Susceptibility Testing Q. Why should I use an MRSA Screen plate in addition to a regular Mueller Hinton?
A. Methicillin-resistant S. aureus always exists as a mixed population of sensitive and resistant strains, hence the term “heteroresistant”. The sensitive strains may mask the resistant portion of the population on an ordinary Mueller Hinton plate. The MRSA Screen plate contains added NaCl that the resistant strains prefer. It also contains oxacillin, so that any growth in 24 hours is considered positive for MRSA. It is recommended to incubate no longer than 24 hours at no more than 35 degrees C. for S. aureus. Refer to the technical information sheet for MRSA Screen plate (Cat. no. G47) for more information.
Related Questions
- What should I do when my QC zone sizes are out of range for one or two antimicrobics when testing my Mueller Hinton Agar?
- Susceptibility Testing Q. Why should I use an MRSA Screen plate in addition to a regular Mueller Hinton?
- Is it acceptable to use Mueller Hinton Sheep Blood for susceptibility testing on the day it expires?
