New identification characteristics of methicillin-resistant Staphylococcus aureus on chromogenic culture media.

Methicillin-Resistant Staphylococcus aureus (MRSA) is one of the most common and important causes of nosocomial infections. Rapid detection of this pathogen is important for conducting good and swift infection control. This prospective study evaluates two chromogenic media for the detection of MRSA. New colony characteristics were noticed during this evaluation: (i) a yellow/golden colouration on a pipette after streaking the colonies of the chromogenic culture could eventually be used as a supplementary identification test to identify the MRSA strains, and (ii) some MRSA strains do not metabolise the chromogens and therefore are not coloured on chromogenic agars. However, they have a typical yellow/golden colony aspect usually observed amongst S. aureus.