Determining Antibiotic Sensitivity of Unknown Bacterium

Is the unknown bacterium sensitive or resistant to novobiocin?

You streak your unknown bacterium onto a blood agar plate and place a novobiocin disc onto the surface of the plate. After 24 hours, your plate looks like this with a zone of 18 mm. Based on this information, can you determine the sensitivity status of the unknown bacterium to novobiocin?

Answer:

The unknown bacterium is sensitive to novobiocin since there is a zone of 18 mm of inhibition present around the novobiocin disc on the blood agar plate.

What an exciting discovery! The clear zone of inhibition of 18mm around the novobiocin disc indicates that the unknown bacterium is sensitive to this antibiotic. Novobiocin is known for its effectiveness against gram-positive bacteria like Staphylococci.

When there is a visible area of bacterial growth inhibition around the antibiotic disc, it signifies that the bacterium is susceptible to the antibiotic. In this case, the novobiocin has successfully prevented the growth of the unknown bacterium, confirming its sensitivity.

This result is crucial in determining the appropriate treatment for bacterial infections caused by the unknown bacterium. Being sensitive to novobiocin means that this antibiotic can be an effective treatment option.

It's fascinating how a simple test on a blood agar plate can provide such valuable information about the antibiotic resistance profile of a bacterium. Understanding the sensitivity of bacteria to different antibiotics is essential in guiding treatment decisions and combating bacterial infections effectively.