Adult methicillin-resistant Staphylococcus aureus bacteremia in Taiwan: clinical significance of non–multi-resistant antibiogram and Panton–Valentine leukocidin gene Jiun-Ling Wang a , Jann-Tay Wang a , Shey-Ying Chen b , Po-Ren Hsueh a,c , Hsiang-Chi Kung a,d , Yee-Chun Chen a , Shan-Chwen Chang a,e, ⁎ a Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan b Emergency Medicine, National Taiwan University Hospital, Taipei 100, Taiwan c Laboratory Medicine, National Taiwan University, Taipei 100, Taiwan d Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Douliou, Taiwan e Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei 100, Taiwan Received 11 January 2007; accepted 27 June 2007 Abstract It is poorly defined whether or not adult patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia with a non–multi- resistant antibiogram phenotype and Panton–Valentine leukocidin (PVL) gene carriage have different clinical syndromes. Clinical characteristics of 95 adult patients of MRSA bacteremia, with isolates that were non–multi-resistant to non–β-lactam, were compared with a contemporaneous multiresistant group. Independent risk factors other than community-associated MRSA bacteremia patients associated with recovery of non–multi-resistant MRSA isolates by multivariate analysis included deep-seated infection and catheter insertion site infection. Older age, intensive care unit-onset bacteremia, and postoperative infection were negative independent risk factors associated with non–multi- resistant MRSA isolates. Most of the 60 recoverable non–multi-resistant MRSA isolates belonged to multilocus sequence type 59, and all isolates belonged to staphylococcal chromosomal cassette mec (SCCmec) element type IV or type V. Most PVL-positive MRSA isolates belonged to SCCmec V. PVL-positive CA-MRSA isolates could cause more deep-seated infections in patients presented with non–multi- resistant MRSA bacteremia. © 2007 Elsevier Inc. All rights reserved. Keywords: Methicillin-resistant Staphylococcus aureus; Toxin; Bacteremia; Community-acquired infection 1. Introduction Since the late 1990s, community-associated methicillin- resistant Staphylococcus aureus (CA-MRSA) has emerged worldwide in patients who do not display health care- associated risk factors for MRSA infection (Naimi et al., 2003; Vandenesch et al., 2003). The accepted definition of health care-associated MRSA (HA-MRSA) infection includes MRSA infection with the presence of any of the following health care-associated risk factors within 1 year before the index MRSA bacteremia culture: 1) receipt of systemic antimicrobial treatment, 2) residence in a long-term care facility, 3) prior hospitalization to an acute care facility, 4) use of central intravenous catheters or long-term venous access devices, 5) use of urinary catheters, 6) use of other long-term percutaneous devices, 7) prior surgical procedures, and/or, 8) need of dialysis (Naimi et al., 2003; Seybold et al., 2006). Traditional nosocomial MRSA strains are multiresistant to non–β-lactam antibiotic, and the emerging CA-MRSA strains are usually susceptible to various antibiotics (Naimi et al., 2003; Vandenesch et al., 2003). However, the CA-MRSA strains in Taiwan are only susceptible to trimethoprim/ sulfamethoxazole, ciprofloxacin, gentamicin, and mino- cycline (Boyle-Vavra et al., 2005), and have an extraordinarily high resistance rate to erythromycin and clindamycin (Fang et al., 2004; Wang et al., 2004; Boyle-Vavra et al., 2005; Chen et al., 2005). It has been reported that CA-MRSA strain may spread in the hospital and cause nosocomial infections (Healy Available online at www.sciencedirect.com Diagnostic Microbiology and Infectious Disease 59 (2007) 365 – 371 www.elsevier.com/locate/diagmicrobio ⁎ Corresponding author. Tel.: +886-2-23123456x5401; fax: +886-2- 23958721. E-mail address: changsc@ntu.edu.tw (S.-C. Chang). 0732-8893/$ – see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.diagmicrobio.2007.06.021