High rates of multidrug resistance in Enterococcus faecalis and E. faecium isolated from inpatients and outpatients in Taiwan Jann-Tay Wang a, b, c , Shan-Chwen Chang a, b , Hui-Yin Wang c , Pei-Chen Chen c , Yih-Ru Shiau c , Tsai-Ling Lauderdale c, ⁎, TSAR Hospitals a Division of Infectious Diseases, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan b Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan c National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan abstract article info Article history: Received 9 December 2012 Received in revised form 8 January 2013 Accepted 9 January 2013 Available online 13 February 2013 Keywords: Enterococcus faecalis Enterococcus faecium Vancomycin-resistant enterococci Multidrug resistance Antimicrobial resistance Longitudinal national data on resistance in Enterococcus faecalis and E. faecium from different sources in Taiwan are rare. The present study analyzed data from the Taiwan Surveillance of Antimicrobial Resistance program to address this issue. Between 2002 and 2010, a total of 1696 E. faecalis and 452 E. faecium isolates were studied. Although these 2 species together comprised similar percentages of all enterococci in each study year (94.1–97.2%, P = 0.19), the proportion of E. faecium increased from 12.4% in 2002 to 27.3% in 2010 (P b 0.001). The most noteworthy change in susceptibilities of these 2 species was vancomycin resistance in E. faecium (VREfm), which increased from 0.3% in 2004 to 24.9% in 2010 (P b 0.001). VREfm prevalence differed significantly between geographic regions, patient age groups, and locations. Multidrug resistance was very common in both species even in isolates from outpatients (82.7% for E. faecalis and 98.1% for E. faecium), at rates similar to those from intensive care unit (ICU) and non-ICU patients (80.5–80.9% in E. faecalis and 97.2– 98.6% in E. faecium). Nonsusceptibility to linezolid was b0.5% in both species. All tested isolates were susceptible to daptomycin. Continuous surveillance of VRE prevalence and survey of community reservoirs of multidrug-resistant enterococci are warranted. © 2013 Elsevier Inc. All rights reserved. 1. Introduction Enterococci are Gram-positive, facultative anaerobic bacteria with well-adapted mechanism to colonize human and survive for long periods of time in strict inanimate environments (Arias and Murray, 2012). Although considered as low-virulent bacteria without much clinical significance for many years, enterococci have become one of the leading pathogens causing healthcare-associated infections (HAIs) in recent years (Arias and Murray, 2012; Hidron et al., 2008; Sader et al., 2011; Willems and van Schaik, 2009). In the United States, Enterococcus species accounted for 12% of HAIs in intensive care units during 2006–2007 (Hidron et al., 2008). In Taiwan, the incidence of HAIs caused by Enterococcus species in ICUs has also increased during the past decade (Jean and Hsueh, 2011). Enterococci are also a frequent community pathogen, being responsible for 6–10% of community-acquired urinary tract infections (Laupland et al., 2007; Lee et al., 2011). E. faecalis and E. faecium are the 2 species most commonly encountered in clinical setting, accounting for approximately 80% and 20% of enterococcal infections, respectively (Arias and Murray, 2012). Other than urinary tract infections, enterococci can also cause bacteremia, skin and soft tissue infections, and infective endocarditis (Arias and Murray, 2012; Hidron et al., 2008). Their increasing resistance to various antibiotics has made treating enterococcal infections a challenge (Arias et al., 2010). The 3 most noteworthy types of resistance in enterococci are ampicillin resistance, high-level aminoglycoside resistance, and glycopeptide resistance because these 3 types of antibiotics are the mainstay for treating enterococcal infections (Arias et al., 2010). In addition to increased resistance to various antibiotics, recent studies also reported changes (decreasing) in the E. faecalis/E. faecium ratio among Enterococcus species causing infection (Leavis et al., 2006; Lester et al., 2008). This change of ratio is a great concern because vancomycin resistance is more common in E. faecium than in E. faecalis (Arias et al., 2010; Sader et al., 2011), and because infections caused by vancomycin-resistant enterococci are associated with higher mortality (Lodise et al., 2002). In addition, infections caused by vancomycin- resistant E. faecium tended to have a worse outcome compared to those caused by vancomycin-resistant E. faecalis (Ghanem et al., 2007). Therefore, longitudinal surveillance of drug resistance and species distribution of Enterococcus from different sources is important to help provide information to clinicians on empirical therapy choices for patients with suspected enterococcal infection. National data on this Diagnostic Microbiology and Infectious Disease 75 (2013) 406–411 ⁎ Corresponding author. Tel.: +886-37-246166; fax: +886-37-586457. E-mail address: lauderdale@nhri.org.tw (T.-L. Lauderdale). 0732-8893/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.diagmicrobio.2013.01.004 Contents lists available at SciVerse ScienceDirect Diagnostic Microbiology and Infectious Disease journal homepage: www.elsevier.com/locate/diagmicrobio