Novobiocin test by diffusimetric method.
REFERENCES
1. Afanaseva TI, Shcherbakova NA, Givental NI, Bogdanova LF. Significance of determining novobiocin sensitivity in the taxonomy of
staphylococci. Antibiotiki. 1979 Nov;24(11):824-7.
2. Dumitru Buiuc, Marian Negut, 2009. Tratat de microbiologie clinica. Ed. medicala, 453-481.
Resistance to Novobiocin test
DESCRIPTION
The Novobiocin Test is used to differentiate between Staphylococcus species, together with other biochemical tests.
PROCEDURE
Steps are similar to diffusimetric antibiogram. It was shown (1) that the method of the
paper sensitivity discs compares very favourably with the method of serial dilutions

and it is preffered due to it's simplicity.

1. select a pure culture of aerobic, catalase-positive, oxidase-negative and
Gram-positive cocci.
2. prepare an inoculum of 0.5 density on McFarland scale.
3. disperse de inoculum on a Mueller-Hinton agar plate, with a swab
4. place a novobiocin paper disk  in the middle of the plate
5. incubate at 35 ± 1 ºC for 18 ± 2 h within 15 minutes from application of the disks.
During the incubation the antibiotic will diffuse in the area surrounding each disk, and
a rounded clear area  (where the strain's growth is  inhibited) will appear.
6. reading: measure zone edges as the point showing no growth looking from the
back of the plate against a black background illuminated with reflected light. Compare
results with manufacturer's interpretation table.
QUALITY CONTROLS
Staphylococcus epidermidis ATCC 12228 - susceptible.
Staphylococcus saprophyticus  ATCC 15305 - resistant.
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