones of inhibition (e.g., whether the agent is water soluble and able to diffuse in the agar), larger zones typically correlate to increased inhibition effectiveness of the chemical agent. The diameter across each zone is measured in millimeters.
What information does a zone of inhibition tell us about the bacteria that was cultured on the plate?
These are called zones of inhibition. They indicate that the organism was susceptible to the antimicrobial agent.
What factors influence the size of the zone of inhibition?
The size of the zone of inhibition of growth is influenced by the depth of the agar, since the antimicrobial diffuses in three dimensions, thus a shallow layer of agar will produce a larger zone of inhibition than a deeper layer.
What does a large inhibition zone mean?
susceptible
Large zones of inhibition indicate that the organism is susceptible, while small or no zone of inhibition indicateresistance. An interpretation of intermediate is given for zones which fall between the accepted cutoffs for the other interpretations.