Epidemiology of Staphylococcus aureus Infections and the prevalence of Infection Caused by Community- Acquired Methicillin-Resistant Staphylococcus aureus in Hospitalized Patients at Siriraj Hospital Sripetcharat Mekviwattanawong MD*, Somporn Srifuengfung PhD**, Kulkanya Chokepaibulkit MD***, Darin Lohsiriwat MD****,Visanu Thamlikitkul MD*,
*Division of Infectious Diseases and Tropical Medicine, Department of Medicine, **Department of Microbiology, ***Division of Infectious Diseases, Department of Pediatrics and ****Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University
Affiliation :
Background : The CA-MRSA infections have emerged in many parts of the world over the past decade. To our
knowledge, the prevalence of CA-MRSA infections in Thai patients is unknown.
Objective : To determine an epidemiology of Staphylococcus aureus (S. aureus) infections in hospitalized
patients in Siriraj Hospital and the prevalence of infections caused by community-acquired methicillin-resis-
tant S. aureus (CA-MRSA).
Materials and Methods : The study was carried out at Siriraj Hospital from January to May 2005. The eligible
patients were hospitalized patients whom S. aureus were isolated from their clinical specimens submitted to
Department of Microbiology. S. aureus isolate was classified into infection or colonization. S. aureus infec-
tions were further classified into methicillin-resistant S. aureus (MRSA) or methicillin-sensitive S. aureus
(MSSA) infections, and hospital-acquired (HA) or community-acquired (CA) infections. CA-MRSA infection
is defined as infection caused by MRSA isolated from the patient within 72-hour of hospitalization and has no
features of HA MRSA infections.
Results : There were 669 S. aureus isolates from 448 patients. Two hundred and sixty two patients (58.5%)
were MSSA whereas 186 (41.5%) were MRSA infections. CA-MRSA was found in three isolates (0.9% of total
MRSA) from two patients.
Conclusion : The prevalence of CA-MRSA infections in hospitalized patients in Siriraj Hospital was uncom-
mon and these patients could probably be HA MRSA infections.
Keywords : Prevalence, Staphylococcus aureus, Methicillin-resistant, Community-acquired, Cross sectional study, Cohort study,Thailand
