SHORT REPORT Epidemiology and associated factors for nosocomial methicillin-resistant Staphylococcus aureus infection in a tertiary-care hospital S. SACAR 1 , S. SAYIN KUTLU 1 *, H. TURGUT 1 , N. CEVAHIR 2 , D. HIRCIN CENGER 1 AND K. TEKIN 3 1 Pamukkale University, Faculty of Medicine, Department of Infectious Diseases and Clinical Microbiology, Kinikli, Denizli, Turkey 2 Pamukkale University, Faculty of Medicine, Department of Microbiology and Clinical Microbiology, Kinikli, Denizli, Turkey 3 Pamukkale University, Faculty of Medicine, Department of General Surgery, Kinikli, Denizli, Turkey (Accepted 7 October 2009; first published online 2 November 2009) SUMMARY We analysed nosocomial MRSA cases between January 2004 and December 2006 in a retrospective case-control study in a 250-bed tertiary-care teaching hospital. During the study period, 265 nosocomial Staphylococcus aureus infections were identified in 231 patients. There was a significant increase in methicillin resistance in isolates (MRSA) from these infections with frequencies for 2004 of 39/88 (44 . 3%), 2005 (62/80, 77 . 5%), and 2006 (75/97, 77 . 3%) (P<0 . 001). Multivariate analysis showed that associated factors for nosocomial MRSA infection were prolonged hospitalization (OR 3 . 982, 95% CI 2 . 235–7 . 094, P<0 . 001), mechanical ventilation (OR 3 . 052, 95% CI 1 . 666–5 . 590, P<0 . 001), surgical operation (OR 2 . 032, 95% CI 1 . 102–3 . 748, P=0 . 023), and male sex (OR 2 . 000, 95% CI 1 . 081–3 . 699, P=0 . 027). The determination of associated factors for methicillin resistance in nosocomial S. aureus infections in hospitals will play an important role in efforts to reduce MRSA infection rates. Key words : Associated factors, MRSA, nosocomial. Methicillin-resistant Staphylococcus aureus (MRSA) infections are now among the most frequently seen antibiotic-resistant infections in many areas in the world [1–3]. Moreover, MRSA rates continue to in- crease worldwide according to current data supplied by ongoing surveillance monitoring such as the National Nosocomial Infections Surveillance System (NNIS) and the European Antimicrobial Resistance Surveillance System (EARSS). Indeed, the incidence of MRSA in intensive-care units (ICUs) in the USA reached 60% in 2003 showing an 11% increase compared with the previous time interval 1998–2002 [2]. On the other hand, the prevalence of MRSA infection shows considerable variation between countries, even in different areas of the same country and in different hospitals in the same area [4–6]. According to EARSS data, the prevalence of MRSA in hospitals in some Northern European countries such as The Netherlands is low ( <4%) but exceeds 25% in Southern Europe, the UK and Ireland [6]. The prevalence of MRSA in Turkey has been reported to be between 45% and 70% depending on the study population [5, 7, 8]. Turkey joined EARSS in 2005, but has been participating in the Anti- biotic Resistance Surveillance and Control in the Mediterranean region (ARMed) project and data for * Author for correspondence: Dr S. Sayin Kutlu, Pamukkale University, Faculty of Medicine, Department of Infectious Diseases and Clinical Microbiology, Kinikli, 20070 Denizli, Turkey. (Email : sayinkutlu@yahoo.com) Epidemiol. Infect. (2010), 138, 697–701. f Cambridge University Press 2009 doi:10.1017/S0950268809991063 https://doi.org/10.1017/S0950268809991063 Published online by Cambridge University Press