Geographic variations and trends in antimicrobial resistance among Enterococcus faecalis and Enterococcus faecium in the SENTRY Antimicrobial Surveillance Program (1997–2000)

Abstract

In the 1990s, the Enterococcus emerged as an important pathogen because of increasing prevalence and acquired resistances to glycopeptides and other agents. The seriousness of this problem can vary markedly worldwide and within nations; the SENTRY Antimicrobial Surveillance Program documents these differences. Over 8,000 enterococci were processed in the program (1997-2000) and the Enterococcus faecalis (EF; 4,034 strains) and Enterococcus faecium (EFM; 1,123 strains) isolates are tabulated. All strains were processed by three regional monitors using reference dilution methods. Identification to species was performed by participants and confirmed by the central laboratories. EF occurrence was greater than EFM by ratios of 3:1 to 5:1 in the Asia-Pacific (APAC), European (EU), and North American (NA) regions; the ratio was 17:1 in Latin America (LA). EF and EFM represented approximately 80-90% of all isolated enterococci. Glycopeptide-resistant enterococci (GRE) rates varied from nil for EF in APAC and LA to 43 to 54% in EFM in NA. A slight increase in GRE was noted in NA (EFM only). Van A phenotypes predominated all regions. The most recent (2000) rank order of % GRE by region was: for NA (13%) > LA (4%) > EU (3%) > APAC (1%). In NA potential therapeutic agents were (% S): ampicillin (81%), chloramphenicol (87%), quinupristin/dalfopristin (20%), ciprofloxacin (39%), gatifloxacin (51%), nitrofurantoin (83%) and linezolid (>99%). Resistances in enterococci continue to be documented worldwide, but rates within endemic areas like NA appears to be stabilizing. Van A resistance patterns predominate and therapeutic options continue to present dilemmas, although some of the older agents remain usable as primary therapy or as alternatives to the newer agents such as the oxazolidinones.