Table 1. Incidences of 10 top-ranking pathogens causing nosocomial infections and infections from four body sites at National Taiwan University Hospital, 1981 to 1999 % of indicated pathogen causing nosocomial infection (1981-1986/1987-1992/1993-1998/1999)a All BSI 3.7/9.1/14.4/16.2 1.0/9.2/16.4/16.2 RTI 2.0/5.8/2.1/2.2 UTI 8.4/16.0/23.6/14.3 5.2/9.1/12.1/12.0 5.2/9.3/11.5/13.0 4.0/8.4/16.9/12.6 1.4/2.6/3.3/2.1 12.7/14.0/11.1/11.8 12.1/8.4/9.5/9.9 8.1/5.5/7.2/6.8 6.0/7.6/7.4/6.4 8.8/7.8/6.7/6.2 4.4/5.1/4.9/5.4 2.8/6.9/6.6/5.1 5.7/6.1/4.8/4.1 10.0/9.4/7.2/7.8 18.7/9.7/8.7/9.0 11.6/6.6/7.7/7.0 8.0/8.6/7.3/6.9 8.7/6.2/6.3/7.6 6.1/8.8/7.2/7.6 2.7/8.5/7.9/4.9 5.9/7.7/6.8/6.7 19.6/21.9/23.8/25.7 4.8/2.4/3.5/3.7 10.9/9.4/11.5/10.8 5.2/8.1/11.8/8.6 11.0/13.4/9.3/13.0 12.3/13.1/7.8/8.2 3.5/1.9/3.7/4.1 3.2/2.2/2.4/1.1 11.7/11.2/11.0/10.4 19.1/19.9/18.6/18.4 9.0/7.0/8.6/8.2 9.0/8.4/6.7/6.3 11.6/9.7/8.1/6.5 7.4/6.5/4.4/2.8 3.8/3.8/3.8/3.7 5.9/4.4/2.4/2.4 Pathogen Candida spp. Staphylococcus aureus Pseudomonas aeruginosa Escherichia coli Klebsiella pneumoniae Enterobacter spp. Enterococcus spp. Acinetobacter spp. CoNS Other NFGNB S. marcescens Proteus spp. Citrobacter spp. Viribans streptococci Bacteroides spp. aAbbreviations: BSI = bloodstream infection; RTI = respiratory tract infection; UTI = urinary tract infection; SSI = surgical site infection; CoNS = coagulase-negative staphylococci; NFGNB = nonfermentative gram-negative bacilli. 1993-1998 (9.3%) but second in 1999 (13.0%); Candida spe- cies accounted for only 2.2% in 1999. The distributions of selected antimicrobial drug-resistant pathogens causing all nosocomial infections and BSIs of patients hospitalized in intensive care units or general wards is shown in Table 2. Antimicrobial drug-resistant pathogens caus- ing BSIs that increased markedly over the study period were methicillin-resistant S. aureus (4.3% in 1981-1986, 58.9% in 1993-1998, and 69.2% in 1999), cefotaxime-resistant E. coli (0% in 1981-1986, 6.1% in 1993-1998, and 12.5% in 1999), and cefotaxime-resistant Klebsiella pneumoniae (4.0% in 1981-1986, and 25.8% in 1993-1998). The frequencies of these three resistant pathogens were considerably higher in isolates from ICUs than those from general wards (84.6% vs. 48.3% for MRSA, 17.1% vs. 5.1% for cefotaxime-resistant E. coli, and 51.1% vs. 18.3% for cefotaxime-resistant K. pneumoniae in 1993-1998). The incidence of methicillin-resistant coagu- lase-negative staphylococci (MRCoNS) remained high (72%- 90%) during the 19-year period. Ceftazidime use is associated with trends of several antimi- crobial-resistant pathogens during the period 1991 to 1999 (Figure 2). Restriction of third-generation cephalosporins (par- ticularly ceftazidime) was implemented in 1997. In 1999, resis- tance to cefotaxime in K. pneumoniae diminished; however, resistance to cefotaxime in E. coli and resistance to ceftazidime in P. aeruginosa slightly increased. The first clinical isolate of VRE was recognized in 1995 (25,26). Since then, 80 isolates of VRE (49 of E. faecalis and 31 of E. faecium) have been recovered from hospitalized patients. The incidence of VRE in isolates causing nosocomial infection increased from 1.8% in 1995 to 6.7% in 1997 and 25.2% in 1999 (Figure 3). Among these VRE isolates, 4 were from blood, 15 from urine, and the rest were pus or drainage fluid. Only 12 (15%) of these isolates were from patients admitted to ICUs, and 6 of these 12 isolates were recovered in 1999. The incidence of VRE in enterococci causing nosoco- mial infections in ICUs was 7.0%. The relationship of increas- ing vancomycin use and the increase in vancomycin resistance in enterococci is shown in Figure 3. The incidences of imipenem-resistant P. aeruginosa (1993 to 1998) and imipenem-resistant Acinetobacter baumannii (1999) isolated from ICUs were five- to ten-fold higher than isolates recovered from non-ICU settings. However, this was not the case with imipenem-resistant P. aeruginosa in 1999 or imipenem-resistant A. baumannii in 1993-1998 (Figure 4). All 150 isolates of Candida species were inhibited by 1 µg/ mL of amphotericin B (MIC range 0.03 to 1 µg/mL). The MIC50 and MIC90 of C. glabrata were 16 µg/mL and >32 µg/ mL, respectively. Twenty-one isolates (70%) of C. glabrata were nonsusceptible to fluconazole (MICs >8 µg/mL). Four (15.4%) of the C. parapsilosis isolates had MICs >8 µg/mL (2 had MICs 16 µg/mL and the other 2 had MICs 64 µg/mL). Emerging Infectious Diseases • Vol. 8, No. 1, January 2002 65 RESEARCH SSI 2.4/5.1/5.9/6.4 5.5/5.2/13.0/15.4 11.1/17.4/14.3/16.0 11.7/5.8/5.8/6.8 6.9/3.5/4.2/4.6 4.5/7.9/7.8/5.5 10.1/12.6/9.6/7.9 3.2/7.1/9.1/6.8 5.2/5.8/4.2/3.5 9.7/4.7/5.0/3.1