[Prevalence of antimicrobial resistance in enterococci isolated from blood in Madrid (1994-1995)].

BACKGROUND

The aim of this study was to evaluate the antimicrobial resistance of enterococci isolated from blood samples in three hospitals in Madrid (Spain) from 1994 to 1995.

METHODS

One hundred strains, 83 Enterococcus faecalis, 15 E. faecium, and 2 E. durans, isolated from January 1994 to April 1995 were studied. The minimum inhibitory concentrations (MIC) of 11 antimicrobians were determined by the agar dilution method.

RESULTS

Four percent of the strains were resistant to ampicillin and 7% to penicillin. Ninety-two percent were sensitive to vancomycin. The percentage of strains with a high level of resistance (HLR) to some aminoglucoside was 60%. HLR was observed to gentamycin in 41%, to streptomycin in 46% and to kanamycin in 58% of the strains. Half of the isolates were resistant to the fluoroquinolones tested. HLR was significantly associated with aminoglucosides with HLR (MIC > or = 16 mg/l) to fluoroquinolones in the strains studied (p < 0.001).

CONCLUSIONS

The incidence of resistance to ampicillin and vancomycin is low and very high to aminoglucosides and fluoroquinolones. There is also a very significant association between HLR to fluoroquinolones and HLR to aminoglucosides.