[Importance of Clinical Laboratory and Molecular Epidemiology for Investigation of MRSA Outbreak].

MRSA has been a major pathogen associated with nosocomial outbreaks. Moreover, the isolation of community-acquired MRSA(CA-MRSA) is increasing even in Japanese hospitals. It is necessary to carry out outbreak investigations in cooperation with the clinical laboratory as it is the site where MRSA is identi- fied. "Timing of information on MRSA from the clinical laboratory" is crucial for the ICT. To detect signs of an outbreak, information on the number of MRSA isolates is essential in every ward per week or month. It is desirable to perform active surveillance routinely. However, there are problems to be solved such as the cost of active surveillance, workload of laboratory technicians, and shortage of private rooms for isolation. It is necessary that the infection control department confirms clonal spread on analysis of the molecular epi- demiology, including the PCR-based open reading frame typing (POT) method. When the number of MRSA isolates increased and some strains had the same POT number on a ward, we suspected MRSA outbreak and strengthened infection control measures. We describe herein the importance of the relationship with the clinical laboratory for infection control and how to control an MRSA outbreak rapidly. [Review].