Beta-lactam resistance among Escherichia coli and Klebsiella species blood culture isolates in Finnish hospitals. Finnish Study Group for Antimicrobial Resistance.

The aim of this study was to investigate beta-lactam resistance in Escherichia coli and Klebsiella spp. blood culture isolates in Finland. Special attention was given to extended-spectrum beta-lactamases. A total of 566 Escherichia coli and 108 Klebsiella spp. blood culture isolates were collected from hospitals throughout Finland and their susceptibility to beta-lactam antibiotics studied. Twenty percent of Escherichia coli and 69% of Klebsiella spp. strains were resistant to ampicillin. The mechanisms of resistance were studied by hybridization, isoelectric focusing and the clavulanate double-disk potentiation test. Of the ampicillin-resistant Escherichia coli strains, 83% produced TEM-1. Of the ampicillin-resistant Klebsiella spp. strains, 43% produced SHV-1. Only nine Escherichia coli and three Klebsiella spp. isolates were resistant to cefuroxime (MIC > or = 32 micrograms/ml), and none were resistant to third-generation cephalosporins. These data were compared with cefuroxime and third-generation cephalosporin consumption levels in Finnish hospitals. Although the use of cephalosporins is far more extensive in Finland than in other Scandinavian countries, none of the isolates produced extended-spectrum beta-lactamases. In conclusion, resistance to cefuroxime has remained rare in Finland, and cefuroxime is still an alternative to third-generation cephalosporins in the treatment of septicemia.