The antimicrobial susceptibility of bacteraemia isolates of Enterococcus faecalis and E. faecium in a London hospital, 19902002
Abstract number: 1134_01_347
King A., Phillips I.
Enterococci are common in faecal flora and can cause serious infection in humans. We wished relate the antibiotic susceptibility of enterococci from bacteraemic patients to changes in human and animal use of antibiotics.
The antibiotic susceptibility of all enterococci isolated from the blood of bacteraemic patients in St Thomas Hospital, London, between 1990 and 2002 was determined either by broth microdilution or by agar dilution. We noted local changes in clinical services, and thus of antibiotic use (related to the union of two hospitals), as well as published information on the use of growth-promoting antibiotics in food animals.
We isolated 392 E. faecalis and 147 E. faecium during the 12 years. The annual isolation rate of both species increased markedly from 9 E. faecalis and 3 E. faecium in 1990 to a peak of 60 and 42 respectively in 2000. All isolates of E. faecalis were ampicillin susceptible but 89% of E. faecium were resistant. Resistance rates for other antibiotics for E. faecalis and E. faecium were erythromycin 83% and 99% respectively, vancomycin 5% and 26%, teicoplanin 3% and 22%, chloramphenicol 33% and 12%, ciprofloxacin 60% and 89%, gentamicin (high-level) 44% and 39% and tetracycline 75% and 38%. In addition, 0.5% of E. faecalis were linezolid resistant and 2% of E. faecium were Q/D resistant. When the years 19901996 (use of growth-promoting antibiotics in food animals) and 19972002 (relocations of clinical services) were compared, resistance rates for erythromycin, glycopeptides, ciprofloxacin, and aminoglycosides increased for both species, and for ampicillin, tetracycline, and Q/D for E. faecium. However, resistance to Q/D and linezolid was negligible.
The two species of enterococci became more common and more resistant largely in relation to relocation of clinical services commonly associated with high-level antibiotic use. Use of avoparcin and virginiamycin in animals before 1996, had minimal or no potential effect on resistance, since resistance appeared after their animal use had been discontinued, but when local use of their counterparts in human medicine had markedly increased or, in the case of Q/D, begun. Despite the occasional use of Q/D and later linezolid, resistance to these two antibacterials remained rare. Fortunately, newer antibiotics, such as daptomycin, are active against all isolates, including those resistant to virtually all other antibiotics.
|Session name:||XXIst ISTH Congress|
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