Mrsa Infection – Lab Detection

MRSA infection can be confirmed in a patient only after performing certain tests in certified laboratories. Cefoxitin disk screen test and latex agglutination test for PPBP2a are two of the tests that are recommended by the Clinical and Laboratory Standards Institute (CLSI) formerly called as National committee for clinical Laboratory Standards (NCCLS). In case in the laboratory if a plate contains oxacillin whose amount is 6 microgram per milliliter in the Mueller-Hinton agar supplemented with sodium chloride (4% w/v 0.68 mol/L) then the person is said to be affected with mrsa infection. The accuracy in the detection of the mrsa infection is less as there are two types of subpopulations that are present in the infection site where one of the types is susceptible and the other type is resistive. Though all the cells in the culture have the information regarding resistance only certain cells can actually convey the resistance in vitro and this characteristic is known as hetero resistance which is very common in infection that have resistance to penicillin. In case there are cells that have the hyper resistance property then the detection becomes difficult if the temperature is above 35 degree Celsius and it takes time to grow. Most of the mrsa infection can be detected by performing the agar based or broth based tests and often cefoxitin disk diffusion method is used to just support the findings of the other tests