Resistance to second- and third-generation cephalosporins among Escherichia coli and Klebsiella species is rare in Finland

Objective: To investigate the antimicrobial resistance of Escherichia coli and Klebsiella spp. from pus, urine and respiratory specimens, with particular emphasis on the detection of third-generation cephalosporin resistance.
Methods: E. coli (698) and Klebsiella sp. (476) strains from pus, respiratory and urinary specimens from hospital patients were collected from 19 laboratories. Data about consumption of third-generation cephalosporins and cefuroxime were collected from 24 hospitals. Antimicrobial susceptibility was tested with disk diffusion in primary laboratories and by an agar dilution method. Extended-spectrum β-lactamase (ESBL) production was studied with a double disk synergy test and an ESBL Etest. The β-lactamase classes were characterized with polymerase chain reaction probes of the TEM and SHV β-lactamase families and isoelectric focusing.
Results: Only 0.6% of E. coli and 2.3% of Klebsiella spp. strains were resistant or intermediately resistant to cefotaxime, ceftriaxone and/or ceftazidime. The ESBL producers detected comprised one E. coli harboring TEM-like genes and five Klebsiella pneumoniae strains, two of which harbored SHV-like genes, two TEM-like genes and one both. Although consumption of cefuroxime has increased in the years 1990–1994, from 3.48 to 5.84 defined daily doses/100 bed-days, and the consumption of third-generation cephalosporins from 1.25 to 1.94 defined daily doses/100 bed-days, cefuroxime resistance of E. coli was only 3%.
Conclusion: Although the use of broad-spectrum cephalosporins has increased, resistance to second- and thirdgeneration cephalosporins is still rare in Finland.