Nosocomial infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci at a university hospital in Taiwan from 1991 to 2003: resistance trends, antibiotic usage and in vitro activities of newer antimicrobial agents

Abstract

A rapid increase of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection (from 39% in 1991 to 75% in 2003) and vancomycin-resistant enterococci (VRE) (from 1.2% in 1996 to 6.1% in 2003) at a university hospital in Taiwan was found. The noticeable rise of MRSA and VRE was significantly correlated with the increased consumption of glycopeptides, beta-lactam-beta-lactamase inhibitor combinations, extended-spectrum cephalosporins, carbapenems and fluoroquinolones (Pearson's correlation coefficient, P < 0.05). Minimum inhibitory concentrations (MICs) of 100 non-duplicate blood isolates of MRSA (in 2003) and of 25 non-duplicate isolates of vancomycin-resistant Enterococcus faecalis and 172 vancomycin-resistant Enterococcus faecium (in 1996-2003) causing nosocomial infection recovered from various clinical specimens of patients treated at the hospital to nine antimicrobial agents were determined by the agar dilution method. All of these isolates were susceptible to linezolid and were inhibited by 0.5mg/L of tigecycline, and all MRSA isolates were inhibited by daptomycin 1mg/L, including two isolates of MRSA with heteroresistance to vancomycin. Daptomycin had two-fold better activity against vancomycin-resistant E. faecalis (MIC90, 2 mg/L) than against vancomycin-resistant E. faecium (MIC90, 4 mg/L). Decreased susceptibilities of vancomycin-resistant E. faecium and MRSA to quinupristin/dalfopristin (non-susceptibility 25% and 8%, respectively) were found. Telithromycin had poor activity against the isolates tested (MIC90, 8 mg/L). Linezolid, daptomycin and tigecycline may represent therapeutic options for infections caused by these resistant Gram-positive organisms.

Susceptibility of clinical methicillin-resistant Staphylococci isolates to new antibiotics

“…Only one study reported daptomycin resistance (MIC: 2 µg/mL) in MRSA strains outside Turkey [32]. In many studies, daptomycin has been indicated to be a good treatment option for especially serious and resistant Gram-positive bacteria infections [16,36]. In a study conducted in Canada, the sensitivity ratio in MRSA strains was found to be 100% for daptomycin and linezolid, and 99.8% for tigecycline [52].…”

Resistance of Haemophilus influenzae Isolates in Children Under 5 Years Old with Acute Respiratory Infections in China between 2000 and 2002

“…31,32 Secondly, there may be specific resistantgene clones that prevail within certain regions. 33 The genes of resistant strains can be relatively stable and may only disappear over a long period of time.…”

High Rate of Resistance to Quinupristin-Dalfopristin in Enterococcus faecium Clinical Isolates from Korea

“…Previous data from Korea with 56 E. faecium isolates also showed that only one isolate was resistant to QD (6). Based on previous reports, Taiwan showed very high rates of resistance to QD in E. faecium isolates, ranging from 9% to 51% (5,14). Recent data from the SENTRY project in the Asian-Pacific region confirmed the high QD resistance rate in E. faecium from Taiwan (19.0%) and also showed increasing resistance to QD (29.4%) in Korea, with 17 isolates of E. faecium (J. M. Bell and J. D. Turnidge, Abstr.…”